Constrained electrode assembly

This application is a U.S. utility application, which claims the benefit of priority from U.S. Patent Application No. 62/586,737 filed on 15 Nov. 2017, which is hereby incorporated by reference herein in their entireties.

This disclosure generally relates to structures for use in energy storage devices, to energy storage devices employing such structures, and to methods for producing such structures and energy devices.

Rocking chair or insertion secondary batteries are a type of energy storage device in which carrier ions, such as lithium, sodium, potassium, calcium or magnesium ions, move between a positive electrode and a negative electrode through an electrolyte. The secondary battery may comprise a single battery cell, or two or more battery cells that have been electrically coupled to form the battery, with each battery cell comprising a positive electrode, a negative electrode, a microporous separator, and an electrolyte.

In rocking chair battery cells, both the positive and negative electrodes comprise materials into which a carrier ion inserts and extracts. As a cell is discharged, carrier ions are extracted from the negative electrode and inserted into the positive electrode. As a cell is charged, the reverse process occurs: the carrier ion is extracted from the positive and inserted into the negative electrode.

When the carrier ions move between electrodes, one of the persistent challenges resides in the fact that the electrodes tend to expand and contract as the battery is repeatedly charged and discharged. The expansion and contraction during cycling tends to be problematic for reliability and cycle life of the battery because when the electrodes expand, electrical shorts and battery failures occur. Yet another issue that can occur is that mismatch in electrode alignment, for example caused by physical or mechanical stresses on the battery during manufacture, use or transport, can lead to shorting and failure of the battery.

Therefore, there remains a need for controlling the expansion and contraction of electrodes during battery cycling to improve reliability and cycle life of the battery. There also remains a need for controlling electrode alignment, and structures that improve mechanical stability of the battery without excessively increasing the battery footprint.

Briefly, therefore, one aspect of this disclosure relates to the implementation of constraint structures to mitigate or prevent the macroscopic expansion of electrodes, thereby improving the energy density, reliability, and cycle life of batteries.

A secondary battery for cycling between a charged and a discharged state, the secondary battery comprising a battery enclosure, an electrode assembly, and carrier ions within the battery enclosure, and a set of electrode constraints, wherein

(a) the electrode assembly has mutually perpendicular transverse, longitudinal and vertical axes corresponding to the x, y and z axes, respectively, of an imaginary three-dimensional cartesian coordinate system, a first longitudinal end surface and a second longitudinal end surface separated from each other in the longitudinal direction, and a lateral surface surrounding an electrode assembly longitudinal axis A EA and connecting the first and second longitudinal end surfaces, the lateral surface having opposing first and second regions on opposite sides of the longitudinal axis and separated in a first direction that is orthogonal to the longitudinal axis, the electrode assembly having a maximum width W EA measured in the longitudinal direction, a maximum length L EA bounded by the lateral surface and measured in the transverse direction, and a maximum height H EA bounded by the lateral surface and measured in the vertical direction, (b) the electrode assembly further comprises a population of electrode structures, a population of electrode current collectors, a population of separators that are ionically permeable to the carrier ions, a population of counter-electrode structures, a population of counter-electrode collectors, and a population of unit cells wherein

(i) members of the electrode and counter-electrode structure populations are arranged in an alternating sequence in the longitudinal direction, (ii) each member of the population of electrode structures comprises a layer of an electrode active material having a length L E that corresponds to the Feret diameter of the electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the electrode active material layer, and a height H E that corresponds to the Feret diameter of the electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the electrode active material layer, and a width W E that corresponds to the Feret diameter of the electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the electrode active material layer, and each member of the population of counter-electrode structures comprises a layer of a counter-electrode active material having a length L c , that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the counter-electrode active material layer, and a height H c that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the counter-electrode active material layer, and a width W c that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the counter-electrode active material layer, (iii) each unit cell comprises a unit cell portion of a first member of the electrode current collector population, a member of the separator population that is ionically permeable to the carrier ions, a first electrode active material layer of one member of the electrode population, a unit cell portion of first member of the counter-electrode current collector population and a first counter-electrode active material layer of one member of the counter-electrode population, wherein (aa) the first electrode active material layer is proximate a first side of the separator and the first counter-electrode material layer is proximate an opposing second side of the separator, (bb) the separator electrically isolates the first electrode active material layer from the first counter-electrode active material layer and carrier ions are primarily exchanged between the first electrode active material layer and the first counter-electrode active material layer via the separator of each such unit cell during cycling of the battery between the charged and discharged state, and (cc) within each unit cell,

a. the first transverse end surfaces of the electrode and counter-electrode active material layers are on the same side of the electrode assembly, a 2D map of the median transverse position of the first opposing transverse end surface of the electrode active material layer in the X-Z plane, along the height H E of the electrode active material layer, traces a first transverse end surface plot, E TP1 , a 2D map of the median transverse position of the first opposing transverse end surface of the counter-electrode in the X-Z plane, along the height H c of the counter-electrode active material layer, traces a first transverse end surface plot, CE TP1 , wherein for at least 60% of the height H c of the counter electrode active material layer (i) the absolute value of a separation distance, S X1 , between the plots E TP1 and CE TP1 measured in the transverse direction is 1000 μm≥|S X1 |≥5 μm and (ii) as between the first transverse end surfaces of the electrode and counter-electrode active material layers, the first transverse end surface of the counter-electrode active material layer is inwardly disposed with respect to the first transverse end surface of the electrode active material layer, b. the second transverse end surfaces of the electrode and counter-electrode active material layers are on the same side of the electrode assembly, and oppose the first transverse end surfaces of the electrode and counter-electrode active material layers, respectively, a 2D map of the median transverse position of the second opposing transverse end surface of the electrode active material layer in the X-Z plane, along the height H E of the electrode active material layer, traces a second transverse end surface plot, E TP2 , a 2D map of the median transverse position of the second opposing transverse end surface of the counter-electrode in the X-Z plane, along the height H c of the counter-electrode active material layer, traces a second transverse end surface plot, CE TP2 , wherein for at least 60% of the height H c of the counter-electrode active material layer (i) the absolute value of a separation distance, S X2 , between the plots E TP2 and CE TP2 measured in the transverse direction is 1000 μm≥|S X2 |≥5 μm and (ii) as between the second transverse end surfaces of the electrode and counter-electrode active material layers, the second transverse end surface of the counter-electrode active material layer is inwardly disposed with respect to the second transverse end surface of the electrode active material layer, c. the first vertical end surfaces of the electrode and the counter- electrode active material layers are on the same side of the electrode assembly, a 2D map of the median vertical position of the first opposing vertical end surface of the electrode active material in the X-Z plane, along the length L E of the electrode active material layer, traces a first vertical end surface plot, E VP1 , a 2D map of the median vertical position of the first opposing vertical end surface of the counter-electrode active material layer in the X-Z plane, along the length L c of the counter-electrode active material layer, traces a first vertical end surface plot, CE VP1 , wherein for at least 60% of the length L c of the first counter-electrode active material layer (i) the absolute value of a separation distance, S Z1 , between the plots E VP1 and CE VP1 measured in the vertical direction is 1000 μm≥|S Z1 |≥5 μm, and (ii) as between the first vertical end surfaces of the electrode and counter-electrode active material layers, the first vertical end surface of the counter-electrode active material layer is inwardly disposed with respect to the first vertical end surface of the electrode active material layer, d. the second vertical end surfaces of the electrode and counter-electrode active material layer are on the same side of the electrode assembly, and oppose the first vertical end surfaces of the electrode and counter-electrode active material layers, respectively, a 2D map of the median vertical position of the second opposing vertical end surface of the electrode active material layer in the X-Z plane, along the length L E of the electrode active material layer, traces a second vertical end surface plot, E VP2 , a 2D map of the median vertical position of the second opposing vertical end surface of the counter-electrode active material layer in the X-Z plane, along the length L c of the counter-electrode active material layer, traces a second vertical end surface plot, CE VP2 , wherein for at least 60% of the length L c of the counter-electrode active material layer (i) the absolute value of a separation distance, S Z2 , between the plots E VP2 and CE VP2 as measured in the vertical direction is 1000 μm≥|S Z2 |≥5 μm, and (ii) as between the second vertical end surfaces of the electrode and counter-electrode active material layers, the second vertical end surface of the counter-electrode active material layer is inwardly disposed with respect to the second vertical end surface of the electrode active material layer,

(c) the set of electrode constraints comprises a primary constraint system comprising first and second primary growth constraints and at least one primary connecting member, the first and second primary growth constraints separated from each other in the longitudinal direction, and the at least one primary connecting member connecting the first and second primary growth constraints, wherein the primary constraint system restrains growth of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%.

A secondary battery for cycling between a charged and a discharged state, the secondary battery comprising a battery enclosure, an electrode assembly, and carrier ions within the battery enclosure, and a set of electrode constraints, wherein

(a) the electrode assembly has mutually perpendicular transverse, longitudinal and vertical axes corresponding to the x, y and z axes, respectively, of an imaginary three-dimensional cartesian coordinate system, a first longitudinal end surface and a second longitudinal end surface separated from each other in the longitudinal direction, and a lateral surface surrounding an electrode assembly longitudinal axis A EA and connecting the first and second longitudinal end surfaces, the lateral surface having opposing first and second regions on opposite sides of the longitudinal axis and separated in a first direction that is orthogonal to the longitudinal axis, the electrode assembly having a maximum width W EA measured in the longitudinal direction, a maximum length L EA bounded by the lateral surface and measured in the transverse direction, and a maximum height H EA bounded by the lateral surface and measured in the vertical direction,

(b) the electrode assembly further comprises a population of electrode structures, a population of electrode current collectors, a population of separators that are ionically permeable to carrier ions, a population of counter-electrode structures, a population of counter-electrode collectors, a carrier ion insulating material layer, and a population of unit cells, wherein

(i) each electrode current collector of the population is electrically isolated from each counter-electrode active material layer of the population, and each counter-electrode current collector of the population is electrically isolated from each electrode active material layer of the population,

(ii) members of the electrode and counter-electrode structure populations are arranged in an alternating sequence in the longitudinal direction,

(iii) each member of the population of electrode structures comprises a layer of an electrode active material having a length L E that corresponds to the Feret diameter of the electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the electrode active material layer, and a width W E that corresponds to the Feret diameter of the electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the electrode active material layer, and a height H E that corresponds to the Feret diameter of the electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the electrode active material layer, and each member of the population of counter-electrode structures comprises a layer of a counter-electrode active material having a length L C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the counter-electrode active material layer, and a width W C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the longitudinal direction between first and second opposing longitudinal end surfaces of the counter-electrode active material layer, and a height H C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the counter-electrode active material layer,

(iv) each unit cell comprises a unit cell portion of a first member of the electrode current collector population, a member of the separator population that is ionically permeable to the carrier ions, a first electrode active material layer of one member of the electrode population, a unit cell portion of a first member of the counter-electrode current collector population and a first counter-electrode active material layer of one member of the counter-electrode population, wherein (aa) the first electrode active material layer is proximate a first side of the separator and the first counter-electrode material layer is proximate an opposing second side of the separator, (bb) the separator electrically isolates the first electrode active material layer from the first counter-electrode active material layer and carrier ions are primarily exchanged between the first electrode active material layer and the first counter-electrode active material layer via the separator of each such unit cell during cycling of the battery between the charged and discharged state, and (cc) within each unit cell,

a. the first transverse end surfaces of the electrode and counter-electrode active material layers are on the same side of the electrode assembly, a 2D map of the median transverse position of the first opposing transverse end surface of the electrode active material layer in the X-Z plane, along the height H E of the electrode active material layer, traces a first transverse end surface plot, E TP1 , a 2D map of the median transverse position of the first opposing transverse end surface of the counter-electrode in the X-Z plane, along the height H C of the counter-electrode active material layer, traces a first transverse end surface plot, CE TP1 , and wherein an absolute value of a separation distance, |S X1 | is the distance as measured in the transverse direction between the plots E TP1 and CE TP1

b. the second transverse end surfaces of the electrode and counter-electrode active material layers are on the same side of the electrode assembly, and oppose the first transverse end surfaces of the electrode and counter-electrode active material layers, respectively, a 2D map of the median transverse position of the second opposing transverse end surface of the electrode active material layer in the X-Z plane, along the height H E of the electrode active material layer, traces a second transverse end surface plot, E TP2 , a 2D map of the median transverse position of the second opposing transverse end surface of the counter-electrode in the X-Z plane, along the height H C of the counter-electrode active material layer, traces a second transverse end surface plot, CE TP2 , and wherein an absolute value of a separation distance, |S X2 | is the distance as measured in the transverse direction between the plots E TP2 and CE TP2 ,

c. the first vertical end surfaces of the electrode and the counter-electrode active material layers are on the same side of the electrode assembly, a 2D map of the median vertical position of the first opposing vertical end surface of the electrode active material in the Y-Z plane, along the length L E of the electrode active material layer, traces a first vertical end surface plot, E VP1 , a 2D map of the median vertical position of the first opposing vertical end surface of the counter-electrode active material layer in the Y-Z plane, along the length L C of the counter-electrode active material layer, traces a first vertical end surface plot, CE VP1 , and wherein an absolute value of a separation distance, |S Z1 | is the distance as measured in the transverse direction between the plots E VP1 and CE VP1 ,

d. the second vertical end surfaces of the electrode and counter-electrode active material layer are on the same side of the electrode assembly, and oppose the first vertical end surfaces of the electrode and counter-electrode active material layers, respectively, a 2D map of the median vertical position of the second opposing vertical end surface of the electrode active material layer in the Y-Z plane, along the length L E of the electrode active material layer, traces a second vertical end surface plot, E VP2 , a 2D map of the median vertical position of the second opposing vertical end surface of the counter-electrode active material layer in the Y-Z plane, along the length L C of the counter-electrode active material layer, traces a second vertical end surface plot, CE VP2 , and wherein an absolute value of a separation distance, |S Z2 | is the distance as measured in the transverse direction between the plots E VP2 and CE VP2 ,

e. the carrier ion insulating material layer has an ionic conductance of carrier ions that does not exceed 10% of the ionic conductance of the separator of carrier ions during cycling of the battery, and ionically insulates a surface of the electrode current collector layer from the electrolyte that is proximate to and within a distance D CC of (i) the first transverse end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S X1 |, and/or (ii) second transverse end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S X2 |, and/or (iii) the first vertical end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S Z1 |, (iv) the second vertical end surface of the electrode active material layer wherein D CC equals the sum of W E and |S Z2 |.

A method for preparing an electrode assembly comprising a constraint for a secondary battery configured to cycle between a charged and a discharged state, the method comprising: forming a sheet structure; cutting the sheet structure into pieces; stacking the pieces; and applying a set of constraints to the stacked pieces, wherein the sheet structure comprises at least one of a unit cell and a component of a unit cell, wherein the pieces comprise an electrode active material layer, an electrode current collector, a counter-electrode active material layer, a counter-electrode current collector, and a separator, wherein the set of constraints comprise a primary constraint system comprising first and second primary growth constraints and at least one primary connecting member, the first and second primary growth constraints separated from each other in the longitudinal direction, and the at least one primary connecting member connecting the first and second primary growth constraints, wherein the primary constraint system restrains growth of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%, and wherein one or more of the first and second primary growth constraints are attached to at least one of the electrode active material layer, electrode current collector, counter-electrode active material layer, counter-electrode current collector, and separator.

Other aspects, features and embodiments of the present disclosure will be, in part, discussed and, in part, apparent in the following description and drawing.

FIG. 1 is a perspective view of one embodiment of a constraint system employed with an electrode assembly.

FIG. 2A is a schematic of one embodiment of a three-dimensional electrode assembly.

FIGS. 2B-2C are schematics of one embodiment of a three-dimensional electrode assembly, depicting anode structure population members in constrained and expanded configurations.

FIGS. 3A-3H show exemplary embodiments of different shapes and sizes for an electrode assembly.

FIG. 4A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , and further illustrates elements of the primary and secondary growth constraint systems.

FIG. 4B illustrates a cross-section of an embodiment of the electrode assembly taken along the line B-B′ as shown in FIG. 1 , and further illustrates elements of the primary and secondary growth constraint systems.

FIG. 4C illustrates a cross-section of an embodiment of the electrode assembly taken along the line B-B′ as shown in FIG. 1 , and further illustrates elements of the primary and secondary growth constraint systems.

FIG. 5 illustrates a cross section of an embodiment of the electrode assembly taken along the line A-A 1 ′ as shown in FIG. 1 .

FIG. 6A illustrates one embodiment of a top view of a porous secondary growth constraint over an electrode assembly, and one embodiment for adhering the secondary growth constraint to the electrode assembly.

FIG. 6B illustrates one embodiment of a top view of a porous secondary growth constraint over an electrode assembly, and another embodiment for adhering the secondary growth constraint to the electrode assembly.

FIG. 6C illustrates one embodiment of a top view of a porous secondary growth constraint over an electrode assembly, and yet another embodiment for adhering the secondary growth constraint to the electrode assembly.

FIG. 6D illustrates one embodiment of a top view of a porous secondary growth constraint over and electrode assembly, and still yet another embodiment for adhering the secondary growth constraint to the electrode assembly.

FIG. 7 illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary constraint system and one embodiment of a secondary constraint system.

FIGS. 8A-8B illustrate a force schematics, according to one embodiment, showing the forces exerted on the electrode assembly by the set of electrode constraints, as well as the forces being exerted by electrode structures upon repeated cycling of a battery containing the electrode assembly.

FIG. 9A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints.

FIG. 9B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including another embodiment of a primary growth constraint system and another embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints.

FIG. 9C illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including yet another embodiment of a primary growth constraint system and yet another embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints.

FIG. 10 illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including still yet another embodiment of a primary growth constraint system and still yet another embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints.

FIG. 11A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via notches.

FIG. 11B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including another embodiment of a primary growth constraint system and another embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via notches.

FIG. 11C illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including yet another embodiment of a primary growth constraint system and yet another embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via notches.

FIG. 12A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 12B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including another embodiment of a primary growth constraint system and another embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 12C illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including yet another embodiment of a primary growth constraint system and yet another embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 13A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via slots.

FIG. 13B illustrates a inset cross-section from FIG. 13A of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via slots.

FIG. 13C illustrates a inset cross-section from FIG. 13A of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode backbones are used for assembling the set of electrode constraints via slots.

FIG. 14 illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the counter-electrode current collectors are used for assembling the set of electrode constraints via slots.

FIG. 15A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the electrode backbones are used for assembling the set of electrode constraints.

FIG. 15B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the electrode current collectors are used for assembling the set of electrode constraints.

FIG. 16A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 16B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including another embodiment of a primary growth constraint system and another embodiment of a secondary growth constraint system where the electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 16C illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including yet another embodiment of a primary growth constraint system and yet another embodiment of a secondary growth constraint system where the electrode current collectors are used for assembling the set of electrode constraints via notches.

FIG. 17 illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the electrode current collectors are used for assembling the set of electrode constraints via slots.

FIG. 18A illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the primary growth constraint system is hybridized with the secondary growth constraint system and used for assembling the set of electrode constraints.

FIG. 18B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including another embodiment of a primary growth constraint system and another embodiment of a secondary growth constraint system where the primary growth constraint system is hybridized with the secondary growth constraint system and used for assembling the set of electrode constraints.

FIG. 19 illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1 , further including a set of electrode constraints, including one embodiment of a primary growth constraint system and one embodiment of a secondary growth constraint system where the primary growth constraint system is fused with the secondary growth constraint system and used for assembling the set of electrode constraints.

FIG. 20 illustrates an exploded view of an embodiment of an energy storage device or a secondary battery utilizing one embodiment of a set of growth constraints.

FIG. 21 illustrates an embodiment of a flowchart for the general assembly of an energy storage device or a secondary battery utilizing one embodiment of a set of growth constraints.

FIGS. 22A-22C illustrate embodiments for the determination of vertical offsets and/or separation distances S Z1 and S Z2 , between vertical end surfaces of electrode and counter-electrode active material layers.

FIGS. 23A-23C illustrate embodiments for the determination of transverse offsets and/or separation distances S X1 and S X2 , between transverse end surfaces of electrode and counter-electrode active material layers.

FIGS. 24A-24B illustrate embodiments for the determination of the height H EA , H C and length L E , L C of the electrode and/or counter-electrode active material layers, according to the Feret diameters thereof.

FIGS. 25A-25H illustrate cross-sections in a Z-Y plane, of embodiments of unit cells having electrode and counter-electrode active material layers, both with and without vertical offsets and/or separation distances.

FIGS. 26A-26F illustrate cross-sections in a Y-X plane, of embodiments of unit cells having electrode and counter-electrode active material layers, both with and without transverse offsets and/or separation distances.

FIGS. 27A-27F illustrate embodiments of electrode assemblies having electrode and/or counter-electrode busbars. FIGS. 27A ′- 27 F′ illustrate the respective cross-sections of FIGS. 27A-27F taken in a X-Y plane.

FIGS. 28A-28D illustrate cross-sections in a Y-X plane, of embodiments of unit cells with configurations of a separator disposed between electrode and counter-electrode active material layers.

FIGS. 29A-29D illustrate embodiments of electrode and/or counter-electrode current collector ends, and configurations for attachment to a portion of a set of constraints.

FIG. 30 illustrates an embodiment of a secondary battery having an alternating arrangement of electrode and counter-electrode structures.

FIGS. 31A-31B illustrate cross-sections in a Z-Y plane, of embodiments of an electrode assembly, with auxiliary electrodes.

FIGS. 31C-31D illustrate cross-sections in the X-Y plane, of embodiments of an electrode assembly, with configurations of openings and/or slots.

FIGS. 32A-32B illustrate cross-sections in the Z-Y plane, of embodiments of an electrode assembly having varying vertical heights from an end to an interior of the electrode assembly.

FIGS. 33A-33D illustrate cross-sections in the Z-Y plane, of embodiments of portions of an electrode assembly having a carrier ion insulating material layer to insulate at least a portion of an electrode current collector from carrier ions.

FIGS. 34A-34C illustrate embodiments for the determination of vertical offsets and/or separation distances S Z1 and S Z2 , between vertical end surfaces of electrode and counter-electrode active material layers, for a unit cell having a carrier ion insulating material layer.

FIGS. 35A-35C illustrate embodiments for the determination of transverse offsets and/or separation distances S X1 and SX 2 , between transverse end surfaces of electrode and counter-electrode active material layers, for a unit cell having a carrier ion insulating material layer.

FIG. 36 is an exploded view, with cross sections, of an embodiment of a 2D electrode assembly having 2D electrodes in the shape of sheets.

FIGS. 37A-37B depict cross sections in either the XY and/or ZY plane showing embodiments of transverse and/or vertical separation distances and/or offsets for electrode active material layer and counter-electrode active material layers in a unit cell having a carrier ion insulating material layer that insulates at least a portion of a surface of an electrode current collector in the unit cell from carrier ions.

Other aspects, embodiments and features of the inventive subject matter will become apparent from the following detailed description when considered in conjunction with the accompanying drawing. The accompanying figures are schematic and are not intended to be drawn to scale. For purposes of clarity, not every element or component is labeled in every figure, nor is every element or component of each embodiment of the inventive subject matter shown where illustration is not necessary to allow those of ordinary skill in the art to understand the inventive subject matter.

“A,” “an,” and “the” (i.e., singular forms) as used herein refer to plural referents unless the context clearly dictates otherwise. For example, in one instance, reference to “an electrode” includes both a single electrode and a plurality of similar electrodes.

“About” and “approximately” as used herein refers to plus or minus 10%, 5%, or 1% of the value stated. For example, in one instance, about 250 μm would include 225 μm to 275 μm. By way of further example, in one instance, about 1,000 μm would include 900 μm to 1,100 μm. Unless otherwise indicated, all numbers expressing quantities (e.g., measurements, and the like) and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations. Each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

“Anode” as used herein in the context of a secondary battery refers to the negative electrode in the secondary battery.

“Anodically active” as used herein means material suitable for use in an anode of a secondary battery.

“Cathode” as used herein in the context of a secondary battery refers to the positive electrode in the secondary battery.

“Cathodically active” as used herein means material suitable for use in a cathode of a secondary battery.

“Charged state” as used herein in the context of the state of a secondary battery refers to a state where the secondary battery is charged to at least 75% of its rated capacity. For example, the battery may be charged to at least 80% of its rated capacity, at least 90% of its rated capacity, and even at least 95% of its rated capacity, such as 100% of its rated capacity.

“C-rate” as used herein refers to a measure of the rate at which a secondary battery is discharged, and is defined as the discharge current divided by the theoretical current draw under which the battery would deliver its nominal rated capacity in one hour. For example, a C-rate of 1C indicates the discharge current that discharges the battery in one hour, a rate of 2C indicates the discharge current that discharges the battery in ½ hours, a rate of C/2 indicates the discharge current that discharges the battery in 2 hours, etc.

“Discharged state” as used herein in the context of the state of a secondary battery refers to a state where the secondary battery is discharged to less than 25% of its rated capacity. For example, the battery may be discharged to less than 20% of its rated capacity, such as less than 10% of its rated capacity, and even less than 5% of its rated capacity, such as 0% of its rated capacity.

A “cycle” as used herein in the context of cycling of a secondary battery between charged and discharged states refers to charging and/or discharging a battery to move the battery in a cycle from a first state that is either a charged or discharged state, to a second state that is the opposite of the first state (i.e., a charged state if the first state was discharged, or a discharged state if the first state was charged), and then moving the battery back to the first state to complete the cycle. For example, a single cycle of the secondary battery between charged and discharged states can include, as in a charge cycle, charging the battery from a discharged state to a charged state, and then discharging back to the discharged state, to complete the cycle. The single cycle can also include, as in a discharge cycle, discharging the battery from the charged state to the discharged state, and then charging back to a charged state, to complete the cycle.

“Feret diameter” as referred to herein with respect to the electrode assembly, the electrode active material layer and/or counter-electrode active material layer is defined as the distance between two parallel planes restricting the structure, i.e. the electrode assembly electrode active material layer and/or counter-electrode active material layer, as measured in a direction perpendicular to the two planes. For example, a Feret diameter of the electrode assembly in the longitudinal direction is the distance as measured in the longitudinal direction between two parallel planes restricting the electrode assembly that are perpendicular to the longitudinal direction. As another example, a Feret diameter of the electrode assembly in the transverse direction is the distance as measured in the transverse direction between two parallel planes restricting the electrode assembly that are perpendicular to the transverse direction. As yet another example, a Feret diameter of the electrode assembly in the vertical direction is the distance as measured in the vertical direction between two parallel planes restricting the electrode assembly that are perpendicular to the vertical direction. As another example, a Feret diameter of the electrode active material layer in the transverse direction is the distance as measured in the transverse direction between two parallel planes restricting the electrode active material layer that are perpendicular to the transverse direction. As yet another example, a Feret diameter of the electrode active material layer in the vertical direction is the distance as measured in the vertical direction between two parallel planes restricting the electrode active material layer that are perpendicular to the vertical direction. As another example, a Feret diameter of the counter-electrode active material layer in the transverse direction is the distance as measured in the transverse direction between two parallel planes restricting the counter-electrode active material layer that are perpendicular to the transverse direction. As yet another example, a Feret diameter of the counter-electrode active material layer in the vertical direction is the distance as measured in the vertical direction between two parallel planes restricting the counter-electrode active material layer that are perpendicular to the vertical direction.

“Longitudinal axis,” “transverse axis,” and “vertical axis,” as used herein refer to mutually perpendicular axes (i.e., each are orthogonal to one another). For example, the “longitudinal axis,” “transverse axis,” and the “vertical axis” as used herein are akin to a Cartesian coordinate system used to define three-dimensional aspects or orientations. As such, the descriptions of elements of the inventive subject matter herein are not limited to the particular axis or axes used to describe three-dimensional orientations of the elements. Alternatively stated, the axes may be interchangeable when referring to three-dimensional aspects of the inventive subject matter.

“Longitudinal direction,” “transverse direction,” and “vertical direction,” as used herein, refer to mutually perpendicular directions (i.e., each are orthogonal to one another). For example, the “longitudinal direction,” “transverse direction,” and the “vertical direction” as used herein may be generally parallel to the longitudinal axis, transverse axis and vertical axis, respectively, of a Cartesian coordinate system used to define three-dimensional aspects or orientations.

“Repeated cycling” as used herein in the context of cycling between charged and discharged states of the secondary battery refers to cycling more than once from a discharged state to a charged state, or from a charged state to a discharged state. For example, repeated cycling between charged and discharged states can including cycling at least 2 times from a discharged to a charged state, such as in charging from a discharged state to a charged state, discharging back to a discharged state, charging again to a charged state and finally discharging back to the discharged state. As yet another example, repeated cycling between charged and discharged states at least 2 times can include discharging from a charged state to a discharged state, charging back up to a charged state, discharging again to a discharged state and finally charging back up to the charged state By way of further example, repeated cycling between charged and discharged states can include cycling at least 5 times, and even cycling at least 10 times from a discharged to a charged state. By way of further example, the repeated cycling between charged and discharged states can include cycling at least 25, 50, 100, 300, 500 and even 1000 times from a discharged to a charged state.

“Rated capacity” as used herein in the context of a secondary battery refers to the capacity of the secondary battery to deliver a specified current over a period of time, as measured under standard temperature conditions (25° C.). For example, the rated capacity may be measured in units of Amp-hour, either by determining a current output for a specified time, or by determining for a specified current, the time the current can be output, and taking the product of the current and time. For example, for a battery rated 20 Amp-hr, if the current is specified at 2 amperes for the rating, then the battery can be understood to be one that will provide that current output for 10 hours, and conversely if the time is specified at 10 hours for the rating, then the battery can be understood to be one that will output 2 amperes during the 10 hours. In particular, the rated capacity for a secondary battery may be given as the rated capacity at a specified discharge current, such as the C-rate, where the C-rate is a measure of the rate at which the battery is discharged relative to its capacity. For example, a C-rate of 1C indicates the discharge current that discharges the battery in one hour, 2C indicates the discharge current that discharges the battery in ½ hours, C/2 indicates the discharge current that discharges the battery in 2 hours, etc. Thus, for example, a battery rated at 20 Amp-hr at a C-rate of 1C would give a discharge current of 20 Amp for 1 hour, whereas a battery rated at 20 Amp-hr at a C-rate of 2C would give a discharge current of 40 Amps for ½ hour, and a battery rated at 20 Amp-hr at a C-rate of C/2 would give a discharge current of 10 Amps over 2 hours.

“Maximum width” (W EA ) as used herein in the context of a dimension of an electrode assembly corresponds to the greatest width of the electrode assembly as measured from opposing points of longitudinal end surfaces of the electrode assembly in the longitudinal direction.

“Maximum length” (L EA ) as used herein in the context of a dimension of an electrode assembly corresponds to the greatest length of the electrode assembly as measured from opposing points of a lateral surface of the electrode assembly in the transverse direction.

“Maximum height” (H EA ) as used herein in the context of a dimension of an electrode assembly corresponds to the greatest height of the electrode assembly as measured from opposing points of the lateral surface of the electrode assembly in the transverse direction.

In general, the present disclosure is directed to an energy storage device 100 , such as a secondary battery 102 , as shown for example in FIG. 2A and/or FIG. 20 , that cycles between a charged and a discharged state. The secondary battery 102 includes a battery enclosure 104 , an electrode assembly 106 , carrier ions, and a non-aqueous liquid electrolyte within the battery enclosure. The secondary battery 102 also includes a set of electrode constraints 108 that restrain growth of the electrode assembly 106 . The growth of the electrode assembly 106 that is being constrained may be a macroscopic increase in one or more dimensions of the electrode assembly 106 .

Aspects of the present disclosure further provide for a reduced offset and/or separation distance in vertical and transverse directions, for electrode active material layers and counter-electrode active material layers, which may improve storage capacity of a secondary battery, without excessively increasing the risk of shorting or failure of the secondary battery, as is described in more detail below. Aspects of the present disclosure may also provide for methods of fabricating secondary batteries, and/or structures and configurations that may provide high energy density of the secondary battery with a reduced footprint.

Further, in certain embodiments, aspects of the present disclosure include three-dimensional constraint structures offering particular advantages when incorporated into energy storage devices 100 such as batteries, capacitors, fuel cells, and the like. In one embodiment, the constraint structures have a configuration and/or structure that is selected to resist at least one of growth, swelling, and/or expansion of an electrode assembly 106 that can otherwise occur when a secondary battery 102 is repeatedly cycled between charged and discharged states. In particular, in moving from a discharged state to a charged state, carrier ions such as, for example, one or more of lithium, sodium, potassium, calcium and magnesium, move between the positive and negative electrodes in the battery. Upon reaching the electrode, the carrier ions may then intercalate or alloy into the electrode material, thus increasing the size and volume of that electrode. Conversely, reversing to move from the charged state to the discharged state can cause the ions to de-intercalate or de-alloy, thus contracting the electrode. This alloying and/or intercalation and de-alloying and/or de-intercalation can cause significant volume change in the electrode. In yet another embodiment, the transport of carrier ions our of electrodes can increase the size of the electrode, for example by increasing the electrostatic repulsion of the remaining layers of material (e.g., with LCO and some other materials). Other mechanisms that can cause swelling in secondary batteries 102 can include, for example, the formation of SEI on electrodes, the decomposition of electrolyte and other components, and even gas formation. Thus, the repeated expansion and contraction of the electrodes upon charging and discharging, as well as other swelling mechanisms, can create strain in the electrode assembly 106 , which can lead to reduced performance and ultimately even failure of the secondary battery.

Referring to FIGS. 2A-2C , the effects of the repeated expansion and/or contraction of the electrode assembly 106 , according to an embodiment of the disclosure, can be described. FIG. 2A shows an embodiment of a three-dimensional electrode assembly 106 , with a population of electrode structures 110 and a population of counter-electrode structures 112 (e.g., population of anode and cathode structures, respectively). The three-dimensional electrode assembly 106 in this embodiment provides an alternating set of the electrodes structures 110 and counter electrode structures 112 that are interdigitated with one another and, in the embodiment shown in FIG. 2A , has a longitudinal axis AA parallel to the Y axis, a transverse axis (not shown) parallel to the X axis, and a vertical axis (not shown) parallel to the Z axis. The X, Y and Z axes shown herein are arbitrary axes intended only to show a basis set where the axes are mutually perpendicular to one another in a reference space, and are not intended in any way to limit the structures herein to a specific orientation. Upon charge and discharge cycling of a secondary battery 102 having the electrode assembly 106 , the carrier ions travel between the electrode and counter-electrode structures 110 and 112 , respectively, such as generally in a direction that is parallel to the Y axis as shown in the embodiment depicted in FIG. 2A , and can intercalate into electrode material of one or more of the electrode structures 110 and counter-electrode structures 112 that is located within the direction of travel. The effect of intercalation and/or alloying of carrier ions into the electrode material can be seen in the embodiments illustrated in FIGS. 2B-2C . In particular, FIG. 2B depicts an embodiment of the electrode assembly 106 with electrode structures 110 in a relatively unexpanded state, such as prior to repeated cycling of the secondary battery 106 between charged and discharged states. By comparison, FIG. 2C depicts an embodiment of the electrode assembly 106 with electrode structures 110 after repeated cycling of the secondary battery for a predetermined number of cycles. As shown in this figure, the dimensions of the electrode structures 110 can increase significantly in the stacking direction (e.g., Y-direction), due to the intercalation and/or alloying of carrier ions into the electrode material, or by other mechanisms such as those described above. The dimensions of the electrode structures 110 can also significantly increase in another direction, such as in the Z-direction (not shown in FIG. 2C ). Furthermore, the increase in size of the electrode structures 110 can result in the deformation of the structures inside the electrode assembly, such as deformation of the counter-electrode structures 112 and separator 130 in the assembly, to accommodate the expansion in the electrode structures 110 . The expansion of the electrode structures 110 can ultimately result in the bulging and/or warping of the electrode assembly 106 at the longitudinal ends thereof, as depicted in the embodiment shown in FIG. 2C (as well as in other directions such as at the top and bottom surfaces in the Z-direction). Accordingly, the electrode assembly 106 according to one embodiment can exhibit significant expansion and contraction along the longitudinal (Y axis) of the assembly 106 , as well as other axis, due to the intercalation and de-intercalation of the carrier ions during the charging and discharging process.

Thus, in one embodiment, a primary growth constraint system 151 is provided to mitigate and/or reduce at least one of growth, expansion, and/or swelling of the electrode assembly 106 in the longitudinal direction (i.e., in a direction that parallels the Y axis), as shown for example in FIG. 1 . For example, the primary growth constraint system 151 can include structures configured to constrain growth by opposing expansion at longitudinal end surfaces 116 , 118 of the electrode assembly 106 . In one embodiment, the primary growth constraint system 151 comprises first and second primary growth constraints 154 , 156 , that are separated from each other in the longitudinal direction, and that operate in conjunction with at least one primary connecting member 162 that connects the first and second primary growth constraints 154 , 156 together to restrain growth in the electrode assembly 106 . For example, the first and second primary growth constraints 154 , 156 may at least partially cover first and second longitudinal end surfaces 116 , 118 of the electrode assembly 106 , and may operate in conjunction with connecting members 162 , 164 connecting the primary growth constraints 154 , 156 to one another to oppose and restrain any growth in the electrode assembly 106 that occurs during repeated cycles of charging and/or discharging. Further discussion of embodiments and operation of the primary growth constraint system 151 is provided in more detail below.

In addition, repeated cycling through charge and discharge processes in a secondary battery 102 can induce growth and strain not only in a longitudinal direction of the electrode assembly 106 (e.g., Y-axis in FIG. 2A ), but can also induce growth and strain in directions orthogonal to the longitudinal direction, as discussed above, such as the transverse and vertical directions (e.g., X and Z axes, respectively, in FIG. 2A ). Furthermore, in certain embodiments, the incorporation of a primary growth constraint system 151 to inhibit growth in one direction can even exacerbate growth and/or swelling in one or more other directions. For example, in a case where the primary growth constraint system 151 is provided to restrain growth of the electrode assembly 106 in the longitudinal direction, the intercalation of carrier ions during cycles of charging and discharging and the resulting swelling of electrode structures can induce strain in one or more other directions. In particular, in one embodiment, the strain generated by the combination of electrode growth/swelling and longitudinal growth constraints can result in buckling or other failure(s) of the electrode assembly 106 in the vertical direction (e.g., the Z axis as shown in FIG. 2A ), or even in the transverse direction (e.g., the X axis as shown in FIG. 2A ).

Accordingly, in one embodiment of the present disclosure, the secondary battery 102 includes not only a primary growth constraint system 151 , but also at least one secondary growth constraint system 152 that may operate in conjunction with the primary growth constraint system 151 to restrain growth of the electrode assembly 106 along multiple axes of the electrode assembly 106 . For example, in one embodiment, the secondary growth constraint system 152 may be configured to interlock with, or otherwise synergistically operate with, the primary growth constraint system 151 , such that overall growth of the electrode assembly 106 can be restrained to impart improved performance and reduced incidence of failure of the secondary battery having the electrode assembly 106 and primary and secondary growth constraint systems 151 and 152 , respectively. Further discussion of embodiments of the interrelationship between the primary and secondary growth constraint systems 151 and 152 , respectively, and their operation to restrain growth of the electrode assembly 106 , is provided in more detail below.

By constraining the growth of the electrode assembly 106 , it is meant that, as discussed above, an overall macroscopic increase in one or more dimensions of the electrode assembly 106 is being constrained. That is, the overall growth of the electrode assembly 106 may be constrained such that an increase in one or more dimensions of the electrode assembly 106 along (the X, Y, and Z axes) is controlled, even though a change in volume of one or more electrodes within the electrode assembly 106 may nonetheless occur on a smaller (e.g., microscopic) scale during charge and discharge cycles. The microscopic change in electrode volume may be observable, for example, via scanning electron microscopy (SEM). While the set of electrode constraints 108 may be capable of inhibiting some individual electrode growth on the microscopic level, some growth may still occur, although the growth may at least be restrained. The volume change in the individual electrodes upon charge/discharge, while it may be a small change on the microscopic level for each individual electrode, can nonetheless have an additive effect that results in a relatively larger volume change on the macroscopic level for the overall electrode assembly 106 in cycling between charged and discharged states, thereby potentially causing strain in the electrode assembly 106 .

According to one embodiment, an electrode active material used in an electrode structure 110 corresponding to an anode of the electrode assembly 106 comprises a material that expands upon insertion of carrier ions into the electrode active material during charge of the secondary battery 102 . For example, the electrode active materials may comprise anodically active materials that accept carrier ions during charging of the secondary battery, such as by intercalating with or alloying with the carrier ions, in an amount that is sufficient to generate an increase in the volume of the electrode active material. For example, in one embodiment the electrode active material may comprise a material that has the capacity to accept more than one mole of carrier ion per mole of electrode active material, when the secondary battery 102 is charged from a discharged to a charged state. By way of further example, the electrode active material may comprise a material that has the capacity to accept 1.5 or more moles of carrier ion per mole of electrode active material, such as 2.0 or more moles of carrier ion per mole of electrode active material, and even 2.5 or more moles of carrier ion per mole of electrode active material, such as 3.5 moles or more of carrier ion per mole of electrode active material. The carrier ion accepted by the electrode active material may be at least one of lithium, potassium, sodium, calcium, and magnesium. Examples of electrode active materials that expand to provide such a volume change include one or more of silicon (e.g., SiO), aluminum, tin, zinc, silver, antimony, bismuth, gold, platinum, germanium, palladium, and alloys and compounds thereof.

Yet further embodiments of the present disclosure may comprise energy storage devices 100 , such as secondary batteries 102 , and/or structures therefor, including electrode assemblies 106 , that do not include constraint systems, or that are constrained with a constraint system that is other than the set of electrode constraints 108 described herein.

Electrode Assembly

Referring again to FIG. 2A , in one embodiment, an interdigitated electrode assembly 106 includes a population of electrode structures 110 , a population of counter-electrode structures 112 , and an electrically insulating microporous separator 130 electrically insulating the electrode structures 110 from the counter-electrode structures 112 . In one embodiment, the electrode structures 110 comprise an electrode active material layer 132 , an electrode backbone 134 that supports the electrode active material layer 132 , and an electrode current collector 136 , which may be an ionically porous current collector to allow ions to pass therethrough, as shown in the embodiment depicted in FIG. 7 . For example, the electrode structure 110 , in one embodiment, can comprise an anode structure, with an anodically active material layer, an anode backbone, and an anode current collector. Similarly, in one embodiment, the counter-electrode structures 112 comprise a counter-electrode active material layer 138 , a counter-electrode current collector 140 , and a counter-electrode backbone 141 that supports one or more of the counter-electrode current collector 140 and/or the counter-electrode active material layer 138 , as shown for example in the embodiment depicted in FIG. 7 . For example, the counter-electrode structure 112 can comprise, in one embodiment, a cathode structure comprising a cathodically active material layer, a cathode current collector, and a cathode backbone. The electrically insulating microporous separator 130 allows carrier ions to pass therethrough during charge and/or discharge processes, to travel between the electrode structures 110 and counter-electrode structures 112 in the electrode assembly 106 . Furthermore, it should be understood that the electrode and counter electrode structures 110 and 112 , respectively, are not limited to the specific embodiments and structures described herein, and other configurations, structures, and/or materials other than those specifically described herein can also be provided to form the electrode structures 110 and counter-electrode structures 112 . For example, the electrode and counter electrode structures 110 , 112 can be provided in a form where the structures are substantially absent any electrode and/or counter-electrode backbones 134 , 141 , such as in a case where the region of the electrode and/or counter-electrode structures 110 , 112 that would contain the backbones is instead made up of electrode active material and/or counter-electrode active material.

According to the embodiment as shown in FIG. 2A , the members of the electrode and counter-electrode structure populations 110 and 112 , respectively, are arranged in alternating sequence, with a direction of the alternating sequence corresponding to the stacking direction D. The electrode assembly 106 according to this embodiment further comprises mutually perpendicular longitudinal, transverse, and vertical axes, with the longitudinal axis A EA generally corresponding or parallel to the stacking direction D of the members of the electrode and counter-electrode structure populations. As shown in the embodiment in FIG. 2A , the longitudinal axis A EA is depicted as corresponding to the Y axis, the transverse axis is depicted as corresponding to the X axis, and the vertical axis is depicted as corresponding to the Z axis.

Further, the electrode assembly 106 has a maximum width W EA measured in the longitudinal direction (i.e., along the y-axis), a maximum length L EA bounded by the lateral surface and measured in the transverse direction (i.e., along the x-axis), and a maximum height H EA also bounded by the lateral surface and measured in the vertical direction (i.e., along the z-axis). The maximum width W EA can be understood as corresponding to the greatest width of the electrode assembly 106 as measured from opposing points of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 where the electrode assembly is widest in the longitudinal direction. For example, referring to the embodiment of the electrode assembly 106 in FIG. 2 , the maximum width W EA can be understood as corresponding simply to the width of the assembly 106 as measured in the longitudinal direction. However, referring to the embodiment of the electrode assembly 106 shown in FIG. 3H , it can be seen that the maximum width W EA corresponds to the width of the electrode assembly as measured from the two opposing points 300 a , 300 b , where the electrode assembly is widest in the longitudinal direction, as opposed to a width as measured from opposing points 301 a , 301 b where the electrode assembly 106 is more narrow. Similarly, the maximum length L EA can be understood as corresponding to the greatest length of the electrode assembly as measured from opposing points of the lateral surface 142 of the electrode assembly 106 where the electrode assembly is longest in the transverse direction. Referring again to the embodiment in FIG. 2A , the maximum length L EA can be understood as simply the length of the electrode assembly 106 , whereas in the embodiment shown in FIG. 3H , the maximum length L EA corresponds to the length of the electrode assembly as measured from two opposing points 302 a , 302 b , where the electrode assembly is longest in the transverse direction, as opposed to a length as measured from opposing points 303 a , 303 b where the electrode assembly is shorter. Along similar lines, the maximum height H EA can be understood as corresponding to the greatest height of the electrode assembly as measured from opposing points of the lateral surface 143 of the electrode assembly where the electrode assembly is highest in the vertical direction. That is, in the embodiment shown in FIG. 2A , the maximum height H EA is simply the height of the electrode assembly. While not specifically depicted in the embodiment shown in FIG. 3H , if the electrode assembly had different heights at points across one or more of the longitudinal and transverse directions, then the maximum height H EA of the electrode assembly would be understood to correspond to the height of the electrode assembly as measured from two opposing points where the electrode assembly is highest in the vertical direction, as opposed to a height as measured from opposing points where the electrode assembly is shorter, as analogously described for the maximum width W EA and maximum length L EA . The maximum length L EA , maximum width W EA , and maximum height H EA of the electrode assembly 106 may vary depending upon the energy storage device 100 and the intended use thereof. For example, in one embodiment, the electrode assembly 106 may include maximum lengths L EA , widths W EA , and heights H EA typical of conventional secondary battery dimensions. By way of further example, in one embodiment, the electrode assembly 106 may include maximum lengths L EA , widths W EA , and heights H EA typical of thin-film battery dimensions.

In some embodiments, the dimensions L EA , W EA , and H EA are selected to provide an electrode assembly 106 having a maximum length L EA along the transverse axis (X axis) and/or a maximum width W EA along the longitudinal axis (Y axis) that is longer than the maximum height H EA along the vertical axis (Z axis). For example, in the embodiment shown in FIG. 2A , the dimensions L EA , W EA , and H EA are selected to provide an electrode assembly 106 having the greatest dimension along the transverse axis (X axis) that is orthogonal with electrode structure stacking direction D, as well as along the longitudinal axis (Y axis) coinciding with the electrode structure stacking direction D. That is, the maximum length L EA and/or maximum width W EA may be greater than the maximum height H EA . For example, in one embodiment, a ratio of the maximum length L EA to the maximum height H EA may be at least 2:1. By way of further example, in one embodiment a ratio of the maximum length L EA to the maximum height H EA may be at least 5:1. By way of further example, in one embodiment, the ratio of the maximum length L EA to the maximum height H EA may be at least 10:1. By way of further example, in one embodiment, the ratio of the maximum length L EA to the maximum height H EA may be at least 15:1. By way of further example, in one embodiment, the ratio of the maximum length L EA to the maximum height H EA may be at least 20:1. The ratios of the different dimensions may allow for optimal configurations within an energy storage device to maximize the amount of active materials, thereby increasing energy density.

In some embodiments, the maximum width W EA may be selected to provide a width of the electrode assembly 106 that is greater than the maximum height H EA . For example, in one embodiment, a ratio of the maximum width W EA to the maximum height H EA may be at least 2:1. By way of further example, in one embodiment, the ratio of the maximum width W EA to the maximum height H EA may be at least 5:1. By way of further example, in one embodiment, the ratio of the maximum width W EA to the maximum height H EA may be at least 10:1. By way of further example, in one embodiment, the ratio of the maximum width W EA to the maximum height H EA may be at least 15:1. By way of further example, in one embodiment, the ratio of the maximum width W EA to the maximum height H EA may be at least 20:1.

According to one embodiment, a ratio of the maximum width W EA to the maximum length L EA may be selected to be within a predetermined range that provides for an optimal configuration. For example, in one embodiment, a ratio of the maximum width W EA to the maximum length L EA may be in the range of from 1:5 to 5:1. By way of further example, in one embodiment a ratio of the maximum width W EA to the maximum length L EA may be in the range of from 1:3 to 3:1. By way of yet a further example, in one embodiment a ratio of the maximum width W EA to the maximum length LA may be in the range of from 1:2 to 2:1.

In the embodiment as shown in FIG. 2A , the electrode assembly 106 has the first longitudinal end surface 116 and the opposing second longitudinal end surface 118 that is separated from the first longitudinal end surface 116 along the longitudinal axis A EA . The electrode assembly 106 further comprises a lateral surface 142 that at least partially surrounds the longitudinal axis A EA , and that connects the first and second longitudinal end surfaces 116 , 118 . In one embodiment, the maximum width W EA is the dimension along the longitudinal axis A EA as measured from the first longitudinal end surface 116 to the second longitudinal end surface 118 . Similarly, the maximum length L EA may be bounded by the lateral surface 142 , and in one embodiment, may be the dimension as measured from opposing first and second regions 144 , 146 of the lateral surface 142 along the transverse axis that is orthogonal to the longitudinal axis. The maximum height H EA , in one embodiment, may be bounded by the lateral surface 142 and may be measured from opposing first and second regions 148 , 150 of the lateral surface 142 along the vertical axis that is orthogonal to the longitudinal axis.

For the purposes of clarity, only four electrode structures 110 and four counter-electrode structures 112 are illustrated in the embodiment shown in FIG. 2A . For example, the alternating sequence of members of the electrode and counter-electrode structure populations 110 and 112 , respectively, may include any number of members for each population, depending on the energy storage device 100 and the intended use thereof, and the alternating sequence of members of the electrode and counter-electrode structure populations 110 and 112 may be interdigitated, for example, as shown in FIG. 2A . By way of further example, in one embodiment, each member of the population of electrode structures 110 may reside between two members of the population of counter-electrode structures 112 , with the exception of when the alternating sequence terminates along the stacking direction, D. By way of further example, in one embodiment, each member of the population of counter-electrode structures 112 may reside between two members of the population of electrode structures 110 , with the exception of when the alternating sequence terminates along the stacking direction, D. By way of further example, in one embodiment, and stated more generally, the population of electrode structures 110 and the population of counter-electrode structures 112 each have N members, each of N−1 electrode structure members 110 is between two counter-electrode structure members 112 , each of N−1 counter-electrode structure members 112 is between two electrode structure members 110 , and N is at least 2. By way of further example, in one embodiment, N is at least 4. By way of further example, in one embodiment, N is at least 5. By way of further example, in one embodiment, N is at least 10. By way of further example, in one embodiment, N is at least 25. By way of further example, in one embodiment, N is at least 50. By way of further example, in one embodiment, N is at least 100 or more. In one embodiment, members of the electrode and/or counter-electrode populations extend sufficiently from an imaginary backplane (e.g., a plane substantially coincident with a surface of the electrode assembly) to have a surface area (ignoring porosity) that is greater than twice the geometrical footprint (i.e., projection) of the members in the backplane. In certain embodiments, the ratio of the surface area of a non-laminar (i.e., three-dimensional) electrode and/or counter-electrode structure to its geometric footprint in the imaginary backplane may be at least about 5, at least about 10, at least about 50, at least about 100, or even at least about 500. In general, however, the ratio will be between about 2 and about 1000. In one such embodiment, members of the electrode population are non-laminar in nature. By way of further example, in one such embodiment, members of the counter-electrode population are non-laminar in nature. By way of further example, in one such embodiment, members of the electrode population and members of the counter-electrode population are non-laminar in nature.

According to one embodiment, the electrode assembly 106 has longitudinal ends 117 , 119 at which the electrode assembly 106 terminates. According to one embodiment, the alternating sequence of electrode and counter-electrode structures 110 , 112 , respectively, in the electrode assembly 106 terminates in a symmetric fashion along the longitudinal direction, such as with electrode structures 110 at each end 117 , 119 of the electrode assembly 106 in the longitudinal direction, or with counter-electrode structures 112 at each end 117 , 119 of the electrode assembly 106 , in the longitudinal direction. In another embodiment, the alternating sequence of electrode 110 and counter-electrode structures 112 may terminate in an asymmetric fashion along the longitudinal direction, such as with an electrode structure 110 at one end 117 of the longitudinal axis A EA , and a counter-electrode structure 112 at the other end 119 of the longitudinal axis A EA . According to yet another embodiment, the electrode assembly 106 may terminate with a substructure of one or more of an electrode structure 110 and/or counter-electrode structure 112 at one or more ends 117 , 119 of the electrode assembly 106 . By way of example, according to one embodiment, the alternating sequence of the electrode 110 and counter-electrode structures 112 can terminate at one or more substructures of the electrode 110 and counter-electrode structures 112 , including an electrode backbone 134 , counter-electrode backbone 141 , electrode current collector 136 , counter-electrode current collector 140 , electrode active material layer 132 , counter-electrode active material layer 138 , and the like, and may also terminate with a structure such as the separator 130 , and the structure at each longitudinal end 117 , 119 of the electrode assembly 106 may be the same (symmetric) or different (asymmetric). The longitudinal terminal ends 117 , 119 of the electrode assembly 106 can comprise the first and second longitudinal end surfaces 116 , 118 that are contacted by the first and second primary growth constraints 154 , 156 to constrain overall growth of the electrode assembly 106 .

According to yet another embodiment, the electrode assembly 106 has first and second transverse ends 145 , 147 (see, e.g., FIG. 2A ) that may contact one or more electrode and/or counter electrode tabs 190 , 192 (see, e.g., FIG. 20 ) that may be used to electrically connect the electrode and/or counter-electrode structures 110 , 112 to a load and/or a voltage supply (not shown). For example, the electrode assembly 106 can comprise an electrode bus 194 (see, e.g., FIG. 2A ), to which each electrode structure 110 can be connected, and that pools current from each member of the population of electrode structures 110 . Similarly, the electrode assembly 106 can comprise a counter-electrode bus 196 to which each counter-electrode structure 112 may be connected, and that pools current from each member of the population of counter-electrode structures 112 . The electrode and/or counter-electrode buses 194 , 196 each have a length measured in direction D, and extending substantially the entire length of the interdigitated series of electrode structures 110 , 112 . In the embodiment illustrated in FIG. 20 , the electrode tab 190 and/or counter electrode tab 192 includes electrode tab extensions 191 , 193 which electrically connect with, and run substantially the entire length of electrode and/or counter-electrode bus 194 , 196 . Alternatively, the electrode and/or counter electrode tabs 190 , 192 may directly connect to the electrode and/or counter-electrode bus 194 , 196 , for example, an end or position intermediate thereof along the length of the buses 194 , 196 , without requiring the tab extensions 191 , 193 . Accordingly, in one embodiment, the electrode and/or counter-electrode buses 194 , 196 can form at least a portion of the terminal ends 145 , 147 of the electrode assembly 106 in the transverse direction, and connect the electrode assembly to the tabs 190 , 192 for electrical connection to a load and/or voltage supply (not shown). Furthermore, in yet another embodiment, the electrode assembly 106 comprises first and second terminal ends 149 , 153 disposed along the vertical (Z) axis. For example, according to one embodiment, each electrode 110 and/or counter-electrode structure 112 , is provided with a top and bottom coating of separator material, as shown in FIG. 2A , where the coatings form the terminal ends 149 , 153 of the electrode assembly 106 in the vertical direction. The terminal ends 149 , 153 that may be formed of the coating of separator material can comprise first and second surface regions 148 , 150 of the lateral surface 142 along the vertical axis that can be placed in contact with the first and second secondary growth constraints 158 , 160 to constrain growth in the vertical direction.

In general, the electrode assembly 106 can comprise longitudinal end surfaces 116 , 118 that are planar, co-planar, or non-planar. For example, in one embodiment the opposing longitudinal end surfaces 116 , 118 may be convex. By way of further example, in one embodiment the opposing longitudinal end surfaces 116 , 118 may be concave. By way of further example, in one embodiment the opposing longitudinal end surfaces 116 , 118 are substantially planar. In certain embodiments, electrode assembly 106 may include opposing longitudinal end surfaces 116 , 118 having any range of two-dimensional shapes when projected onto a plane. For example, the longitudinal end surfaces 116 , 118 may independently have a smooth curved shape (e.g., round, elliptical, hyperbolic, or parabolic), they may independently include a series of lines and vertices (e.g., polygonal), or they may independently include a smooth curved shape and include one or more lines and vertices. Similarly, the lateral surface 142 of the electrode assembly 106 may be a smooth curved shape (e.g., the electrode assembly 106 may have a round, elliptical, hyperbolic, or parabolic cross-sectional shape) or the lateral surface 142 may include two or more lines connected at vertices (e.g., the electrode assembly 106 may have a polygonal cross-section). For example, in one embodiment, the electrode assembly 106 has a cylindrical, elliptic cylindrical, parabolic cylindrical, or hyperbolic cylindrical shape. By way of further example, in one such embodiment, the electrode assembly 106 may have a prismatic shape, having opposing longitudinal end surfaces 116 , 118 of the same size and shape and a lateral surface 142 (i.e., the faces extending between the opposing longitudinal end surfaces 116 and 118 ) being parallelogram-shaped. By way of further example, in one such embodiment, the electrode assembly 106 has a shape that corresponds to a triangular prism, the electrode assembly 106 having two opposing triangular longitudinal end surfaces 116 and 118 and a lateral surface 142 consisting of three parallelograms (e.g., rectangles) extending between the two longitudinal ends. By way of further example, in one such embodiment, the electrode assembly 106 has a shape that corresponds to a rectangular prism, the electrode assembly 106 having two opposing rectangular longitudinal end surfaces 116 and 118 , and a lateral surface 142 comprising four parallelogram (e.g., rectangular) faces. By way of further example, in one such embodiment, the electrode assembly 106 has a shape that corresponds to a pentagonal prism, hexagonal prism, etc. wherein the electrode assembly 106 has two pentagonal, hexagonal, etc., respectively, opposing longitudinal end surfaces 116 and 118 , and a lateral surface comprising five, six, etc., respectively, parallelograms (e.g., rectangular) faces.

Referring now to FIGS. 3A-3H , several exemplary geometric shapes are schematically illustrated for electrode assembly 106 . More specifically, in FIG. 3A , electrode assembly 106 has a triangular prismatic shape with opposing first and second longitudinal end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including the three rectangular faces connecting the longitudinal end surfaces 116 , 118 , that are about the longitudinal axis A EA . In FIG. 3B , electrode assembly 106 has a parallelepiped shape with opposing first and second parallelogram longitudinal end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including the four parallelogram-shaped faces connecting the two longitudinal end surfaces 116 , 118 , and surrounding longitudinal axis A EA . In FIG. 3C , electrode assembly 106 has a rectangular prism shape with opposing first and second rectangular longitudinal end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including the four rectangular faces connecting the two longitudinal end surfaces 116 , 118 and surrounding longitudinal axis A EA . In FIG. 3D , electrode assembly 106 has a pentagonal prismatic shape with opposing first and second pentagonal longitudinal end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including the five rectangular faces connecting the two longitudinal end surfaces 116 , 118 and surrounding longitudinal axis A EA . In FIG. 3E , electrode assembly 106 has a hexagonal prismatic shape with opposing first and second hexagonal longitudinal end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including the six rectangular faces connecting the two longitudinal end surfaces 116 , 118 and surrounding longitudinal axis A EA . In FIG. 3E , the electrode assembly has a square pyramidal frustum shape with opposing first and second square end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including four trapezoidal faces connecting the two longitudinal end surfaces 116 , 118 and surrounding longitudinal axis A EA , with the trapezoidal faces tapering in dimension along the longitudinal axis from a greater dimension at the first surface 116 to a smaller dimension at the second surface 118 , and the size of the second surface being smaller than that of the first surface. In FIG. 3F , the electrode assembly has a pentagonal pyramidal frustum shape with opposing first and second square end surfaces 116 , 118 separated along longitudinal axis A EA , and a lateral surface 142 including five trapezoidal faces connecting the two longitudinal end surfaces 116 , 118 and surrounding longitudinal axis A EA , with the trapezoidal faces tapering in dimension along the longitudinal axis from a greater dimension at the first surface 116 to a smaller dimension at the second surface 118 , and the size of the second surface being smaller than that of the first surface. In FIG. 3H , the electrode assembly 106 has a pyramidal shape in the longitudinal direction, by virtue of electrode and counter-electrode structures 110 , 112 having lengths that decrease from a first length towards the middle of the electrode assembly 106 on the longitudinal axis, to second lengths at the longitudinal ends 117 , 119 of the electrode assembly 106 .

Electrode/Counter-Electrode Separation Distance

In one embodiment, the electrode assembly 106 has electrode structures 110 and counter-electrode structures 112 , where an offset in height (in the vertical direction) and/or length (in the transverse direction) between the electrode active material layers 132 and counter-electrode material layers 138 , in neighboring electrode and counter-electrode structures 110 , 112 , is selected to be within a predetermined range. By way of explanation, FIG. 25A depicts an embodiment of a section of an electrode assembly 106 comprising an electrode active material layer 132 of an electrode structure 110 , adjacent a counter-electrode active material layer 138 of a counter-electrode structure 112 , with a microporous separator 130 therebetween. In this cross-sectional cut-away as shown, the height in the z direction of the electrode active material layer 132 is roughly equivalent to the height in the z direction of the counter-electrode active material layer 138 . While structures with a same height of the electrode active material layer 132 and counter-electrode active material layer 138 may have benefits in terms of matching of the carrier ion capacity between the layers, thereby improving the storage capacity of a secondary battery 102 having equal height layers, such equal height layers can also be problematic. Specifically, for counter-electrode active material layers 138 that have a height that is excessively close to that of the electrode active material layers 132 , the carrier ions may become attracted to a vertical end surface 500 of the electrode active material layer 132 , and/or an exposed portion of an electrode current collector 136 forming a part of the electrode structure 110 . The result may be plating out of carrier ions and/or the formation of dendrites, which can ultimately lead to performance degradation and/or failure of the battery. While the height of the cathode active material layer 138 can be reduced with respect to the electrode active material layer 34 to mitigate this issue, excessive inequalities in size effect the storage capacity and function of the secondary battery. Furthermore, even when an offset or separation distance between the layers 138 , 132 is provided, it may be the case that mechanical jarring or bumping of a secondary battery having the layers, such as during use or transport of the secondary battery 106 , can move and alter the alignment of the layers 138 , 132 , such that any original offset and/or separation distance between the layers becomes negligible or is even eliminated.

Accordingly, aspects of the present disclosure are directed to the discovery that, by providing a set of constraints 108 (such as a set corresponding to any of the embodiments described herein) an alignment between the layers 138 , 132 in the electrode structures 110 and counter-electrode structures 112 can be maintained, even under physical and mechanical stresses encountered during normal use or transport of the secondary battery. Thus, a predetermined offset and/or separation distance can be selected that is small enough to provide good storage capacity of the secondary battery 106 , while also imparting reduced risk of shorting or failure of the battery, with the predetermined offset being as little as 5 μm, and generally no more than 500 μm.

Referring to FIGS. 25A-25H , further aspects according to the present disclosure are described. Specifically, it is noted that the electrode assembly 106 comprises a population of electrode structures 110 , a population of electrode current collectors 136 , a population of separators 130 , a population of counter-electrode structures 112 , a population of counter-electrode collectors 140 , and a population of unit cells 504 . As also shown by reference to FIG. 2A , members of the electrode and counter-electrode structure populations are arranged in an alternating sequence in the longitudinal direction. Each member of the population of electrode structures 110 comprises an electrode current collector 136 and a layer of an electrode active material 132 having a length L E that corresponds to the Feret diameter as measured in the transverse direction between first and second opposing transverse end surfaces 502 a,b of the electrode active material layer (see, e.g., FIG. 26A ) and a height H E that corresponds to the Feret diameter of the electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces 500 a,b of the electrode active material layer 132 (see, e.g., FIG. 30 ). Each member of the population of electrode structures 110 also has a layer of electrode active material 132 having a width W E that corresponds to the Feret diameter of the electrode active material layer 132 as measured in the longitudinal direction between first and second opposing surfaces of the electrode active material layer (see, e.g., FIG. 25A ). Each member of the population of counter-electrode structures further comprises a counter-electrode current collector 140 and a layer of a counter-electrode active material 138 having a length L C that corresponds to the Feret diameter of the counter-electrode active material (see, e.g., FIG. 26A ), as measured in the transverse direction between first and second opposing transverse end surfaces 503 a,b of the counter-electrode active material layer 138 , and a height H C that corresponds to the Feret diameter as measured in the vertical direction between first and second opposing vertical end surfaces 501 a , 501 b of the counter-electrode active material layer 138 (see, e.g., FIG. 30 ). Each member of the population of counter-electrode structures 112 also has a layer of counter-electrode active material 138 having a width W C that corresponds to the Feret diameter of the counter-electrode active material layer 138 as measured in the longitudinal direction between first and second opposing surfaces of the electrode active material layer (see, e.g., FIG. 25A ).

As defined above, a Feret diameter of the electrode active material layer 132 in the transverse direction is the distance as measured in the transverse direction between two parallel planes restricting the electrode active material layer that are perpendicular to the transverse direction. A Feret diameter of the electrode active material layer 132 in the vertical direction is the distance as measured in the vertical direction between two parallel planes restricting the electrode active material layer that are perpendicular to the vertical direction. A Feret diameter of the counter-electrode active material layer 138 in the transverse direction is the distance as measured in the transverse direction between two parallel planes restricting the counter-electrode active material layer that are perpendicular to the transverse direction. A Feret diameter of the counter-electrode active material layer 138 in the vertical direction is the distance as measured in the vertical direction between two parallel planes restricting the counter-electrode active material layer that are perpendicular to the vertical direction. For purposes of explanation, FIGS. 24A and 24B depict a Feret diameter for an electrode active material layer 132 and/or counter-electrode active material layer 138 , as determined in a single 2D plane. Specifically, FIG. 24A depicts a 2D slice of an electrode active material layer 132 and/or counter-electrode active material layer, as take in the Z-Y plane. A distance between two parallel X-Y planes ( 505 a , 505 b ) that restrict the layer in the z direction (vertical direction) correspond to the height of the layer H (i.e., H E or H C ) in the plane. That is, the Feret diameter in the vertical direction can be understood to correspond to a measure of the maximum height of the layer. While the depiction in FIG. 24A is only that for a 2D slice, for purposes of explanation, it can be understood that in 3D space the Feret diameter in the vertical direction is not limited to a single slice, but is the distance between the X-Y planes 505 a , 505 b separated from each other in the vertical direction that restrict the three-dimensional layer therebetween. Similarly, FIG. 24B depicts a 2D slice of an electrode active material layer 132 and/or counter-electrode active material layer 138 , as take in the X-Z plane. A distance between two parallel Z-Y planes ( 505 c , 505 d ) that restrict the layer in the x direction (transverse direction) correspond to the length of the layer L (i.e., L E or L C ) in the plane. That is, the Feret diameter in the transverse direction can be understood to correspond to a measure of the maximum length of the layer. While the depiction in FIG. 24B is only that for a 2D slice, for purposes of explanation, it can be understood that in 3D space the Feret diameter in the transverse direction is not limited to a single slice, but is the distance between the Z-Y planes 505 c , 505 d separated from each other in the transverse direction that restrict the three-dimensional layer therebetween. Feret diameters of the electrode active material layer and/or counter-electrode active material in the longitudinal direction, so as to obtain a width W E of the electrode active material layer 132 and/or width W C of the counter-electrode active material layer 138 , can be similarly obtained.

In one embodiment, the electrode assembly 106 , as has also been described elsewhere herein, can be understood as having mutually perpendicular transverse, longitudinal and vertical axes corresponding to the x, y and z axes, respectively, of an imaginary three-dimensional cartesian coordinate system, a first longitudinal end surface and a second longitudinal end surface separated from each other in the longitudinal direction, and a lateral surface surrounding an electrode assembly longitudinal axis AA and connecting the first and second longitudinal end surfaces, the lateral surface having opposing first and second regions on opposite sides of the longitudinal axis and separated in a first direction that is orthogonal to the longitudinal axis, the electrode assembly having a maximum width W EA measured in the longitudinal direction, a maximum length L EA bounded by the lateral surface and measured in the transverse direction, and a maximum height H EA bounded by the lateral surface and measured in the vertical direction.

Referring again to FIGS. 25A-25H , it can be seen that each unit cell 504 comprises a unit cell portion of a first electrode current collector 136 of the electrode current collector population, a separator 130 that is ionically permeable to the carrier ions (e.g., a separator comprising a porous material), a first electrode active material layer 132 of one member of the electrode population, a unit cell portion of first counter-electrode current collector 140 of the counter-electrode current collector population and a first counter-electrode active material layer 138 of one member of the counter-electrode population. In one embodiment, in the case of contiguous and/or adjacent members 504 a , 504 b , 504 c of the unit cell population (e.g., as depicted in FIG. 31A ), at least a portion of the electrode current collector 136 and/or counter-electrode current collector may be shared between units ( 504 a and 504 b , and 504 b and 504 c ). For example, referring to FIG. 31A , it can be seen that unit cells 504 a and 504 b share the counter-electrode current collector 140 , whereas unit cells 504 b and 504 c share electrode current collector 136 . In one embodiment, each unit cell comprises ½ of the shared current collector, although other structural arrangements can also be provided. According to yet another embodiment, for a current collector forming a part of a terminal unit cell at a longitudinal end of the electrode assembly 106 , the unit cell 504 can comprise an unshared current collector, and thus comprises the entire current collector as a part of the cell.

Furthermore, referring again to the unit cells depicted in FIGS. 25A-25H and FIG. 31A , it can be seen that, within each unit cell 504 , the first electrode active material layer 132 a is proximate a first side 506 a of the separator 130 and the first counter-electrode material layer 138 a is proximate an opposing second side 506 b of the separator 130 . As shown in the embodiment of FIG. 31A , the electrode structures 110 comprise both the first electrode active material layer 132 a forming a part of the unit cell 504 a , as well as a second electrode active material layer 132 b that forms a part of the next adjacent until cell in the longitudinal direction. Similarly, the counter-electrode structures 112 comprise both the first counter electrode active material layer 138 a forming a part of the unit cell 504 a , as well as a second counter-electrode active material layer 138 b that forms a part of the next adjacent until cell ( 504 b ) in the longitudinal direction. The separator 130 electrically isolates the first electrode active material layer 132 a from the first counter-electrode active material layer 138 a , and carrier ions are primarily exchanged between the first electrode active material layer 132 a and the first counter-electrode active material 138 a layer via the separator 130 of each such unit cell 504 during cycling of the battery between the charged and discharged state.

To further clarify the offset and/or separation distance between the first electrode active material layer 132 a and the first counter-electrode active material layer 138 a in each unit cell 504 , reference is made to FIGS. 22A-C and 23 A-C. Specifically, referring to FIGS. 22A-C , an offset and/or separation distance in the vertical direction is described. As depicted in FIG. 22A of this embodiment, the first vertical end surfaces 500 a , 501 a of the electrode and the counter-electrode active material layers 132 , 138 are on the same side of the electrode assembly 106 . Furthermore, a 2D map of the median vertical position of the first opposing vertical end surface 500 a of the electrode active material 132 in the X-Z plane, along the length L E of the electrode active material layer, traces a first vertical end surface plot, E VP1 . That is, as shown by reference to FIG. 22C , for each ZY plane along the transverse direction (X), the median vertical position (z position) of the vertical end surface 500 a of the electrode active material layer 132 can be determined, by taking the median of the z position for the surface, as a function of y, at the specific transverse position (e.g., X 1 , X 2 , X 3 , etc.) for that ZY plane. FIG. 22C generally depicts an example of a line showing the median vertical position (z position) of the vertical end surface 500 a for the specific ZY plane at the selected x slice (e.g., slice at X 1 ). (Note that FIG. 22C generally depicts determination of median vertical positions (dashed lines at top and bottom of figures) for vertical end surfaces generally, i.e. of either the first and second vertical end surface 500 a,b of the electrode active material layer 132 , and/or the first and second vertical end surfaces 501 a,b of the counter-electrode active material layer 138 .) FIG. 22B depicts an embodiment where the 2D map of this median vertical position, as determined along the length L E of the electrode active material (i.e., at each x position X 1 , X 2 , X 3 along the length L E ), traces first vertical end surface plot E VP1 that corresponds to the median vertical position (z position) plotted as a function of x (e.g., at X 1 , X 2 , X 3 , etc.). For example, the median vertical position of the vertical end surface 500 a of the electrode active material layer 132 can be plotted as a function of x (transverse position) for x positions corresponding to X 0E at a first transverse end of the electrode active material layer to X LE at a second transverse end of the electrode active material layer, where X LE −X L0 is equivalent to the Feret diameter of the electrode active material layer 132 in the transverse direction (the length L E of the electrode active material layer 132 ).

Similarly, in the case of the first opposing end surface 501 a of the counter-electrode active material layer 138 , a 2D map of the median vertical position of the first opposing vertical end surface 501 a of the counter-electrode active material layer 138 in the X-Z plane, along the length L C of the counter-electrode active material layer 138 , traces a first vertical end surface plot, CE VP1 . Referring again to FIG. 22C , it can be understood that for each ZY plane along the transverse direction, the median vertical position (z position) of the vertical end surface 501 a of the counter-electrode active material layer 138 can be determined, by taking the median of the z position for the surface, as a function of y, at the specific transverse position (e.g., X 1 , X 2 , X 3 , etc.) for that ZY plane. FIG. 22C generally depicts an example of a line showing the median vertical position (z position) of the vertical end surface 501 a for the specific YZ plane at the selected x slice (e.g., slice at X 1 ). FIG. 22B depicts an embodiment where the 2D map of this median vertical position, as determined along the length L C of the counter-44=electrode active material (i.e., at each x position X 1 , X 2 , X 3 along the length L C ), traces first vertical end surface plot CE VP1 that corresponds to the median vertical position (z position) plotted as a function of x (e.g., at X 1 , X 2 , X 3 , etc.). For example, the median vertical position of the vertical end surface 501 a of the counter-electrode active material layer 138 can be plotted as a function of x (transverse position) for x positions corresponding to X 0C at a first transverse end of the counter-electrode active material layer to X LC at a second transverse end of the counter-electrode active material layer, where X LC −X L0 is equivalent to the Feret diameter of the counter electrode active material layer 138 in the transverse direction (the length L C of the counter-electrode active material layer 138 ).

Furthermore, the offset and/or separation distance requirements for the vertical separation between the first vertical surfaces 500 a , 501 a of the electrode active and counter-electrode active material layers 132 , 138 require that, for at least 60% of the length L c of the first counter-electrode active material layer: (i) the absolute value of the separation distance, S Z1 , between the plots E VP1 and CE VP1 measured in the vertical direction is 1000 μm≥|S Z1 |≥5 μm. Also, in one embodiment, it is required that, for at least 60% of the length L c of the first counter-electrode active material layer: (ii) as between the first vertical end surfaces 500 a , 500 b of the electrode and counter-electrode active material layers 132 , 138 , the first vertical end surface of the counter-electrode active material layer is inwardly disposed (e.g., inwardly along 508) with respect to the first vertical end surface of the electrode active material layer. That is, by referring to FIG. 22B , it can be seen that the absolute value of the separation distance S z1 , that corresponds to the distance between the plots E VP1 and CE VP1 at any given point along x, is required to be no greater than 1000 μm, and no less than 5 μm, for at least 60% of the length L C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position x from X 0C to X Lc (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction). Also, it can be seen that the first vertical end surface of the counter-electrode active material layer is inwardly disposed with respect to the first vertical end surface of the electrode active material layer, for at least 60% of the length L C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position x from X 0C to X Lc (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction)

In one embodiment, the absolute value of S Z1 may be ≥5 μm, such as ≥10 μm, ≥15 μm, a 20 μm, ≥35 μm, ≥45 μm, Z 50 μm, ≥75 μm, ≥100 μm, ≥150 μm, and ≥200 μm. In another embodiment, the absolute value of S Z1 may be ≤1000 microns, such as ≤500 μm, such as ≤475 μm, ≤425 μm, ≤400 μm, ≤375 μm, ≤350 μm, ≤325 μm, ≤300 μm, and ≤250 μm. In one embodiment, the absolute value of S Z1 may follow the relationship 1000 μm≥|S Z1 |≥5 μm, and/or 500 μm≥|S Z1 |≥10 μm, and/or 250 μm≥|S Z1 |≥20 μm. In yet another embodiment, for a Feret Diameter of the width W E of the counter-electrode active material layer 132 in the unit cell, the absolute value of S Z1 may be in a range of from 5×W E ≥|S Z1 |≥0.05×W E . Furthermore, in one embodiment, any of the above values and/or relationships for |S Z1 | may hold true for more than 60% of the length L c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the length L c of the first counter-electrode active material layer.

Furthermore, for at least 60% of the position x from X 0C to X Lc (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction), the first vertical end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first vertical end surface of the electrode active material layer. That is, the electrode active material layer 132 can be understood to have a median vertical position (position in z in a YZ plane for a specified X slice, as in FIG. 22C ) that is closer to the lateral surface, than the counter-electrode active material layer 130 , for at least 60% of the length L C of the counter-electrode active material layer. Stated another way, the counter-electrode active material layer 138 can be understood to have a median vertical position (position in z in a YZ plane for a specified X slice, as in FIG. 22C ) that is further along an inward direction 508 of the electrode assembly 106 , than the median vertical position of the electrode active material layer 132 . This vertical offset of the electrode active material layer 132 with respect to the counter-electrode active material layer 138 can also be seen with respect to the embodiment in FIG. 22A , which depicts a height of the electrode material layer 132 exceeding that of the counter-electrode active material layer 138 , and the plots of FIG. 22B , which depicts the median vertical position E VP1 of the electrode active material layer 132 exceeding the median vertical position CE VP1 of the counter-electrode active material layer along the transverse direction. In one embodiment, the first vertical end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first vertical end surface of the electrode active material layer for more than 60% of the length L c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the length L c of the first counter-electrode active material layer.

In one embodiment, the relationship described above for the separation distance S z1 with respect to the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers 132 , 138 , also similarly can be determined for the second vertical surfaces 500 b , 501 b of the electrode and counter-electrode active material layers 132 , 138 (e.g., as shown in FIG. 31A ). That is, the second vertical end surfaces 500 b and 501 b are on the same side of the electrode assembly 106 as each other, and oppose the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers 132 , 138 , respectively. Furthermore, in analogy to the description given for the separation distance and/or offset S z1 given above, a 2D map of the median vertical position of the second opposing vertical end surface 500 b of the electrode active material 132 in the X-Z plane, along the length L E of the electrode active material layer, traces a second vertical end surface plot, E VP2 . That is, as shown by reference to FIG. 22A-C , for each YZ plane along the transverse direction, the median vertical position (z position) of the second vertical end surface 500 b of the electrode active material layer 132 can be determined, by taking the median of the z position for the surface, as a function of y, at the specific transverse position (e.g., X 1 , X 2 , X 3 , etc.) for that YZ plane. FIG. 22C generally depicts an example of a line showing the median vertical position (z position) of the second vertical end surface 500 b for the specific YZ plane at the selected x slice (e.g., slice at X 1 ). FIG. 22B depicts an embodiment where the 2D map of this median vertical position, as determined along the length L E of the electrode active material (i.e., at each x position X 1 , X 2 , X 3 along the length L E ), traces second vertical end surface plot E VP2 that corresponds to the median vertical position (z position) plotted as a function of x (e.g., at X 1 , X 2 , X 3 , etc.). For example, the median vertical position of the second vertical end surface 500 b of the electrode active material layer 132 can be plotted as a function of x (transverse position) for x positions corresponding to X 0E at a first transverse end of the electrode active material layer to X LE at a second transverse end of the electrode active material layer, where X LE −X L0 is equivalent to the Feret diameter of the electrode active material layer 132 in the transverse direction (the length L E of the electrode active material layer 132 ).

Similarly, in the case of the second opposing end surface 501 b of the counter-electrode active material layer 138 , a 2D map of the median vertical position of the second opposing vertical end surface 501 b of the counter-electrode active material layer 138 in the X-Z plane, along the length L C of the counter-electrode active material layer 138 , traces a second vertical end surface plot, CE VP2 . Referring again to FIGS. 22 A-C, it can be understood that for each YZ plane along the transverse direction, the median vertical position (z position) of the second vertical end surface 501 b of the counter-electrode active material layer 138 can be determined, by taking the median of the z position for the surface, as a function of y, at the specific transverse position (e.g., X 1 , X 2 , X 3 , etc.) for that YZ plane. FIG. 22C generally depicts an example of a line showing the median vertical position (z position) of the second vertical end surface 501 b for the specific YZ plane at the selected x slice (e.g., slice at X 1 ). FIG. 22B depicts an embodiment where the 2D map of this median vertical position, as determined along the length L C of the counter-electrode active material (i.e., at each x position X 1 , X 2 , X 3 along the length L C ), traces second vertical end surface plot CE VP2 that corresponds to the median vertical position (z position) plotted as a function of x (e.g., at X 1 , X 2 , X 3 , etc.). For example, the median vertical position of the second vertical end surface 501 b of the counter-electrode active material layer 138 can be plotted as a function of x (transverse position) for x positions corresponding to X 0C at a first transverse end of the counter-electrode active material layer to X LC at a second transverse end of the counter-electrode active material layer, where X LC −X L0 is equivalent to the Feret diameter of the counter electrode active material layer 138 in the transverse direction (the length L C of the counter-electrode active material layer 138 ).

Furthermore, the offset and/or separation distance requirements for the vertical separation between the second vertical surfaces 500 b , 501 b of the electrode active and counter-electrode active material layers 132 , 138 require that, for at least 60% of the length L c of the first counter-electrode active material layer (i) the absolute value of the separation distance, S Z2 , between the plots E VP2 and CE VP2 measured in the vertical direction is 1000 μm≥|S Z2 |≥5 μm. Also, in one embodiment, it is required that, for at least 60% of the length L c of the first counter-electrode active material layer (ii) as between the second vertical end surfaces 500 b , 501 b of the electrode and counter-electrode active material layers 132 , 138 , the second vertical end surface of the counter-electrode active material layer is inwardly disposed with respect to the second vertical end surface of the electrode active material layer. That is, by referring to FIG. 22B , it can be seen that the absolute value of the separation distance S z2 , that corresponds to the distance between the plots E VP2 and CE VP2 at any given point along x, is required to be no greater than 1000 μm, and no less than 5 μm, for at least 60% of the length L C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position x from X 0C to X Lc (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction). Also, it can be seen that the second vertical end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the second vertical end surface of the electrode active material layer, for at least 60% of the length L C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position x from X 0C to X LC (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction)

In one embodiment, the absolute value of S Z2 may be ≥5 μm, such as ≥10 μm, ≥15 μm, a 20 μm, ≥35 μm, ≥45 μm, ≥50 μm, ≥75 μm, ≥100 μm, ≥150 μm, and ≥200 μm. In another embodiment, the absolute value of S Z2 may be ≤1000 microns, such as ≤500 μm, such as ≤475 μm, ≤425 μm, ≤400 μm, ≤375 μm, ≤350 μm, ≤325 μm, ≤300 μm, and ≤250 μm. In one embodiment, the absolute value of S Z2 may follow the relationship 1000 μm≥|S Z2 |≥5 μm, and/or 500 μm≥|S Z2 |≥10 μm, and/or 250 μm≥|S Z2 |≥20 μm. In yet another embodiment, for a Feret Diameter of the width W E of the counter-electrode active material layer 132 in the unit cell, the absolute value of S Z2 may be in a range of from 5×W E ≥|S Z2 |≥0.05×W E . Furthermore, in one embodiment, any of the above values and/or relationships for |S Z2 | may hold true for more than 60% of the length L c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the length L c of the first counter-electrode active material layer. Furthermore, the value and/or relationships described above for S Z2 may be the same and/or different than those for S Z1 , and/or may hold true for a different percentage of the length L C than for S Z1 .

Furthermore, for at least 60% of the position x from X 0C to X Lc (60% of the Feret diameter of the counter-electrode active material layer in the transverse direction), the second vertical end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the second vertical end surface of the electrode active material layer. That is, the electrode active material layer 132 can be understood to have a median vertical position (position in z in a YZ plane for a specified X slice, as in FIG. 22C ) that is closer to the lateral surface, than the counter-electrode active material layer 130 , for at least 60% of the length L C of the counter-electrode active material layer. Stated another way, the counter-electrode active material layer 138 can be understood to have a median vertical position (position in z in a YZ plane for a specified X slice, as in FIG. 22C ) that is further along an inward direction 508 of the electrode assembly 106 , than the median vertical position of the electrode active material layer 132 . This vertical offset of the electrode active material layer 132 with respect to the counter-electrode active material layer 138 can also be seen with respect to the embodiment in FIG. 22A , which depicts a height of the electrode material layer 132 exceeding that of the counter-electrode active material layer 138 , and the plots of FIG. 22B , which depicts the median vertical position E VP2 of the electrode active material layer 132 below the median vertical position CE VP2 of the counter-electrode active material layer along the transverse direction. In one embodiment, the second vertical end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first vertical end surface of the electrode active material layer for more than 60% of the length L c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the length L c of the first counter-electrode active material layer. Also, the percentage of the length L c along which the counter-electrode active material is more inward than the electrode active material may be different at the first vertical surfaces as compared to the second vertical surfaces.

Furthermore, in one embodiment, the electrode assembly 106 further comprises a transverse offset and/or separation distance between transverse ends of the electrode and counter-electrode active material layers 132 , 138 in each unit cell. Referring to FIGS. 23A-C , an offset and/or separation distance in the transverse direction is described. As depicted in FIG. 23A of this embodiment, the first transverse end surfaces 502 a , 503 a of the electrode and the counter-electrode active material layers 132 , 138 are on the same side of the electrode assembly 106 (see, also, FIGS. 26A-26F ). Furthermore, a 2D map of the median transverse position of the first opposing transverse end surface 502 a of the electrode active material 132 in the X-Z plane, along the height H E of the electrode active material layer, traces a first transverse end surface plot, E TP1 . That is, as shown by reference to FIG. 23A , for each YX plane along the vertical direction, the median transverse position (x position) of the transverse end surface 502 a of the electrode active material layer 132 can be determined, by taking the median of the x position for the surface, as a function of y, at the specific vertical position (e.g., Z 1 , Z 2 , Z 3 , etc.) for that YX plane. FIG. 23C generally depicts an example of a line showing the median transverse position (x position) of the first transverse end surface 502 a for the specific YX plane at the selected z slice (e.g., slice at Z 1 ). (Note that FIG. 23C generally depicts determination of median transverse positions (dashed lines at top and bottom of figures) for transverse end surfaces generally, i.e. of either the first and second transverse end surface 5002 a,b of the electrode active material layer 132 , and/or the first and second transverse end surfaces 503 a, b of the counter-electrode active material layer 138 .) FIG. 23B depicts an embodiment where the 2D map of this median transverse position, as determined along the height H E of the electrode active material (i.e., at each z position Z 1 , Z 2 , Z 3 along the height H E ), traces first transverse end surface plot E TP1 that corresponds to the median transverse position (x position) plotted as a function of z (e.g., at Z 1 , Z 2 , Z 3 , etc.). For example, the median transverse position of the transverse end surface 502 a of the electrode active material layer 132 can be plotted as a function of z (vertical position) for z positions corresponding to Z 0E at a first vertical end of the electrode active material layer to Z HE at a second vertical end of the electrode active material layer, where Z HE -Z 0E is equivalent to the Feret diameter of the electrode active material layer 132 in the vertical direction (the height H E of the electrode active material layer 132 ).

Similarly, in the case of the first transverse end surface 503 a of the counter-electrode active material layer 138 , a 2D map of the median transverse position of the first opposing transverse end surface 503 a of the counter-electrode active material layer 138 in the X-Z plane, along the height H C of the counter-electrode active material layer 138 , traces a first transverse end surface plot, CE TP1 . Referring again to FIGS. 23A-C , it can be understood that for each YX plane along the vertical direction, the median transverse position (x position) of the transverse end surface 503 a of the counter-electrode active material layer 138 can be determined, by taking the median of the x position for the surface, as a function of y, at the specific vertical position (e.g., Z 1 , Z 2 , Z 3 , etc.) for that YX plane. FIG. 23C generally depicts an example of a line showing the median transverse position (x position) of the transverse end surface 503 a for the specific YX plane at the selected z slice (e.g., slice at Z 1 ). FIG. 23B depicts an embodiment where the 2D map of this median transverse position, as determined along the height H C of the counter-electrode active material (i.e., at each z position Z 1 , Z 2 , Z 3 along the height H C ), traces first transverse end surface plot CE TP1 that corresponds to the median transverse position (x position) plotted as a function of z (e.g., at Z 1 , Z 2 , Z 3 , etc.). For example, the median transverse position of the transverse end surface 503 a of the counter-electrode active material layer 138 can be plotted as a function of z (vertical position) for z positions corresponding to Z 0C at a first vertical end of the counter-electrode active material layer to Z HC at a second vertical end of the counter-electrode active material layer, where Z HC −Z 0C is equivalent to the Feret diameter of the counter electrode active material layer 138 in the vertical direction (the height H C of the counter-electrode active material layer 138 ).

Furthermore, the offset and/or separation distance requirements for the transverse separation between the first transverse surfaces 502 a , 502 b of the electrode active and counter-electrode active material layers 132 , 138 require that, for at least 60% of the height H c of the first counter-electrode active material layer (i) the absolute value of the separation distance, S X1 , between the plots E TP1 and CE TP1 measured in the vertical direction is 1000 μm≥|S X1 ≥5 μm. Also, in one embodiment, it is required that, for at least 60% of the height H c of the first counter-electrode active material layer: (ii) as between the first transverse end surfaces 502 a , 503 a of the electrode and counter-electrode active material layers 132 , 138 , the first transverse end surface of the counter-electrode active material layer is inwardly disposed with respect to the first transverse end surface of the electrode active material layer. That is, by referring to FIG. 23B , it can be seen that the absolute value of the separation distance S X1 , that corresponds to the distance between the plots E TP1 and CE TP1 at any given point along z, is required to be no greater than 1000 μm, and no less than 5 μm, for at least 60% of the height H C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position z from Z 0C to Z Hc (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction). Also, it can be seen that the first transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first transverse end surface of the electrode active material layer, for at least 60% of the height H C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position z from Z 0C to Z Hc (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction)

In one embodiment, the absolute value of S x1 may be ≥5 μm, such as ≥10 μm, ≥15 μm, ≥20 μm, ≥35 μm, ≥45 μm, a 50 μm, ≥75 μm, ≥100 μm, ≥150 μm, and ≥200 μm. In another embodiment, the absolute value of S X1 may be ≤1000 microns, such as ≤500 μm, such as ≤475 μm, ≤425 μm, ≤400 μm, ≤375 μm, ≤350 μm, ≤325 μm, ≤300 μm, and ≤250 μm. In one embodiment, the absolute value of S X1 may follow the relationship 1000 μm≥|S X1 |≥5 μm, and/or 500 μm≥|S X1 |≥10 μm, and/or 250 μm≥|S X1 |≥20 μm. In yet another embodiment, for a Feret Diameter of the width W E of the counter-electrode active material layer 132 in the unit cell, the absolute value of S X1 may be in a range of from 5×W E ≥|S X1 |≥0.05×W E . Furthermore, in one embodiment, any of the above values and/or relationships for |S X1 | may hold true for more than 60% of the height H c of the counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the height H c of the counter-electrode active material layer. Furthermore, the value and/or relationships described above for S X1 may be the same and/or different than those for S Z1 , and/or S Z2 .

Furthermore, for at least 60% of the position z from Z 0C to Z Hc (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction), the first transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first transverse end surface of the electrode active material layer. That is, the electrode active material layer 132 can be understood to have a median transverse position (position in x in a XY plane for a specified Z slice, as in FIG. 23C ) that is closer to the lateral surface, than the counter-electrode active material layer 130 , for at least 60% of the height H C of the counter-electrode active material layer. Stated another way, the counter-electrode active material layer 138 can be understood to have a median transverse position (position in x in a XY plane for a specified X slice, as in FIG. 23C ) that is further along an inward direction 510 of the electrode assembly 106 , than the median transverse position of the electrode active material layer 132 . This transverse offset of the electrode active material layer 132 with respect to the counter-electrode active material layer 138 can also be seen with respect to the embodiment in FIG. 23A , which depicts a length of the electrode material layer 132 exceeding that of the counter-electrode active material layer 138 , and the plots of FIG. 23B , which depicts the median transverse position E TP1 of the electrode active material layer 132 exceeding the median transverse position CE TP1 of the counter-electrode active material layer along the vertical direction. In one embodiment, the first transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the first transverse end surface of the electrode active material layer for more than 60% of the height H c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the height H c of the first counter-electrode active material layer. Also, the percentage of the height H c along which the counter-electrode active material is more inward than the electrode active material may be different at the first transverse end surfaces as compared to the second transverse end surfaces.

In one embodiment, the relationship described above for the separation distance S X1 with respect to the first transverse end surfaces 502 a , 503 a of the electrode and counter-electrode active material layers 132 , 138 , also can be determined for the second transverse surfaces 502 b , 503 b of the electrode and counter-electrode active material layers 132 , 138 (e.g., as shown in FIGS. 26A-26F ). That is, the second transverse end surfaces 502 b and 503 b are on the same side of the electrode assembly 106 as each other, and oppose the first transverse end surfaces 502 a , 503 a of the electrode and counter-electrode active material layers 132 , 138 , respectively. Furthermore, in analogy to the description given for the separation distance and/or offset S X1 given above, a 2D map of the median transverse position of the second opposing transverse end surface 502 b of the electrode active material 132 in the X-Z plane, along the height H E of the electrode active material layer, traces a second transverse end surface plot, E TP2 . That is, as shown by reference to FIGS. 23A-C , for each YX plane along the vertical direction, the median transverse position (x position) of the second transverse end surface 502 b of the electrode active material layer 132 can be determined, by taking the median of the x position for the surface, as a function of y, at the specific vertical position (e.g., Z 1 , Z 2 , Z 3 , etc.) for that YX plane. FIG. 23C generally depicts an example of a line showing the median transverse position (x position) of the second transverse end surface 502 b for the specific YX plane at the selected a slice (e.g., slice at Z 1 ). FIG. 23B depicts an embodiment where the 2D map of this median transverse position, as determined along the height H E of the electrode active material (i.e., at each z position Z 1 , Z 2 , Z 3 along the height H E ), traces second transverse end surface plot E TP2 that corresponds to the median transverse position (x position) plotted as a function of z (e.g., at Z 1 , Z 2 , Z 3 , etc.). For example, the median transverse position of the second transverse end surface 502 b of the electrode active material layer 132 can be plotted as a function of z (vertical position) for z positions corresponding to Z 0E at a first vertical end of the electrode active material layer to Z HE at a second vertical end of the electrode active material layer, where Z HE −Z 0E is equivalent to the Feret diameter of the electrode active material layer 132 in the vertical direction (the height H E of the electrode active material layer 132 ).

Similarly, in the case of the second opposing transverse end surface 503 b of the counter-electrode active material layer 138 , a 2D map of the median transverse position of the second opposing transverse end surface 503 b of the counter-electrode active material layer 138 in the X-Z plane, along the height H C of the counter-electrode active material layer 138 , traces a second transverse end surface plot, CE T m. Referring again to FIGS. 23A-C , it can be understood that for each YX plane along the vertical direction, the median transverse position (x position) of the second transverse end surface 503 b of the counter-electrode active material layer 138 can be determined, by taking the median of the z position for the surface, as a function of y, at the specific vertical position (e.g., Z 1 , Z 2 , Z 3 , etc.) for that YX plane. FIG. 23C generally depicts an example of a line showing the median transverse position (x position) of the second transverse end surface 503 b for the specific YX plane at the selected z slice (e.g., slice at Z 1 ). FIG. 23B depicts an embodiment where the 2D map of this median transverse position, as determined along the height H C of the counter-electrode active material (i.e., at each z position Z 1 , Z 2 , Z 3 along the height H C ), traces second transverse end surface plot CE TP2 that corresponds to the median transverse position (x position) plotted as a function of z (e.g., at Z 1 , Z 2 , Z 3 , etc.). For example, the median transverse position of the second transverse end surface 503 b of the counter-electrode active material layer 138 can be plotted as a function of z (vertical position) for z positions corresponding to Z 0C at a first transverse end of the counter-electrode active material layer to Z HC at a second transverse end of the counter-electrode active material layer, where Z HC −X 0C is equivalent to the Feret diameter of the counter electrode active material layer 138 in the vertical direction (the height H C of the counter-electrode active material layer 138 ).

Furthermore, the offset and/or separation distance requirements for the transverse separation between the second transverse surfaces 502 b , 503 b of the electrode active and counter-electrode active material layers 132 , 138 require that, for at least 60% of the height H c of the first counter-electrode active material layer: (i) the absolute value of the separation distance, S X2 , between the plots E TP2 and CE TP2 measured in the vertical direction is 1000 μm≥|S X2 |≥5 μm. Also, in one embodiment, it is required that, for at least 60% of the height H c of the first counter-electrode active material layer: (ii) as between the second transverse end surfaces 502 b , 503 b of the electrode and counter-electrode active material layers 132 , 138 , the second transverse end surface of the counter-electrode active material layer is inwardly disposed with respect to the second transverse end surface of the electrode active material layer. That is, by referring to FIG. 23B , it can be seen that the absolute value of the separation distance S X2 , that corresponds to the distance between the plots E TP2 and CE TP2 at any given point along z, is required to be no greater than 1000 μm, and no less than 5 μm, for at least 60% of the height H C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position z from Z 0C to Z Hc (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction). Also, it can be seen that the second transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the second transverse end surface of the electrode active material layer, for at least 60% of the height H C of the first counter-electrode active material layer 138 , i.e. for at least 60% of the position z from Z 0C to Z Hc (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction)

In one embodiment, the absolute value of S x2 may be ≥5 μm, such as ≥10 μm, ≥15 μm, ≥20 μm, 2 35 μm, ≥45 μm, 2 50 μm, ≥75 μm, ≥100 μm, 2 150 μm, and ≥200 μm. In another embodiment, the absolute value of S X2 may be ≤1000 microns, such as ≤500 μm, such as ≤475 μm, ≤425 μm, ≤400 μm, ≤375 μm, ≤350 μm, ≤325 μm, ≤300 μm, and ≤250 μm. In one embodiment, the absolute value of S X2 may follow the relationship 1000 μm≥|S X2 |≥5 μm, and/or 500 μm≥|S X2 |≥10 μm, and/or 250 μm≥|S X2 |≥20 μm. In yet another embodiment, for a Feret Diameter of the width W E of the counter-electrode active material layer 132 in the unit cell, the absolute value of S X2 may be in a range of from 5×W E ≥|S X2 |≥0.05×W E . Furthermore, in one embodiment, any of the above values and/or relationships for |S X2 | may hold true for more than 60% of the height H c of the counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the height H c of the counter-electrode active material layer. Furthermore, the value and/or relationships described above for S X2 may be the same and/or different than those for S X1 , S Z1 and/or S Z2 .

Furthermore, for at least 60% of the position z from Z 0C to Z HC (60% of the Feret diameter of the counter-electrode active material layer in the vertical direction), the second transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the second transverse end surface of the electrode active material layer. That is, the electrode active material layer 132 can be understood to have a median transverse position (position in x in a XY plane for a specified Z slice, as in FIG. 23C ) that is closer to the lateral surface, than the counter-electrode active material layer 130 , for at least 60% of the height H C of the counter-electrode active material layer. Stated another way, the counter-electrode active material layer 138 can be understood to have a median transverse position (position in x in a XY plane for a specified X slice, as in FIG. 23C ) that is further along an inward direction 510 of the electrode assembly 106 , than the median transverse position of the electrode active material layer 132 . This transverse offset of the electrode active material layer 132 with respect to the counter-electrode active material layer 138 can also be seen with respect to the embodiment in FIG. 23A , which depicts a length of the electrode material layer 132 exceeding that of the counter-electrode active material layer 138 , and the plots of FIG. 23B , which depicts the median transverse position E TP2 of the electrode active material layer 132 below the median transverse position CE TP2 of the counter-electrode active material layer along the vertical direction. In one embodiment, the second transverse end surface of the of the counter-electrode active material layer is inwardly disposed with respect to the second transverse end surface of the electrode active material layer for more than 60% of the height H c of the first counter-electrode active material layer, such as for at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and even at least 95% of the height H c of the first counter-electrode active material layer. Also, the percentage of the height He along which the counter-electrode active material is more inward than the electrode active material may be different at the first transverse end surfaces as compared to the second transverse end surfaces.

According to one embodiment, the offset and/or separation distances in the vertical and/or transverse directions can be maintained by providing a set of electrode constraints 108 that are capable of maintaining and stabilizing the alignment of the electrode active material layers 132 and counter-electrode active material layers 138 in each unit cell, and even stabilizing the position of the electrode structures 110 and counter-electrode structures 112 with respect to each other in the electrode assembly 106 . In one embodiment, the set of electrode constraints 108 comprises any of those described herein, including any combination or portion thereof. For example, in one embodiment, the set of electrode constraints 108 comprises a primary constraint system 151 comprising first and second primary growth constraints 154 , 156 and at least one primary connecting member 162 , the first and second primary growth constraints 154 , 156 separated from each other in the longitudinal direction, and the at least one primary connecting member 162 connecting the first and second primary growth constraints 154 , 156 , wherein the primary constraint system 151 restrains growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%. In yet another embodiment, the set of electrode constraints 108 further comprises a secondary constraint system 152 comprising first and second secondary growth constraints 158 , 160 separated in a second direction and connected by at least one secondary connecting member 166 , wherein the secondary constraint system 155 at least partially restrains growth of the electrode assembly 106 in the second direction upon cycling of the secondary battery 106 , the second direction being orthogonal to the longitudinal direction. Further embodiments of the set of electrode constraints 108 are described below.

Returning to FIGS. 25A-25H , various different configurations of the unit cells 504 , with respect to the vertical separation distance and/or offset are described. In the embodiments as shown, a portion of the set of constraints 108 is positioned at at least one vertical end of the layers 132 , and may be connected to one or more structures of the unit cell 504 . For example, the set of electrode constraints 108 comprises first and second secondary growth constraints 158 , 160 , and the growth constraints can be connected to the vertical ends of structures in the unit cell. In the embodiment as shown in FIG. 25A , the first and second growth constraints 158 , 160 are attached via adhesive layers 516 that bond structures of the unit cell to the constraints 158 , 160 (the cut-away of FIG. 1A shows upper constraint 158 ). In FIG. 25A , the vertical ends of the electrode current collector 136 , separator layer 130 and counter-electrode current collector 140 are bonded via an adhesive layer 516 to the first and second growth constraints 158 , 160 . Accordingly, as is described in further detail below, one of or more of the electrode current collector 136 , separator layer 130 and counter-electrode current collector 140 , either individually or collectively, may act as a secondary connecting member 166 connecting the first and second growth constraints, to constrain growth of the electrode assembly 106 . FIG. 25B shows a further embodiment where all of the electrode current collector 136 , separator layer 130 and counter-electrode current collector 140 , of a unit cell 504 , are bonded to the first and second secondary growth constraints 158 , 160 . Alternatively, certain of the structures may be bonded to a first secondary growth constraint 158 , while others are bonded to the second secondary growth constraint. In the embodiment as shown in FIG. 25C , the vertical ends of both the electrode current collector 136 and the separator layer 130 are bonded to the first and second secondary growth constraints 158 , 160 , while the counter-electrode current collector 140 ends before contacting the first and secondary growth constraints in the vertical direction. In the embodiments as shown in FIGS. 25D-25E , the vertical ends of both the electrode current collector 136 and the counter-electrode current collector 140 are bonded to the first and second secondary growth constraints 158 , 160 , while the separator 130 ends before contacting the first and secondary growth constraints in the vertical direction. In the embodiments as shown in FIG. 25F , the vertical ends of the electrode current collector 136 are bonded to the first and second secondary growth constraints 158 , 160 , while the separator 130 and counter-electrode current collector 140 end before contacting the first and secondary growth constraints in the vertical direction. In the embodiments as shown in FIG. 25G-25H , the vertical ends of the counter-electrode current collector 140 are bonded to the first and second secondary growth constraints 158 , 160 , while the separator 130 and electrode current collector 136 end before contacting the first and secondary growth constraints in the vertical direction.

Furthermore, in one embodiment, the unit cells 504 can comprise one or more insulator members 514 disposed between one or more of the first and second vertical surfaces of the electrode active material layer 132 and/or the counter-electrode active material layer. The insulator members 514 may be electrically insulating to inhibit shorting between structures in the unit cell 504 . The insulator members may also be non-ionically permeable, or at least less ionically permeable than the separator 130 , to inhibit the passage of carrier ions therethrough. That is, the insulator members 514 may be provide to insulate vertical surfaces of the electrode and counter-electrode active material layers 132 , 138 , from plating out, dendrite formation, and/or other electrochemical reactions that the exposed surfaces may otherwise be susceptible to, to extend the life of the secondary battery 102 having the unit cells 504 with the insulating members 514 . For example, the insulating member 514 may have an ionic permeability and/or ionic conductance that is less than that of a separator 130 that is provided in the same unit cell 504 . For example, the insulating member 514 may have a permeability and/or conductance to carrier ions that is the same as and/or similar to that of the carrier ion insulating material layer 674 described further below. The insulating member 514 can be prepared from a number of different materials, including ceramics, polymers, glass, and combinations and/or composites thereof.

In the embodiment shown in FIG. 25A , the unit cell 504 does not have an insulating member 514 , as both first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers 132 , 138 have a vertical dimension z that is close to, and even substantially flush with, the first secondary growth constraint 158 . The second vertical end surfaces 500 b , 501 b may similarly reach the second secondary growth constraint 160 in the opposing vertical direction (not shown). In certain embodiments, even if an insulating member 514 is not provided at a vertical surface of one or more of the electrode and counter-electrode active material layers 132 , 138 , the unit cell may comprise predetermined vertical offsets S z1 and S z2 , as described above. Accordingly, in one aspect, the embodiment as shown in FIG. 25A may have an offset S z1 and/or S z2 (not explicitly shown), even though no insulating member 514 is provided.

The embodiment shown in FIG. 25B depicts a unit cell 504 having a clear offset S Z1 between the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, and/or an offset S z2 between the second vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers (not shown). In this embodiment, an insulating member 514 is provided between the first vertical end surface 501 a of the counter-electrode active material layer 138 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 501 b of the counter-electrode active material layer 138 and an inner surface of the second secondary growth constraint 160 (not shown). Although not shown in the 2D Z-Y plane shown in FIG. 25B , the insulating member 515 may extend substantially and even entirely over the vertical surface(s) of the counter-electrode active material layer 138 , such as in the longitudinal direction (y direction) and the transverse direction (x direction—into the page in FIG. 25B ), to cover one or more of the vertical surfaces 501 a, b . Furthermore, in the embodiment depicted in FIG. 25B , the insulator member 514 is disposed between and/or bounded by the separator 130 at one longitudinal end of the counter-electrode active material layer 138 , and the counter-electrode current collector 140 at the other longitudinal end.

The embodiment shown in FIG. 25C also depicts a unit cell 504 having a clear offset S z1 between the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, and/or an offset S z2 between the second vertical end surfaces 500 b , 501 b of the electrode and counter-electrode active material layers (not shown). Also in this embodiment, an insulating member 514 is provided between the first vertical end surface 500 a of the counter-electrode active material layer 138 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 501 b of the counter-electrode active material layer 138 and an inner surface of the second secondary growth constraint 160 (not shown). Although not shown in the 2D Z-Y plane shown in FIG. 25C , the insulating member 515 may extend substantially and even entirely over the vertical surface(s) of the counter-electrode active material layer 138 , such as in the longitudinal direction (y direction) and the transverse direction (x direction—into the page in FIG. 25C ), to cover one or more of the vertical surfaces 501 a, b . Furthermore, in the embodiment depicted in FIG. 25C , the insulator member 514 is bounded by the separator 130 at one longitudinal end of the counter-electrode active material layer, but extends over vertical surface(s) 516 a of the counter-electrode current collector 140 at the other longitudinal end. That is, the insulating member may extend longitudinally towards and abut a neighboring until cell structure, such as an adjacent counter-electrode active material layer 138 of a neighboring unit cell structure. In one embodiment, the insulating member 514 may extend across one or more vertical surfaces 501 a,b of adjacent counter-electrode active material layers 138 , by passing over a counter-electrode current collector 140 separating the layers 138 in adjacent unit cells 504 a , 504 b , and over the vertical surfaces of the adjacent counter-electrode active material layers 138 in the neighboring cells. That is, the insulating member 514 may extend across one or more vertical surfaces 501 a,b of the counter-electrode active material layer 138 in a first unit cell 504 a , and over one or more vertical surfaces 501 a,b of the counter-electrode active material layer 138 in a second unit cell 504 b adjacent the first unit cell 504 a , by traversing vertical surface of the counter-electrode current collector 140 separating the unit cells 504 a,b from one another in the longitudinal direction.

The embodiment shown in FIG. 25D depicts a unit cell 504 where an insulating member 514 is provided between the first vertical end surface 500 a of the counter-electrode active material layer 138 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 500 b of the counter-electrode active material layer 138 and an inner surface of the second secondary growth constraint 160 (not shown), and also extends over one or more vertical surfaces 518 a,b of the separator 130 to also cover one or more vertical end surfaces 500 a , 500 b of the electrode active material layer 138 . That is, the insulating member 514 is also provided between the first vertical end surface 500 a of the electrode active material layer 132 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 500 b of the electrode active material layer 132 and an inner surface of the second secondary growth constraint 160 (not shown) (as well as in the space between the first and second secondary growth constraints 158 , 160 and the vertical surfaces 518 a,b of the separator 130 ). Although not shown in the 2D Z-Y plane shown in FIG. 25D , the insulating member 515 may extend substantially and even entirely over the vertical surface(s) of the electrode and counter-electrode active material layers 132 138 , such as in the longitudinal direction (y direction) and the transverse direction (x direction—into the page in FIG. 25D ), to cover one or more of the vertical surfaces 500 a,b , 501 a,b . Furthermore, in the embodiment depicted in FIG. 25D , the insulator member 514 is disposed between and/or bounded by the electrode current collector 136 at one longitudinal end of the unit cell 504 , and the counter-electrode current collector 140 at the other longitudinal end.

The embodiment depicted in FIG. 25D does not clearly depict an offset S V1 between the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, and/or an offset S V2 between the second vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, but aspects of the embodiment depicted in FIG. 25D could also be modified by including one or more of the vertical offsets S z1 and/or S z2 , as described herein. For example, the embodiment as shown in FIG. 25E comprises the same and/or similar structures as FIG. 25D , in that the insulating member 514 covers not only one or more vertical end surfaces 501 a,b of the counter-electrode active material layer 138 but also covers one of more vertical end surfaces 500 a.b of the electrode active material layer 132 . However, FIG. 25E depicts a clear vertical offset and/or separation distance S z1 between the vertical end surfaces 500 a,b of the electrode active material layer 132 and the vertical end surfaces 501 a,b of the counter-electrode active material layer 138 . Accordingly, in the embodiment as shown, the insulating member 514 comprises a first thickness T 1 , as measured between inner and outer vertical surfaces of the insulating member 514 , over first and second vertical end surfaces 500 a,b of the electrode active material layer 132 , and second thicknesses T 2 , as measured between inner and outer vertical surfaces of the insulating member 514 , over the first and second vertical end surfaces 501 a,b of the counter-electrode active material layer 138 , the first thicknesses T 1 being less than the second thicknesses T 2 . Also, while only a single insulating member 514 is shown, it may also be the case that a plurality of insulating members 514 are provided, such as a first member having a first thickness T 1 over the electrode active material layer, and a second insulating member 514 having the second thickness T 2 over the counter-electrode active material layer 138 . The embodiment depicted in FIG. 25F is similar to that in FIG. 25E , in that the one or more insulating members 514 have thicknesses T 1 and T 2 with respect to placement over vertical end surfaces of the electrode active material layer and counter-electrode active material layer, respectively. However, in this embodiment, the insulating member 514 extends over one or more vertical surfaces 516 of the counter-electrode current collector 140 , and may even extend to cover surfaces in an adjoining unit cell, as described above in reference to FIG. 25C .

The embodiment shown in FIG. 25G depicts a unit cell 504 where an insulating member 514 is provided between the first vertical end surface 500 a of the counter-electrode active material layer 138 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 500 b of the counter-electrode active material layer 138 and an inner surface of the second secondary growth constraint 160 (not shown), and also extends over one or more vertical surfaces 518 a,b of the separator 130 to also cover one or more vertical end surfaces 500 a , 500 b of the electrode active material layer 138 . That is, the insulating member 514 is also provided between the first vertical end surface 500 a of the electrode active material layer 132 and an inner surface of the first secondary growth constraint 158 , and/or between the second vertical end surface 500 b of the electrode active material layer 132 and an inner surface of the second secondary growth constraint 160 (not shown) (as well as in the space between the first and second secondary growth constraints 158 , 160 and the vertical surfaces 518 a,b of the separator 130 ). Although not shown in the 2D Z-Y plane shown in FIG. 25D , the insulating member 515 may extend substantially and even entirely over the vertical surface(s) of the electrode and counter-electrode active material layers 132 138 , such as in the longitudinal direction (y direction) and the transverse direction (x direction—into the page in FIG. 1 d ), to cover one or more of the vertical surfaces 500 a,b , 501 a,b . Furthermore, in the embodiment depicted in FIG. 25G , the insulator member 514 is bounded by the counter-electrode current collector 140 at one longitudinal end of the unit cell 504 , but extends in the other longitudinal direction over one or more vertical end surfaces 520 of the electrode current collector 136 . For example, analogously to FIG. 25C above, the insulating member 514 may extend longitudinally towards and abut a neighboring until cell structure, such as an adjacent electrode active material layer 132 of a neighboring unit cell structure. In one embodiment, the insulating member 514 may extend across one or more vertical surfaces 500 a,b of adjacent electrode active material layers 132 , by passing over an electrode current collector 136 separating the layers 132 between adjacent unit cells 504 a , 504 b , and over the vertical surfaces of the adjacent electrode active material layers 132 in the neighboring cells. That is, the insulating member 514 may extend across one or more vertical surfaces 500 a,b of the electrode active material layer 132 in a first unit cell 504 a , and over vertical surfaces 500 a,b of the electrode active material layer 132 in a second unit cell 504 b adjacent the first unit cell 504 a , by traversing the vertical end surface 520 a,b of the counter-electrode current collector 140 separating the unit cells 504 a,b from one another in the longitudinal direction.

The embodiment depicted in FIG. 25G does not clearly depict an offset S z1 between the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, and/or an offset S z2 between the second vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, but aspects of the embodiment depicted in FIG. 25G could also be modified by including one or more of the vertical offsets S z1 and/or S z2 , as described herein. For example, the embodiment as shown in FIG. 25H comprises the same and/or similar structures as FIG. 25G , in that the insulating member 514 covers not only one or more vertical end surfaces 501 a,b of the counter-electrode active material layer 138 but also covers one of more vertical end surfaces 500 a.b of the electrode active material layer 132 . However, FIG. 25H depicts a clear vertical offset and/or separation distance Sv 1 between the vertical end surfaces 500 a,b of the electrode active material layer 132 and the vertical end surfaces 501 a,b of the counter-electrode active material layer 138 . Accordingly, in the embodiment as shown, the insulating member 514 comprises a first thickness T 1 , as measured between inner and outer vertical surfaces of the insulating member 514 , over first and second vertical end surfaces 500 a,b of the electrode active material layer 132 , and second thicknesses T 2 , as measured between inner and outer vertical surfaces of the insulating member 514 , over the first and second vertical end surfaces 501 a,b of the counter-electrode active material layer 138 , the first thicknesses T 1 being less than the second thicknesses T 2 . Also, while only a single insulating member 514 is shown, it may also be the case that a plurality of insulating members 514 are provided, such as a first member having a first thickness T 1 over the electrode active material layer, and a second insulating member 514 having the second thickness T 2 over the counter-electrode active material layer 138 .

Referring to FIGS. 26A-26F , further embodiments of the unit cells 504 , with or without insulating members 514 and/or transverse offsets S X1 and S X2 , are described. In the embodiment shown in FIG. 26A , the electrode active material layer 132 and 138 are depicted without having a discernible transverse offset S X1 and/or S X2 , although the offset and/or separation distance described above can be provided along the x axis, for example as shown in the embodiment of FIG. 26B . As shown via 2D slice in the Y-X plane, the unit cell 504 as depicted in FIG. 26A comprises an electrode current collector 136 , an electrode active material layer 132 , a separator 130 , a counter-electrode active material layer 138 , and a counter-electrode current collector 140 . While the embodiment in FIG. 26A does not include an insulating member 514 , it can be seen that the electrode current collector 136 extends past second transverse ends 502 b , 503 b of the electrode and counter-electrode active material layers 132 , 138 , and may be connected to an electrode busbar 600 , for example as shown in FIGS. 27A-27F . Similarly, the counter-electrode current collector 140 extends past first transverse ends 502 a , 503 a of the electrode and counter-electrode active material layers 132 , 138 , and may be connected to a counter-electrode busbar 602 , for example as shown in FIGS. 27A-27F .

Referring to the embodiment shown in FIG. 26B , a unit cell configuration with insulating member 514 extending over at least one of the transverse surfaces 503 a,b of the counter-electrode active material layer 138 is shown. In the embodiment as shown, an insulating member 514 is disposed at either transverse end of the counter-electrode active material layer 138 , and is position between (and bounded by) the counter-electrode current collector 140 on one longitudinal end of the unit cell 504 , and by the separator 130 at the other longitudinal end of the unit cell. The insulating members have a transverse extent that matches the length L E of the electrode active material layer 132 , in the embodiment as shown, and are separated from the electrode active material layer 132 by a separator having the same length in the transverse direction as the electrode active material layer. The transverse extent of the insulating member 514 in the x direction may, in one embodiment, be the same as the transverse separation distance and/or offset S X1 , S X2 , as shown in FIG. 26B . Also, while not shown in the 2D Y-X plane depicted in FIG. 26B , the insulating member may also extend in the z-direction, such as along a height H E of the counter-electrode active material layer 138 , and between opposing vertical end surfaces 501 a,b.

The embodiment shown in FIG. 26C also depicts a unit cell configuration with insulating member 514 extending over at least one of the transverse surfaces 503 a,b of the counter-electrode active material layer 138 . In the embodiment as shown, an insulating member 514 is disposed at either transverse end of the counter-electrode active material layer 138 , and has the separator layer 130 on at least one longitudinal end of the unit cell 504 . On the other longitudinal end, at least one of the insulating members is further bounded by the counter-electrode current collector 140 . However, at least one of the insulating members 514 may also extend over one of the transverse surfaces 522 a,b of the counter-electrode current collector 140 at the other longitudinal end of the unit cell 504 . That is, the insulating member 514 may extend in the longitudinal direction past the transverse end surface of the counter-electrode active material layer 138 to cover the counter-electrode current collector 140 , and may even extend to cover a transverse surface of a counter-electrode active layer of a neighboring unit cell. In the embodiment as shown in FIG. 26B , the insulating members 514 have a transverse extent that matches the length L E of the electrode active material layer 132 , and are separated from the electrode active material layer 132 by a separator having the same length in the transverse direction as the electrode active material layer 132 . The transverse extent of the insulating member 514 in the x direction may, in one embodiment, be the same as the transverse separation distance and/or offset S X1 , S X2 , as shown in FIG. 26C . Also, while not shown in the 2D Y-X plane depicted in FIG. 26C , the insulating member may also extend in the z-direction, such as along a height H E of the counter-electrode active material layer 138 , and between opposing vertical end surfaces 501 a,b . FIG. 26E has a configuration similar to that of 26 C, with the exception that the counter-electrode current collector 140 has a length that extends past transverse surfaces of the insulating member 514 , and the length of the current collector 136 also extends past transverse end surfaces of the electrode active material layer.

The embodiment shown in FIG. 26D depicts a unit cell configuration with insulating member 514 extending over at least one of the transverse surfaces 502 a,b , 503 a,b of the both the electrode active material layer 132 and the counter-electrode active material layer 138 . In the embodiment as shown, an insulating member 514 is disposed at either transverse end of the electrode and counter-electrode active material layers 132 , 138 . The insulating member is disposed between (and bound by) the electrode current collector 136 on one longitudinal end, and the counter-electrode current collector 140 on the other longitudinal end. The insulating member 514 may extend over transverse end surfaces 524 a,b of the separator 130 to pass over the transverse surfaces of the electrode and counter-electrode layers 132 , 138 . In the embodiment as shown in FIG. 26D , the insulating members 514 have a transverse extent that matches the length of the electrode current collector 136 on one transverse end, and the length of the counter-electrode current collector 140 on the other transverse end. In the embodiment as shown, the electrode and counter-electrode active material layers 132 , 138 are not depicted as having a transverse offset and/or separation distance, although a separation distance and/or offset may also be provided. Also, while not shown in the 2D Y-X plane depicted in FIG. 26D , the insulating member may also extend in the z-direction, such as along a height H E of the counter-electrode active material layer 138 , and between opposing vertical end surfaces 501 a,b.

The embodiment shown in FIG. 26F also depicts a unit cell configuration with insulating member 514 extending over at least one of the transverse surfaces 503 a,b of the counter-electrode active material layer 138 . In the embodiment as shown, an insulating member 514 is disposed at either transverse end of the counter-electrode active material layer 138 . The insulating member 514 covers transverse surfaces of both the electrode and the counter-electrode active material layer, and is disposed between (bound by), on one longitudinal end, the electrode current collector 136 , and on the other end, at at least one transverse end, the counter-electrode current collector 140 . In the embodiment as shown, the insulating member further extends over transverse surfaces 524 a,b of the separator 130 , between the electrode and counter-electrode active material layers 132 , 138 , to extend over these surfaces. In the embodiment as shown, the insulating member 514 has a first transverse thickness T 1 extending from the vertical end surface of the electrode active material layer 132 , and has a second transverse thickness T 2 extending from the vertical end surface of the counter-electrode active material layer 138 , with the second transverse thickness being greater than the first transverse thickness. In one embodiment, the difference in the transverse extent of the second thickness T 2 minus the first thickness T 1 may be equivalent to the transverse offset and/or separation distance, S X1 and/or S X2 . Furthermore, in the embodiment as shown, at least one of the insulating members 514 may also extend over one of the transverse surfaces 522 a,b of the counter-electrode current collector 138 at one of the longitudinal ends of the unit cell 504 . That is, the insulating member 514 may extend in the longitudinal direction past the transverse end surface of the counter-electrode active material layer 138 to cover the counter-electrode current collector 140 , and may even extend to cover a transverse surface of a counter-electrode active layer of a neighboring unit cell. The insulating member 514 at the opposing transverse end of the counter-electrode active material layer may, on the other hand, be bounded by the counter-electrode current collector, such that a length of the counter-electrode current collector in the transverse direction exceeds the transverse thickness of the insulating member 514 . On the other longitudinal end, the insulating member 514 is bounded by the electrode current collector 136 , with the transverse thickness of the insulating member meeting the transverse length of the electrode current collector 136 at one transverse end, and the electrode current collector 136 exceeding the transverse thickness of the insulating member at the other transverse end. Also, while not shown in the 2D Y-X plane depicted in FIG. 26C , the insulating member may also extend in the z-direction, such as along a height H E of the counter-electrode active material layer 138 , and between opposing vertical end surfaces 501 a,b.

Furthermore, it is noted that for purposes of determining the first and second vertical and/or transverse end surfaces of the electrode active material layer and/or counter-electrode active material layers 132 and 138 , only those parts of the layers that contain electrode and/or counter-electrode active that can participate in the electrochemical reactions in each unit cell 504 are considered to be a part of the active material layers 132 , 138 . That is, if an electrode or counter-electrode active material is modified in a such a way that it can no longer act as electrode or counter-electrode active material, such as for example by covering the active with an ionically insulating material, then that portion of the material that has been effectively removed as a participant in the electrochemical unit cell is not counted as a part of the electrode active and/or counter-electrode active material layers 132 , 138 . For example, referring to the embodiment in FIG. 37A , for an electrode active material layer 132 having a carrier ion insulating layer 674 extending into the layer, the surface 500 a of the electrode active material layer 132 is considered to be at the interface 500 a between the carrier ion insulating layer 674 coated portion and the non-coated portion of the layer 132 , as opposed to at a surface 800 a where the coated electrode active material ends.

Electrode and Counter-Electrode Busbars

In one embodiment, the secondary battery 102 comprises one of more of an electrode busbar 600 and a counter-electrode busbar 602 (e.g., as shown in FIG. 30 ), to collect current from the electrode current collectors 136 and the counter-electrode current collectors, respectively. As similarly described with respect to embodiments having the offset and/or separation distance above, the electrode assembly 106 can comprise a population of electrode structures, a population of electrode current collectors, a population of separators, a population of counter-electrode structures, a population of counter-electrode collectors, and a population of unit cells wherein members of the electrode and counter-electrode structure populations are arranged in an alternating sequence in the longitudinal direction. Furthermore, each member of the population of electrode structures comprises an electrode current collector and a layer of an electrode active material having a length L E that corresponds to the Feret diameter of the electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the electrode active material layer, and a height H E that corresponds to the Feret diameter of the electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the electrode active material layer, and a width W E that corresponds to the Feret diameter of the electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the electrode active material layer. Also, each member of the population of counter-electrode structures comprises a counter-electrode current collector and a layer of a counter-electrode active material having a length L C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the counter-electrode active material layer, and a height H C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the counter-electrode active material layer, and a width W C that corresponds to the Feret diameter of the counter-electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the counter-electrode active material layer.

Furthermore, as has also been described elsewhere herein, in one embodiment, the electrode assembly has mutually perpendicular transverse, longitudinal and vertical axes corresponding to the x, y and z axes, respectively, of an imaginary three-dimensional cartesian coordinate system, a first longitudinal end surface and a second longitudinal end surface separated from each other in the longitudinal direction, and a lateral surface surrounding an electrode assembly longitudinal axis AA and connecting the first and second longitudinal end surfaces, the lateral surface having opposing first and second regions on opposite sides of the longitudinal axis and separated in a first direction that is orthogonal to the longitudinal axis, the electrode assembly having a maximum width W EA measured in the longitudinal direction, a maximum length L EA bounded by the lateral surface and measured in the transverse direction, and a maximum height H EA bounded by the lateral surface and measured in the vertical direction.

Referring to FIG. 30 , each member of the population of electrode structures 110 comprises an electrode current collector 136 to collect current from the electrode active material layer 132 , the electrode current collector extending at least partially along the length L E of the electrode active material layer 132 in the transverse direction, and comprises an electrode current collector end 604 that extends past the first transverse end surface 503 a of the counter-electrode active material layer 138 . Furthermore, each member of the population of counter-electrode structures 112 comprises a counter-electrode current collector 140 to collect current from the counter-electrode active material layer 138 , the counter-electrode current collector 140 extending at least partially along the length L C of the counter-electrode active material layer 132 in the transverse direction and comprising a counter-electrode current collector end 606 that extends past the second transverse end surface 502 b of the electrode active material layer in the transverse direction (e.g., as also shown in FIG. 26A ). In the embodiment depicted in FIG. 30 , the electrode and counter-electrode current collectors 136 , 140 are sandwiched in between adjacent layers of electrode active material (in the case of the electrode structures 110 ) or adjacent layers of counter-electrode active material (in the case of counter-electrode structures 112 ). However, the current collectors may also be a surface current collector that is present on at least a portion of a surface of the electrode and/or counter-electrode active material layers that is facing the separator 130 in between the electrode and counter-electrode structures 110 , 112 . Furthermore, in the embodiment as shown in FIG. 30 , the electrode busbar 600 and counter-electrode busbar 602 are disposed on opposing transverse sides of the electrode assembly 106 , with the electrode current collector ends 604 being electrically and/or physically connected to the electrode busbar 600 at one transverse end, and the counter-electrode current collector ends 606 being electrically and/or physically connected to the counter-electrode busbar 602 at the opposing transverse end.

Also, as similarly described above, each unit cell 504 of the electrode assembly comprises a unit cell portion of a first electrode current collector of the electrode current collector population, a first electrode active material layer of one member of the electrode population, a separator that is ionically permeable to the carrier ions, a first counter-electrode active material layer of one member of the counter-electrode population, and a unit cell portion of a first counter-electrode current collector of the counter-electrode current collector population, wherein (aa) the first electrode active material layer is proximate a first side of the separator and the first counter-electrode material layer is proximate an opposing second side of the separator, and (bb) the separator electrically isolates the first electrode active material layer from the first counter-electrode active material layer, and carrier ions are primarily exchanged between the first electrode active material layer and the first counter-electrode active material layer via the separator of each such unit cell during cycling of the battery between the charged and discharged state.

Referring to FIG. 27A , which shows an embodiment of a busbar that may be either an electrode busbar 600 or a counter-electrode busbar 602 (according to whether electrode current collectors or counter-electrode current collectors are attached thereto). That is FIGS. 27A-27F can be understood as depicting structures suitable for either an electrode busbar 600 or counter-electrode busbar 602 . FIGS. 27A ′- 27 F′ are depicted with respect to an electrode busbar 600 , however, it should be understood that the same structures depicted therein are also suitable for the counter-electrode busbar 602 , as described herein, even though not specifically shown. The secondary battery can comprise a single electrode busbar 600 and single counter-electrode busbar 602 to connect to all of the electrode current collectors and counter-electrode current collectors, respectively, of the electrode assembly 106 , and/or plural busbars and/or counter-electrode busbars can be provided. For example, in the case where FIG. 27A is understood as showing an embodiment of an electrode busbar 600 , it can be seen that the electrode busbar 600 comprises at least one conductive segment 608 configured to electrically connect to the population of electrode current collectors 136 , and extending in the longitudinal direction (y direction) between the first and second longitudinal end surfaces 116 , 118 of the electrode assembly 106 . The conductive segment 608 comprises a first side 610 having an interior surface 612 facing the first transverse end surfaces 503 a of the counter-electrode active material layers 136 , and an opposing second side 614 having an exterior surface 616 . Furthermore, the conductive segment 608 optionally comprises a plurality of apertures 618 spaced apart along the longitudinal direction. The conductive segment 608 of the electrode busbar 600 is arranged with respect to the electrode current collector ends 604 , such that the electrode current collector ends 604 extend at least partially past a thickness of the conductive segment 608 , to electrically connect thereto. The total thickness t of the conductive segment 608 may be measured between the interior 612 and exterior surfaces 616 , and the electrode current collector ends 608 may extend at least a distance into the thickness of the conductive segment, such as via apertures 618 , and may even extend entirely past the thickness of the conductive segment (i.e., extending past the thickness t as measured in the transverse direction). While an electrode busbar 600 having a single conductive segment 608 is depicted in FIG. 27A , certain embodiments may also comprise plural conductive segments.

Furthermore, in the case where FIG. 27A is understood as showing an embodiment of a counter-electrode busbar 602 , it can be seen that the counter-electrode busbar 602 comprises at least one conductive segment 608 configured to electrically connect to the population of counter-electrode current collectors 140 , and extends in the longitudinal direction (y direction) between the first and second longitudinal end surfaces 116 , 118 of the electrode assembly 106 . The conductive segment 608 comprises a first side 610 having an interior surface 612 facing the second transverse end surfaces 502 b of the electrode active material layers 136 , and an opposing second side 614 having an exterior surface 616 . Furthermore, the conductive segment 608 optionally comprises a plurality of apertures 618 spaced apart along the longitudinal direction. The conductive segment 608 of the electrode busbar 600 is arranged with respect to the counter-electrode current collector ends 606 , such that the counter-electrode current collector ends 606 extend at least partially past a thickness of the conductive segment 608 , to electrically connect thereto. The total thickness t of the conductive segment 608 may be measured between the interior 612 and exterior surfaces 616 , and the counter-electrode current collector ends 606 may extend at least a distance into the thickness of the conductive segment, such as via apertures 618 , and may even extend entirely past the thickness of the conductive segment (i.e., extending past the thickness t as measured in the transverse direction). While the counter-electrode busbar 602 having a single conductive segment 608 is depicted in FIG. 27A , certain embodiments may also comprise plural conductive segments. FIGS. 27B-27F can similarly understood as depicting either electrode and/or counter-electrode busbar embodiments, analogously with the description given for FIG. 27A above.

Furthermore, according to one embodiment, the secondary battery 102 having the busbar and counter-electrode busbar 600 , 602 further comprises a set of electrode constraints, such as any of the constraints described herein. For example, in one embodiment, the set of electrode constraints 108 comprises a primary constraint system 151 comprising first and second primary growth constraints 154 , 156 and at least one primary connecting member 162 , the first and second primary growth constraints 154 , 156 separated from each other in the longitudinal direction, and the at least one primary connecting member 162 connecting the first and second primary growth constraints 154 , 156 , wherein the primary constraint system 151 restrains growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%. In yet another embodiment, the set of electrode constraints 108 further comprises a secondary constraint system 152 comprising first and second secondary growth constraints 158 , 160 separated in a second direction and connected by at least one secondary connecting member 166 , wherein the secondary constraint system 155 at least partially restrains growth of the electrode assembly 106 in the second direction upon cycling of the secondary battery 106 , the second direction being orthogonal to the longitudinal direction. Further embodiments of the set of electrode constraints 108 are described below.

Further embodiments of the electrode busbar 600 and/or counter-electrode busbar 602 are described with reference to FIGS. 27A-27F . In one embodiment, as shown in FIG. 27A , the electrode busbar 600 comprises a conductive segment 608 having a plurality of apertures 618 spaced apart along the longitudinal direction, wherein each of the plurality of apertures 618 are configured to allow one or more electrode current collector ends 604 to extend at least partially therethrough to electrically connect the one or more electrode current collector ends 604 to the electrode busbar 600 . Similarly, the counter-electrode busbar 602 can comprise a conductive segment 608 comprises a plurality of apertures 618 spaced apart along the longitudinal direction, wherein each of the plurality of apertures 618 are configured to allow one or more counter-electrode current collector ends 606 to extend at least partially therethrough to electrically connect the one or more counter-electrode current collector ends 606 to the counter-electrode busbar 602 . Referring to the cut-away as shown in FIG. 27A ′, it can be seen that, on the electrode busbar side, the current collectors 136 of the electrode structures 110 extend past the first transverse surfaces 502 a of the electrode active material layers 132 , and extend through the apertures 618 formed in the conductive segment. The electrode current collector ends 604 are connected to the exterior surface 616 of the electrode busbar 600 . Analogously, although not specifically shown, on the other transverse end where the counter-electrode busbar 602 is located, the electrode current collectors 140 of the counter-electrode structures 112 extend past the second transverse surfaces 503 b of the counter-electrode active material layers 138 , and extend through the apertures 618 formed in the conductive segment. The counter-electrode current collector ends 606 are connected to the exterior surface 616 of the counter-electrode busbar 600 .

Furthermore, while in one embodiment both the electrode busbar and counter-electrode busbar 600 , 602 may both comprise the plurality of apertures 618 , in yet another embodiment only the electrode busbar 600 comprises the apertures 618 , and in a further embodiment only the counter-electrode busbar 602 comprises the apertures 618 . In yet another embodiment, the secondary battery may comprise both an electrode busbar and counter-electrode busbar, whereas in further embodiments the secondary battery may comprise only an electrode busbar or counter-electrode busbar, and current is collected from the remaining current collectors via a different mechanism. In the embodiment as shown in FIG. 27A and FIG. 27A ′, the apertures 618 are shown as being sized to allow an electrode current collector or counter-electrode current collector therethrough. While in one embodiment, the apertures may be sized and configured to allow only a single current collector through each aperture, in yet another embodiment the apertures may be sized to allow more than one electrode current collector 136 and/or counter-electrode current collector 140 therethrough. Furthermore, in the embodiment as shown in FIG. 27A and FIG. 27A ′, the electrode current collector ends and/or counter-electrode current collector ends extend entirely through one or more of the apertures 618 , and the ends 604 , 606 are bent towards an exterior surface 616 of the electrode busbar and/or counter-electrode busbar, to attach to a portion 622 of the exterior surface electrode busbar and/or counter-electrode busbar between apertures 618 . The ends 604 , 608 may also and/or optionally be connected to other parts of the conductive segment 608 , such as portions of the conductive segment above or below the apertures in the vertical direction, and/or to an inner surface 624 of the apertures 618 themselves.

In the embodiment as shown in FIG. 27B and FIG. 27B ′, the electrode current collector ends and/or counter-electrode current collector ends 604 , 606 extend entirely through one or more of the apertures 618 , and the ends are bent towards an exterior surface 616 of the electrode busbar and/or counter-electrode busbar. However, in this embodiment, at least one or more of the current collector ends extends at least partially in the longitudinal direction either to or past an adjacent aperture 618 (e.g., past the adjacent aperture as shown in FIG. 27B ′), to attach to a separate electrode current collector end and/or counter-electrode current collector end. That is, the ends of the electrode and/or counter-electrode current collectors may be attached to one another. In yet another embodiment, as is also shown in FIG. 27B ′, the electrode current collector ends and/or counter-electrode current collector ends attach at a first end region 624 to a portion 622 of an exterior surface 616 of the electrode busbar and/or counter-electrode busbar that is between apertures 618 , and attach at a second end region 626 to another separate electrode current collector end and/or counter-electrode current collector end.

In one embodiment, the electrode current collector ends 604 and/or counter-electrode current collector ends 606 are attached to one or more of the portion 622 of the exterior surface of the electrode busbar and/or counter-electrode busbar, and/or a separate electrode current collector end and/or counter-electrode current collector end, (such as an adjacent current collector extending through an adjacent aperture) via at least one of an adhesive, welding, crimping, brazing, via rivets, mechanical pressure/friction, clamping and soldering. The ends 604 , 604 may also be connected to other parts of the electrode busbar and/or counter-electrode busbar, such as an inner surface 624 of apertures 618 or other parts of the busbars, also via such attachment. Furthermore, the number of current collector ends that are attached to each other versus being attached only to the busbars can be selected according to a preferred embodiment. For example, in one embodiment, each of the electrode current collector ends and counter-electrode current collector ends, in a given population, is separately attached to a portion 622 of the exterior surface 616 of the electrode and/or counter-electrode busbar 600 , 602 . In yet another embodiment, at least some of the electrode current collector ends and/or counter-electrode current collector ends are attached to each other (e.g., by extending through apertures and then longitudinally towards or past adjacent apertures to connect to adjacent current collector ends extending through the adjacent apertures), while at least one of the electrode current collector ends and/or counter-electrode current collector ends are attached to a portion of the exterior surface of the electrode busbar and/or counter-electrode busbar (e.g., to provide an electrical connection between the busbars and the current collector ends that are attached to one another. In yet another embodiment, all of the current collectors in a population may be individually connected to busbar, without being attached to other current collector ends.

In yet a further embodiment, the electrode current collector ends and/or counter-electrode current collector ends have a surface region (such as the first region 624 ) that attaches to a surface (such as the exterior surface) of the busbar and/or counter-electrode busbar. For example, the electrode current collector ends and/or counter-electrode current collector ends have a surface region that attaches to at least one of an exterior surface of the electrode busbar and/or counter-electrode busbar, and an inner surface 624 of an aperture 618 of the busbar and/or counter-electrode busbar. In one embodiment, one or more of the ends of the electrode busbar and/or counter-electrode busbar may comprise a surface region that attaches to the interior surface 612 of the busbar and/or counter-electrode busbar. The size of the connecting surface region can be selected according to the type of attachment to be selected for attaching the ends to the electrode and/or counter-electrode busbar. In one embodiment, for example as shown in FIG. 27A ′ and FIG. 27B ′, the electrode busbar and/or counter-electrode busbar comprises a layer 628 of insulating material on an interior surface 612 proximate the transverse ends of the electrode and/or counter-electrodes, and layer of conductive material (e.g., the conductive segment 608 ) on an exterior surface 616 opposing the interior surface. The layer 628 of insulating material may include an insulating member 514 as described elsewhere herein, disposed between the transverse surfaces of the electrode and/or counter-electrode active material layers 132 , 138 and the busbar, and/or can comprise a separate layer 632 of insulating material along the interior surface of the busbar to insulate the electrode assembly from the conductive segment of the busbar (see, e.g., FIG. 27C ′ and FIG. 27D ′).

In one embodiment, the material and/or physical properties of the electrode and/or counter-electrode current collectors 136 , 140 , may be selected to provide for good electrical contact to the busbar, while also imparting good structural stability to the electrode assembly. For example, in one embodiment, the electrode current collector ends 604 and/or counter-electrode current collector ends 606 (and optionally, at least a portion and even the entirety of the electrode and/or counter-electrode current collector) comprise the same material as a material making up the electrode busbar and/or counter-electrode busbar. For example, in a case where the busbar and/or counter-electrode busbar comprises aluminum, the electrode and/or counter-electrode current collectors may also comprise aluminum. In one embodiment, the electrode current collector ends and/or counter-electrode current collector ends comprise any selected from the group consisting of aluminum, copper, stainless steel, nickel, nickel alloys, carbon, and combinations/alloys thereof. Furthermore, in one embodiment, the electrode current collector ends and/or counter-electrode current collector ends comprise a material having a conductivity that is relatively close to the conductivity of a material of the electrode bus and/or counter-electrode bus, and/or the electrode and/or counter-electrode current collectors may comprise a same material as that of the electrode and/or counter-electrode bus.

In yet another embodiment, as depicted in FIG. 27C , FIG. 27C ′, FIG. 27D and FIG. 27D ′, the electrode current collector ends and/or counter-electrode current collector ends 604 , 606 are attached to the electrode busbar and/or counter-electrode busbar 600 , 602 via an at least partially conductive material 630 formed about the current collector ends and/or counter-electrode current collector ends 604 , 606 , to electrically connect the ends to the electrode busbar and/or counter-electrode busbar 600 , 602 . For example, in the embodiment as shown in FIG. 27D ′, a coating 630 of a conductive material is formed about the electrode current collector ends and/or counter-electrode current collector ends to electrically connect the ends to the electrode busbar and/or counter-electrode busbar. The coating 632 of the conductive material may be coated onto the exterior surface 616 of the electrode busbar and/or counter-electrode busbar, and can at least partially infiltrate the apertures 618 formed therein, to electrically connect the ends to the electrode busbar and/or counter-electrode busbar. For example, as shown in FIG. 27C , the ends of the current collectors extend at least partially into and even slightly past the apertures 618 , and the coating infiltrates the apertures to connect the portion of the ends disposed in the aperture to the adjoining aperture inner surface, as well as to connect a portion of the ends extending above the apertures to busbar exterior surface. In one embodiment, the coating 632 of conductive material comprises a conductive metal selected from the group consisting of aluminum, copper, stainless steel, nickel, nickel alloys, and combinations/alloys thereof.

In yet a further embodiment, the electrode current collector ends and/or counter-electrode current collector ends are attached to the electrode busbar and/or counter-electrode busbar via an at least partially conductive material 630 inserted into apertures 618 in the electrode busbar and/or counter-electrode busbar to electrically connect the ends to the busbar and/or counter-electrode busbar. For example, referring to FIG. 27D and FIG. 27D ′, in one embodiment the electrode current collector ends and/or counter-electrode current collector ends are attached to the electrode busbar and/or counter-electrode busbar via an at least partially conductive material 630 formed about the current collector ends and/or counter-electrode current collector ends, the at least partially conductive material comprising a polymeric material that is a positive temperature coefficient material, and which exhibits an increase resistance with an increase in temperature. The positive temperature coefficient material may not only advantageously mechanically and/or electrically connect the current collector ends to the busbar, but may also provide a “shut-off” mechanism by which electrical connection to a particular current collector end may be cut off in a case where excessive temperatures arise, thereby inhibiting run-away processes that could otherwise result in failure of the electrode assembly. Furthermore, in the embodiment as shown in FIGS. 27D and 27D ′, the positive coefficient material may be provided in the form of individual inserts 634 that are each individually inserted into apertures 618 . That is, one or more ends of the electrode current collectors and/or counter-electrode current collectors may have individual inserts comprising polymeric positive temperature coefficient material to electrically connect the ends to the electrode bus-bar and/or counter-electrode busbar, where first individual insert 634 a about a first end is physically separate from a second individual insert 634 b about a second end, the first and second ends being electrically connected to the same electrode busbar and/or counter-electrode busbar. In one embodiment, each current collector end that connects to the busbar comprises an individual insert 634 comprising the polymeric positive temperature coefficient material, with each insert being physically separate from the others. In another embodiment, at least two current collector ends share the same insert 634 , the insert comprising the polymeric positive temperature coefficient material. For example, in one embodiment, the secondary battery 102 comprises a plurality of inserts 634 comprising polymeric positive temperature coefficient material at least partially inserted into apertures 618 in the electrode busbar and/or counter-electrode busbar 600 , 602 , the plugs at least partially surrounding a portion of the ends 604 , 606 of the electrode current collector and/or counter-electrode current collector that is disposed in the apertures 618 (and optionally also a portion of the ends that extends out of the apertures in the transverse direction).

In yet another embodiment, the ends of the electrode current collectors and/or counter-electrode current collectors extend through apertures 618 of the electrode busbar and/or counter-electrode busbar, and are bent back towards and exterior surface 616 of the electrode busbar and/or counter-electrode bus bar to attach thereto, and wherein a region 624 of the ends that is bent to attach to the exterior surface is substantially planar, for example as shown in FIGS. 27A and 27A ′. In yet another embodiment, the ends of the electrode current collectors and/or counter-electrode current collectors extend through apertures 618 of the electrode busbar and/or counter-electrode busbar, and are bent back towards and exterior surface 616 of the electrode busbar and/or counter-electrode bus bar to attach thereto, and wherein a region 624 of the ends that is bent to attach to the exterior surface is curved, as shown for example in FIGS. 27F and 27F ′.

In yet another embodiment, as shown in FIG. 27E and FIG. 27E ′ the conductive segment 608 of the busbar is configured such that the ends 604 , 606 of the electrode current collectors and/or counter-electrode current collectors extend over and/or under the conductive segment 608 of electrode busbar and/or counter-electrode busbar 600 , 602 in the vertical direction, to pass over and/or under the conductive segment, and are attached to the exterior surface 616 of the conductive segment 608 . That is, referring to FIGS. 27E and 27E ′, the height of the electrode current collector end 604 and/or counter-electrode current collector end 606 in the vertical direction may exceeds a height Has of the conductive segment 608 of the electrode busbar and/or counter-electrode busbar 600 , 602 , and/or the vertical position of the electrode and/or counter-electrode current collector 604 , 606 may be offset from the vertical position of the conductive segment 608 of the electrode busbar and/or counter-electrode busbar, such that ends 604 , 606 of the electrode current collector and/or counter-electrode current collector can pass over and/or under the conductive segment 608 of the electrode busbar and/or counter-electrode busbar. For example, the ends may pass over an upper and/or lower surfaces 636 a,b of the conductive segment 608 in the vertical direction. Furthermore, in one embodiment, the ends of the electrode current collector and/or counter-electrode current collector are configured to pass over and/or under the conductive segment of the electrode busbar and/or counter-electrode busbar, and are bent back towards the conductive segment in a vertical direction to attach to an exterior surface 616 of the electrode busbar and/or counter-electrode busbar. In the embodiment as shown in FIG. 27E , the portion of the current collector ends 604 , 606 extending over the conductive segment 608 are folded first in a longitudinal direction, and then in a vertical direction, such that the rectangular ends can be shaped into a fold that provides an attachment region for flush connection to the exterior surface 616 of the conductive segment.

In yet another embodiment as shown in FIGS. 27F and 27F ′, the conductive segment of the electrode busbar and/or counter-electrode busbar 600 , 602 comprises a plurality of apertures 618 therein, with the apertures having openings in both a thickness direction t of the conductive segment, as well as in the vertical direction. In the embodiment as shown, the ends of the electrode current collectors and/or counter-electrode current collectors 604 606 extend through apertures 618 of the electrode busbar and/or counter-electrode busbar, and are bent back towards an exterior surface 616 of the electrode busbar and/or counter-electrode bus bar to attach thereto. Furthermore, in the embodiment as shown, the vertical end surface 638 (either the upper or lower vertical end surface 638 a , 638 b ) of the current collector ends may be at a same z position, or even higher than (or lower than), an upper or lower surface 636 a,b of the conductive segment 608 , as the vertical end surface 638 of the collector end can pass through the vertical opening 640 in the aperture. In one embodiment, a second electrode assembly 106 stacked vertically above the assembly as shown may have busbars with apertures in a configuration that is the mirror image of that shown in FIGS. 27F and 27F ′, such that the vertical opening 640 of apertures in the lower electrode assembly align with, and form a complete aperture structure with, the vertical openings facing the opposing direction in the upper electrode assembly. The conductive segments of such adjacent busbars may be electrically and/or physically connected, or may be physically and/or electrically isolated from one another, but may form a common aperture 618 (extending from the lower electrode assembly to the upper electrode assembly) through which the current collector ends may extend.

In yet a further embodiment, the secondary battery further comprises a second electrode busbar and and/or counter-electrode busbar, with a second conductive segment the extends in the longitudinal direction between first and second longitudinal end surfaces of the electrode assembly, to electrically connect to ends of the electrode current collector and/or counter-electrode current collector. However, in one embodiment, at least 50% of the electrode current collectors and/or counter-electrode current collectors of the electrode assembly 106 are electrically connected to and in physical contact with the same electrode busbar and/or counter-electrode busbar, respectively. In yet another embodiment, at least 75% of the electrode current collectors and/or counter-electrode current collectors in the electrode assembly are electrically connected to and in physical contact with the same electrode busbar and/or counter-electrode busbar, respectively. In yet a further embodiment, at least 90% of the electrode current collectors and/or counter-electrode current collectors in the electrode assembly are electrically connected to and in physical contact with the same electrode busbar and/or counter-electrode busbar, respectively. For example, in one embodiment, a significant fraction of the electrode and/or counter-electrode current collectors in the electrode assembly may be individually connected (i.e. in direct physical contact with) the electrode and/or counter-electrode busbars, so that if one current collector were to fail, the remaining current collectors would maintain their individual connection with the electrode and/or counter-electrode busbar. That is, in one embodiment, no more than 25% of the electrode and/or counter-electrode current collectors in the electrode assembly are in indirect contact with the busbars, such as by being connected via attachment to an adjacent current collector, and instead at least 75%, such as at least 80%, 90%, 95%, and even at least 99% of the electrode and/or counter-electrode current collectors are in direct physical contact (e.g., individually attached to) the respective electrode and/or counter-electrode busbar. In one embodiment, the electrode and/or counter-electrode current collectors comprise internal current collectors, and are disposed between layers of electrode active material and/or counter-electrode active material in the electrode structures 110 and/or counter-electrode structures 112 , respectively (see, e.g., FIGS. 27A ′- 27 F′). In yet another embodiment, the electrode current collectors 136 and/or counter-electrode current collectors 140 extend along an outer surface 644 , 646 (e.g., surface facing the separator 130 ) of one or more of the layers of electrode material and/or counter-electrode material in the electrode structures and/or counter-electrode structures, respectively. The current collectors may also comprise a combination of “internal” current collectors disposed between active material layers in the electrode and/or counter-electrode structures 110 , 112 , and “surface” current collectors disposed along the outer surfaces 644 , 646 of the layers. Either or both of the “internal” and “surface” current collectors may be connected to the electrode and/or counter-electrode busbars via any of the configurations described herein.

In one embodiment, the electrode current collector and/or counter-electrode current collector 136 , 140 extend at least 50% along the length of the layer of electrode material L E and/or layer of counter-electrode material L C , respectively, in the transverse direction, where L E and L C are defined as described above. For example, in one embodiment, the electrode current collector and/or counter-electrode current collector extend at least 60% along the length of the layer of electrode material L E and/or layer of counter-electrode material L C , respectively, in the transverse direction. In another embodiment, the electrode current collector and/or counter-electrode current collector extend at least 70% along the length of the layer of electrode material L E and/or layer of counter-electrode material L C , respectively, in the transverse direction. In yet another embodiment, the electrode current collector and/or counter-electrode current collector extend at least 80% along the length of the layer of electrode material L E and/or layer of counter-electrode material L C , respectively, in the transverse direction. In a further embodiment, the electrode current collector and/or counter-electrode current collector extend at least 90% along the length of the layer of electrode material L E and/or layer of counter-electrode material L C , respectively, in the transverse direction.

Furthermore, in one embodiment, the electrode current collector and/or counter-electrode current collector extend at least 50% along the height H E of the layer of electrode material and/or layer of counter-electrode material H C , respectively, in the vertical direction, with H E and He being defined as describe above. For example, in one embodiment, electrode current collector and/or counter-electrode current collector extend at least 60% along the height H E of the layer of electrode material and/or layer of counter-electrode material H C , respectively, in the vertical direction. In another embodiment, the electrode current collector and/or counter-electrode current collector extend at least 70% along the height H E of the layer of electrode material and/or layer of counter-electrode material H C , respectively, in the vertical direction. In yet another embodiment, the electrode current collector and/or counter-electrode current collector extend at least 80% along the height H E of the layer of electrode material and/or layer of counter-electrode material H C , respectively, in the vertical direction. In a further embodiment, the electrode current collector and/or counter-electrode current collector extend at least 90% along the height H E of the layer of electrode material and/or layer of counter-electrode material H C , respectively, in the vertical direction.

According to yet another embodiment aspect, referring to FIGS. 31A and 31B , the electrode assembly 106 comprises at least one of vertical electrode current collector ends 640 and vertical counter-electrode current collector ends 642 that extend past one or more of first and second vertical surfaces 500 a,b 501 a,b of adjacent electrode active material layers 132 and/or counter-electrode active material layers 138 . In one embodiment, the vertical current collector ends 640 , 642 can also be at least partially coated with a carrier ion insulating material, as described in further detail below, to reduce the likelihood of shorting and/or plating out of carrier ions on the exposed vertical current collector ends.

According to one embodiment, for at least one of members of the electrode population and members of the counter-electrode population, either (I) each member of the population of electrode structures 110 comprises an electrode current collector 136 to collect current from the electrode active material layer 132 , the electrode current collector 136 extending at least partially along the height H E of the electrode active material layer 132 in the vertical direction, and comprising at least one of (a) a first vertical electrode current collector end 640 a that extends past the first vertical end surface 500 a of the electrode active material layer 132 , and (b) a second vertical electrode current collector end 640 b that extends past the second vertical end surface 500 b of the electrode active material layer 132 , and/or (II) each member of the population of counter-electrode structures 112 comprises a counter-electrode current collector 140 to collect current from the counter-electrode active material layer 138 , the counter-electrode current collector 140 extending at least partially along the height H C of the counter-electrode active material layer 138 in the vertical direction, and comprising at least one of (a) a first vertical counter-electrode current collector end 642 a that extends past the first vertical end surface 501 a of the counter-electrode active material layer 138 in the vertical direction, and (b) a second vertical electrode current collector end 642 b that extends past the second vertical end surface 501 b of the electrode active material layer 138 . Referring to the embodiment as shown in FIG. 31A , it can be seen that vertical ends 640 a,b , 642 a, b of both the electrode current collectors 136 and counter-electrode current collectors 140 extend past first and second vertical end surface of the electrode active and counter-electrode active material layers 132 , 138 .

Referring to the embodiments in FIGS. 29A-29D , according to one aspect, the vertical ends 640 a,b , 642 a,b of the current collectors 136 , 140 may be at least partially covered with a carrier ion insulating material 645 , to inhibit shorting and/or plating out on the ends. In one embodiment, the carrier ion insulating material 645 may have a permeability to the carrier ions that is less than that of the ionically permeably separator 130 provided in the same unit cell 504 as the current collector. For example, the carrier ion insulating material 645 may form a layer having a conductance for carrier ions does not exceed 10% of that of the ionically permeable separator, such as no more than 5%, 1%, 0.1%, 0.01%, 0.001% and even 0.0001% of that of the ionically permeable separator. In one embodiment, one or more vertical ends 640 a , 640 b of members of the population of electrode current collectors 136 comprise the carrier ion insulating material 645 , such as either or both of the first and second vertical ends 640 a , 640 . In another embodiment, one or more vertical ends 642 a , 642 b of members of the population of counter-electrode current collectors 140 comprise the carrier ion insulating material 645 , such as either or both of the first and second vertical ends 640 a , 640 . The carrier ion insulating material 645 may also act as an adhesive material, as is discussed in further detail below, and may also in certain embodiments correspond to any of the carrier ion insulating materials and/or adhesives as otherwise described herein.

In the embodiments as shown in FIGS. 29A-29D , the carrier ion insulating material 645 covers at least a portion of the surfaces 646 , 648 at the vertical ends 640 a,b , 642 a,b of one or more of the electrode and counter-electrode current collectors 136 , 140 . For example, referring to the embodiment shown in FIG. 29A , the carrier ion insulating material 645 can cover surfaces 646 , 648 at the vertical ends that can include the first and/or second vertical end surfaces 516 , 520 of the electrode and counter-electrode current collector, as well as longitudinal surfaces 670 , b , 672 a, b of the electrode and/or counter-electrode current collector that are in a region adjacent the vertical ends surfaces. That is, the carrier ion insulating 645 can be provided in the form of a coating 674 that coats surfaces at the vertical ends of the electrode and/or counter-electrode current collectors, and in particular may coat surfaces 646 , 648 at the vertical ends that are exposed by virtue of having a position in z that extends past (i.e., above or below), the adjacent electrode and/or counter-electrode active material layers (e.g., as shown in the embodiment depicted in FIG. 31A ). That is, the carrier ion insulating material can comprise a coating and/or layer 674 that at least partially covers surfaces adjacent the vertical ends of the electrode and/or counter-electrode current collectors that extend vertically past the first and/or second vertical end surfaces of adjacent electrode and/or counter-electrode active material layers. Furthermore, the carrier ion insulating material and/or coating can also extend along the transverse direction of the surfaces, along a predetermined distance or at predetermined areas along the electrode and/or counter-electrode length L E , L C . In one embodiment, the coating 674 may cover at least 10% of the surfaces of the members of the electrode current collector population and/or counter-electrode current collector population that extend past the first and/or second vertical end surfaces of adjacent electrode and/or counter-electrode active material layers, such as at least 20%, at least 45%, at least 50%, at least 75%, at least 90%, at least 95% and even at least 98% of such surfaces. Suitable carrier ion insulating materials can comprise, for example, at least one of epoxy, polymer, ceramic, composites, and mixtures of these.

In yet another embodiment, referring again to FIGS. 29A-29D and 31A-31B , one or more of members of the electrode current collector and/or counter-electrode current collector populations comprise attachment sections 676 a,b , 678 a,b , disposed respectively at the vertical ends 640 a,b , 642 a,b thereof, to attach to at least a portion of the set of electrode constraints 108 that restrain growth of the electrode assembly 106 during charge and/or discharge of the secondary battery 102 having the electrode assembly 106 . For example, in one embodiment, the attachment sections 676 a,b 678 a,b may be configured to attach to a portion of a secondary constraint system 155 , such as one or more of a first and second secondary growth constraint 158 , 160 . The attachment sections 676 a,b , 678 a,b may further extend and/or repeat in a transverse direction along the ends of the electrode and/or counter-electrode current collectors. For example, referring to FIG. 31C , which is a top-down view of the electrode assembly 106 , an embodiment is shown where the attachment sections 676 a,b of the electrode current collector ends may extend continuously in the transverse direction along each end of the population of electrode current collectors, to connect with the first and/or second secondary growth constraint 158 , 160 . However, the attachment sections 678 a,b of the ends of the electrode and/or counter-electrode current collectors 136 , 140 have discrete start and stopping points along the transverse direction of the ends of the electrode and counter-electrode current collectors 136 , 140 , due to the presence of holes and/or openings 680 in the constraint 158 , 160 formed over/under the electrode and/or counter-electrode current collector ends, that may be provided, for example, to allow electrolyte to flow into the electrode assembly 106 . That is, the ends of the electrode and/or counter-electrode current collectors 140 may comprise a plurality of attachment sections along a transverse section thereof. Furthermore, the holes and/or openings 680 may be over the counter-electrode current collectors, as shown in the top section of FIG. 31C , or over the electrode current collectors, as shown in the bottom section of FIG. 31C . Conversely, in the embodiment shown in in FIG. 31D , the attachment sections 678 a,b of the counter-electrode current collector ends may extend continuously in the transverse direction, to connect with the first and/or second secondary growth constraint 158 , 160 . As shown in this embodiment, the attachment sections 676 a,b of the ends of the electrode current collectors 136 have discrete start and stopping points along the transverse direction of the ends of the electrode current collectors 136 , due to the presence of holes and/or openings 680 in the constraint 158 , 160 that are formed over/under the electrode current collectors and/or separators, and that may be provided, for example, to allow electrolyte to flow into the electrode assembly 106 . In one embodiment, the holes and/or opening are formed over the separator 130 , as depicted in the top section of FIG. 31D , and/or continuous holes and/or slots may also be formed over the population of electrodes and/or counter-electrodes, as shown in the bottom section of FIG. 31D . That is, the ends of the electrode current collectors 136 and/or counter-electrode current collectors 140 may comprise a plurality of attachment sections along a transverse section thereof.

In one embodiment, as shown in FIGS. 31C and 31D , one or more of the constraints 158 , 160 can comprise a plurality of openings 680 comprise a plurality of holes spaced apart from one another and extending across the x-direction of the constraint surface to form a column of holes 682 at a plurality of positions in the longitudinal direction. In the embodiments depicted in FIG. 31C , the each column of holes 682 is depicted as being positioned such that the holes are centered about a counter-electrode current collector, the column of holes extending across a length direction thereof, whereas in the embodiment depicted in FIG. 31D , each column of holes 682 is depicted as being positioned such that the holes are centered about an electrode current collector, the column of holes 682 extending across a length direction thereof. In yet another embodiment as depicted in FIG. 31D , the plurality of openings 680 can comprise a plurality of longitudinally oriented slots 684 extending across the constraint 158 , 160 in the longitudinal direction, such as across one or even a plurality of members of the electrode and/or counter-electrode members 110 , 112 . The openings 680 may be provided to allow for a flow of electrolyte into the electrode assembly 106 and/or between adjacent electrode assemblies. They openings 680 may also be provided to facilitate replenishment of carrier ions by one or more reference electrodes 686 located outside the constraints 158 , 160 . That is, one or more auxiliary electrodes 686 can be provided as a replenishment source of carrier ions to replenish the electrode and/or counter-electrode active material layers 132 , 138 , either before, during or after a charge and/or discharge cycle, and/or to supplement carrier ions during battery formation. The one or more auxiliary electrodes 686 can be electrically connected to the population of electrode structures 110 , the population of counter-electrode structures 112 , or both. For example, if at least two auxiliary electrodes 686 are provided, they can be independently connected to members of the population of electrode structures, members of the population of counter-electrode structures, each individually to the members of the electrode and/or counter-electrode structures. The auxiliary electrode(s) 686 can be connected by a passive resistor or active circuit, as examples, and can be controlled by applying a current or potential between the auxiliary electrode(s) and electrode and/or counter-electrode structures 110 , 112 . In the embodiment as depicted in FIGS. 31A-31B , the auxiliary electrodes are located externally to the constraints 158 , 160 , but adjacent to the openings 680 in the constraint (e.g., extending along the longitudinal direction across a length of the electrode assembly), such that carrier ions from and to the auxiliary electrodes 686 can pass through the openings 680 to reach the electrode and/or counter-electrode structures.

In one embodiment, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and even all of the electrode current collectors 136 in the electrode assembly 106 comprise attachment sections 676 a,b that are attached to one or more of the constraints 158 , 160 . In another embodiment at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and even all of the counter-electrode current collectors 136 in the electrode assembly 106 comprise attachment sections 678 a,b that are attached to one or more of the constraints 158 , 160 . Furthermore, in one embodiment, the attachment sections 676 a,b of the members of the electrode current collector population comprise at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and even the entire length L E of the members of the population. In another embodiment, the attachment sections 678 a,b of the members of the counter-electrode current collector population comprise at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, and even the entire length L C of the members of the population.

Furthermore, in one embodiment, as depicted for example in FIGS. 29A-29D , the attachment sections 676 a,b , 678 a,b of the electrode and/or counter-electrode current collector vertical ends can be configured to facilitate attachment thereof to a portion of a constraint system. For example, the attachment sections can comprise any one or combination of structural and/or surface features, such as any one or combination of textured surface, openings extending through the vertical ends in the longitudinal direction, grooves, protrusions, and indentations. The surface and/or structural modifications may be provided, for example, to improve adhesion of the attachment surfaces at the current collector vertical ends to one or more of the first and second secondary constraints 158 , 160 , and/or to influence the flow of adhesive and/or carrier ion insulating material to flow in a vertical or transverse direction along the electrode and/or counter-electrode current collector. In one embodiment, the surface and/or structural modifications may be provided to improve adhesion by an adhesive layer that is provided to the attachment surface to secure the electrode and/or counter-electrode current collector vertical end to the growth constraint. For example, in one embodiment, one or more of the attachment sections 676 a,b , 678 a,b is adhered to a portion of the constraint system by an adhesive layer 516 and/or carrier ion insulating layer that extends from a surface of one or more of the first and second secondary growth constraints 158 , 160 , and along at least a portion of the surfaces 646 , 648 of the attachment sections in the vertical direction, as shown in FIGS. 29A-29D . In one embodiment, the adhesive layer 516 comprises and/or corresponds to the carrier ion insulating material 645 described above. For example, in one embodiment, the adhesive layer 516 extends along the vertical direction to at least partially and even substantially entirely cover an exposed surface of the electrode current collector and/or counter-electrode current collector that extends vertically past the vertical end surfaces of electrode active material layers and/or counter-electrode active material layers, as described for the carrier ion insulating material 645 above. In yet another embodiment, the adhesive layer and/or carrier ion insulating material may even extends in a vertical direction along the surface of the electrode current collector and/or counter-electrode current collector, and to the vertical end surfaces of the electrode active material layers and/or counter-electrode active material layers. In yet another embodiment, the adhesive layer and/or carrier ion insulating material may extend in the vertical direction to the vertical end surfaces of the electrode active material layers and/or counter-electrode active material layers, and may even cover at least a portion or even all of the vertical end surfaces of the electrode active material layers and/or counter-electrode active material layers.

In one embodiment, the attachment sections 676 a,b 678 a,b of the electrode current collector and/or counter-electrode current collector are textured to facilitate adhesion of the vertical ends to the portion of the constraint system. For example, the surface of the current collector at the attachment sections can be textured via one or more of texturing, machining, etching of the surface, knurling, crimping embossing, slitting and punching. For example, referring to the embodiment depicted in FIG. 29C , the surface of the attachment section can be surface roughened and/or textured to provide a textured surface portion having a surface roughness. In yet another embodiment, referring to FIG. 29A , the attachment sections 676 a,b , 678 a,b of the electrode and/or counter-electrode current collectors 136 , 160 can comprise one or more openings 688 therein extending between opposing longitudinal surfaces 670 a,b , 672 a,b of the current collector in the longitudinal direction, the openings begin configured to allow the adhesive layer to at least partially infiltrate therein. For example, as shown in the embodiment of FIG. 29A , the attachment section may comprise a plurality of openings 688 that are spaced apart in the transverse direction (e.g., along the width of the current collector), to facilitate infiltration of the adhesive layer and/or carrier ion insulating material thereinto for attachment to the growth constraint 158 , 160 . According to yet another embodiment, as depicted in FIG. 29B , the attachment sections comprise one or more grooves 690 therein to facilitate attachment of the adhesive to the vertical ends of the current collector. For example, the grooves can comprise one or more of vertically oriented grooves that are spaced apart along the transverse direction of the current collector, and/or can comprise transverse oriented grooves that extend a predetermined transverse length of the current collector. In one embodiment, referring to FIG. 29B , the attachment section comprises a set of first vertically oriented groves 690 a that are spaced apart from one another along the transverse direction of the vertical ends, and at least one transverse oriented groove 690 b , and wherein the vertically oriented grooves are arranged with respect to the at least one transverse oriented groove such that ends 691 of the vertically oriented grooves that are distal from the portion of the constraint system 108 to which the current collector is attached, are in communication with and open to the at least one transverse oriented groove 690 b . In yet another embodiment, referring to FIG. 29D , a plurality of openings 688 are formed in at least a portion of one or more of the vertically and/or transverse oriented grooves. For example, the attachment section may comprise a set of first vertically oriented grooves 690 a , and at least one transverse oriented groove 690 b as in FIG. 29B , with the addition of a plurality of openings 688 , with each formed in one of the vertically oriented grooves.

Furthermore, referring to the embodiments as depicted in FIGS. 32A and 32B , according to one aspect, the electrode assembly 106 comprises a vertical dimension that is non-planar. For example, as depicted in FIGS. 32A and 32B , one or more of the first and second secondary growth constraints 158 , 160 may be non-planar, such as by being curved in one or more of the longitudinal and/or transverse directions, or having a vertical height towards a center of the electrode assembly that is larger than that at the longitudinal ends. For example, the first and/or second secondary growth constraints 158 , 160 may have vertical separation from one another at longitudinal ends of the electrode assembly (V 1 ) that is shorter than a vertical separation towards an interior of the electrode assembly in the longitudinal direction (V 2 ), or that is longer than a vertical separation towards an interior. The vertical dimension of the electrode assembly 106 may also be symmetric in the longitudinal and/or transverse directions (e.g., as shown in FIG. 32A ) or may be asymmetric (e.g., as shown in FIG. 32B ). In the embodiment shown in FIG. 32A , the vertical separation V 1 between the constraints 158 , 160 at a first longitudinal end is shorter than a vertical separation at the second opposing longitudinal end. Also, the heights H EA and H C of the electrode and counter-electrode active material layers 132 , 138 , may be adjusted and/or staggered to accommodate a non-planar vertical shape, for example with the height H E of a first electrode active material layer 132 a in a first unit cell 504 a being shorter and/or longer than that of a second electrode active material layer 132 b in an adjacent second unit cell 504 b.

Insulation of Electrode Current Collector by Carrier Ion Insulating Layer

According to one embodiment, a carrier ion insulating layer 674 is provided to insulate at least a portion of the electrode current collector 136 , to inhibit shorting and/or plating onto the electrode current collector 136 . Furthermore, by providing the carrier ion insulating layer 674 , embodiments of the disclosure may allow for a vertical offset S Z1 and/or S Z2 and/or transverse offset S X1 and/or S X2 between the electrode active material layer 132 and counter-electrode material layer 138 in the same unit cell 504 to be set to provide enhanced effects. In particular, in a case where vertical end surfaces 501 a , 501 b of the counter electrode active material layer 138 are further inward than the vertical end surfaces 500 a, b of the electrode active material layer 138 , the vertical offsets S Z1 , S Z2 may be selected to be relatively small, such that the vertical end surfaces 500 a,b , 501 a,b are relatively close to one another. In yet another embodiment, providing the carrier ion insulating layer 674 over at least a portion of the exposed surface of the electrode current collector 136 may allow for the vertical end surfaces 500 a,b of the electrode active material layers 132 to even be flush with the vertical end surfaces 501 a,b of the counter-electrode active material layer 138 in the same unit cell, or even to be offset such that the vertical end surfaces 500 a,b of the electrode active material layers 132 are more inwardly positioned than the vertical end surfaces 501 a,b of the electrode active material layer 132 . The same characteristics and/or properties may also be provided for the first and second transverse surfaces 502 a,b , 503 a,b of the electrode and counter-electrode active material layers 132 , 138 . For example, referring to the embodiment shown in FIG. 33A , the first vertical end surface 500 a may be slightly higher in the z direction, or even flush with or lower in the z direction (as shown), than the first vertical end surface 501 a of the counter-electrode active material layer 138 .

In particular, as has been described above, the electrode assembly 106 having the carrier ion insulating layer 674 may be a part of a secondary battery for cycling between a charged and a discharged state, the secondary battery comprising a battery enclosure, an electrode assembly, and carrier ions within the battery enclosure, and a set of electrode constraints. The electrode assembly has mutually perpendicular transverse, longitudinal and vertical axes corresponding to the x, y and z axes, respectively, of an imaginary three-dimensional cartesian coordinate system, a first longitudinal end surface and a second longitudinal end surface separated from each other in the longitudinal direction, and a lateral surface surrounding an electrode assembly longitudinal axis A EA and connecting the first and second longitudinal end surfaces, the lateral surface having opposing first and second regions on opposite sides of the longitudinal axis and separated in a first direction that is orthogonal to the longitudinal axis, the electrode assembly having a maximum width W EA measured in the longitudinal direction, a maximum length L EA bounded by the lateral surface and measured in the transverse direction, and a maximum height H EA bounded by the lateral surface and measured in the vertical direction. The electrode assembly further comprises a population of electrode structures, a population of electrode current collectors, a population of separators, a population of counter-electrode structures, a population of counter-electrode collectors, and a population of unit cells, wherein members of the electrode and counter-electrode structure populations are arranged in an alternating sequence in the longitudinal direction. Furthermore, according to one aspect, each electrode current collector 136 of the population is electrically isolated from each counter-electrode active material layer 138 of the population, and each counter-electrode current collector 140 of the population is electrically isolated from each electrode active material layer 132 of the population.

Furthermore, each member of the population of electrode structures 110 comprises an electrode current collector 136 and a layer of an electrode active material 132 having a length L E that corresponds to the Feret diameter of the electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the electrode active material layer 132 , as has been described elsewhere herein. The layer of electrode active material also has a width W E that corresponds to the Feret diameter of the electrode active material layer 132 as measured in the longitudinal direction between first and second opposing surfaces 706 a , 706 b of the electrode active material layer 132 . Each member of the population of counter-electrode structures comprises a counter-electrode current collector and a layer of a counter-electrode active material has a length L C that corresponds to the Feret diameter of the counter-electrode active material layer 132 as measured in the transverse direction between first and second opposing transverse end surfaces of the counter-electrode active material layer, as has been defined elsewhere herein, and also comprises a width W C that corresponds to the Feret diameter of the counter-electrode active material layer 138 as measured in the longitudinal direction between first and second opposing longitudinal end surfaces 708 a,b of the counter-electrode active material layer 138 .

Furthermore, as also described in embodiments above, each unit cell comprises a unit cell portion of a first electrode current collector of the electrode current collector population, a separator that is ionically permeable to the carrier ions, a first electrode active material layer of one member of the electrode population, a unit cell portion of first counter-electrode current collector of the counter-electrode current collector population and a first counter-electrode active material layer of one member of the counter-electrode population, wherein (aa) the first electrode active material layer is proximate a first side of the separator and the first counter-electrode material layer is proximate an opposing second side of the separator, (bb) the separator electrically isolates the first electrode active material layer from the first counter-electrode active material layer and carrier ions are primarily exchanged between the first electrode active material layer and the first counter-electrode active material layer via the separator of each such unit cell during cycling of the battery between the charged and discharged state, and (cc) within each unit cell.

Furthermore, as shown in FIGS. 33A-33D , each member of the population of electrode structures 110 can comprise a carrier ion insulating material, such as a carrier ion insulating layer 674 , that is disposed about the electrode current collector so as to at least partially insulate the electrode current collector from carrier ions. The carrier ion insulating layer 674 may be disposed to insulate, for example, surfaces of the electrode current collector that extend in a vertical direction past the first and second end surfaces 500 a , 500 b of one or more electrode active material layers 132 a , 132 b that are adjacent the electrode current collector 136 . For example, referring to FIG. 33A , the carrier ion insulating layer 674 may be provided to insulate first and second vertical end surfaces 640 a,b of the electrode current collector 136 , as well as opposing longitudinal surfaces 670 a,b of the electrode current collector that extend vertically past the first and second vertical end surfaces 500 a,b of the adjacent electrode active material layers 132 a,b in each adjacent unit cell 504 a,b.

As discussed above, by providing the carrier ion insulating material layer 674 to protect the exposed surfaces of the electrode current collector 136 , vertical offsets S Z1 and S Z2 and/or transverse offsets S X1 , S X2 between the first and second vertical end surfaces of the electrode and counter-electrode active material layers 132 , 138 in each cell, can be selected such that an offset is relatively small, and/or may be set such that vertical and/or transverse end surfaces of the electrode active material layers 132 may even be positioned inwardly towards an interior of the electrode assembly 106 , as compared to the vertical and/or transverse end surfaces of the counter-electrode active material layers 138 . This may be advantageous in certain embodiments, as it may allow for unit cells where relatively less electrode active material can be provided compared to counter-electrode active material, substantially without deleteriously affecting the electrode current collector of the electrode active material layer. That is, it has been discovered that because the electrode current collector is being protected, the vertical and/or transverse extent of the electrode active material layer may be advantageously reduced.

The vertical offsets S Z1 and S Z2 , between the vertical end surfaces of the electrode and counter-electrode active material layers, can be determined as has been discussed elsewhere herein. Specifically, as discussed above (see, e.g., FIGS. 22A-22B ), for first vertical end surfaces 500 a , 501 a of the electrode and the counter-electrode active material layers 132 , 138 on the same side of the electrode assembly 106 , a 2D map of the median vertical position of the first opposing vertical end surface 500 a of the electrode active material 132 in the Z-X plane, along the length L E of the electrode active material layer 132 , traces a first vertical end surface plot, E VP1 . Similarly, a 2D map of the median vertical position of the first opposing vertical end surface 501 a of the counter-electrode active material layer 138 in the Z-X plane, along the length L C of the counter-electrode active material layer 138 , traces a first vertical end surface plot, CE VP1 . An absolute value of the separation distance, |S z1 | is the distance as measured in the vertical direction between the plots E VP1 and CE VP1 (see, e.g., FIGS. 34A-34C ). Similarly, for second vertical end surfaces 500 b , 501 b of the electrode and the counter-electrode active material layers 132 , 138 on the same side of the electrode assembly 106 , and opposing the first vertical end surfaces 500 a , 501 a of the electrode and counter-electrode active material layers, respectively, a 2D map of the median vertical position of the second opposing vertical end surface 500 b of the electrode active material 132 in the Z-X plane, along the length L E of the electrode active material layer 132 , traces a second vertical end surface plot, E VP2 . Similarly, a 2D map of the median vertical position of the second opposing vertical end surface 501 b of the counter-electrode active material layer 138 in the Z-X plane, along the length L C of the counter-electrode active material layer 138 , traces a second vertical end surface plot, CE VP2 . An absolute value of the separation distance, |S z2 | is the distance as measured in the vertical direction between the plots E VP2 and CE VP2 (see, e.g., FIGS. 34A-34C ).

Furthermore, for first transverse end surfaces 502 a , 503 a of the electrode and the counter-electrode active material layers 132 , 138 on the same side of the electrode assembly 106 , a 2D map of the median transverse position of the first opposing transverse end surface 502 a of the electrode active material 132 in the Y-Z plane, along the length L E of the electrode active material layer 132 , traces a first vertical end surface plot, E TP1 . Similarly, a 2D map of the median transverse position of the first opposing transverse end surface 503 a of the counter-electrode active material layer 138 in the Y-Z plane, along the length L C of the counter-electrode active material layer 138 , traces a first transverse end surface plot, CE TP1 . An absolute value of the separation distance, |S x1 | is the distance as measured in the transverse direction between the plots E TP1 and CE TP1 (see, e.g., FIGS. 35A-35C ). Similarly, for second transverse end surfaces 502 b , 503 b of the electrode and the counter-electrode active material layers 132 , 138 on the same side of the electrode assembly 106 , and opposing the first transverse end surfaces 502 a , 503 a of the electrode and counter-electrode active material layers, respectively, a 2D map of the median transverse position of the second opposing vertical end surface 500 b of the electrode active material 132 in the Y-Z plane, along the length L E of the electrode active material layer 132 , traces a second transverse end surface plot, E TP2 . Similarly, a 2D map of the median transverse position of the second opposing transverse end surface 501 b of the counter-electrode active material layer 138 in the Y-Z plane, along the length L C of the counter-electrode active material layer 138 , traces a second transverse end surface plot, CE TP2 . An absolute value of the separation distance, |S x2 | is the distance as measured in the vertical direction between the plots E TP2 and CE TP2 (see, e.g., FIGS. 35A-35C ).

Furthermore, in one embodiment, the carrier ion insulating material layer 674 provided in each unit cell 504 in the population of unit cells has an ionic conductance of carrier ions that does not exceed 10% of the ionic conductance of the separator in that cell for carrier ions, during cycling of the battery. For example, the ionic conductance may not exceed 5%, 1%, 0.1%, 0.01%, 0.001%, and even 0.0001% of the conductance of the separator for carrier ions. The carrier ions may be any of those described herein, such as for example Li, Na, Mg ions, among others. Furthermore, the carrier ion insulating material layer 674 may ionically insulate a surface of the electrode current collector layer from the electrolyte that is proximate to and within a distance D CC of (i) the first transverse end surface of the electrode active material layer, wherein D CC equals the sum of 2×W E and |S X1 |, and/or (ii) second transverse end surface of the electrode active material layer, wherein D CC equals the sum of 2×W E and |S X2 |, and/or (iii) the first vertical end surface of the electrode active material layer, wherein D CC equals the sum of 2×W E and |S Z1 |, (iv) the second vertical end surface of the electrode active material layer wherein D CC equals the sum of 2×W E and |S Z2 |. Furthermore, the carrier ion insulating material layer 674 may ionically insulate a surface of the electrode current collector layer from the electrolyte that is proximate to and within a distance D CC of (i) the first transverse end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S X1 |, and/or (ii) second transverse end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S X2 |, and/or (iii) the first vertical end surface of the electrode active material layer, wherein D CC equals the sum of W E and |S Z1 |≥, (iv) the second vertical end surface of the electrode active material layer wherein D CC equals the sum of W E and |S Z2 |. Referring to FIGS. 37A-37B , an embodiment is shown where Sx 1 is the offset between the surface (transverse or vertical) 501 a , 503 a of the counter-electrode active material layer 138 , and the surface (transverse or vertical) 500 a , 502 a of the electrode active material layer 132 . The width W E for the electrode active material layer 132 is shown, and the figures also show the first transverse offset/separation distance S X1 , although the offsets S X2 , S Z1 and/or S Z2 could similarly be provided in a manner as for S X1 . The distance D cc as shown is then equal to the offset/separation distance relevant for the surface at hand (e.g., first or second vertical, first or second transverse), plus an amount equivalent to the width or twice the width of the electrode active material W E . That is, the carrier ion insulating material layer 674 is provided to insulate the surface of the electrode current collector 136 at at least a portion of the surface that falls within the range D CC . According to one embodiment, each of the offsets S X1 , S X2 , S Z1 and/or S Z2 may be set independently of one another, to different amounts. Furthermore, the offsets S X1 , S X2 , S Z1 and/or S Z2 may be required to be within a predetermined range over an extent of the electrode active material and/or counter-electrode active materials, such as over a length L C , L E and/or height H C , H E , as has been described, such as over at least 60%, 70%, 80%, 90%, and/or 95% of L E and/or L C , and/or over at least 60% 60%, 70%, 80%, 90%, and/or 95% of H E and/or H C . The offsets S X1 S X2 , SZ 1 and/or S Z2 may be set, for example, such that the electrode active material layer is flush with or inwardly disposed with respect to the counter-electrode active material layer, and/or may be set such that the counter-electrode active material is somewhat more inwardly disposed with respect to the electrode active material layer. For example, in one embodiment, at least one of S X1 , S X2 , S Z1 and/or S Z2 , as determined by subtracting the more inwardly directed layer from the outer one, may be in the range of from about 100 microns (counter-electrode active material layer being more inward) to −1000 microns (electrode active material layer being more inward), such as from 50 microns to −500 microns. Also, the offsets may be in a range relative to multiples of the electrode active material width W E , such as in a range of from about 2×W E (counter-electrode active material layer being more inward) or 1×W E to −10×W E (electrode active material layer being more inward).

According to yet another embodiment, as described above, at least a portion of the electrode structure 110 may comprise carrier ion insulating material layer 674 that is permeated into an electrode active material layer 132 , and/or may cover opposing surfaces in the longitudinal direction and/or other surfaces of the electrode active material layer 132 , as shown for example in FIG. 37A . In this case, those portions of the electrode active material layer 132 that are covered by the layer 674 may be inactive, as they are insulated from carrier ions, and accordingly the surface (vertical and/or transverse end surface) of the electrode active material layer 132 is considered to be at the interface 500 a between where the covered portion of the layer 132 begins and where uncovered and active material of the layer 132 begins. That is, the distance D CC in FIG. 37A is measured from 500 a (where the active electrode active material ends) and not 800 a (where the layer is covered by the layer 674 of carrier ion insulating material.

In one embodiment, the carrier ion insulating material layer 674 is disposed on the surface of the electrode current collector layer 136 , to insulate the surface from carrier ions. The carrier ion insulating material layer 674 may also cover a predetermined amount of the distance D CC . For example, the carrier ion insulating material layer 674 may extend at least 50% of D CC , at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, and even substantially all of D CC . The carrier ion insulating material layer 674 may also be provided in one or more segments along D CC , and/or may be a single continuous layer along D CC . The carrier ion insulating material layer 674 may also extend in a direction that is orthogonal to the offset. For example, for a distance D CC in relation to the vertical offset, the carrier ion insulating material layer 674 may also extend in a transverse direction across the electrode current collector surface in a least a portion of the region defined vertically by D CC . As another example, for a distance D CC in relation to the transverse offset, the carrier ion insulating material layer 674 may also extend in a vertical direction across the electrode current collector surface in a least a portion of the region defined in the transverse direction by D CC .

Furthermore, in one embodiment the carrier ion insulating material layer 674 may be provided to insulate a surface of an electrode current collector 136 in a 3D secondary battery 102 , such as a battery having an electrode assembly with electrode structures and counter-electrode structures, where a length L E of the electrode active material layers 132 of the electrode structures 110 and/or a length L C of the counter-electrode active material layers 138 is much greater than that of the height H C , H E and/or width W C , W E of the electrode and/or counter-electrode layers 132 , 138 . That is, a length L E of the electrode active material layer may be at least 5:1, such as at least 8:1, and even at least 10:1 of that of the Width W E and height H E of the electrode active material layer. Similarly, a length L C of the counter-electrode active material layer may be at least 5:1, such as at least 8:1, and even at least 10:1 of that of the Width WC and height H C of the counter-electrode active material layer. An example of an electrode assembly 106 having such 3D electrodes is depicted in FIG. 2A . In another embodiment, the carrier ion insulating material layer 674 may be provided to insulate a surface of an electrode current collector 136 in a 2D secondary battery 102 , such as a battery having an electrode assembly with electrode structures and counter-electrode structures, where a length L E of the electrode active material layers 132 of the electrode structures 110 and/or a length L C of the counter-electrode active material layers 138 , as well as the height H E of the electrode active material layers 132 of the electrode structures 110 and/or a height H C of the counter-electrode active material layers 138 is much greater than that of the width W C , W E of the electrode and/or counter-electrode layers 132 , 138 . That is, a length L E and height H E of the electrode active material layer may be at least 2:1, such as at least 5:1, and even at least 10:1 of that of the Width W E of the electrode active material layer. Similarly, a length L C and height H c of the counter-electrode active material layer may be at least 2:1, such as at least 5:1, and even at least 10:1 of that of the Width W C of the counter-electrode active material layer. An example of an electrode assembly 106 having such 2D electrodes (e.g., planar sheet-like electrodes) is depicted in FIG. 36 .

According to one embodiment, the electrode assembly having the carrier ion insulating material layer protecting the surfaces of the electrode current collector 136 , may further comprise a set of electrode constraints 108 , which may correspond to any described herein. For example, the set of electrode constraints can comprise a primary constraint system 151 comprising first and second primary growth constraints 154 , 156 and at least one primary connecting member 162 , the first and second primary growth constraints separated from each other in the longitudinal direction, and the at least one primary connecting member connecting the first and second primary growth constraints, wherein the primary constraint system restrains growth of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%. The electrode assembly 106 can also comprise a secondary constraint system 155 configured to constrain growth in a direction orthogonal to the longitudinal direction, such as the vertical direction, as is described in further detail herein.

Referring to FIGS. 33A-33C , embodiments of the carrier ion insulating material layer 674 are described. For example, the carrier ion insulating material layer 674 can be provided to cover at least a predetermined percentage of the electrode current collector 136 , and may also cover at least a portion of a surface of one or more first and second electrode active material layers 132 a , 132 b adjacent the electrode current collector. In the embodiment as shown in FIG. 33A , the carrier ion insulating material 674 is applied over surfaces of the electrode current collector, including vertical end surfaces 640 a,b and longitudinal side surfaces 670 a,b , from the vertical end surfaces of the electrode current collector to a point where the longitudinal side surfaces 670 a,b , meet the first and second vertical end surfaces of one or more of the adjacent first and second electrode active material layers 132 a,b on either side of the electrode current collector 136 . As is also shown in FIG. 33A , the carrier ion insulating material layer may also be provided to cover at least a portion of one or more of the first and/or second vertical end surfaces 500 a,b of one or more of the adjacent first and second electrode active material layers 132 a,b . For example, the carrier ion insulating material layer may extend longitudinally from the electrode current collector to cover at least a portion of the first and/or second vertical end surfaces 500 a,b of one or more of the adjacent first and second electrode active material layers 132 a,b . That is, the carrier ion insulating material layer may cover at least 10%, at least 20%, at least 50%, at least 75%, at least 90%, at least 95%, and even substantially all of the first and/or second vertical end surfaces 500 a,b of one or more of the adjacent first and second electrode active material layers 132 a,b . Referring to FIG. 33B , an embodiment is depicted where the carrier ion insulating material layer not only covers the first and/or second vertical end surfaces of the adjacent electrode active material layers, but also extends beyond an edge of the surfaces and at least partially down a longitudinal side 702 a , 702 b of the layers of electrode active material, the longitudinal sides 702 a , 702 b of each electrode active material layer 132 a,b being that side that faces the separator 130 in each unit cell 504 a , 504 b . Referring to FIG. 33C , an embodiment is depicted where the carrier ion insulating material comprises a layer of material 674 that covers the exposed surfaces of the electrode current collector 135 , as well as the vertical end surfaces and at least a portion of the longitudinal side surfaces of first and second electrode active material layers adjacent the electrode current collector, and also attaches and/or adheres to a portion of the set of constraints 108 . For example, in the embodiment depicted in FIG. 33C , the layer 674 of material attaches to first or second secondary growth constraint 158 , 160 that constrains growth of the electrode assembly 106 in the vertical direction. That is, the carrier ion insulating material layer can comprise an adhesive material capable of adhering structures of the electrode assembly to portions of the constraint system, as has been described elsewhere herein.

Referring to FIG. 33D , an embodiment is shown for a solid-electrolyte type battery. While a liquid electrolyte can be provided for the embodiments shown herein, such as for example in FIGS. 33A-C , solid electrolyte secondary batteries may also benefit from a carrier ion insulating materials protecting the electrode current collectors 136 . In the embodiment as shown, the layer 674 of carrier ion insulating material is provided over exposed surfaces of the electrode current collector 136 , and also extends at least partially over first and second vertical end surfaces of an adjacent electrode active material layer 132 . The layer 674 thus protects the electrode current collector 136 from shorting and/or plating out by carrier ions passing through the solid-electrolyte-type separator 130 from the counter-electrode active material layer 138 .

Separator Configurations

Referring to FIGS. 28 a -28 d , embodiments of configurations of the separator 130 are described. In certain embodiments, the separator 130 can comprise an ionically permeable, microporous material, that is capable of passing carrier ions therethrough between the electrode active material layer 132 and counter-electrode active material layer 138 in each unit cell 504 , while also at least partially insulating the electrode and counter-electrode active material layers 132 , 138 from one another, to inhibit electrical shorting between the layers. In the embodiment shown in FIG. 28A , the separator 130 comprises at least one, such as a single sheet, or even plural sheets, of separator material, sandwiched between the electrode active material layer 132 and the counter-electrode active material. The at least one sheet of separator material may extend in the transverse direction at least the length Lc of the counter-electrode active material layer 138 , and even at least the height Hc (into the page in FIG. 28A ), of the counter-electrode active material layer 138 , to electrically insulate the layers 132 , 138 from one another. In the embodiment as shown, the separator 130 extends at least partially past the end of the transverse surfaces 502 a,b , 503 a,b , of the electrode active material layer 132 and counter-electrode active material layer.

In yet another embodiment, as shown in FIG. 28B , the separator 130 can comprise a layer formed on the surface of the counter-electrode active material layer 138 , and may be conformal with the surface of the layer. In the embodiment as shown, a conformal separator layer 130 is formed over an internal surface 512 of the counter-electrode active material layer 138 , that faces the electrode active material layer 132 , and extends over the transverse ends of the counter-electrode material layer 138 to at least partially and even entirely cover the transverse surfaces 503 a , 503 b of the counter-electrode active material layer, as well as optionally the vertical end surfaces 501 a , 501 b of the counter-electrode active material layer. In another embodiment, as shown in FIG. 28C , the separator 130 can comprise a layer formed on the surface of the electrode active material layer 132 , and may be conformal with the surface of the layer. In the embodiment as shown, a conformal separator layer 130 is formed over an internal surface 514 of the electrode active material layer 132 , that faces the counter-electrode active material layer 138 , and extends over the transverse ends of the electrode material layer 132 to at least partially and even entirely cover the transverse surfaces 502 a , 502 b of the electrode active material layer, as well as optionally the vertical end surfaces 500 a , 500 b of the electrode active material layer.

In yet another embodiment as shown in FIG. 28D , the separator 130 can comprise a multi-layer structure with a first layer 130 a of separator material conformal with the surface of the electrode active material layer 132 , and a second layer 130 b of separator material conformal with the surface of the counter electrode active material layer 138 . In the embodiment as shown, a first conformal separator layer 130 a is formed over an internal surface 514 of the electrode active material layer 132 , that faces the counter-electrode active material layer 138 , and extends over the transverse ends of the electrode material layer 132 to at least partially and even entirely cover the transverse surfaces 502 a , 502 b of the electrode active material layer, as well as optionally the vertical end surfaces 500 a , 500 b of the electrode active material layer. A second conformal separator layer 130 b is formed over an internal surface 512 of the counter-electrode active material layer 138 that faces the electrode active material layer 132 , and extends over the transverse ends of the counter-electrode material layer 138 to at least partially and even entirely cover the transverse surfaces 503 a , 503 b of the counter-electrode active material layer, as well as optionally the vertical end surfaces 501 a , 501 b of the counter-electrode active material layer. In one embodiment, the conformal separator layers 130 can be formed by depositing, spraying, and/or tape casting separator layers onto the surfaces of the electrode and/or counter-electrode active material layers, to form a conformal coating of the separator material on the surface.

The separator 130 may be formed of a separator material that is capable of being permeated with liquid electrolyte for use in a liquid electrolyte secondary battery, such as a non-aqueous liquid electrolyte corresponding to any of those described herein. The separator 130 may also be formed of a separator material suitable for use with any of polymer electrolyte, gel electrolyte and/or ionic liquids. For example, the electrolyte may be liquid (e.g., free flowing at ambient temperatures and/or pressures) or solid, aqueous or non-aqueous. The electrolyte may also be a gel, such as a mixture of liquid plastizers and polymer to give a semi-solid consistency at ambient temperature, with the carrier ions being substantially solvated by the plastizers. The electrolyte may also be a polymer, such as a polymeric compound, and may be an ionic liquid, such as a molten salt and/or a liquid at ambient temperature.

Method of Preparing Electrode Assembly

In one embodiment, a method for preparing an electrode assembly 106 comprising a set of constraints 108 is provided, where the electrode assembly 106 may be used as a part of a secondary battery that is configured to cycle between a charged and a discharged state. The method can generally comprise forming a sheet structure, cutting the sheet structure into pieces (and/or pieces), stacking the pieces, and applying a set of constraints. By strip, it is understood that a piece other than one being in the shape of a strip could be used. The pieces comprise an electrode active material layer, an electrode current collector, a counter-electrode active material layer, a counter-electrode current collector, and a separator, and may be stacked so as to provide an alternating arrangement of electrode active material and/or counter-electrode active material. The sheets can comprise, for example, at least one of a unit cell 504 and/or a component of a unit cell 504 . For example, the sheets can comprise a population of unit cells, which can be cut to a predetermined size (such as a size suitable for a 3D battery), and then the sheets of unit cells can be stacked to form the electrode assembly 106 . In another example, the sheets can comprise one or more components of a unit cell, such as for example at least one of an electrode current collector 136 , an electrode active material layer 132 , a separator 130 , a counter-electrode active material layer 138 , and a counter-electrode current collector 140 . The sheets of components can be cut to predetermined sizes to form the pieces (such as sizes suitable for a 3D battery), and then stacked to form an alternating arrangement of the electrode and counter-electrode active material layer components.

In yet another embodiment, the set of constraints 108 that are applied may correspond to any of those described herein, such as for example a set of constraints comprising a primary constraint system comprising first and second primary growth constraints and at least one primary connecting member, the first and second primary growth constraints separated from each other in the longitudinal direction, and the at least one primary connecting member connecting the first and second primary growth constraints, wherein the primary constraint system restrains growth of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20%. Furthermore, the set of electrode constraints can comprise a secondary constraint system comprising first and second secondary growth constraints separated in a direction orthogonal to the longitudinal direction (such as the vertical or transverse direction) and connected by at least one secondary connecting member, wherein the secondary constraint system at least partially restrains growth of the electrode assembly in the vertical direction upon cycling of the secondary battery. At least one of the primary connecting member, or first and/or second primary growth constraints of the primary constraint system, and the secondary connecting member, or first and/or second secondary growth constraints of the secondary constraint system, can be one or more of the assembly components that make up the pieces, such as for example at least one of the electrode active material layer, electrode current collector, counter-electrode active material layer, counter-electrode current collector, and separator. For example, in one embodiment, the secondary connecting member of the secondary constraint system, can be one or more of the assembly components that make up the pieces, such as for example at least one of the electrode active material layer, electrode current collector, counter-electrode active material layer, counter-electrode current collector, and separator. That is, the application of the constraints may involve applying the first and second primary growth constraints to a primary member that is one of the structures in the stack of pieces. A secondary constraint system, such as any of those described elsewhere herein, may also be provided.

As an example, in one embodiment, the method may involve preparing sheets of electrode active material, counter-electrode active material, electrode current collector material, and counter-electrode current collector material, such as for example by dicing the sheets into the length, height and width dimensions suitable for an electrode active material layer 132 , a counter-electrode active material layer 138 , an electrode current collector 136 , and a counter-electrode current collector 140 . For example, in one method, the sheets are preparing by dicing and/or cutting the electrode and/or counter-electrode active material layers into sheets having a ratio of the length dimension L E , L C to the height H E , H C and width dimensions W E , W C of at least 5:1, such as at least 8:1 and even at least 10:1. A ratio of W E , W C to H E , H may be in the range of 1:1 to 5:1, and typically not more than 20:1. In yet another embodiment, sheets comprising unit cells having each of the components may be formed, and then diced and/or cut to the predetermined size, such as for example to provide the electrode and/or counter-electrode active material layer ratios above or otherwise described elsewhere herein.

As yet a further example, the method can further comprise layering the sheets of electrode active material with sheets of electrode current collector material to form electrode structures 110 , and layering the sheets of counter-electrode active material with sheets of counter-electrode current collector material to form counter-electrode structures 112 . The method further comprises arranging an alternating stack of the electrode structures 110 and counter-electrode structures 112 , with layers of separator material 130 separating each electrode structure from each counter-electrode structure. While the dicing of the sheets to form the proper layer size is described above as occurring before the layering process, it is also possible that dicing to form proper electrode and/or counter-electrode can be performed after layering; or a combination of before and after layering.

Furthermore, the method as described above may be used to form electrode assemblies 106 and secondary batteries 102 having the structures and structural elements as are elsewhere described herein.

FIG. 21 depicts a specific embodiment of the method. In the embodiment of FIG. 21 , in Step S 1 , an electrode structure 110 is fabricated having an electrode structure backbone 134 . For example, referring to the embodiment shown in FIG. 5 , an electrode structure 110 can be fabricated having layers 132 of electrode active material that are disposed on opposite sides of a backbone, and where the backbone corresponds to an electrode current collector 136 . In Step S 2 , a counter electrode structure 112 is fabricated having a counter-electrode structure backbone 134 . For example, referring again to the embodiment shown in FIG. 30 , a counter-electrode structure 112 can be fabricated having layers 138 of counter-electrode active material on opposite sides of a backbone, where the backbone corresponds to a counter-electrode current collector 140 . In step S 3 , at least one separator layer 130 is added to the electrode structure and/or counter-electrode structure 110 , 112 , such as for example via any of the methods depicted in the embodiments of FIG. 28A-28D . In step S 4 , the electrode structures 110 and counter-electrode structures 112 , including the separator layer 130 formed in step S 3 , are combined into electrode and counter-electrode pairs. That is, the electrode structures 110 and counter-electrode structures 112 are provided in a longitudinal stack, with the separator layer 130 in between each electrode structure 110 and counter-electrode structure 112 , thereby forming the electrode assembly 106 . In step S 5 , the constraint elements are applied to the electrode assembly 106 , for example the set of electrode constraints 108 including both the primary constraint system 151 and secondary constraints system 155 may be applied. As yet another example, in step S 5 , application of the constraint elements may include applying the first and second secondary growth constraints 158 , 160 , such as for example to constrain growth in the vertical direction. For example, in the embodiment as shown in FIG. 28A-28D , one or more vertical ends 638 , 640 of electrode and/or counter-electrode current collectors 136 , 140 may be connected to the first and second secondary growth constraints 158 , 160 , such as for example by adhering the ends thereto. In step S 6 , the electrode bus bar and/or counter-electrode busbars 600 , 602 are attached, for example by electrically and/or physically connecting to the respective electrode and/or counter-electrode current collectors 136 , 140 . For example, the electrode and/or counter-electrode busbars 600 , 602 can comprise any of the structures and/or connecting arrangements as shown in any of the embodiments as shown in FIGS. 27A-27F . In step S 7 , final steps for preparation of the secondary battery 106 are performed, including any final tabbing steps, pouching, filling with electrolyte, and sealing.

Electrode Constraints

In one embodiment, a set of electrode constraints 108 is provided that that restrains overall macroscopic growth of the electrode assembly 106 , as illustrated for example in FIG. 1 . The set of electrode constraints 108 may be capable of restraining growth of the electrode assembly 106 along one or more dimensions, such as to reduce swelling and deformation of the electrode assembly 106 , and thereby improve the reliability and cycling lifetime of an energy storage device 100 having the set of electrode constraints 108 . As discussed above, without being limited to any one particular theory, it is believed that carrier ions traveling between the electrode structures 110 and counter electrode structures 112 during charging and/or discharging of a secondary battery 102 can become inserted into electrode active material, causing the electrode active material and/or the electrode structure 110 to expand. This expansion of the electrode structure 110 can cause the electrodes and/or electrode assembly 106 to deform and swell, thereby compromising the structural integrity of the electrode assembly 106 , and/or increasing the likelihood of electrical shorting or other failures. In one example, excessive swelling and/or expansion and contraction of the electrode active material layer 132 during cycling of an energy storage device 100 can cause fragments of electrode active material to break away and/or delaminate from the electrode active material layer 132 , thereby compromising the efficiency and cycling lifetime of the energy storage device 100 . In yet another example, excessive swelling and/or expansion and contraction of the electrode active material layer 132 can cause electrode active material to breach the electrically insulating microporous separator 130 , thereby causing electrical shorting and other failures of the electrode assembly 106 . Accordingly, the set of electrode constraints 108 inhibit this swelling or growth that can otherwise occur with cycling between charged and discharged states to improve the reliability, efficiency, and/or cycling lifetime of the energy storage device 100 .

According to one embodiment, the set of electrode constraints 108 comprises a primary growth constraint system 151 to restrain growth and/or swelling along the longitudinal axis (e.g., Y-axis in FIG. 1 ) of the electrode assembly 106 . In another embodiment, the set of electrode constraints 108 may include a secondary growth constraint system 152 that restrains growth along the vertical axis (e.g., Z-axis in FIG. 1 ). In yet another embodiment, the set of electrode constraints 108 may include a tertiary growth constraint system 155 that restrains growth along the transverse axis (e.g., X-axis in FIG. 4C ). In one embodiment, the set of electrode constraints 108 comprises primary growth and secondary growth constraint systems 151 , 152 , respectively, and even tertiary growth constraint systems 155 that operate cooperatively to simultaneously restrain growth in one or more directions, such as along the longitudinal and vertical axis (e.g., Y axis and Z axis), and even simultaneously along all of the longitudinal, vertical, and transverse axes (e.g., Y, Z, and X axes). For example, the primary growth constraint system 151 may restrain growth that can otherwise occur along the stacking direction D of the electrode assembly 106 during cycling between charged and discharged states, while the secondary growth constraint system 152 may restrain swelling and growth that can occur along the vertical axis, to prevent buckling or other deformation of the electrode assembly 106 in the vertical direction. By way of further example, in one embodiment, the secondary growth constraint system 152 can reduce swelling and/or expansion along the vertical axis that would otherwise be exacerbated by the restraint on growth imposed by the primary growth constraint system 151 . The tertiary growth constraint system 155 can also optionally reduce swelling and/or expansion along the transverse axis that could occur during cycling processes. That is, according to one embodiment, the primary growth and secondary growth constraint systems 151 , 152 , respectively, and optionally the tertiary growth constraint system 155 , may operate together to cooperatively restrain multi-dimensional growth of the electrode assembly 106 .

Referring to FIGS. 4A-4B , an embodiment of a set of electrode constraints 108 is shown having a primary growth constraint system 151 and a secondary growth constraint system 152 for an electrode assembly 106 . FIG. 4A shows a cross-section of the electrode assembly 106 in FIG. 1 taken along the longitudinal axis (Y axis), such that the resulting 2-D cross-section is illustrated with the vertical axis (Z axis) and longitudinal axis (Y axis). FIG. 4B shows a cross-section of the electrode assembly 106 in FIG. 1 taken along the transverse axis (X axis), such that the resulting 2-D cross-section is illustrated with the vertical axis (Z axis) and transverse axis (X axis). As shown in FIG. 4A , the primary growth constraint system 151 can generally comprise first and second primary growth constraints 154 , 156 , respectively, that are separated from one another along the longitudinal direction (Y axis). For example, in one embodiment, the first and second primary growth constraints 154 , 156 , respectively, comprise a first primary growth constraint 154 that at least partially or even entirely covers a first longitudinal end surface 116 of the electrode assembly 106 , and a second primary growth constraint 156 that at least partially or even entirely covers a second longitudinal end surface 118 of the electrode assembly 106 . In yet another version, one or more of the first and second primary growth constraints 154 , 156 may be interior to a longitudinal end 117 , 119 of the electrode assembly 106 , such as when one or more of the primary growth constraints comprise an internal structure of the electrode assembly 106 . The primary growth constraint system 151 can further comprise at least one primary connecting member 162 that connects the first and second primary growth constraints 154 , 156 , and that may have a principal axis that is parallel to the longitudinal direction. For example, the primary growth constraint system 151 can comprise first and second primary connecting members 162 , 164 , respectively, that are separated from each other along an axis that is orthogonal to the longitudinal axis, such as along the vertical axis (Z axis) as depicted in the embodiment. The first and second primary connecting members 162 , 164 , respectively, can serve to connect the first and second primary growth constraints 154 , 156 , respectively, to one another, and to maintain the first and second primary growth constraints 154 , 156 , respectively, in tension with one another, so as to restrain growth along the longitudinal axis of the electrode assembly 106 .

According to one embodiment, the set of electrode constraints 108 including the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction (i.e., electrode stacking direction, D) such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 20% between charged and discharged states. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 30 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 50 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 80 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 100 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 200 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 300 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 500 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 800 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 1000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 2000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 3000 consecutive cycles of the secondary battery to less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 8000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10,000 consecutive cycles of the secondary battery is less than 20%.

In yet another embodiment, the set of electrode constraints 108 including the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 30 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 50 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 80 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 100 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 200 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 300 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 500 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 800 consecutive cycles of the secondary battery is less than 10% between charged and discharged states. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 1000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 2000 consecutive cycles is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 3000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 8000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10,000 consecutive cycles of the secondary battery is less than 10%.

In yet another embodiment, the set of electrode constraints 108 including the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 30 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 50 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 80 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 100 consecutive cycles of the secondary battery, is less than 5. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 200 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 300 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 500 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 800 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 1000 consecutive cycles of the secondary battery is less than 5% between charged and discharged states. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 2000 consecutive cycles of the secondary battery is less than 5% between charged and discharged states. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 3000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 8000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10,000 consecutive cycles of the secondary battery is less than 5%.

In yet another embodiment, the set of electrode constraints 108 including the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction per cycle of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 20 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 30 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 50 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 80 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 100 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 200 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 300 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 500 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 800 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 1000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 2000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 3000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 5000 consecutive cycles of the secondary battery is less than 1% between charged and discharged states. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 8000 consecutive cycles of the secondary battery to less than 1%. By way of further example, in one embodiment the primary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the longitudinal direction such that any increase in the Feret diameter of the electrode assembly in the longitudinal direction over 10,000 consecutive cycles of the secondary battery to less than 1%.

By charged state it is meant that the secondary battery 102 is charged to at least 75% of its rated capacity, such as at least 80% of its rated capacity, and even at least 90% of its rated capacity, such as at least 95% of its rated capacity, and even 100% of its rated capacity. By discharged state it is meant that the secondary battery is discharged to less than 25% of its rated capacity, such as less than 20% of its rated capacity, and even less than 10%, such as less than 5%, and even 0% of its rated capacity. Furthermore, it is noted that the actual capacity of the secondary battery 102 may vary over time and with the number of cycles the battery has gone through. That is, while the secondary battery 102 may initially exhibit an actual measured capacity that is close to its rated capacity, the actual capacity of the battery will decrease over time, with the secondary battery 102 being considered to be at the end of its life when the actual capacity drops below 80% of the rated capacity as measured in going from a charged to a discharged state.

Further shown in FIGS. 4A and 4B , the set of electrode constraints 108 can further comprise the secondary growth constraint system 152 , that can generally comprise first and second secondary growth constraints 158 , 160 , respectively, that are separated from one another along a second direction orthogonal to the longitudinal direction, such as along the vertical axis (Z axis) in the embodiment as shown. For example, in one embodiment, the first secondary growth constraint 158 at least partially extends across a first region 148 of the lateral surface 142 of the electrode assembly 106 , and the second secondary growth constraint 160 at least partially extends across a second region 150 of the lateral surface 142 of the electrode assembly 106 that opposes the first region 148 . In yet another version, one or more of the first and second secondary growth constraints 154 , 156 may be interior to the lateral surface 142 of the electrode assembly 106 , such as when one or more of the secondary growth constraints comprise an internal structure of the electrode assembly 106 . In one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, are connected by at least one secondary connecting member 166 , which may have a principal axis that is parallel to the second direction, such as the vertical axis. The secondary connecting member 166 may serve to connect and hold the first and second secondary growth constraints 158 , 160 , respectively, in tension with one another, so as to restrain growth of the electrode assembly 106 along a direction orthogonal to the longitudinal direction, such as for example to restrain growth in the vertical direction (e.g., along the Z axis). In the embodiment depicted in FIG. 4A , the at least one secondary connecting member 166 can correspond to at least one of the first and second primary growth constraints 154 , 156 . However, the secondary connecting member 166 is not limited thereto, and can alternatively and/or in addition comprise other structures and/or configurations.

According to one embodiment, the set of constraints including the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in a second direction orthogonal to the longitudinal direction, such as the vertical direction (Z axis), such that any increase in the Feret diameter of the electrode assembly in the second direction over 20 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 30 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 50 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 80 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 100 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 200 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 300 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 500 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 800 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 1000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 2000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 3000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 8000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10,000 consecutive cycles of the secondary battery is less than 20% between charged and discharged states.

In embodiment, the set of constraints including the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10 consecutive cycles of the secondary battery is less than 10% between charged and discharged states. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 20 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 30 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 50 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 80 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 100 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 200 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 300 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 500 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 800 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 1000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 2000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 3000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 8000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10,000 consecutive cycles of the secondary battery is less than 10%.

In embodiment, the set of constraints including the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5 consecutive cycles of the secondary battery is less than 5% between charged and discharged states. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 20 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 30 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 50 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 80 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 100 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 200 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 300 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 500 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 800 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 1000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 2000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 3000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 8000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10,000 consecutive cycles of the secondary battery is less than 5%.

In embodiment, the set of constraints including the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction per cycle of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 20 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 30 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 50 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 80 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 100 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 200 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 300 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 500 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 800 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 1000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 2000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 3000 consecutive cycles of the secondary battery is less than 1% between charged and discharged states. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 5000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 8000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the secondary growth constraint system 151 may be capable of restraining growth of the electrode assembly 106 in the second direction such that any increase in the Feret diameter of the electrode assembly in the second direction over 10,000 consecutive cycles of the secondary battery is less than 1%.

FIG. 4C shows an embodiment of a set of electrode constraints 108 that further includes a tertiary growth constraint system 155 to constrain growth of the electrode assembly in a third direction that is orthogonal to the longitudinal and second directions, such as the transverse direction (X) direction. The tertiary growth constraint system 155 can be provided in addition to the primary and secondary growth constraint systems 151 , 152 , respectively, to constrain overall growth of the electrode assembly 106 in three dimensions, and/or may be provided in combination with one of the primary or secondary growth constraint systems 151 , 152 , respectively, to constrain overall growth of the electrode assembly 106 in two dimensions. FIG. 4C shows a cross-section of the electrode assembly 106 in FIG. 1 taken along the transverse axis (X axis), such that the resulting 2-D cross-section is illustrated with the vertical axis (Z axis) and transverse axis (X axis). As shown in FIG. 4C , the tertiary growth constraint system 155 can generally comprise first and second tertiary growth constraints 157 , 159 , respectively, that are separated from one another along the third direction such as the transverse direction (X axis). For example, in one embodiment, the first tertiary growth constraint 157 at least partially extends across a first region 144 of the lateral surface 142 of the electrode assembly 106 , and the second tertiary growth constraint 159 at least partially extends across a second region 146 of the lateral surface 142 of the electrode assembly 106 that opposes the first region 144 in the transverse direction. In yet another version, one or more of the first and second tertiary growth constraints 157 , 159 may be interior to the lateral surface 142 of the electrode assembly 106 , such as when one or more of the tertiary growth constraints comprise an internal structure of the electrode assembly 106 . In one embodiment, the first and second tertiary growth constraints 157 , 159 , respectively, are connected by at least one tertiary connecting member 165 , which may have a principal axis that is parallel to the third direction. The tertiary connecting member 165 may serve to connect and hold the first and second tertiary growth constraints 157 , 159 , respectively, in tension with one another, so as to restrain growth of the electrode assembly 106 along a direction orthogonal to the longitudinal direction, for example, to restrain growth in the transverse direction (e.g., along the X axis). In the embodiment depicted in FIG. 4C , the at least one tertiary connecting member 165 can correspond to at least one of the first and second secondary growth constraints 158 , 160 . However, the tertiary connecting member 165 is not limited thereto, and can alternatively and/or in addition comprise other structures and/or configurations. For example, the at least one tertiary connecting member 165 can, in one embodiment, correspond to at least one of the first and second primary growth constraints 154 , 156 (not shown).

According to one embodiment, the set of constraints having the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in a third direction orthogonal to the longitudinal direction, such as the transverse direction (X axis), such that any increase in the Feret diameter of the electrode assembly in the third direction over 20 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 30 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 50 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 80 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 100 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 200 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 300 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 500 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 800 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 1000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 2000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 3000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 8000 consecutive cycles of the secondary battery is less than 20%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10,000 consecutive cycles of the secondary battery is less than 20%.

In one embodiment, the set of constraints having the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 20 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 30 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 50 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 80 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 100 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 200 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 300 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 500 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 800 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 1000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 2000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 3000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5000 consecutive cycles of the secondary battery is less than 10% between charged and discharged states. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 8000 consecutive cycles of the secondary battery is less than 10%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10,000 consecutive cycles of the secondary battery is less than 10%.

In one embodiment, the set of constraints having the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 20 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 30 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 50 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 80 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 100 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 200 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 300 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 500 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 800 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 1000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 2000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 3000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 8000 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10,000 consecutive cycles of the secondary battery is less than 5%.

In one embodiment, the set of constraints having the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction per cycle of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 20 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 30 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 50 consecutive cycles of the secondary battery is less than 5%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 80 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 100 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 200 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 300 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 500 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 152 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 800 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 1000 consecutive cycles of the secondary battery is less than 1% between charged and discharged states. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 2000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 3000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 5000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 8000 consecutive cycles of the secondary battery is less than 1%. By way of further example, in one embodiment the tertiary growth constraint system 155 may be capable of restraining growth of the electrode assembly 106 in the third direction such that any increase in the Feret diameter of the electrode assembly in the third direction over 10,000 consecutive cycles of the secondary battery is less than 1%.

According to one embodiment, the primary and secondary growth constraint systems 151 , 152 , respectively, and optionally the tertiary growth constraint system 155 , are configured to cooperatively operate such that portions of the primary growth constraint system 151 cooperatively act as a part of the secondary growth constraint system 152 , and/or portions of the secondary growth constraint system 152 cooperatively act as a part of the primary growth constraint system 151 , and the portions of any of the primary and/or secondary constraint systems 151 , 152 , respectively, may also cooperatively act as a part of the tertiary growth constraint system, and vice versa. For example, in the embodiment shown in in FIGS. 4A and 4B , the first and second primary connecting members 162 , 164 , respectively, of the primary growth constraint system 151 can serve as at least a portion of, or even the entire structure of, the first and second secondary growth constraints 158 , 160 that constrain growth in the second direction orthogonal to the longitudinal direction. In yet another embodiment, as mentioned above, one or more of the first and second primary growth constraints 154 , 156 , respectively, can serve as one or more secondary connecting members 166 to connect the first and second secondary growth constrains 158 , 160 , respectively. Conversely, at least a portion of the first and second secondary growth constraints 158 , 160 , respectively, can act as first and second primary connecting members 162 , 164 , respectively, of the primary growth constraint system 151 , and the at least one secondary connecting member 166 of the secondary growth constraint system 152 can, in one embodiment, act as one or more of the first and second primary growth constraints 154 , 156 , respectively. In yet another embodiment, at least a portion of the first and second primary connecting members 162 , 164 , respectively, of the primary growth constraint system 151 , and/or the at least one secondary connecting member 166 of the secondary growth constraint system 152 can serve as at least a portion of, or even the entire structure of, the first and second tertiary growth constraints 157 , 159 , respectively, that constrain growth in the transverse direction orthogonal to the longitudinal direction. In yet another embodiment, one or more of the first and second primary growth constraints 154 , 156 , respectively, and/or the first and second secondary growth constraints 158 , 160 , respectively, can serve as one or more tertiary connecting members 166 to connect the first and second tertiary growth constraints 157 , 159 , respectively. Conversely, at least a portion of the first and second tertiary growth constraints 157 , 159 , respectively, can act as first and second primary connecting members 162 , 164 , respectively, of the primary growth constraint system 151 , and/or the at least one secondary connecting member 166 of the secondary growth constraint system 152 , and the at least one tertiary connecting member 165 of the tertiary growth constraint system 155 can in one embodiment act as one or more of the first and second primary growth constraints 154 , 156 , respectively, and/or one or more of the first and second secondary growth constraints 158 , 160 , respectively. Alternatively and/or additionally, the primary and/or secondary and/or tertiary growth constraints can comprise other structures that cooperate to restrain growth of the electrode assembly 106 . Accordingly, the primary and secondary growth constraint systems 151 , 152 , respectively, and optionally the tertiary growth constraint system 155 , can share components and/or structures to exert restraint on the growth of the electrode assembly 106 .

In one embodiment, the set of electrode constraints 108 can comprise structures such as the primary and secondary growth constraints, and primary and secondary connecting members, that are structures that are external to and/or internal to the battery enclosure 104 , or may be a part of the battery enclosure 104 itself. For example, the set of electrode constraints 108 can comprise a combination of structures that includes the battery enclosure 104 as well as other structural components. In one such embodiment, the battery enclosure 104 may be a component of the primary growth constraint system 151 and/or the secondary growth constraint system 152 ; stated differently, in one embodiment, the battery enclosure 104 , alone or in combination with one or more other structures (within and/or outside the battery enclosure 104 , for example, the primary growth constraint system 151 and/or a secondary growth constraint system 152 ) restrains growth of the electrode assembly 106 in the electrode stacking direction D and/or in the second direction orthogonal to the stacking direction, D. For example, one or more of the primary growth constraints 154 , 156 and secondary growth constraints 158 , 160 can comprise a structure that is internal to the electrode assembly. In another embodiment, the primary growth constraint system 151 and/or secondary growth constraint system 152 does not include the battery enclosure 104 , and instead one or more discrete structures (within and/or outside the battery enclosure 104 ) other than the battery enclosure 104 restrains growth of the electrode assembly 106 in the electrode stacking direction, D, and/or in the second direction orthogonal to the stacking direction, D. The electrode assembly 106 may be restrained by the set of electrode constraints 108 at a pressure that is greater than the pressure exerted by growth and/or swelling of the electrode assembly 106 during repeated cycling of an energy storage device 100 or a secondary battery having the electrode assembly 106 .

In one exemplary embodiment, the primary growth constraint system 151 includes one or more discrete structure(s) within the battery enclosure 104 that restrains growth of the electrode structure 110 in the stacking direction D by exerting a pressure that exceeds the pressure generated by the electrode structure 110 in the stacking direction D upon repeated cycling of a secondary battery 102 having the electrode structure 110 as a part of the electrode assembly 106 . In another exemplary embodiment, the primary growth constraint system 151 includes one or more discrete structures within the battery enclosure 104 that restrains growth of the counter-electrode structure 112 in the stacking direction D by exerting a pressure in the stacking direction D that exceeds the pressure generated by the counter-electrode structure 112 in the stacking direction D upon repeated cycling of a secondary battery 102 having the counter-electrode structure 112 as a part of the electrode assembly 106 . The secondary growth constraint system 152 can similarly include one or more discrete structures within the battery enclosure 104 that restrain growth of at least one of the electrode structures 110 and counter-electrode structures 112 in the second direction orthogonal to the stacking direction D, such as along the vertical axis (Z axis), by exerting a pressure in the second direction that exceeds the pressure generated by the electrode or counter-electrode structure 110 , 112 , respectively, in the second direction upon repeated cycling of a secondary battery 102 having the electrode or counter electrode structures 110 , 112 , respectively.

In yet another embodiment, the first and second primary growth constraints 154 , 156 , respectively, of the primary growth constraint system 151 restrain growth of the electrode assembly 106 by exerting a pressure on the first and second longitudinal end surfaces 116 , 118 of the electrode assembly 106 , meaning, in a longitudinal direction, that exceeds a pressure exerted by the first and second primary growth constraints 154 , 156 on other surfaces of the electrode assembly 106 that would be in a direction orthogonal to the longitudinal direction, such as opposing first and second regions of the lateral surface 142 of the electrode assembly 106 along the transverse axis and/or vertical axis. That is, the first and second primary growth constraints 154 , 156 may exert a pressure in a longitudinal direction (Y axis) that exceeds a pressure generated thereby in directions orthogonal thereto, such as the transverse (X axis) and vertical (Z axis) directions. For example, in one such embodiment, the primary growth constraint system 151 restrains growth of the electrode assembly 106 with a pressure on first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 by the primary growth constraint system 151 in at least one, or even both, of the two directions that are perpendicular to the stacking direction D, by a factor of at least 3. By way of further example, in one such embodiment, the primary growth constraint system 151 restrains growth of the electrode assembly 106 with a pressure on first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 by the primary growth constraint system 151 in at least one, or even both, of the two directions that are perpendicular to the stacking direction D by a factor of at least 4. By way of further example, in one such embodiment, the primary growth constraint system 151 restrains growth of the electrode assembly 106 with a pressure on first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 in at least one, or even both, of the two directions that are perpendicular to the stacking direction D, by a factor of at least 5.

Similarly, in one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, of the primary growth constraint system 151 restrain growth of the electrode assembly 106 by exerting a pressure on first and second opposing regions of the lateral surface 142 of the electrode assembly 106 in a second direction orthogonal to the longitudinal direction, such as first and second opposing surface regions along the vertical axis 148 , 150 , respectively (i.e., in a vertical direction), that exceeds a pressure exerted by the first and second secondary growth constraints 158 , 160 , respectively, on other surfaces of the electrode assembly 106 that would be in a direction orthogonal to the second direction. That is, the first and second secondary growth constraints 158 , 160 , respectively, may exert a pressure in a vertical direction (Z axis) that exceeds a pressure generated thereby in directions orthogonal thereto, such as the transverse (X axis) and longitudinal (Y axis) directions. For example, in one such embodiment, the secondary growth constraint system 152 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 148 , 150 , respectively (i.e., in the vertical direction), that exceeds the pressure maintained on the electrode assembly 106 by the secondary growth constraint system 152 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 3. By way of further example, in one such embodiment, the secondary growth constraint system 152 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 148 , 150 , respectively (i.e., in the vertical direction), that exceeds the pressure maintained on the electrode assembly 106 by the secondary growth constraint system 152 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 4. By way of further example, in one such embodiment, the secondary growth constraint system 152 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 148 , 150 , respectively (i.e., in the vertical direction), that exceeds the pressure maintained on the electrode assembly 106 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 5.

In yet another embodiment, the first and second tertiary growth constraints 157 , 159 , respectively, of the tertiary growth constraint system 155 restrain growth of the electrode assembly 106 by exerting a pressure on first and second opposing regions of the lateral surface 142 of the electrode assembly 106 in a direction orthogonal to the longitudinal direction and the second direction, such as first and second opposing surface regions along the transverse axis 161 , 163 , respectively (i.e., in a transverse direction), that exceeds a pressure exerted by the tertiary growth constraint system 155 on other surfaces of the electrode assembly 106 that would be in a direction orthogonal to the transverse direction. That is, the first and second tertiary growth constraints 157 , 159 , respectively, may exert a pressure in a transverse direction (X axis) that exceeds a pressure generated thereby in directions orthogonal thereto, such as the vertical (Z axis) and longitudinal (Y axis) directions. For example, in one such embodiment, the tertiary growth constraint system 155 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 144 , 146 (i.e., in the transverse direction) that exceeds the pressure maintained on the electrode assembly 106 by the tertiary growth constraint system 155 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 3. By way of further example, in one such embodiment, the tertiary growth constraint system 155 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 144 , 146 , respectively (i.e., in the transverse direction), that exceeds the pressure maintained on the electrode assembly 106 by the tertiary growth constraint system 155 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 4. By way of further example, in one such embodiment, the tertiary growth constraint system 155 restrains growth of the electrode assembly 106 with a pressure on first and second opposing surface regions 144 , 146 , respectively (i.e., in the transverse direction), that exceeds the pressure maintained on the electrode assembly 106 in at least one, or even both, of the two directions that are perpendicular thereto, by a factor of at least 5.

In one embodiment, the set of electrode constraints 108 , which may include the primary growth constraint system 151 , the secondary growth constraint system 152 , and optionally the tertiary growth constraint system 155 , is configured to exert pressure on the electrode assembly 106 along two or more dimensions thereof (e.g., along the longitudinal and vertical directions, and optionally along the transverse direction), with a pressure being exerted along the longitudinal direction by the set of electrode constraints 108 being greater than any pressure(s) exerted by the set of electrode constraints 108 in any of the directions orthogonal to the longitudinal direction (e.g., the Z and X directions). That is, when the pressure(s) exerted by the primary, secondary, and optionally tertiary growth constraint systems 151 , 152 , 155 , respectively, making up the set of electrode constraints 108 are summed together, the pressure exerted on the electrode assembly 106 along the longitudinal axis exceeds the pressure(s) exerted on the electrode assembly 106 in the directions orthogonal thereto. For example, in one such embodiment, the set of electrode constraints 108 exerts a pressure on the first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 by the set of electrode constraints 108 in at least one or even both of the two directions that are perpendicular to the stacking direction D, by a factor of at least 3. By way of further example, in one such embodiment, the set of electrode constraints 108 exerts a pressure on first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 by the set of electrode constraints 108 in at least one, or even both, of the two directions that are perpendicular to the stacking direction D by a factor of at least 4. By way of further example, in one such embodiment, the set of electrode constraints 108 exerts a pressure on first and second longitudinal end surfaces 116 , 118 (i.e., in the stacking direction D) that exceeds the pressure maintained on the electrode assembly 106 in at least one, or even both, of the two directions that are perpendicular to the stacking direction D, by a factor of at least 5.

According to one embodiment, the first and second longitudinal end surfaces 116 , 118 , respectively, have a combined surface area that is less than a predetermined amount of the overall surface area of the entire electrode assembly 106 . For example, in one embodiment, the electrode assembly 106 may have a geometric shape corresponding to that of a rectangular prism with first and second longitudinal end surfaces 116 , 118 , respectively, and a lateral surface 142 extending between the end surfaces 116 , 118 , respectively, that makes up the remaining surface of the electrode assembly 106 , and that has opposing surface regions 144 , 146 in the X direction (i.e., the side surfaces of the rectangular prism) and opposing surface regions 148 , 150 in the Z direction (i.e., the top and bottom surfaces of the rectangular prism, wherein X, Y and Z are dimensions measured in directions corresponding to the X, Y, and Z axes, respectively). The overall surface area is thus the sum of the surface area covered by the lateral surface 142 (i.e., the surface area of the opposing surfaces 144 , 146 , 148 , and 150 in X and Z), added to the surface area of the first and second longitudinal end surfaces 116 , 118 , respectively. In accordance with one aspect of the present disclosure, the sum of the surface areas of the first and second longitudinal end surfaces 116 , 118 , respectively, is less than 33% of the surface area of the total surface of the electrode assembly 106 . For example, in one such embodiment, the sum of the surface areas of the first and second longitudinal end surfaces 116 , 118 , respectively, is less than 25% of the surface area of the total surface of the electrode assembly 106 . By way of further example, in one embodiment, the sum of the surface areas of the first and second longitudinal end surfaces 116 , 118 , respectively, is less than 20% of the surface area of the total surface of the electrode assembly. By way of further example, in one embodiment, the sum of the surface areas of the first and second longitudinal end surfaces 116 , 118 , respectively, is less than 15% of the surface area of the total surface of the electrode assembly. By way of further example, in one embodiment, the sum of the surface areas of the first and second longitudinal end surfaces 116 , 118 , respectively, is less than 10% of the surface area of the total surface of the electrode assembly.

In yet another embodiment, the electrode assembly 106 is configured such that a surface area of a projection of the electrode assembly 106 in a plane orthogonal to the stacking direction (i.e., the longitudinal direction), is smaller than the surface areas of projections of the electrode assembly 106 onto other orthogonal planes. For example, referring to the electrode assembly 106 embodiment shown in FIG. 2A (e.g., a rectangular prism), it can be seen that surface area of a projection of the electrode assembly 106 into a plane orthogonal to the stacking direction (i.e., the X-Z plane) corresponds to L EA ×H EA . Similarly, a projection of the electrode assembly 106 into the Z-Y plane corresponds to W EA ×H EA , and a projection of the electrode assembly 106 into the X-Y plane corresponds to L EA ×W EA . Accordingly, the electrode assembly 106 is configured such that the stacking direction intersects the plane in which the projection having the smallest surface area lies. Accordingly, in the embodiment in FIG. 2A , the electrode assembly 106 is positioned such that the stacking direction intersects the X-Z plane in which the smallest surface area projection corresponding to H EA ×L EA lies. That is, the electrode assembly is positioned such that the projection having the smallest surface area (e.g., H EA ×L EA ) is orthogonal to the stacking direction.

In yet another embodiment, the secondary battery 102 can comprise a plurality of electrode assemblies 106 that are stacked together to form an electrode stack, and can be constrained by one or more shared electrode constraints. For example, in one embodiment, at least a portion of one or more of the primary growth constraint system 151 and the secondary growth constraint system 152 can be shared by a plurality of electrode assemblies 106 forming the electrode assembly stack. By way of further example, in one embodiment, a plurality of electrode assemblies forming an electrode assembly stack may be constrained in a vertical direction by a secondary growth constraint system 152 having a first secondary growth constraint 158 at a top electrode assembly 106 of the stack, and a second secondary growth constraint 160 at a bottom electrode assembly 106 of the stack, such that the plurality of electrode assemblies 106 forming the stack are constrained in the vertical direction by the shared secondary growth constraint system. Similarly, portions of the primary growth constraint system 151 could also be shared. Accordingly, in one embodiment, similarly to the single electrode assembly described above, a surface area of a projection of the stack of electrode assemblies 106 in a plane orthogonal to the stacking direction (i.e., the longitudinal direction), is smaller than the surface areas of projections of the stack of electrode assemblies 106 onto other orthogonal planes. That is, the plurality of electrode assemblies 106 may be configured such that the stacking direction (i.e., longitudinal direction) intersects and is orthogonal to a plane that has a projection of the stack of electrode assemblies 106 that is the smallest of all the other orthogonal projections of the electrode assembly stack.

According to one embodiment, the electrode assembly 106 further comprises electrode structures 110 that are configured such that a surface area of a projection of the electrode structures 110 into a plane orthogonal to the stacking direction (i.e., the longitudinal direction), is larger than the surface areas of projections of the electrode structures 100 onto other orthogonal planes. For example, referring to the embodiments as shown in FIGS. 2 and 7 , the electrodes 110 can each be understood to have a length L ES measured in the transverse direction, a width W ES measured in the longitudinal direction, and a height H ES measured in the vertical direction. The projection into the X-Z plane as shown in FIGS. 2 and 7 thus has a surface area L ES ×H ES , the projection into the Y-Z plane has a surface area W ES ×H ES , and the projection into the XY plane has a surface area L ES ×W ES . Of these, the plane corresponding to the projection having the largest surface area is the one that is selected to be orthogonal to the stacking direction. Similarly, the electrodes 110 may also be configured such that a surface area of a projection of the electrode active material layer 132 into a plane orthogonal to the stacking direction is larger than the surface areas of projections of the electrode active material layer onto other orthogonal planes. For example, in the embodiments shown in FIGS. 2 and 7 , the electrode active material layer may have a length L A measured in the transverse direction, a width W A measured in the longitudinal direction, and a height H A measured in the vertical direction, from the surface areas of projections can be calculated (L ES , L A , W ES , W A H ES and H A may also correspond to the maximum of these dimensions, in a case where the dimensions of the electrode structure and/or electrode active material layer 132 vary along one or more axes). In one embodiment, by positioning the electrode structures 110 such that the plane having the highest projection surface area of the electrode structure 100 and/or electrode active material layer 132 is orthogonal to the stacking direction, a configuration can be achieved whereby the surface of the electrode structure 110 having the greatest surface area of electrode active material faces the direction of travel of the carrier ions, and thus experiences the greatest growth during cycling between charged and discharged states due to intercalation and/or alloying.

In one embodiment, the electrode structure 110 and electrode assembly 106 can be configured such that the largest surface area projection of the electrode structure 110 and/or electrode active material layer 132 , and the smallest surface area projection of the electrode assembly 106 are simultaneously in a plane that is orthogonal to the stacking direction. For example, in a case as shown in FIGS. 2 and 7 , where the projection of the electrode active material layer 132 in the X-Z plane (L A ×H A ) of the electrode active material layer 132 is the highest, the electrode structure 110 and/or electrode active material layer 132 is positioned with respect to the smallest surface area projection of the electrode assembly (L EA ×H EA ) such the projection plane for both projections is orthogonal to the stacking direction. That is, the plane having the greatest surface area projection of the electrode structure 110 and/or electrode active material is parallel to (and/or in the same plane with) the plane having the smallest surface area projection of the electrode assembly 106 . In this way, according to one embodiment, the surfaces of the electrode structures that are most likely to experience the highest volume growth, i.e., the surfaces having the highest content of electrode active material layer, and/or surfaces that intersect (e.g., are orthogonal to) a direction of travel of carrier ions during charge/discharge of a secondary battery, face the surfaces of the electrode assembly 106 having the lowest surface area. An advantage of providing such a configuration may be that the growth constraint system used to constrain in this greatest direction of growth, e.g. along the longitudinal axis, can be implemented with growth constraints that themselves have a relatively small surface area, as compared to the area of other surfaces of the electrode assembly 106 , thereby reducing the volume required for implementing a constraint system to restrain growth of the electrode assembly.

In one embodiment, the constraint system 108 occupies a relatively low volume % of the combined volume of the electrode assembly 106 and constraint system 108 . That is, the electrode assembly 106 can be understood as having a volume bounded by its exterior surfaces (i.e., the displacement volume), namely the volume enclosed by the first and second longitudinal end surfaces 116 , 118 and the lateral surface 42 connecting the end surfaces. Portions of the constraint system 108 that are external to the electrode assembly 106 (i.e., external to the longitudinal end surfaces 116 , 118 and the lateral surface), such as where first and second primary growth constraints 154 , 156 are located at the longitudinal ends 117 , 119 of the electrode assembly 106 , and first and second secondary growth constraints 158 , 160 are at the opposing ends of the lateral surface 142 , the portions of the constrain system 108 similarly occupy a volume corresponding to the displacement volume of the constraint system portions. Accordingly, in one embodiment, the external portions of the set of electrode constraints 108 , which can include external portions of the primary growth constraint system 151 (i.e., any of the first and second primary growth constraints 154 , 156 and at least one primary connecting member that are external, or external portions thereof), as well as external portions of the secondary growth constraint system 152 (i.e., any of the first and second secondary growth constraints 158 , 160 and at least one secondary connecting member that are external, or external portions thereof) occupies no more than 80% of the total combined volume of the electrode assembly 106 and external portion of the set of electrode constraints 108 . By way of further example, in one embodiment the external portions of the set of electrode constraints occupies no more than 60% of the total combined volume of the electrode assembly 106 and the external portion of the set of electrode constraints. By way of yet a further example, in one embodiment the external portion of the set of electrode constraints 106 occupies no more than 40% of the total combined volume of the electrode assembly 106 and the external portion of the set of electrode constraints. By way of yet a further example, in one embodiment the external portion of the set of electrode constraints 106 occupies no more than 20% of the total combined volume of the electrode assembly 106 and the external portion of the set of electrode constraints. In yet another embodiment, the external portion of the primary growth constraint system 151 (i.e., any of the first and second primary growth constraints 154 , 156 and at least one primary connecting member that are external, or external portions thereof) occupies no more than 40% of the total combined volume of the electrode assembly 106 and the external portion of the primary growth constraint system 151 . By way of further example, in one embodiment the external portion of the primary growth constraint system 151 occupies no more than 30% of the total combined volume of the electrode assembly 106 and the external portion of the primary growth constraint system 151 . By way of yet a further example, in one embodiment the external portion of the primary growth constraint system 151 occupies no more than 20% of the total combined volume of the electrode assembly 106 and the external portion of the primary growth constraint system 151 . By way of yet a further example, in one embodiment the external portion of the primary growth constraint system 151 occupies no more than 10% of the total combined volume of the electrode assembly 106 and the external portion of the primary growth constraint system 151 . In yet another embodiment, the external portion of the secondary growth constraint system 152 (i.e., any of the first and second secondary growth constraints 158 , 160 and at least one secondary connecting member that are external, or external portions thereof) occupies no more than 40% of the total combined volume of the electrode assembly 106 and the external portion of the secondary growth constraint system 152 . By way of further example, in one embodiment, the external portion of the secondary growth constraint system 152 occupies no more than 30% of the total combined volume of the electrode assembly 106 and the external portion of the secondary growth constraint system 152 . By way of yet another example, in one embodiment, the external portion of the secondary growth constraint system 152 occupies no more than 20% of the total combined volume of the electrode assembly 106 and the external portion of the secondary growth constraint system 152 . By way of yet another example, in one embodiment, the external portion of the secondary growth constraint system 152 occupies no more than 10% of the total combined volume of the electrode assembly 106 and the external portion of the secondary growth constraint system 152 .

According to one embodiment, a rationale for the relatively low volume occupied by portions of the set of electrode constraints 108 can be understood by referring to the force schematics shown in FIGS. 8A and 8B . FIG. 8A depicts an embodiment showing the forces exerted on the first and second primary growth constraints 154 , 156 upon cycling of the secondary battery 102 , due to the increase in volume of the electrode active material layers 132 . The arrows 198 b depict the forces exerted by the electrode active material layers 132 upon expansion thereof, where w shows the load applied to the first and second primary growth constraints 154 , 156 , due to the growth of the electrode active material layers 132 , and P shows the pressure applied to the first and second primary growth constraints 154 , 156 as a result of the increase in volume of the electrode active material layers 132 . Similarly, FIG. 8B depicts an embodiment showing the forces exerted on the first and second secondary growth constraints 158 , 160 upon cycling of the secondary battery 102 , due to the increase in volume of the electrode active material layers 132 . The arrows 198 a depict the forces exerted by the electrode active material layers 132 upon expansion thereof, where w shows the load applied to the first and second secondary growth constraints 158 , 160 , due to the growth of the electrode active material layers 132 , and P shows the pressure applied to the first and second secondary growth constraints 158 , 160 as a result of the increase in volume of the electrode active material layers 132 . While the electrode active material expands isotropically (i.e., in all directions), during cycling of the secondary battery, and thus the pressure P in each direction is the same, the load w exerted in each direction is different. By way of explanation, referring to the embodiment depicted in FIGS. 8A and 8B , it can be understood that the load in the X-Z plane on a first or secondary primary growth constraint 154 , 156 is proportional to P×L ES ×H ES , where P is the pressure exerted due to the expansion of the electrode active material layers 132 on the primary growth constraints 154 , 156 , L ES is length of the electrode structures 110 in the transverse direction, and H ES is the height of the electrode structures 110 in the vertical direction. Similarly, the load in the X-Y plane on a first or second secondary growth constraint 158 , 160 is proportional to P×L ES ×W ES , where P is the pressure exerted due to the expansion of the electrode active material layers 132 on the secondary growth constraints 158 , 160 , L ES is length of the electrode structures 110 in the transverse direction, and W ES is the width of the electrode structures 110 in the longitudinal direction. In a case where a tertiary constraint system is provided, the load in the Y-Z plane on a first or secondary tertiary growth constraint 157 , 159 is proportional to P×H ES ×W ES , where P is the pressure exerted due to the expansion of the electrode active material layers 132 on the tertiary growth constraints 157 , 159 , H ES is height of the electrode structures 110 in the vertical direction, and W ES is the width of the electrode structures in the longitudinal direction. Accordingly, in a case where L ES is greater than both W ES and H ES , the load in the Y-Z plane will be the least, and in a case where H ES >WES, the load in the X-Y plane will be less than the load in the X-Z plane, meaning that the X-Z plane has the highest load to be accommodated among the orthogonal planes.

Furthermore, according to one embodiment, if a primary constraint is provided in the X-Z plane in a case where the load in that plane is the greatest, as opposed to providing a primary constraint in the X-Y plane, then the primary constraint in the X-Z plane may require a much lower volume that the primary constraint would be required to have if it were in the X-Y plane. This is because if the primary constraint were in the X-Y plane instead of the X-Z plane, then the constraint would be required to be much thicker in order to have the stiffness against growth that would be required. In particular, as is described herein in further detail below, as the distance between primary connecting members increases, the buckling deflection can also increase, and the stress also increases. For example, the equation governing the deflection due to bending of the primary growth constraints 154 , 156 can be written as:

δ= 60 wL 4 /Eh 3

where w=total distributed load applied on the primary growth constraint 154 , 156 due to the electrode expansion; L=distance between the primary connecting members 158 , 160 along the vertical direction; E=elastic modulus of the primary growth constraints 154 , 156 , and h=thickness (width) of the primary growth constraints 154 , 156 . The stress on the primary growth constraints 154 , 156 due to the expansion of the electrode active material 132 can be calculated using the following equation:

σ=3 wL 2 /4 h 2

where w=total distributed load applied on the primary growth constraints 154 , 156 due to the expansion of the electrode active material layers 132 ; L=distance between primary connecting members 158 , 160 along the vertical direction; and h=thickness (width) of the primary growth constraints 154 , 156 . Thus, if the primary growth constraints were in the X-Y plane, and if the primary connecting members were much further apart (e.g., at longitudinal ends) than they would otherwise be if the primary constraint were in the X-Z plane, this can mean that the primary growth constraints would be required to be thicker and thus occupy a larger volume that they otherwise would if they were in the X-Z plane.

According to one embodiment, a projection of the members of the electrode and counter-electrode populations onto first and second longitudinal end surfaces 116 , 118 circumscribes a first and second projected areas 2002 a , 2002 b . In general, first and second projected areas 2002 a , 2002 b will typically comprise a significant fraction of the surface area of the first and second longitudinal end surfaces 122 , 124 , respectively. For example, in one embodiment the first and second projected areas each comprise at least 50% of the surface area of the first and second longitudinal end surfaces, respectively. By way of further example, in one such embodiment the first and second projected areas each comprise at least 75% of the surface area of the first and second longitudinal end surfaces, respectively. By way of further example, in one such embodiment the first and second projected areas each comprise at least 90% of the surface area of the first and second longitudinal end surfaces, respectively.

In certain embodiments, the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a significant compressive load. For example, in some embodiments, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 0.7 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). For example, in one embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 1.75 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). By way of further example, in one such embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 2.8 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). By way of further example, in one such embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 3.5 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). By way of further example, in one such embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 5.25 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). By way of further example, in one such embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 7 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). By way of further example, in one such embodiment, each of the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of at least 8.75 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). In general, however, the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will be under a compressive load of no more than about 10 kPa (e.g., averaged over the total surface area of each of the longitudinal end surfaces, respectively). The regions of the longitudinal end surface of the electrode assembly that are coincident with the projection of members of the electrode and counter-electrode populations onto the longitudinal end surfaces (i.e., the projected surface regions) may also be under the above compressive loads (as averaged over the total surface area of each projected surface region, respectively). In each of the foregoing exemplary embodiments, the longitudinal end surfaces 116 , 118 of the electrode assembly 106 will experience such compressive loads when an energy storage device 100 having the electrode assembly 106 is charged to at least about 80% of its rated capacity.

According to one embodiment, the secondary growth constraint system 152 is capable of restraining growth of the electrode assembly 106 in the vertical direction (Z direction) by applying a restraining force at a predetermined value, and without excessive skew of the growth restraints. For example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 of greater than 1000 psi and a skew of less than 0.2 mm/m. By way of further example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 with less than 5% displacement at less than or equal to 10,000 psi and a skew of less than 0.2 mm/m. By way of further example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 with less than 3% displacement at less than or equal to 10,000 psi and a skew of less than 0.2 mm/m. By way of further example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 with less than 1% displacement at less than or equal to 10,000 psi and a skew of less than 0.2 mm/m. By way of further example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 in the vertical direction with less than 15% displacement at less than or equal to 10,000 psi and a skew of less than 0.2 mm/m after 50 battery cycles. By way of further example, in one embodiment, the secondary growth constraint system 152 may restrain growth of the electrode assembly 106 in the vertical direction by applying a restraining force to opposing vertical regions 148 , 150 with less than 5% displacement at less than or equal to 10,000 psi and a skew of less than 0.2 mm/m after 150 battery cycles.

Referring now to FIG. 5 , an embodiment of an electrode assembly 106 with a set of electrode constraints 108 is shown, with a cross-section taken along the line A-A′ as shown in FIG. 1 . In the embodiment shown in FIG. 5 , the primary growth constraint system 151 can comprise first and second primary growth constraints 154 , 156 , respectively, at the longitudinal end surfaces 116 , 118 of the electrode assembly 106 , and the secondary growth constraint system 152 comprises first and second secondary growth constraints 158 , 160 at the opposing first and second surface regions 148 , 150 of the lateral surface 142 of the electrode assembly 106 . According to this embodiment, the first and second primary growth constraints 154 , 156 can serve as the at least one secondary connecting member 166 to connect the first and second secondary growth constrains 158 , 160 and maintain the growth constraints in tension with one another in the second direction (e.g., vertical direction) that is orthogonal to the longitudinal direction. However, additionally and/or alternatively, the secondary growth constraint system 152 can comprise at least one secondary connecting member 166 that is located at a region other than the longitudinal end surfaces 116 , 118 of the electrode assembly 106 . Also, the at least one secondary connecting member 166 can be understood to act as at least one of a first and second primary growth constraint 154 , 156 that is internal to the longitudinal ends 116 , 118 of the electrode assembly, and that can act in conjunction with either another internal primary growth restraint and/or a primary growth restraint at a longitudinal end 116 , 118 of the electrode assembly 106 to restrain growth. Referring to the embodiment shown in FIG. 5 , a secondary connecting member 166 can be provided that is spaced apart along the longitudinal axis away from the first and second longitudinal end surfaces 116 , 118 , respectively, of the electrode assembly 106 , such as toward a central region of the electrode assembly 106 . The secondary connecting member 166 can connect the first and second secondary growth constraints 158 , 160 , respectively, at an interior position from the electrode assembly end surfaces 116 , 118 , and may be under tension between the secondary growth constraints 158 , 160 at that position. In one embodiment, the secondary connecting member 166 that connects the secondary growth constraints 158 , 160 at an interior position from the end surfaces 116 , 118 is provided in addition to one or more secondary connecting members 166 provided at the electrode assembly end surfaces 116 , 118 , such as the secondary connecting members 166 that also serve as primary growth constraints 154 , 156 at the longitudinal end surfaces 116 , 118 . In another embodiment, the secondary growth constraint system 152 comprises one or more secondary connecting members 166 that connect with first and second secondary growth constraints 158 , 160 , respectively, at interior positions that are spaced apart from the longitudinal end surfaces 116 , 118 , with or without secondary connecting members 166 at the longitudinal end surfaces 116 , 118 . The interior secondary connecting members 166 can also be understood to act as first and second primary growth constraints 154 , 156 , according to one embodiment. For example, in one embodiment, at least one of the interior secondary connecting members 166 can comprise at least a portion of an electrode or counter electrode structure 110 , 112 , as described in further detail below.

More specifically, with respect to the embodiment shown in FIG. 5 , secondary growth constraint system 152 may include a first secondary growth constraint 158 that overlies an upper region 148 of the lateral surface 142 of electrode assembly 106 , and an opposing second secondary growth constraint 160 that overlies a lower region 150 of the lateral surface 142 of electrode assembly 106 , the first and second secondary growth constraints 158 , 160 being separated from each other in the vertical direction (i.e., along the Z-axis). Additionally, secondary growth constraint system 152 may further include at least one interior secondary connecting member 166 that is spaced apart from the longitudinal end surfaces 116 , 118 of the electrode assembly 106 . The interior secondary connecting member 166 may be aligned parallel to the Z axis and connects the first and second secondary growth constraints 158 , 160 , respectively, to maintain the growth constraints in tension with one another, and to form at least a portion of the secondary constraint system 152 . In one embodiment, the at least one interior secondary connecting member 166 , either alone or with secondary connecting members 166 located at the longitudinal end surfaces 116 , 118 of the electrode assembly 106 , may be under tension between the first and secondary growth constraints 158 , 160 in the vertical direction (i.e., along the Z axis), during repeated charge and/or discharge of an energy storage device 100 or a secondary battery 102 having the electrode assembly 106 , to reduce growth of the electrode assembly 106 in the vertical direction. Furthermore, in the embodiment as shown in FIG. 5 , the set of electrode constraints 108 further comprises a primary growth constraint system 151 having first and second primary growth constraints 154 , 156 , respectively, at the longitudinal ends 117 , 119 of the electrode assembly 106 , that are connected by first and second primary connecting members 162 , 164 , respectively, at the upper and lower lateral surface regions 148 , 150 , respectively, of the electrode assembly 106 . In one embodiment, the secondary interior connecting member 166 can itself be understood as acting in concert with one or more of the first and second primary growth constraints 154 , 156 , respectively, to exert a constraining pressure on each portion of the electrode assembly 106 lying in the longitudinal direction between the secondary interior connecting member 166 and the longitudinal ends 117 , 119 of the electrode assembly 106 where the first and second primary growth constraints 154 , 156 , respectively, can be located.

In one embodiment, one or more of the primary growth constraint system 151 and secondary growth constraint system 152 includes first and secondary primary growth constraints 154 , 156 , respectively, and/or first and second secondary growth constraints 158 , 160 , respectively, that include a plurality of constraint members. That is, each of the primary growth constraints 154 , 156 and/or secondary growth constraints 158 , 160 may be a single unitary member, or a plurality of members may be used to make up one or more of the growth constraints. For example, in one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, can comprise single constraint members extending along the upper and lower surface regions 148 , 150 , respectively, of the electrode assembly lateral surface 142 . In another embodiment, the first and second secondary growth constraints 158 , 160 , respectively, comprise a plurality of members extending across the opposing surface regions 148 , 150 , of the lateral surface. Similarly, the primary growth constraints 154 , 156 may also be made of a plurality of members, or can each comprise a single unitary member at each electrode assembly longitudinal end 117 , 119 . To maintain tension between each of the primary growth constraints 154 , 156 and secondary growth constraints 158 , 160 , the connecting members (e.g., 162 , 164 , 165 , 166 ) are provided to connect the one or plurality of members comprising the growth constraints to the opposing growth constraint members in a manner that exerts pressure on the electrode assembly 106 between the growth constraints.

In one embodiment, the at least one secondary connecting member 166 of the secondary growth constraint system 152 forms areas of contact 168 , 170 with the first and second secondary growth constraints 158 , 160 , respectively, to maintain the growth constraints in tension with one another. The areas of contact 168 , 170 are those areas where the surfaces at the ends 172 , 174 of the at least one secondary connecting member 166 touches and/or contacts the first and second secondary growth constraints 158 , 160 , respectively, such as where a surface of an end of the at least one secondary connecting member 166 is adhered or glued to the first and second secondary growth constraints 158 , 160 , respectively. The areas of contact 168 , 170 may be at each end 172 , 174 and may extend across a surface area of the first and second secondary growth constraints 158 , 160 , to provide good contact therebetween. The areas of contact 168 , 170 provide contact in the longitudinal direction (Y axis) between the second connecting member 166 and the growth constraints 158 , 160 , and the areas of contact 168 , 170 can also extend into the transverse direction (X-axis) to provide good contact and connection to maintain the first and second secondary growth constraints 158 , 160 in tension with one another. In one embodiment, the areas of contact 168 , 170 provide a ratio of the total area of contact (e.g., the sum of all areas 168 , and the sum of all areas 170 ) of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction that is at least 1%. For example, in one embodiment, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction is at least 2%. By way of further example, in one embodiment, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction, is at least 5%. By way of further example, in one embodiment, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction, is at least 10%. By way of further example, in one embodiment, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction, is at least 25%. By way of further example, in one embodiment, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction, is at least 50%. In general, a ratio of the total area of contact of the one or more secondary connecting members 166 in the longitudinal direction (Y axis) with the growth constraints 158 , 160 , per W EA of the electrode assembly 106 in the longitudinal direction, will be less than 100%, such as less than 90%, and even less than 75%, as the one or more connecting members 166 typically do not have an area of contact 168 , 170 that extends across the entire longitudinal axis. However, in one embodiment, an area of contact 168 , 170 of the secondary connecting members 166 with the growth constraints 158 , 160 , may extend across a significant portion of the transverse axis (X axis), and may even extend across the entire L EA of the electrode assembly 106 in the transverse direction. For example, a ratio of the total area of contact (e.g., the sum of all areas 168 , and the sum of all areas 170 ) of the one or more secondary connecting members 166 in the transverse direction (X axis) with the growth constraints 158 , 160 , per L EA of the electrode assembly 106 in the transverse direction, may be at least about 50%. By way of further example, a ratio of the total area of contact of the one or more secondary connecting members 166 in the transverse direction (X axis) with the growth constraints 158 , 160 , per L EA of the electrode assembly 106 in the transverse direction (X-axis), may be at least about 75%. By way of further example, a ratio of the total area of contact of the one or more secondary connecting members 166 in the transverse direction (X axis) with the growth constraints 158 , 160 , per L EA of the electrode assembly 106 in the transverse direction (X axis), may be at least about 90%. By way of further example, a ratio of the total area of contact of the one or more secondary connecting members 166 in the transverse direction (X axis) with the growth constraints 158 , 160 , per L EA of the electrode assembly 106 in the transverse direction (X axis), may be at least about 95%.

According to one embodiment, the areas of contact 168 , 170 between the one or more secondary connecting members 166 and the first and second secondary growth constraints 158 , 160 , respectively, are sufficiently large to provide for adequate hold and tension between the growth constraints 158 , 160 during cycling of an energy storage device 100 or a secondary battery 102 having the electrode assembly 106 . For example, the areas of contact 168 , 170 may form an area of contact with each growth constraint 158 , 160 that makes up at least 2% of the surface area of the lateral surface 142 of the electrode assembly 106 , such as at least 10% of the surface area of the lateral surface 142 of the electrode assembly 106 , and even at least 20% of the surface area of the lateral surface 142 of the electrode assembly 106 . By way of further example, the areas of contact 168 , 170 may form an area of contact with each growth constraint 158 , 160 that makes up at least 35% of the surface area of the lateral surface 142 of the electrode assembly 106 , and even at least 40% of the surface area of the lateral surface 142 of the electrode assembly 106 . For example, for an electrode assembly 106 having upper and lower opposing surface regions 148 , 150 , respectively, the at least one secondary connecting member 166 may form areas of contact 168 , 170 with the growth constraints 158 , 160 along at least 5% of the surface area of the upper and lower opposing surface regions 148 , 150 , respectively, such as along at least 10% of the surface area of the upper and lower opposing surface regions 148 , 150 , respectively, and even at least 20% of the surface area of the upper and lower opposing surface regions 148 , 150 , respectively. By way of further example, an electrode assembly 106 having upper and lower opposing surface regions 148 , 150 , respectively, the at least one secondary connecting member 166 may form areas of contact 168 , 170 with the growth constraints 158 , 160 along at least 40% of the surface area of the upper and lower opposing surface regions 148 , 150 , respectively, such as along at least 50% of the surface area of the upper and lower opposing surface regions 148 , 150 , respectively. By forming a contact between the at least one connecting member 166 and the growth constraints 158 , 160 that makes up a minimum surface area relative to a total surface area of the electrode assembly 106 , proper tension between the growth constraints 158 , 160 can be provided. Furthermore, according to one embodiment, the areas of contact 168 , 170 can be provided by a single secondary connecting member 166 , or the total area of contact may be the sum of multiple areas of contact 168 , 170 provided by a plurality of secondary connecting members 166 , such as one or a plurality of secondary connecting members 166 located at longitudinal ends 117 , 119 of the electrode assembly 106 , and/or one or a plurality of interior secondary connecting members 166 that are spaced apart from the longitudinal ends 117 , 119 of the electrode assembly 106 .

Further still, in one embodiment, the primary and secondary growth constraint systems 151 , 152 , respectively, (and optionally the tertiary growth constraint system) are capable of restraining growth of the electrode assembly 106 in both the longitudinal direction and the second direction orthogonal to the longitudinal direction, such as the vertical direction (Z axis) (and optionally in the third direction, such as along the X axis), to restrain a volume growth % of the electrode assembly.

In certain embodiments, one or more of the primary and secondary growth constraint systems 151 , 152 , respectively, comprises a member having pores therein, such as a member made of a porous material. For example, referring to FIG. 6A depicting a top view of a secondary growth constraint 158 over an electrode assembly 106 , the secondary growth constraint 158 can comprise pores 176 that permit electrolyte to pass therethrough, so as to access an electrode assembly 106 that is at least partially covered by the secondary growth constraint 158 . In one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, have the pores 176 therein. In another embodiment, each of the first and second primary growth constraints 154 , 156 , respectively, and the first and second secondary growth constraints 158 , 160 , respectively, have the pores 176 therein. In yet another embodiment, only one or only a portion of the first and second secondary growth constraints 158 , 160 , respectively, contain the pores therein. In yet a further embodiment, one or more of the first and second primary connecting members 162 , 164 , respectively, and the at least one secondary connecting member 166 contains pores therein. Providing the pores 176 may be advantageous, for example, when the energy storage device 100 or secondary battery 102 contains a plurality of electrode assemblies 106 stacked together in the battery enclosure 104 , to permit electrolyte to flow between the different electrode assemblies 106 in, for example, the secondary battery 102 as shown in the embodiment depicted in FIG. 20 . For example, in one embodiment, a porous member making up at least a portion of the primary and secondary growth constraint system 151 , 152 , respectively, may have a void fraction of at least 0.25. By way of further example, in some embodiments, a porous member making up at least a portion of the primary and secondary growth constraint systems 151 , 152 , respectively, may have a void fraction of at least 0.375. By way of further example, in some embodiments, a porous member making up at least a portion of the primary and secondary growth constraint systems 151 , 152 , respectively, may have a void fraction of at least 0.5. By way of further example, in some embodiments, a porous member making up at least a portion of the primary and secondary growth constraint systems 151 , 152 , respectively, may have a void fraction of at least 0.625. By way of further example, in some embodiments, a porous member making up at least a portion of the primary and secondary growth constraint systems 151 , 152 , respectively, may have a void fraction of at least 0.75.

In one embodiment, the set of electrode constraints 108 may be assembled and secured to restrain growth of the electrode assembly 106 by at least one of adhering, bonding, and/or gluing components of the primary growth constraint system 151 to components of the secondary growth constraint system 152 . For example, components of the primary growth constraint system 151 may be glued, welded, bonded, or otherwise adhered and secured to components of the secondary growth constraint system 152 . For example, as shown in FIG. 4A , the first and second primary growth constraints 154 , 156 , respectively, can be adhered to first and second primary connecting members 162 , 164 , respectively, that may also serve as first and second secondary growth constraints 158 , 160 , respectively. Conversely, the first and second secondary growth constraints 158 , 150 , respectively, can be adhered to at least one secondary connecting member 166 that serves as at least one of the first and second primary growth constraints 154 , 156 , respectively, such as growth constraints at the longitudinal ends 117 , 119 of the electrode assembly 106 . Referring to FIG. 5 , the first and second secondary growth constraints 158 , 160 , respectively, can also be adhered to at least one secondary connecting member 166 that is an interior connecting member 166 spaced apart from the longitudinal ends 117 , 119 . In one embodiment, by securing portions of the primary and secondary growth constraint systems 151 , 152 , respectively, to one another, the cooperative restraint of the electrode assembly 106 growth can be provided.

FIGS. 6A-6D illustrate embodiments for securing one or more of the first and second secondary growth constraints 158 , 160 , respectively, to one or more secondary connecting members 166 . FIGS. 6A-6D provide a top view of an embodiment of the electrode assembly 106 having the first secondary growth constraint 158 over an upper surface region 148 of the lateral surface 142 of the electrode assembly 106 . Also shown are first and second primary growth constraints 154 , 156 , respectively, spaced apart along a longitudinal axis (Y axis). A secondary connecting member 166 which may correspond to at least a part of an electrode structure 110 and/or counter electrode structure 112 is also shown. In the embodiment as shown, the first secondary growth constraint 158 has pores 176 therein to allow electrolyte and carrier ions to reach the electrode 110 and counter-electrode 112 structures. As described above, in certain embodiments, the first and second primary growth constraints 154 , 156 , respectively, can serve as the at least one secondary connecting member 166 to connect the first and second secondary growth constraints 158 , 160 , respectively. Thus, in the version as shown, the first and second secondary growth constraints 158 , 160 , respectively, can be connected at the periphery of the electrode assembly 106 to the first and second primary growth constraints 154 , 156 , respectively. However, in one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, can also be connected via a secondary connecting member 166 that is an interior secondary connecting member 166 . In the version as shown, the first secondary growth constraint 158 comprises bonded regions 178 where the growth constraint 158 is bonded to an underlying interior secondary connecting member 166 , and further comprises non-bonded regions 180 where the growth constraint 158 is not bonded to an underlying secondary connecting member 166 , so as to provide areas of contact 168 between the growth constraint 158 and underlying secondary connecting member 166 in the form of columns of bonded regions 178 that alternate with areas of non-bonded regions 180 . In one embodiment, the non-bonded regions 180 further contain open pores 176 where electrolyte and carrier ions can pass. According to one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, are adhered to a secondary connecting member 166 that comprises at least a portion of an electrode 110 or counter electrode 112 structure, or other interior structure of the electrode assembly 106 . The first and second secondary growth constraints 158 , 160 , respectively, in one embodiment, can be adhered to the top and bottom ends of the counter-electrode structures 112 or other interior structures forming the secondary connecting member 166 , to form columns of adhered areas 178 corresponding to where the constraint is adhered to a counter-electrode 112 or other interior structure, and columns of non-adhered areas 180 between the counter-electrode 112 or other interior structures. Furthermore, the first and second secondary growth constraints 158 , 160 , respectively, may be bonded or adhered to the counter-electrode structure 112 or other structure forming the at least one secondary connecting member 166 such that pores 176 remain open at least in the non-bonded areas 180 , and may also be adhered such that pores 176 in the bonded regions 178 can remain relatively open to allow electrolyte and carrier ions to pass therethrough.

In yet another embodiment as shown in FIG. 6B , the first and second secondary growth constraints 158 , 160 , respectively, are connected at the periphery of the electrode assembly 106 to the first and second primary growth constraints 154 , 156 , respectively, and may also be connected via a secondary connecting member 166 that is an interior secondary connecting member 166 . In the version as shown, the first secondary growth constraint 158 comprises bonded regions 178 where the growth constraint 158 is bonded to an underlying interior secondary connecting member 166 , and further comprises non-bonded regions 180 where the growth constraint 158 is not bonded to an underlying secondary connecting member 166 , so as to provide areas of contact 168 between the growth constraint 158 and underlying secondary connecting member 166 in the form of rows of bonded regions 178 that alternate with areas of non-bonded regions 180 . These bonded and non-bonded regions 178 , 180 , respectively, in this embodiment can extend across a dimension of the secondary connecting member 166 , which may be in the transverse direction (X axis) as shown in FIG. 6B , as opposed to in the longitudinal direction (Y axis) as in FIG. 6A . Alternatively, the bonded and non-bonded regions 178 , 180 , respectively, can extend across both longitudinal and transverse directions in a predetermined pattern. In one embodiment, the non-bonded regions 180 further contain open pores 176 where electrolyte and carrier ions can pass. The first and second secondary growth constraints 158 , 160 , respectively, can in one embodiment, be adhered to the top and bottom ends of the counter-electrode structures 112 or other interior structures forming the secondary connecting member 166 , to form rows of adhered areas 178 corresponding to where the growth constraint is adhered to a counter-electrode 112 or other interior structure, and areas of non-adhered areas 180 between the counter-electrode 112 or other interior structures. Furthermore, the first and second secondary growth constraints 158 , 160 , respectively, may be bonded or adhered to the counter-electrode structure 112 or other structure forming the at least one secondary connecting member 166 such that pores 176 remain open at least in the non-bonded areas 180 , and may also be adhered such that pores 176 in the bonded regions 178 can remain relatively open to allow electrolyte and carrier ions to pass therethrough.

In yet another embodiment as shown in FIG. 6C , an alternative configuration for connection of the first and second secondary growth constraint members 158 , 160 , respectively, to the at least one secondary connecting member 166 is shown. More specifically, the bonded and non-bonded regions 178 , 180 , respectively, of the secondary growth constraints 158 , 160 are shown to be symmetric about an axis of adhesion A G located towards the center of the electrode assembly 106 in the longitudinal direction (Y axis). As shown in this embodiment, the first and second secondary growth constraints 158 , 160 , respectively, are attached to the ends of secondary connecting members 166 that comprise an electrode 110 , counter-electrode 112 , or other interior electrode assembly structure, but the columns of bonded and non-bonded areas are not of equal size. That is, the growth constraints 158 , 160 can be selectively bonded to interior secondary connecting members 166 in an alternating or other sequence, such that the amount of non-bonded area 180 exceeds the amount of bonded area 178 , for example, to provide for adequate numbers of pores 176 open for passage of electrolyte therethrough. That is, the first and second secondary growth constraints 158 , 160 , respectively, may be bonded to every other counter-electrode 112 or other interior structure making up the secondary connecting members 166 , or to one of every 1+n structures (e.g., counter-electrodes 112 ), according to an area of the bonded to non-bonded region to be provided.

FIG. 6D illustrates yet another embodiment of an alternative configuration for connection of the first and second secondary growth constraint members 158 , 160 , respectively, to the at least one secondary connecting member 166 . In this version, the bonded and non-bonded regions 178 , 180 , respectively, of the first and second secondary growth constraints 158 , 160 , respectively, form an asymmetric pattern of columns about the axis of adhesion A G . That is, the first and second secondary growth constraints 158 , 160 , respectively, can be adhered to the secondary connecting member 166 corresponding to the electrode 110 or counter-electrode 112 structure or other internal structure in a pattern that is non-symmetric, such as by skipping adhesion to interior structures according to a random or other non-symmetric pattern. In the pattern in the embodiment as shown, the bonded and non-bonded regions 178 , 180 , respectively, form alternating columns with different widths that are not symmetric about the axis of adhesion A G . Furthermore, while an axis of adhesion A G is shown herein as lying in a longitudinal direction (Y axis), the axis of adhesion A G may also lie along the transverse direction (X axis), or there may be two axes of adhesion along the longitudinal and transverse directions, about which the patterns of the bonded and non-bonded regions 178 , 180 , respectively, can be formed. Similarly, for each pattern described and/or shown with respect to FIGS. 6A-6D , it is understood that a pattern shown along the longitudinal direction (Y axis) could instead be formed along the transverse direction (X axis), or vice versa, or a combination of patterns in both directions can be formed.

In one embodiment, an area of a bonded region 178 of the first or second secondary growth constraints 158 , 160 , respectively, along any secondary connecting member 166 , and/or along at least one of the first or second primary growth constraints 154 , 156 , respectively, to a total area of the bonded and non-bonded regions along the constraint, is at least 50%, such as at least 75%, and even at least 90%, such as 100%. In another embodiment, the first and second secondary growth constraints 158 , 160 , respectively, can be adhered to a secondary connecting member 166 corresponding to an electrode 110 or counter-electrode 112 structure or other interior structure of the electrode assembly 106 in such a way that the pores 176 in the bonded regions 178 remain open. That is, the first and second secondary growth constraints 158 , 160 , respectively, can be bonded to the secondary connecting member 166 such that the pores 176 in the growth constraints are not occluded by any adhesive or other means used to adhere the growth constraint(s) to the connecting member(s). According to one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, are connected to the at least one secondary connecting members 166 to provide an open area having the pores 176 of at least 5% of the area of the growth constraints 158 , 160 , and even an open area having the pores 176 of at least 10% of the area of the growth constraints 158 , 160 , and even an open area having the pores 176 of at least 25% of the area of the growth constraints 158 , 160 , such as an open area having the pores 176 of at least 50% of the area of the growth constraints 158 , 160 .

While the embodiments described above may be characterized with the pores 176 aligned as columns along the Y axis, it will be appreciated by those of skill in the art that the pores 176 may be characterized as being oriented in rows along the X axis in FIGS. 6A-6D , as well, and the adhesive or other means of adhesion may be applied horizontally or along the X axis to assemble the set of electrode constraints 108 . Furthermore, the adhesive or other bonding means may be applied to yield mesh-like air pores 176 . Further, the axis of adhesion A G , as described above, may also be oriented horizontally, or along the X axis, to provide analogous symmetric and asymmetric adhesion and/or bonding patterns.

Further, while the pores 176 and non-bonded regions 180 have been described above as being aligned in columns along the Y axis and in rows along the X axis (i.e., in a linear fashion), it has been further contemplated that the pores 176 and/or non-bonded regions 180 may be arranged in a non-linear fashion. For example, in certain embodiments, the pores 176 may be distributed throughout the surface of the first and second secondary growth constraints 158 , 160 , respectively, in a non-organized or random fashion. Accordingly, in one embodiment, adhesive or other adhesion means may be applied in any fashion, so long as the resulting structure has adequate pores 176 that are not excessively occluded, and contains the non-bonded regions 180 having the non-occluded pores 176 .

Secondary Constraint System Sub-Architecture

According to one embodiment, as discussed above, one or more of the first and second secondary growth constraints 158 , 160 , respectively, can be connected together via a secondary connecting member 166 that is a part of an interior structure of the electrode assembly 106 , such as a part of an electrode 110 and/or counter-electrode structure 112 . In one embodiment, by providing connection between the constraints via structures within the electrode assembly 106 , a tightly constrained structure can be realized that adequately compensates for strain produced by growth of the electrode structure 110 . For example, in one embodiment, the first and second secondary growth constraints 158 , 160 , respectively, may constrain growth in a direction orthogonal to the longitudinal direction, such as the vertical direction, by being placed in tension with one another via connection through a connecting member 166 that is a part of an electrode 110 or counter-electrode structure 112 . In yet a further embodiment, growth of an electrode structure 110 (e.g., an anode structure) can be countered by connection of the secondary growth constraints 158 , 160 through a counter-electrode structure 112 (e.g., cathode) that serves as the secondary connecting member 166 .

In general, in certain embodiments, components of the primary growth constraint system 151 and the secondary growth constraint system 152 may be attached to the electrode 110 and/or counter-electrode structures 112 , respectively, within an electrode assembly 106 , and components of the secondary growth constraint system 152 may also be embodied as the electrode 110 and/or counter-electrode structures 112 , respectively, within an electrode assembly 106 , not only to provide effective restraint but also to more efficiently utilize the volume of the electrode assembly 106 without excessively increasing the size of an energy storage device 110 or a secondary battery 102 having the electrode assembly 106 . For example, in one embodiment, the primary growth constraint system 151 and/or secondary growth constraint system 152 may be attached to one or more electrode structures 110 . By way of further example, in one embodiment, the primary growth constraint system 151 and/or secondary growth constraint system 152 may be attached to one or more counter-electrode structures 112 . By way of further example, in certain embodiments, the at least one secondary connecting member 166 may be embodied as the population of electrode structures 110 . By way of further example, in certain embodiments, the at least one secondary connecting member 166 may be embodied as the population of counter-electrode structures 112 .

Referring now to FIG. 7 , a Cartesian coordinate system is shown for reference having a vertical axis (Z axis), a longitudinal axis (Y axis), and a transverse axis (X axis); wherein the X axis is oriented as coming out of the plane of the page; and a designation of the stacking direction D, as described above, co-parallel with the Y axis. More specifically, FIG. 7 shows a cross section, along the line A-A′ as in FIG. 1 , of a set of electrode constraints 108 , including one embodiment of both a primary growth constraint system 151 and one embodiment of a secondary growth constraint system 152 . Primary growth constraint system 151 includes a first primary growth constraint 154 and a second primary growth constraint 156 , as described above, and a first primary connecting member 162 and a second primary connecting member 164 , as described above. Secondary growth constraint system 152 includes a first secondary growth constraint 158 , a second secondary growth constraint 160 , and at least one secondary connecting member 166 embodied as the population of electrode structures 110 and/or the population of counter-electrode structures 112 ; therefore, in this embodiment, the at least one secondary connecting member 166 , electrode structures 110 , and/or counter-electrode structures 112 can be understood to be interchangeable. Furthermore, the separator 130 may also form a portion of a secondary connecting member 166 . Further, in this embodiment, first primary connecting member 162 and first secondary growth constraint 158 are interchangeable, as described above. Further still, in this embodiment, second primary connecting member 164 and second secondary growth constraint 160 are interchangeable, as described above. More specifically, illustrated in FIG. 7 is one embodiment of a flush connection of the secondary connecting member 166 corresponding to the electrode 110 or counter-electrode structure 112 with the first secondary growth constraint 158 and second secondary growth constraint 160 . The flush connection may further include a layer of glue 182 between the first secondary growth constraint 158 and secondary connecting member 166 , and a layer of glue 182 between the second secondary growth constraint 160 and secondary connecting member 166 . The layers of glue 182 affix first secondary growth constraint 158 to secondary connecting members 166 , and affix the second secondary growth constraint 160 to secondary connecting member 166 .

Also, one or more of the first and second primary growth constraints 154 , 156 , first and second primary connecting members 162 , 164 , first and second secondary growth constraints 158 , 160 , and at least one secondary connecting member 166 may be provided in the form of a plurality of segments 1088 or parts that can be joined together to form a single member. For example, as shown in the embodiment as illustrated in FIG. 7 , a first secondary growth constraint 158 is provided in the form of a main middle segment 1088 a and first and second end segments 1088 b located towards the longitudinal ends 117 , 119 of the electrode assembly 106 , with the middle segment 1088 a being connected to each first and second end segment 1088 b by a connecting portion 1089 provided to connect the segments 1088 , such as notches formed in the segments 1088 that can be interconnected to join the segments 1088 to one another. A second secondary growth constraint 160 may similarly be provided in the form of a plurality of segments 1088 that can be connected together to form the constraint, as shown in FIG. 7 . In one embodiment, one or more of the secondary growth constraints 158 , 160 , at least one primary connecting member 162 , and/or at least one secondary connecting member 166 may also be provided in the form of a plurality of segments 1088 that can be connected together via a connecting portions such as notches to form the complete member. According to one embodiment, the connection of the segments 1088 together via the notch or other connecting portion may provide for pre-tensioning of the member formed of the plurality of segments when the segments are connected.

Further illustrated in FIG. 7 , in one embodiment, are members of the electrode population 110 having an electrode active material layer 132 , an ionically porous electrode current collector 136 , and an electrode backbone 134 that supports the electrode active material layer 132 and the electrode current collector 136 . Similarly, in one embodiment, illustrated in FIG. 7 are members of the counter-electrode population 112 having a counter-electrode active material layer 138 , a counter-electrode current collector 140 , and a counter-electrode backbone 141 that supports the counter-electrode active material layer 138 and the counter-electrode current collector 140 .

Without being bound to any particular theory (e.g., as in FIG. 7 ), in certain embodiments, members of the electrode population 110 include an electrode active material layer 132 , an electrode current collector 136 , and an electrode backbone 134 that supports the electrode active material layer 132 and the electrode current collector 136 . Similarly, in certain embodiments, members of the counter-electrode population 112 include a counter-electrode active material layer 138 , a counter-electrode current collector 140 , and a counter-electrode backbone 141 that supports the counter-electrode active material layer 138 and the counter-electrode current collector 140 .

While members of the electrode population 110 have been illustrated and described herein to include the electrode active material layer 132 being directly adjacent to the electrode backbone 134 , and the electrode current collector 136 directly adjacent to and effectively surrounding the electrode backbone 134 and the electrode active material layer 132 , those of skill in the art will appreciate other arrangements of the electrode population 110 have been contemplated. For example, in one embodiment (not shown), the electrode population 110 may include the electrode active material layer 132 being directly adjacent to the electrode current collector 136 , and the electrode current collector 136 being directly adjacent to the electrode backbone 134 . Stated alternatively, the electrode backbone 134 may be effectively surrounded by the electrode current collector 136 , with the electrode active material layer 132 flanking and being directly adjacent to the electrode current collector 136 . As will be appreciated by those of skill in the art, any suitable configuration of the electrode population 110 and/or the counter-electrode population 112 may be applicable to the inventive subject matter described herein, so long as the electrode active material layer 132 is separated from the counter-electrode active material layer 138 via separator 130 . Also, the electrode current collector 136 is required to be ion permeable if it is located between the electrode active material layer 132 and separator 130 ; and the counter-electrode current collector 140 is required to be ion permeable if it is located between the counter-electrode active material layer 138 and separator 130 .

For ease of illustration, only three members of the electrode population 110 and four members of the counter-electrode population 112 are depicted; in practice, however, an energy storage device 100 or secondary battery 102 using the inventive subject matter herein may include additional members of the electrode 110 and counter-electrode 112 populations depending on the application of the energy storage device 100 or secondary battery 102 , as described above. Further still, illustrated in FIG. 7 is a microporous separator 130 electrically insulating the electrode active material layer 132 from the counter-electrode active material layer 138 .

As described above, in certain embodiments, each member of the population of electrode structures 110 may expand upon insertion of carrier ions (not shown) within an electrolyte (not shown) into the electrode structures 110 , and contract upon extraction of carrier ions from electrode structures 110 . For example, in one embodiment, the electrode structures 110 may be anodically active. By way of further example, in one embodiment, the electrode structures 110 may be cathodically active.

Furthermore, to connect the first and second secondary growth constraints 158 , 160 , respectively, the constraints 158 , 160 can be attached to the at least one connecting member 166 by a suitable means, such as by gluing as shown, or alternatively by being welded, such as by being welded to the current collectors 136 , 140 . For example, the first and/or second secondary growth constraints 158 , 160 , respectively, can be attached to a secondary connecting member 166 corresponding to at least one of an electrode structure 110 and/or counter-electrode structure 112 , such as at least one of an electrode and/or counter-electrode backbone 134 , 141 , respectively, an electrode and/or counter-electrode current collector 136 , 140 , respectively, by at least one of adhering, gluing, bonding, welding, and the like. According to one embodiment, the first and/or second secondary growth constraints 158 , 160 , respectively, can be attached to the secondary connecting member 166 by mechanically pressing the first and/or second secondary growth constraint 158 , 160 , respectively, to an end of one or more secondary connecting member 166 , such as ends of the population of electrode 100 and/or counter-electrode structures 112 , while using a glue or other adhesive material to adhere one or more ends of the electrode 110 and/or counter-electrode structures 112 to at least one of the first and/or second secondary growth constraints 158 , 160 , respectively.

FIGS. 8A-B depict force schematics, according to one embodiment, showing the forces exerted on the electrode assembly 106 by the set of electrode constraints 108 , as well as the forces being exerted by electrode structures 110 upon repeated cycling of a secondary battery 102 containing the electrode assembly 106 . As shown in FIGS. 8A-B , repeated cycling through charge and discharge of the secondary battery 102 can cause growth in electrode structures 110 , such as in electrode active material layers 132 of the electrode structures 110 , due to intercalation and/or alloying of ions (e.g., Li) into the electrode active material layers 132 of the electrode structures 110 . Thus, the electrode structures 110 can exert opposing forces 198 a in the vertical direction, as well as opposing forces 198 b in the longitudinal direction, due to the growth in volume of the electrode structure 110 . While not specifically shown, the electrode structure 110 may also exert opposing forces in the transverse direction due to the change in volume. To counteract these forces, and to restrain overall growth of the electrode assembly 106 , in one embodiment, the set of electrode constraints 108 includes the primary growth constraint system 151 with the first and second primary growth constraints 154 , 156 , respectively, at the longitudinal ends 117 , 119 of the electrode assembly 106 , which exert forces 200 a in the longitudinal direction to counter the longitudinal forces 198 b exerted by the electrode structure 110 . Similarly, in one embodiment, the set of electrode constraints 108 includes the secondary growth constraint system 152 with the first and second secondary growth constraints 158 , 160 , respectively, at opposing surfaces along the vertical direction of the electrode assembly 106 , which exert forces 200 b in the vertical direction to counter the vertical forces 198 a exerted by the electrode structure 110 . Furthermore, a tertiary growth constraint system 155 (not shown) can also be provided, alternatively or in addition, to one or more of the first and second growth constraint systems 151 , 152 , respectively, to exert counter forces in the transverse direction to counteract transverse forces exerted by volume changes of the electrode structures 110 in the electrode assembly 106 . Accordingly, the set of electrode constraints 108 may be capable of at least partially countering the forces exerted by the electrode structure 110 by volume change of the electrode structure 110 during cycling between charge and discharge, such that an overall macroscopic growth of the electrode assembly 106 can be controlled and restrained.

Population of Electrode Structures

Referring again to FIG. 7 , each member of the population of electrode structures 110 may also include a top 1052 adjacent to the first secondary growth constraint 158 , a bottom 1054 adjacent to the second secondary growth constraint 160 , and a lateral surface (not marked) surrounding a vertical axis A ES (not marked) parallel to the Z axis, the lateral surface connecting the top 1052 and the bottom 1054 . The electrode structures 110 further include a length L ES , a width W ES , and a height H ES . The length L ES being bounded by the lateral surface and measured along the X axis. The width W ES being bounded by the lateral surface and measured along the Y axis, and the height H ES being measured along the vertical axis A ES or the Z axis from the top 1052 to the bottom 1054 .

The L ES of the members of the electrode population 110 will vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the members of the electrode population 110 will typically have a L ES in the range of about 5 mm to about 500 mm. For example, in one such embodiment, the members of the electrode population 110 have a L ES of about 10 mm to about 250 mm. By way of further example, in one such embodiment, the members of the electrode population 110 have a L ES of about 20 mm to about 100 mm.

The W ES of the members of the electrode population 110 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, each member of the electrode population 110 will typically have a W ES within the range of about 0.01 mm to 2.5 mm. For example, in one embodiment, the W ES of each member of the electrode population 110 will be in the range of about 0.025 mm to about 2 mm. By way of further example, in one embodiment, the W ES of each member of the electrode population 110 will be in the range of about 0.05 mm to about 1 mm.

The H ES of the members of the electrode population 110 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, members of the electrode population 110 will typically have a H ES within the range of about 0.05 mm to about 10 mm. For example, in one embodiment, the H ES of each member of the electrode population 110 will be in the range of about 0.05 mm to about 5 mm. By way of further example, in one embodiment, the H ES of each member of the electrode population 110 will be in the range of about 0.1 mm to about 1 mm.

In another embodiment, each member of the population of electrode structures 110 may include an electrode structure backbone 134 having a vertical axis A ESB parallel to the Z axis. The electrode structure backbone 134 may also include a layer of electrode active material 132 surrounding the electrode structure backbone 134 about the vertical axis A ESB . Stated alternatively, the electrode structure backbone 134 provides mechanical stability for the layer of electrode active material 132 , and may provide a point of attachment for the primary growth constraint system 151 and/or secondary constraint system 152 . In certain embodiments, the layer of electrode active material 132 expands upon insertion of carrier ions into the layer of electrode active material 132 , and contracts upon extraction of carrier ions from the layer of electrode active material 132 . For example, in one embodiment, the layer of electrode active material 132 may be anodically active. By way of further example, in one embodiment, the layer of electrode active material 132 may be cathodically active. The electrode structure backbone 134 may also include a top 1056 adjacent to the first secondary growth constraint 158 , a bottom 1058 adjacent to the second secondary growth constraint 160 , and a lateral surface (not marked) surrounding the vertical axis A ESB and connecting the top 1056 and the bottom 1058 . The electrode structure backbone 134 further includes a length L ESB , a width W ESB , and a height H ESB . The length L ESB being bounded by the lateral surface and measured along the X axis. The width W ESB being bounded by the lateral surface and measured along the Y axis, and the height H ESB being measured along the Z axis from the top 1056 to the bottom 1058 .

The L ESB of the electrode structure backbone 134 will vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the electrode structure backbone 134 will typically have a L ESB in the range of about 5 mm to about 500 mm. For example, in one such embodiment, the electrode structure backbone 134 will have a L ESB of about 10 mm to about 250 mm. By way of further example, in one such embodiment, the electrode structure backbone 134 will have a L ESB of about 20 mm to about 100 mm. According to one embodiment, the electrode structure backbone 134 may be the substructure of the electrode structure 110 that acts as the at least one connecting member 166 .

The W ESB of the electrode structure backbone 134 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, each electrode structure backbone 134 will typically have a W ESB of at least 1 micrometer. For example, in one embodiment, the W ESB of each electrode structure backbone 134 may be substantially thicker, but generally will not have a thickness in excess of 500 micrometers. By way of further example, in one embodiment, the W ESB of each electrode structure backbone 134 will be in the range of about 1 to about 50 micrometers.

The H ESB of the electrode structure backbone 134 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the electrode structure backbone 134 will typically have a H ESB of at least about 50 micrometers, more typically at least about 100 micrometers. Further, in general, the electrode structure backbone 134 will typically have a H ESB of no more than about 10,000 micrometers, and more typically no more than about 5,000 micrometers. For example, in one embodiment, the H ESB of each electrode structure backbone 134 will be in the range of about 0.05 mm to about 10 mm. By way of further example, in one embodiment, the H ESB of each electrode structure backbone 134 will be in the range of about 0.05 mm to about 5 mm. By way of further example, in one embodiment, the H ESB of each electrode structure backbone 134 will be in the range of about 0.1 mm to about 1 mm.

Depending upon the application, electrode structure backbone 134 may be electrically conductive or insulating. For example, in one embodiment, the electrode structure backbone 134 may be electrically conductive and may include electrode current collector 136 for electrode active material 132 . In one such embodiment, electrode structure backbone 134 includes an electrode current collector 136 having a conductivity of at least about 10 3 Siemens/cm. By way of further example, in one such embodiment, electrode structure backbone 134 includes an electrode current collector 136 having a conductivity of at least about 10′ Siemens/cm. By way of further example, in one such embodiment, electrode structure backbone 134 includes an electrode current collector 136 having a conductivity of at least about 10 5 Siemens/cm. In other embodiments, electrode structure backbone 134 is relatively nonconductive. For example, in one embodiment, electrode structure backbone 134 has an electrical conductivity of less than 10 Siemens/cm. By way of further example, in one embodiment, electrode structure backbone 134 has an electrical conductivity of less than 1 Siemens/cm. By way of further example, in one embodiment, electrode structure backbone 134 has an electrical conductivity of less than 10 −1 Siemens/cm.

In certain embodiments, electrode structure backbone 134 may include any material that may be shaped, such as metals, semiconductors, organics, ceramics, and glasses. For example, in certain embodiments, materials include semiconductor materials such as silicon and germanium. Alternatively, however, carbon-based organic materials, or metals, such as aluminum, copper, nickel, cobalt, titanium, and tungsten, may also be incorporated into electrode structure backbone 134 . In one exemplary embodiment, electrode structure backbone 134 comprises silicon. The silicon, for example, may be single crystal silicon, polycrystalline silicon, amorphous silicon, or a combination thereof.

In certain embodiments, the electrode active material layer 132 may have a thickness of at least one micrometer. Typically, however, the electrode active material layer 132 thickness will not exceed 500 micrometers, such as not exceeding 200 micrometers. For example, in one embodiment, the electrode active material layer 132 may have a thickness of about 1 to 50 micrometers. By way of further example, in one embodiment, the electrode active material layer 132 may have a thickness of about 2 to about 75 micrometers. By way of further example, in one embodiment, the electrode active material layer 132 may have a thickness of about 10 to about 100 micrometers. By way of further example, in one embodiment, the electrode active material layer 132 may have a thickness of about 5 to about 50 micrometers.

In certain embodiments, the electrode current collector 136 includes an ionically permeable conductor material that has sufficient ionic permeability to carrier ions to facilitate the movement of carrier ions from the separator 130 to the electrode active material layer 132 , and sufficient electrical conductivity to enable it to serve as a current collector. Being positioned between the electrode active material layer 132 and the separator 130 , the electrode current collector 136 may facilitate more uniform carrier ion transport by distributing current from the electrode current collector 136 across the surface of the electrode active material layer 132 . This, in turn, may facilitate more uniform insertion and extraction of carrier ions and thereby reduce stress in the electrode active material layer 132 during cycling; since the electrode current collector 136 distributes current to the surface of the electrode active material layer 132 facing the separator 130 , the reactivity of the electrode active material layer 132 for carrier ions will be the greatest where the carrier ion concentration is the greatest.

The electrode current collector 136 includes an ionically permeable conductor material that is both ionically and electrically conductive. Stated differently, the electrode current collector 136 has a thickness, an electrical conductivity, and an ionic conductivity for carrier ions that facilitates the movement of carrier ions between an immediately adjacent electrode active material layer 132 on one side of the ionically permeable conductor layer and an immediately adjacent separator layer 130 on the other side of the electrode current collector 136 in an electrochemical stack or electrode assembly 106 . On a relative basis, the electrode current collector 136 has an electrical conductance that is greater than its ionic conductance when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . For example, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the electrode current collector 136 will typically be at least 1,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the electrode current collector 136 is at least 5,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the electrode current collector 136 is at least 10,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the electrode current collector 136 layer is at least 50,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the electrode current collector 136 is at least 100,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

In one embodiment, and when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 , such as when a secondary battery 102 is charging or discharging, the electrode current collector 136 has an ionic conductance that is comparable to the ionic conductance of an adjacent separator layer 130 . For example, in one embodiment, the electrode current collector 136 has an ionic conductance (for carrier ions) that is at least 50% of the ionic conductance of the separator layer 130 (i.e., a ratio of 0.5:1, respectively) when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the electrode current collector 136 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the electrode current collector 136 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1.25:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the electrode current collector 136 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1.5:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the electrode current collector 136 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 2:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

In one embodiment, the electrode current collector 136 also has an electrical conductance that is substantially greater than the electrical conductance of the electrode active material layer 132 . For example, in one embodiment, the ratio of the electrical conductance of the electrode current collector 136 to the electrical conductance of the electrode active material layer 132 is at least 100:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the electrode current collector 136 to the electrical conductance of the electrode active material layer 132 is at least 500:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the electrode current collector 136 to the electrical conductance of the electrode active material layer 132 is at least 1000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the electrode current collector 136 to the electrical conductance of the electrode active material layer 132 is at least 5000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the electrode current collector 136 to the electrical conductance of the electrode active material layer 132 is at least 10,000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

The thickness of the electrode current collector layer 136 (i.e., the shortest distance between the separator 130 and, in one embodiment, the anodically active material layer (e.g., electrode active material layer 132 ) between which the electrode current collector layer 136 is sandwiched) in certain embodiments will depend upon the composition of the layer 136 and the performance specifications for the electrochemical stack. In general, when an electrode current collector layer 136 is an ionically permeable conductor layer, it will have a thickness of at least about 300 Angstroms. For example, in some embodiments, it may have a thickness in the range of about 300-800 Angstroms. More typically, however, it will have a thickness greater than about 0.1 micrometers. In general, an ionically permeable conductor layer will have a thickness not greater than about 100 micrometers. Thus, for example, in one embodiment, the electrode current collector layer 136 will have a thickness in the range of about 0.1 to about 10 micrometers. By way of further example, in some embodiments, the electrode current collector layer 136 will have a thickness in the range of about 0.1 to about 5 micrometers. By way of further example, in some embodiments, the electrode current collector layer 136 will have a thickness in the range of about 0.5 to about 3 micrometers. In general, it is preferred that the thickness of the electrode current collector layer 136 be approximately uniform. For example, in one embodiment, it is preferred that the electrode current collector layer 136 have a thickness non-uniformity of less than about 25%. In certain embodiments, the thickness variation is even less. For example, in some embodiments, the electrode current collector layer 136 has a thickness non-uniformity of less than about 20%. By way of further example, in some embodiments, the electrode current collector layer 136 has a thickness non-uniformity of less than about 15%. In some embodiments the ionically permeable conductor layer has a thickness non-uniformity of less than about 10%.

In one embodiment, the electrode current collector layer 136 is an ionically permeable conductor layer including an electrically conductive component and an ion conductive component that contribute to the ionic permeability and electrical conductivity. Typically, the electrically conductive component will include a continuous electrically conductive material (e.g., a continuous metal or metal alloy) in the form of a mesh or patterned surface, a film, or composite material comprising the continuous electrically conductive material (e.g., a continuous metal or metal alloy). Additionally, the ion conductive component will typically comprise pores, for example, interstices of a mesh, spaces between a patterned metal or metal alloy containing material layer, pores in a metal film, or a solid ion conductor having sufficient diffusivity for carrier ions. In certain embodiments, the ionically permeable conductor layer includes a deposited porous material, an ion-transporting material, an ion-reactive material, a composite material, or a physically porous material. If porous, for example, the ionically permeable conductor layer may have a void fraction of at least about 0.25. In general, however, the void fraction will typically not exceed about 0.95. More typically, when the ionically permeable conductor layer is porous the void fraction may be in the range of about 0.25 to about 0.85. In some embodiments, for example, when the ionically permeable conductor layer is porous the void fraction may be in the range of about 0.35 to about 0.65.

In the embodiment illustrated in FIG. 7 , electrode current collector layer 136 is the sole anode current collector for electrode active material layer 132 . Stated differently, electrode structure backbone 134 may include an anode current collector. In certain other embodiments, however, electrode structure backbone 134 may optionally not include an anode current collector.

Population of Counter-Electrode Structures

Referring again to FIG. 7 , each member of the population of counter-electrode structures 112 may also include a top 1068 adjacent to the first secondary growth constraint 158 , a bottom 1070 adjacent to the second secondary growth constraint 160 , and a lateral surface (not marked) surrounding a vertical axis A CES (not marked) parallel to the Z axis, the lateral surface connecting the top 1068 and the bottom 1070 . The counter-electrode structures 112 further include a length L CES , a width W CES , and a height H CES . The length L CES being bounded by the lateral surface and measured along the X axis. The width W CES being bounded by the lateral surface and measured along the Y axis, and the height H CES being measured along the vertical axis A CES or the Z axis from the top 1068 to the bottom 1070 .

The L CES of the members of the counter-electrode population 112 will vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the members of the counter-electrode population 112 will typically have a L CES in the range of about 5 mm to about 500 mm. For example, in one such embodiment, the members of the counter-electrode population 112 have a L CES of about 10 mm to about 250 mm. By way of further example, in one such embodiment, the members of the counter-electrode population 112 have a L CES of about 25 mm to about 100 mm.

The W CES of the members of the counter-electrode population 112 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, each member of the counter-electrode population 112 will typically have a W CES within the range of about 0.01 mm to 2.5 mm. For example, in one embodiment, the W CES of each member of the counter-electrode population 112 will be in the range of about 0.025 mm to about 2 mm. By way of further example, in one embodiment, the W CES of each member of the counter-electrode population 112 will be in the range of about 0.05 mm to about 1 mm.

The H CES of the members of the counter-electrode population 112 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, members of the counter-electrode population 112 will typically have a H CES within the range of about 0.05 mm to about 10 mm. For example, in one embodiment, the H CES of each member of the counter-electrode population 112 will be in the range of about 0.05 mm to about 5 mm. By way of further example, in one embodiment, the H CES of each member of the electrode population 112 will be in the range of about 0.1 mm to about 1 mm.

In another embodiment, each member of the population of counter-electrode structures 112 may include a counter-electrode structure backbone 141 having a vertical axis A CESB parallel to the Z axis. The counter-electrode structure backbone 141 may also include a layer of counter-electrode active material 138 surrounding the counter-electrode structure backbone 141 about the vertical axis A CESB . Stated alternatively, the counter-electrode structure backbone 141 provides mechanical stability for the layer of counter-electrode active material 138 , and may provide a point of attachment for the primary growth constraint system 151 and/or secondary growth constraint system 152 . In certain embodiments, the layer of counter-electrode active material 138 expands upon insertion of carrier ions into the layer of counter-electrode active material 138 , and contracts upon extraction of carrier ions from the layer of counter-electrode active material 138 . For example, in one embodiment, the layer of counter-electrode active material 138 may be anodically active. By way of further example, in one embodiment, the layer of counter-electrode active material 138 may be cathodically active. The counter-electrode structure backbone 141 may also include a top 1072 adjacent to the first secondary growth constraint 158 , a bottom 1074 adjacent to the second secondary growth constraint 160 , and a lateral surface (not marked) surrounding the vertical axis A CESB and connecting the top 1072 and the bottom 1074 . The counter-electrode structure backbone 141 further includes a length L CESB , a width W CESB , and a height H CESB . The length L CESB being bounded by the lateral surface and measured along the X axis. The width W CESB being bounded by the lateral surface and measured along the Y axis, and the height H CESB being measured along the Z axis from the top 1072 to the bottom 1074 .

The L CESB of the counter-electrode structure backbone 141 will vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the counter-electrode structure backbone 141 will typically have a L CESB in the range of about 5 mm to about 500 mm. For example, in one such embodiment, the counter-electrode structure backbone 141 will have a L CESB of about 10 mm to about 250 mm. By way of further example, in one such embodiment, the counter-electrode structure backbone 141 will have a L CESB of about 20 mm to about 100 mm.

The W CESB of the counter-electrode structure backbone 141 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, each counter-electrode structure backbone 141 will typically have a W CESB of at least 1 micrometer. For example, in one embodiment, the W CESB of each counter-electrode structure backbone 141 may be substantially thicker, but generally will not have a thickness in excess of 500 micrometers. By way of further example, in one embodiment, the W CESB of each counter-electrode structure backbone 141 will be in the range of about 1 to about 50 micrometers.

The H CESB of the counter-electrode structure backbone 141 will also vary depending upon the energy storage device 100 or the secondary battery 102 and their intended use(s). In general, however, the counter-electrode structure backbone 141 will typically have a H CESB of at least about 50 micrometers, more typically at least about 100 micrometers. Further, in general, the counter-electrode structure backbone 141 will typically have a H CESB of no more than about 10,000 micrometers, and more typically no more than about 5,000 micrometers. For example, in one embodiment, the H CESB of each counter-electrode structure backbone 141 will be in the range of about 0.05 mm to about 10 mm. By way of further example, in one embodiment, the H CESB of each counter-electrode structure backbone 141 will be in the range of about 0.05 mm to about 5 mm. By way of further example, in one embodiment, the H CESB of each counter-electrode structure backbone 141 will be in the range of about 0.1 mm to about 1 mm.

Depending upon the application, counter-electrode structure backbone 141 may be electrically conductive or insulating. For example, in one embodiment, the counter-electrode structure backbone 141 may be electrically conductive and may include counter-electrode current collector 140 for counter-electrode active material 138 . In one such embodiment, counter-electrode structure backbone 141 includes a counter-electrode current collector 140 having a conductivity of at least about 10 3 Siemens/cm. By way of further example, in one such embodiment, counter-electrode structure backbone 141 includes a counter-electrode current collector 140 having a conductivity of at least about 10 4 Siemens/cm. By way of further example, in one such embodiment, counter-electrode structure backbone 141 includes a counter-electrode current collector 140 having a conductivity of at least about 10 5 Siemens/cm. In other embodiments, counter-electrode structure backbone 141 is relatively nonconductive. For example, in one embodiment, counter-electrode structure backbone 141 has an electrical conductivity of less than 10 Siemens/cm. By way of further example, in one embodiment, counter-electrode structure backbone 141 has an electrical conductivity of less than 1 Siemens/cm. By way of further example, in one embodiment, counter-electrode structure backbone 141 has an electrical conductivity of less than 10 −1 Siemens/cm.

In certain embodiments, counter-electrode structure backbone 141 may include any material that may be shaped, such as metals, semiconductors, organics, ceramics, and glasses. For example, in certain embodiments, materials include semiconductor materials such as silicon and germanium. Alternatively, however, carbon-based organic materials, or metals, such as aluminum, copper, nickel, cobalt, titanium, and tungsten, may also be incorporated into counter-electrode structure backbone 141 . In one exemplary embodiment, counter-electrode structure backbone 141 comprises silicon. The silicon, for example, may be single crystal silicon, polycrystalline silicon, amorphous silicon, or a combination thereof.

In certain embodiments, the counter-electrode active material layer 138 may have a thickness of at least one micrometer. Typically, however, the counter-electrode active material layer 138 thickness will not exceed 200 micrometers. For example, in one embodiment, the counter-electrode active material layer 138 may have a thickness of about 1 to 50 micrometers. By way of further example, in one embodiment, the counter-electrode active material layer 138 may have a thickness of about 2 to about 75 micrometers. By way of further example, in one embodiment, the counter-electrode active material layer 138 may have a thickness of about 10 to about 100 micrometers. By way of further example, in one embodiment, the counter-electrode active material layer 138 may have a thickness of about 5 to about 50 micrometers.

In certain embodiments, the counter-electrode current collector 140 includes an ionically permeable conductor that has sufficient ionic permeability to carrier ions to facilitate the movement of carrier ions from the separator 130 to the counter-electrode active material layer 138 , and sufficient electrical conductivity to enable it to serve as a current collector. Whether or not positioned between the counter-electrode active material layer 138 and the separator 130 , the counter-electrode current collector 140 may facilitate more uniform carrier ion transport by distributing current from the counter-electrode current collector 140 across the surface of the counter-electrode active material layer 138 . This, in turn, may facilitate more uniform insertion and extraction of carrier ions and thereby reduce stress in the counter-electrode active material layer 138 during cycling; since the counter-electrode current collector 140 distributes current to the surface of the counter-electrode active material layer 138 facing the separator 130 , the reactivity of the counter-electrode active material layer 138 for carrier ions will be the greatest where the carrier ion concentration is the greatest.

The counter-electrode current collector 140 includes an ionically permeable conductor material that is both ionically and electrically conductive. Stated differently, the counter-electrode current collector 140 has a thickness, an electrical conductivity, and an ionic conductivity for carrier ions that facilitates the movement of carrier ions between an immediately adjacent counter-electrode active material layer 138 on one side of the ionically permeable conductor layer and an immediately adjacent separator layer 130 on the other side of the counter-electrode current collector 140 in an electrochemical stack or electrode assembly 106 . On a relative basis, the counter-electrode current collector 140 has an electrical conductance that is greater than its ionic conductance when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . For example, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the counter-electrode current collector 140 will typically be at least 1,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the counter-electrode current collector 140 is at least 5,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the counter-electrode current collector 140 is at least 10,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the counter-electrode current collector 140 layer is at least 50,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in one such embodiment, the ratio of the electrical conductance to the ionic conductance (for carrier ions) of the counter-electrode current collector 140 is at least 100,000:1, respectively, when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

In one embodiment, and when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 , such as when an energy storage device 100 or a secondary battery 102 is charging or discharging, the counter-electrode current collector 140 has an ionic conductance that is comparable to the ionic conductance of an adjacent separator layer 130 . For example, in one embodiment, the counter-electrode current collector 140 has an ionic conductance (for carrier ions) that is at least 50% of the ionic conductance of the separator layer 130 (i.e., a ratio of 0.5:1, respectively) when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the counter-electrode current collector 140 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the counter-electrode current collector 140 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1.25:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the counter-electrode current collector 140 to the ionic conductance (for carrier ions) of the separator layer 130 is at least 1.5:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the ionic conductance (for carrier ions) of the counter-electrode current collector 140 to the ionic conductance (for (anode current collector layer) carrier ions) of the separator layer 130 is at least 2:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

In one embodiment, the counter-electrode current collector 140 also has an electrical conductance that is substantially greater than the electrical conductance of the counter-electrode active material layer 138 . For example, in one embodiment, the ratio of the electrical conductance of the counter-electrode current collector 140 to the electrical conductance of the counter-electrode active material layer 138 is at least 100:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the counter-electrode current collector 140 to the electrical conductance of the counter-electrode active material layer 138 is at least 500:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the counter-electrode current collector 140 to the electrical conductance of the counter-electrode active material layer 138 is at least 1000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the counter-electrode current collector 140 to the electrical conductance of the counter-electrode active material layer 138 is at least 5000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 . By way of further example, in some embodiments, the ratio of the electrical conductance of the counter-electrode current collector 140 to the electrical conductance of the counter-electrode active material layer 138 is at least 10,000:1 when there is an applied current to store energy in the device 100 or an applied load to discharge the device 100 .

The thickness of the counter-electrode current collector layer 140 (i.e., the shortest distance between the separator 130 and, in one embodiment, the cathodically active material layer (e.g., counter-electrode active material layer 138 ) between which the counter-electrode current collector layer 140 is sandwiched) in certain embodiments will depend upon the composition of the layer 140 and the performance specifications for the electrochemical stack. In general, when an counter-electrode current collector layer 140 is an ionically permeable conductor layer, it will have a thickness of at least about 300 Angstroms. For example, in some embodiments, it may have a thickness in the range of about 300-800 Angstroms. More typically, however, it will have a thickness greater than about 0.1 micrometers. In general, an ionically permeable conductor layer will have a thickness not greater than about 100 micrometers. Thus, for example, in one embodiment, the counter-electrode current collector layer 140 will have a thickness in the range of about 0.1 to about 10 micrometers. By way of further example, in some embodiments, the counter-electrode current collector layer 140 will have a thickness in the range of about 0.1 to about 5 micrometers. By way of further example, in some embodiments, the counter-electrode current collector layer 140 will have a thickness in the range of about 0.5 to about 3 micrometers. In general, it is preferred that the thickness of the counter-electrode current collector layer 140 be approximately uniform. For example, in one embodiment, it is preferred that the counter-electrode current collector layer 140 have a thickness non-uniformity of less than about 25%. In certain embodiments, the thickness variation is even less. For example, in some embodiments, the counter-electrode current collector layer 140 has a thickness non-uniformity of less than about 20%. By way of further example, in some embodiments, the counter-electrode current collector layer 140 has a thickness non-uniformity of less than about 15%. In some embodiments, the counter-electrode current collector layer 140 has a thickness non-uniformity of less than about 10%.

In one embodiment, the counter-electrode current collector layer 140 is an ionically permeable conductor layer including an electrically conductive component and an ion conductive component that contributes to the ionic permeability and electrical conductivity. Typically, the electrically conductive component will include a continuous electrically conductive material (e.g., a continuous metal or metal alloy) in the form of a mesh or patterned surface, a film, or composite material comprising the continuous electrically conductive material (e.g., a continuous metal or metal alloy). Additionally, the ion conductive component will typically comprise pores, for example, interstices of a mesh, spaces between a patterned metal or metal alloy containing material layer, pores in a metal film, or a solid ion conductor having sufficient diffusivity for carrier ions. In certain embodiments, the ionically permeable conductor layer includes a deposited porous material, an ion-transporting material, an ion-reactive material, a composite material, or a physically porous material. If porous, for example, the