Secondary batteries and methods of manufacture thereof are provided. A secondary battery can comprise an offset between electrode and counter-electrode layers in a unit cell. Secondary batteries can be prepared by removing a population of negative electrode subunits from a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet edge margin and at least one negative electrode sheet weakened region that is internal to the negative electrode sheet edge margin, removing a population of separator layer subunits from a separator sheet, and removing a population of positive electrode subunits from a positive electrode sheet, the positive electrode sheet comprising a positive electrode edge margin and at least one positive electrode sheet weakened region that is internal to the positive electrode sheet edge margin, and stacking members of the negative electrode subunit population, the separator layer subunit population and the positive electrode subunit population.

Description

75 parts

›FIELD OF THE INVENTION

This disclosure generally relates to methods of manufacturing electrode assemblies for use in energy storage devices, and to energy storage devices having electrode assemblies manufactured according to methods herein.

›BACKGROUND

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.

Furthermore, there remains a need for reliable and effective means of manufacture of such batteries. That is, there is a need for efficient manufacturing methods for providing batteries having electrode assemblies with carefully controlled alignment, and with controlled expansion of the electrode assemblies during cycling of the battery.

›SUMMARY · 1 of 9

Briefly, therefore, one aspect of this disclosure relates to a secondary battery for cycling between a charged and a discharged state, the secondary battery comprising a battery enclosure and an electrode assembly, carrier ions, and electrode and counter-electrode busbars for collecting current from the electrode assembly within the battery enclosure, 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 E A 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 current 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 of the electrode current collector population, a first electrode active material layer of one member of the electrode population, a member of the separator population 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 member of the 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, (cc) the first member of the electrode current collector population extends at least partially along the length L E of the electrode active material layer in the transverse direction and comprises an electrode current collector end that extends past the first transverse end surface of the counter-electrode active material layer of each such unit cell, and (dd) the counter-electrode current collector extends at least partially along the length L C of the counter-electrode active material layer in the transverse direction and comprises a counter-electrode current collector end that extends past the second transverse end surface of the electrode active material layer in the transverse direction of each such unit cell, and

(c)(i) the electrode busbar comprises at least one conductive segment configured to electrically connect to the population of electrode current collectors, and extending in the longitudinal direction of the electrode assembly, the conductive segment comprising a first side having an interior surface facing the first transverse end surfaces of the counter-electrode active material layers, and an opposing second side having an exterior surface, the conductive segment optionally comprising a plurality of apertures spaced apart on along the longitudinal direction, the conductive segment of the electrode bus bar being arranged with respect to the electrode current collector ends such that the electrode current collector ends extend at least partially past a thickness of the conductive segment, to electrically connect thereto, the thickness of the conductive segment being measured between the interior and exterior surfaces, and

›SUMMARY · 2 of 9

(c)(ii) the counter-electrode busbar comprises at least one conductive segment configured to electrically connect to the population of counter-electrode current collectors, and extending in the longitudinal direction of the electrode assembly, the conductive segment comprising a first side having an interior surface facing the second transverse end surfaces of the electrode active material layers, and an opposing second side having an exterior surface, the conductive segment optionally comprising a plurality of apertures spaced apart on along the longitudinal direction, the conductive segment of the counter-electrode bus bar being arranged with respect to the counter-electrode current collector ends such that the counter-electrode current collector ends extend at least partially past a thickness of the conductive segment, to electrically connect thereto, the thickness of the conductive segment being measured between the interior and exterior surfaces.

Another aspect of the disclosure relates to 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,

(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,

›SUMMARY · 3 of 9

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%.

Yet another aspect of the disclosure relates to 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

›SUMMARY · 4 of 9

(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,

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 .

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 ,

›SUMMARY · 5 of 9

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 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 |.

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.

Another aspect of the disclosure relates to a method for the preparation of an electrode assembly, the method comprising removing a population of negative electrode subunits from a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet edge margin and at least one negative electrode sheet weakened region that is internal to the negative electrode sheet edge margin, the at least one negative electrode sheet weakened region at least partially defining a boundary of the negative electrode subunit population within the negative electrode sheet, the negative electrode subunit of each member of the negative electrode subunit population having a negative electrode subunit centroid,

removing a population of separator layer subunits from a separator sheet, the separator sheet comprising a separator sheet edge margin and at least one separator sheet weakened region that is internal to the separator sheet edge margin, the at least one separator sheet weakened region at least partially defining a boundary of the separator layer subunit population, each member of the separator layer subunit population having opposing surfaces,

removing a population of positive electrode subunits from a positive electrode sheet, the positive electrode sheet comprising a positive electrode edge margin and at least one positive electrode sheet weakened region that is internal to the positive electrode sheet edge margin, the at last one positive electrode sheet weakened region at least partially defining a boundary of the positive electrode subunit population within the positive electrode sheet, the positive electrode subunit of each member of the positive electrode subunit population having a positive electrode subunit centroid,

stacking members of the negative electrode subunit population, the separator layer subunit population and the positive electrode subunit population in a stacking direction to form a stacked population of unit cells, each unit cell in the stacked population comprising at least a unit cell portion of the negative electrode subunit, the separator layer of a stacked member of the separator layer subunit population, and a unit cell portion of the positive electrode subunit, wherein (i) the negative electrode subunit and positive electrode subunit face opposing surfaces of the separator layer comprised by such stacked unit cell population member, and (ii) the separator layer comprised by such stacked unit cell population member is adapted to electrically isolate the portion of the negative electrode subunit and the portion of the positive electrode subunit comprised by such stacked unit cell while permitting an exchange of carrier ions between the negative electrode subunit and the positive electrode subunit comprised by such stacked unit cell.

According to yet another aspect, an energy storage device having an electrode assembly comprising, in a stacked arrangement, a negative electrode subunit, a separator layer, and a positive electrode subunit, is provided, the electrode assembly comprising:

an electrode stack comprising a population of negative electrode subunits and a population of positive electrode subunits stacked in a stacking direction, each of the stacked negative electrode subunits having a length L of the negative electrode subunit in a transverse direction that is orthogonal to the stacking direction, and a height H of the negative electrode subunit in a direction orthogonal to both the transverse direction and stacking directions, wherein (i) each member of the population of negative electrode subunits comprises a first set of two opposing end surfaces that are spaced apart along the transverse direction, (ii) each member of the population of positive electrode subunits comprises a second set of two opposing end surfaces that are spaced apart along the transverse direction,

›SUMMARY · 6 of 9

wherein at least one of the opposing end surfaces of the negative electrode subset and/or positive electrode subunit comprises regions about the opposing end surfaces of one or more of the negative electrode subset and positive electrode subunit that exhibit plastic deformation and fracturing oriented in the transverse direction, due to elongation and narrowing of the cross-section of the negative electrode subunit and/or positive electrode subunit.

Another aspect of the disclosure relates to a secondary battery for cycling between a charged and a discharged state, the secondary battery comprising a battery enclosure, an electrode assembly, and lithium 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, wherein a ratio of the maximum length L EA and the maximum width W EA to the maximum height H EA is at least 2:1

(b) the electrode assembly comprises a series of layers stacked in a stacking direction that parallels the longitudinal axis within the electrode assembly wherein the stacked series of layers comprises a population of negative electrode active material layers, a population of negative electrode current collector layers, a population of separator material layers, a population of positive electrode active material layers, and a population of positive electrode current collector material layers, wherein

(i) each member of the population of negative electrode active material layers has a length L E that corresponds to the Feret diameter of the negative electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the negative electrode active material layer, and a height H E that corresponds to the Feret diameter of the negative electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the negative electrode active material layer, and a width W E that corresponds to the Feret diameter of the negative electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the negative electrode active material layer, wherein a ratio of L E to H E and W E is at least 5:1;

(ii) each member of the population of positive electrode active material layers has a length L C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the positive electrode active material layer, and a height H C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the positive electrode active material layer, and a width W C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the positive electrode active material layer, wherein a ratio of L C to H C and W C is at least 5:1

(iii) members of the negative electrode active material layer population comprise a particulate material having at least 60 wt % of negative electrode active material, less than 20 wt % conductive aid, and binder material, and where the negative electrode active material comprises a silicon-containing material,

(i) the primary constraint system comprises first and second 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 to at least partially restrain growth of the electrode assembly in the longitudinal direction, and

(ii) the secondary constraint system comprises first and second secondary growth constraints separated in a second direction and connected by members of the stacked series of layers wherein the secondary constraint system at least partially restrains growth of the electrode assembly in the second direction upon cycling of the secondary battery, the second direction being orthogonal to the longitudinal direction, and

(iii) the primary constraint system maintains a pressure on the electrode assembly in the stacking direction that exceeds the pressure maintained on the electrode assembly in each of two directions that are mutually perpendicular and perpendicular to the stacking direction, and

(d) the electrode assembly comprises a population of unit cells, wherein each unit cell comprises a unit cell portion of a first member of the electrode current collector layer population, a member of the separator population that is ionically permeable to the carrier ions, a first member of the electrode active material layer population, a unit cell portion of first member of the counter-electrode current collector population and a first member of the counter-electrode active material layer population, wherein (aa) the first member of the electrode active material layer population is proximate a first side of the separator and the first member of the counter-electrode material layer population is proximate an opposing second side of the separator, (bb) the separator electrically isolates the first member of the electrode active material layer population from the first member of the counter-electrode active material layer population and carrier ions are primarily exchanged between the first member of the electrode active material layer population and the first member of the counter-electrode active material layer population 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,

›SUMMARY · 7 of 9

a. 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,

b. 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.

(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, wherein the maximum length L EA and/or maximum width W EA is greater than the maximum height H EA ,

(ii) each member of the population of positive electrode material layers has a length L C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the transverse direction between first and second opposing transverse end surfaces of the positive electrode active material layer, and a height H C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces of the positive electrode active material layer, and a width W C that corresponds to the Feret diameter of the positive electrode active material layer as measured in the longitudinal direction between first and second opposing surfaces of the positive electrode active material layer, wherein a ratio of L C to H C and W C is at least 5:1

›SUMMARY · 8 of 9

(d) the stacked series of layers comprises layers with opposing end surfaces that are spaced apart from one another in the transverse direction, wherein a plurality of the opposing end surfaces of the layers exhibit plastic deformation and fracturing oriented in the transverse direction, due to elongation and narrowing of the layers at the opposing end surfaces.

Another aspect of the disclosure relates to a secondary battery comprising an enclosure, an electrode assembly, carrier ions within the battery enclosure, and a set of electrode constraints, wherein

the electrode assembly comprises a series of layers stacked in a stacking direction to form a stacked population, the stacked population comprising a population of negative electrode layers, a population of positive electrode layers, a population of separator material layers, and a population of unit cells, wherein

(i) each unit cell comprises a unit cell portion of a first member of the negative electrode layers, a member of the population of separator material layers that is ionically permeable to the carrier ions, and a unit cell portion of a first member of the positive electrode layers, wherein the negative electrode layer is proximate a first side of the separator material layer, and the positive electrode layer is proximate an opposing second sider of the separator material layer, and the separator electrically isolates the negative electrode layer from the positive electrode layer, and carrier ions are primarily exchanged between the first member of the negative electrode layers and the first member of the positive electrode layers via the separator material layer of each such unit cell during cycling of the battery between the charged and discharged state

the set of electrode constraints comprises a primary constraint system and a secondary constraint system wherein

(i) the primary constraint system comprises first and second growth constraints and at least one primary connecting member, the first and second primary growth constraints separated from each other in the stacking direction, and the at least one primary connecting member connecting the first and second primary growth constraints to at least partially restrain growth of the electrode assembly in the stacking direction, and

(ii) the secondary constraint system comprises first and second secondary growth constraints separated in a second direction and connected by secondary connecting members comprising at least a portion of the negative electrode layers, wherein the secondary constraint system at least partially restrains growth of the electrode assembly in the second direction, the second direction being orthogonal to the stacking direction, and

each unit cell comprises a cell volume in that unit cell that is located bounded by a centerline of the negative electrode layer, the centerline comprising a reference plane that is located in a plane orthogonal to the stacking direction, and by a surface of the separator material layer that faces the negative electrode layer, as well as by the first and second secondary growth constraints that are connected to one another by the negative electrode layer,

wherein the cell volume comprises a first region that is adjacent the separator surface, and a second region that is adjacent the centerline, and wherein the first region comprises at least 10% of the cell volume and has a void fraction greater than 85%, and the second region comprises at least 10% of the cell volume and has a void fraction of less than 60%.

Yet another aspect of the disclosure relates to a method for the preparation of an electrode assembly, the method comprising:

removing a population of negative electrode subunits from a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet edge margin and at least one negative electrode sheet weakened region that is internal to the negative electrode sheet edge margin, the at least one negative electrode sheet weakened region at least partially defining a boundary of the negative electrode subunit population within the negative electrode sheet, the negative electrode subunit of each member of the negative electrode subunit population having a negative electrode subunit centroid,

›SUMMARY · 9 of 9

affixing a set of electrode constraints to the stacked population of unit cells, the set of electrode constraints comprising a primary constraint system and a secondary constraint system wherein

(i) the primary constraint system comprises first and second growth constraints and at least one primary connecting member, the first and second primary growth constraints separated from each other in the stacking direction, and the at least one primary connecting member connecting the first and second primary growth constraints to at least partially restrain growth of the electrode assembly in the stacking direction, and

(ii) the secondary constraint system comprises first and second secondary growth constraints separated in a second direction and connected by secondary connecting members comprising at least a portion of the negative electrode subunit, wherein the secondary constraint system at least partially restrains growth of the electrode assembly in the second direction, the second direction being orthogonal to the stacking direction, and

providing, for each member of the population of unit cells, a cell volume in that unit cell that is bounded by a centerline of the negative subunit, the centerline comprising a reference plane that is located in a plane orthogonal to the stacking direction, and by a surface of the separator material subunit that faces the negative electrode subunit, as well as by the first and second secondary growth constraints that are connected to one another by the negative electrode subunit, and

wherein the cell volume comprises a first region that is adjacent the surface of the separator subunit, and a second region that is adjacent the centerline, and wherein the first region comprises at least 10% of the cell volume and has a void fraction greater than 85%, and the second region comprises at least 10% of the cell volume and has a void fraction of less than 60%.

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

›BRIEF DESCRIPTION OF THE DRAWINGS · 1 of 4

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

FIG. 1B is a schematic of one embodiment of a three-dimensional electrode assembly for a secondary battery.

FIG. 1C is an inset cross-sectional view of the electrode assembly of FIG. 1B .

FIG. 1D is a cross-sectional view of the electrode assembly of FIG. 1B , taken along line E in FIG. 1B .

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. 1A , 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. 1A , 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. 1A , 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. 1A .

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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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.

›BRIEF DESCRIPTION OF THE DRAWINGS · 2 of 4

FIG. 12B illustrates a cross-section of an embodiment of the electrode assembly taken along the line A-A′ as shown in FIG. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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. 1A , 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.

›BRIEF DESCRIPTION OF THE DRAWINGS · 3 of 4

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 one embodiment of 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 E , 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 S X2 , 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.

FIG. 38 illustrates a schematic of an embodiment of an electrode assembly manufacturing apparatus for aspects of a process for manufacturing an energy storage device.

FIGS. 39A-39B illustrate embodiments of sheets having subunits therein for removal in a process for manufacturing an energy storage device.

FIGS. 40A-40C illustrate embodiments of processes for stacking negative electrode subunits, positive electrode subunits, and separator subunits in an embodiment of a method of manufacturing of an energy storage device.

FIGS. 41A-41C illustrate top view of embodiments of an alignment plate and sheet positioned on the alignment plate, according to aspects herein.

FIG. 41D illustrates an embodiment of a receiving unit for receiving positive electrode, negative electrode, and/or separator subunits that have been removed from negative electrode, positive electrode, and/or separator subunits herein, according to aspects herein.

FIG. 41E illustrates an embodiment of a stacked population of unit cells that is stacked on alignment pins of a receiving device, according to aspects herein.

FIG. 42 illustrates an exploded schematic view of stacked negative electrode, positive electrode and separator subunits, showing the centroid separation distances as projected onto a plane, according to aspects herein.

FIG. 43A illustrates a schematic view in the YZ plane of unit cells of a stacked population.

FIGS. 43B and 43C illustrate centroid separation distances between unit cells in a stacked population as projected onto a plane ( 43 B) and as depicted in graph form for each unit cell ( 43 C).

FIGS. 44A and 44B illustrate schematic embodiments of stacked negative and positive electrode subunits with centroids, according to aspects herein.

FIGS. 45A and 45B illustrate schematic embodiments of positive and negative electrode subunits with alignment features formed therein, according to aspects herein.

FIG. 45C illustrates a cut-away schematic embodiment of an electrode subunit with an alignment feature formed therein, according to aspects herein.

FIGS. 45D-45E illustrate embodiments of cross-sections of the electrode subunit of FIG. 45C .

›BRIEF DESCRIPTION OF THE DRAWINGS · 4 of 4

FIG. 45F illustrates an embodiment of a stacked population comprising negative and positive electrode subunits, and having an offset between first and second ends of the positive and negative electrode subunits, according to aspects herein.

FIGS. 46A-46C illustrate embodiments of an electrode subunit having weakened regions therein, and removal of at least a portion of the electrode subunit at the weakened region, according to aspects herein.

FIGS. 47A-47B illustrate embodiments of a plurality of feeding lines for feeding sheets of material for an aligning and/or stacking process of a manufacturing methods, according to aspects herein.

FIGS. 48A-48M illustrate embodiments of positive and negative electrode subunits having one or more weakened regions and/or alignment features therein, according to aspects herein.

FIG. 49 illustrates embodiments of alignment feature configurations and combinations, according to aspects herein.

FIGS. 50A-50B illustrate embodiments of shapes and configurations of alignment features, according to aspects herein.

FIGS. 51A-51E illustrate embodiments of electrode subunits having different configurations and/or arrangements of weakened regions therein, according to aspects herein.

FIGS. 52A-52C illustrate different types of weakened regions formed in an electrode subunit, according to aspects herein.

FIGS. 53A-53D illustrate embodiments of electrode subunits having current collector ends exposed by removal of portion of the subunits at a weakened region thereof, and depicting embodiments of different shapes and configurations of eth exposed current collector for electrically connecting to a busbar, according to aspects herein.

FIG. 54 illustrates an embodiment of a stacking process for stacking positive and/or negative electrode subunits in a stacked population, having spacer elements about a periphery an electrode subunit, according to aspects herein.

FIG. 55 is a schematic of an image of a negative electrode subunit before and after a current collector end is exposed following removal of an end portion of the negative electrode subunit, and showing the plastic deformation at portions of the current collector end resulting from the removal of the end portion at the current collector end.

FIGS. 56A and 56B illustrate alternative embodiments of stacked positive and negative electrode subunits, showing a stack with alignment features remaining in the stack ( 56 A) and a stack aligned by groove type alignment features ( 56 B).

FIGS. 57A-57I illustrate embodiments of processes for manufacturing an energy storage device such as a secondary battery, according to aspects herein.

FIG. 58 illustrates an embodiment of an electrode assembly having a unit cell with a unit cell volume, and having a first region adjacent a separator with a first void fraction, and a second region adjacent a centerline of a negative electrode layer with a second void fraction.

FIGS. 59A-E illustrate embodiments of negative electrode and/or separator layer subunits having different configurations of protrusions thereon.

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.

›DEFINITIONS · 1 of 2

“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.

›DEFINITIONS · 2 of 2

“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.

“Centroid” as used herein refers to the geometric center of a plane object, which is the arithmetic mean position of all the points in the object. In n-dimensional space, the centroid is the mean position of all the points of the object in all of the coordinate directions. For purposes of describing the centroid of the objects herein, such as for example the negative and positive electrode subunits, and negative and positive electrode active material layers, the objects may be treated as effectively 2-D objects, such that the centroid is effectively the same as the center of mass for the object. For example, the centroid of a positive or negative electrode subunit, or positive or negative electrode active material layer, may be effectively the same as the center of mass thereof.

›DETAILED DESCRIPTION · 1 of 58

In general, aspects of the present disclosure are directed to an energy storage device 100 , such as a secondary battery 102 , as shown for example in FIG. 1B , FIG. 2A and/or FIG. 20 , that cycles between a charged and a discharged state, and a method of manufacture therefor. The secondary battery 102 includes a battery enclosure 104 , an electrode assembly 106 , and carrier ions, and may also contain a non-aqueous liquid electrolyte within the battery enclosure. The secondary battery 102 can also include 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 method of preparation of an electrode assembly, which may allow for efficient and accurate fabrication of the electrode assembly, with improved alignment of assembly parts and/or an assembly with improved energy density and/or reduced shorting risk. In one aspect, a method of preparation is provided that includes removing a population of multilayer electrode subunits from an electrode sheet comprising at least one electrode sheet weakened region, removing a population of separator layer subunits from a separator sheet comprising at least one separator sheet weakened region, and removing a population of multilayer counter-electrode subunits from a counter-electrode sheet comprising at least one counter-electrode sheet weakened region, and stacking to form unit cells.

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 out 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 A EA 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.

›DETAILED DESCRIPTION · 2 of 58

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. 1A . 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. For example, in one embodiment, the electrode active material can comprise a silicon-containing material in particulate form, such as one or more of particulate silicon, particulate silicon oxide, and mixtures thereof. In yet another embodiment, the electrode active material can comprise a material that exhibits a smaller or even negligible volume change. For example, in one embodiment the electrode active material can comprise a carbon-containing material, such as graphite. In yet another embodiment, the electrode structure comprises a layer of lithium, which serves as the electrode active material layer.

›DETAILED DESCRIPTION · 3 of 58

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. 1B and FIG. 2A , in one embodiment, an electrode assembly 106 includes a population of electrode structures 110 , a population of counter-electrode structures 112 , and an electrically insulating separator 130 electrically insulating the electrode structures 110 from the counter-electrode structures 112 . In one example, as shown in FIG. 1B , the electrode assembly comprises a series of stacked layers 800 comprising the electrode structures 110 and counter-electrode structures in an alternating arrangement. FIG. 1C is an inset showing the secondary battery with electrode assembly 106 of FIG. 1B , and FIG. 1D is a cross-section of the secondary battery with electrode assembly 106 of FIG. 1B . As yet another example, in the embodiment as shown in FIG. 2A , the electrode assembly 106 comprises an interdigitated electrode assembly 106 with electrode and counter-electrode structures interdigitated with one another.

Furthermore, as used herein, for each embodiment that describes a material or structure using the term “electrode” such as an “electrode structure” or “electrode active material,” it is to be understood that such structure and/or material may in certain embodiments correspond that of a “negative electrode”, such as a “negative electrode structure” or “negative electrode active material.” Similarly, as used herein, for each embodiment that describes a material or structure using the term “counter-electrode” such as a “counter-electrode structure” or “counter-electrode active material,” it is to be understood that such structure and/or material may in certain embodiments correspond to that of a “positive electrode,” such as a “positive electrode structure” or “positive electrode active material.” That is, where suitable, any embodiments described for an electrode and/or counter-electrode may correspond to the same embodiments where the electrode and/or counter-electrode are specifically a negative electrode and/or positive electrode, including their corresponding structures and materials, respectively.

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. In yet another embodiment, the electrode structure 110 can comprise an anode structure with an anode current collector 136 and an anodically active material layer 132 , as shown in FIG. 1B . For example, the anode currently collector 136 can comprise an anode current collector layer disposed between one or more anode active material layers. In yet another embodiment, the electrode structure 110 can comprise a single layer of material, such as a lithium sheet electrode. 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. In yet another embodiment, the counter-electrode structure 110 can comprise an cathode structure with a cathode current collector 140 and a cathodically active material layer 138 , as shown in FIG. 1B . 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 , as in the case of FIG. 1B , and/or 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. 1B and 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. While FIG. 2A is referred to herein for description of various features, including dimensions and axis with respect to the secondary battery and electrode assembly, it should be understood that such descriptions also apply to the embodiments as depicted in other figures herein, including the embodiments of FIGS. 1B-1E .

›DETAILED DESCRIPTION · 4 of 58

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. 2A , 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 201.

›DETAILED DESCRIPTION · 5 of 58

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 L EA may be in the range of from 1:2 to 2:1.

In the embodiment as shown in FIG. 1B and 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 , and similarly only a limited number of electrode structures 110 and counter-electrode structures are shown in FIG. 1B . In one embodiment, 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, and/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 .

›DETAILED DESCRIPTION · 6 of 58

According to yet another embodiment, the electrode assembly 106 has first and second transverse ends 145 , 147 (see, e.g., FIG. 1B and 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 .

›DETAILED DESCRIPTION · 7 of 58

Manufacturing Method

In one embodiment, a method of manufacturing an electrode assembly 106 is provided. Referring to FIGS. 38 and 40A -C, aspects of a method of manufacturing are described. Embodiments of the method involve removing a population of negative electrode subunits 900 from a negative electrode sheet 906 , where the negative electrode sheet 906 comprises a negative electrode sheet edge margin 907 and at least one electrode sheet weakened region 908 that is internal to the edge margin 907 (see, e.g., FIGS. 39A-39B ), the at least one weakened region at least partially defining a boundary 909 of the negative electrode subunit population within the negative electrode sheet 906 . Members of the negative electrode subunit population can, in certain embodiments, comprise at least one of a negative electrode active material layer 132 and a negative electrode current collector 136 . In certain embodiments, the members of the negative electrode subunit population can comprise a multi-layer subunit comprising a negative electrode active material layer 132 on at least one side, and even both sides 917 a,b , of an electrode current collector layer 136 (see, e.g., FIG. 42 ). Furthermore, according to aspects of the disclosure, the negative electrode subunit 900 of each member of the population has a negative electrode subunit centroid 910 , marking the geometric center of the negative electrode subunit, as shown for example in FIGS. 42 and 43B . According to some aspects, the negative electrode subunit 900 can comprise a negative electrode active material layer 132 having a centroid 911 , which may be at a same or different position than the negative electrode subunit centroid 910 , according to a geometry and configuration of the electrode active material layer with respect to the entire negative electrode subunit 900 .

Aspects of the method further involve removing a population of separator layer subunits 904 from a separator sheet 912 , where the separator sheet 912 comprises a separator sheet edge margin 913 and at least one separator sheet weakened region 914 that is internal to the edge margin 913 , the at least one weakened region at least partially defining a boundary 915 the separator layer subunit population within the separator sheet 912 . Each member of the separator layer subunit population can comprise opposing surfaces 916 a , 916 b.

Aspects of the method further involve removing a population of positive electrode subunits 902 from a positive electrode sheet 918 , where the positive electrode sheet 918 comprises a positive electrode sheet edge margin 919 and at least one positive electrode sheet weakened region 920 that is internal to the edge margin 919 , the at last one weakened region at least partially defining a boundary 921 of the positive electrode subunit population within the positive electrode sheet 918 . Members of the positive electrode subunit population can, in certain embodiments, comprise at least one of a positive electrode active material layer 138 and a positive electrode current collector 140 . In certain embodiments, the members of the positive electrode subunit population can comprise a multi-layer subunit comprising a positive electrode active material layer 138 on at least one side and even both sides 927 a,b of a positive electrode current collector layer 140 (see, e.g., FIG. 42 ). Furthermore, according to aspects of the disclosure, the positive electrode subunit 902 of each member of the population has a positive electrode subunit centroid 922 , marking the geometric center of the positive electrode subunit, as shown for example in FIGS. 42 and 43B . According to some aspects, the positive electrode subunit 902 can comprise a negative electrode active material layer 138 having a centroid 923 , which may be at a same or different position than the positive electrode subunit centroid 910 , according to a geometry and configuration of the electrode active material layer with respect to the entire positive electrode subunit 900 .

Aspects of the method further comprise stacking members of the negative electrode subunit population 900 , the separator layer subunit population 904 and the positive electrode subunit population 902 in the stacking direction D to form a stacked population 925 of unit cells 504 . Referring to FIG. 43A , each unit cell 504 a , 504 b in the stacked population 925 comprises at least a unit cell portion of a negative electrode subunit 900 , the separator layer 130 of a stacked member of the separator layer subunit population 904 , and a unit cell portion of a positive electrode subunit 902 . For example, each unit cell 504 a , 504 b can comprise at least a unit cell portion of the negative electrode current collector layer 136 and the negative electrode active material layer 132 of a stacked member of the negative electrode subunit population 900 , the separator layer 130 of a stacked member of the separator layer subunit population 904 , and the positive electrode active material layer 138 and a unit cell portion of the positive electrode current collector layer 140 of a stacked member of the positive electrode subunits 902 . Furthermore, the negative electrode subunit 900 and positive electrode subunit 902 face opposing surfaces of the separator layer 130 comprised by such stacked unit cell population member. For example, the negative electrode active material 132 and positive electrode active material layers 138 comprised by a member of the stacked unit cell population 504 face opposing surfaces 916 a , 916 b of the separator layer 130 comprised by such stacked unit cell population member 504 . The separator layer comprised by such stacked unit cell population member is adapted to electrically isolate the portion of the negative electrode subunit 900 and the portion of the positive electrode subunit 902 comprised by such stacked unit cell while permitting an exchange of carrier ions between the negative electrode subunit and the positive electrode subunit comprised by such stacked unit cell. For example, the separator layer 130 comprised by such stacked unit cell population member 504 may be adapted to electrically isolate the negative electrode active material 132 and positive electrode active material layer 138 comprised by such stacked unit cell 504 , while permitting an exchange of carrier ions between the negative electrode active material 132 and positive electrode active material layer 134 comprised by such stacked unit cell 504 . Furthermore, according to embodiments herein, the electrode structure 110 as described elsewhere herein can comprise a negative electrode structure having an electrode active material layer that is the negative electrode active material layer 132 , and the counter-electrode structure 112 as described elsewhere herein can comprise a positive electrode structure having the positive electrode active material layer 138 .

›DETAILED DESCRIPTION · 8 of 58

Referring to FIGS. 42 and 43A -C, embodiments of the method are shown where the each member of the stacked population 925 of unit cells 504 has a centroid separation distance S D between the centroids of the portions of the negative electrode subunit and the positive electrode subunit in a unit cell that is within a predetermined range. Furthermore, in certain embodiments, members of the stacked population 925 of unit cells 504 may have a separation distance S D between centroids of negative electrode and positive electrode active material layers of the unit cell 504 . In the case of a separation distance S D between negative and positive electrode subunit centroids 910 , 922 , the centroid separation distance S D for an individual member of the population of unit cells 504 is the absolute value of the distance between the centroid 910 of the unit cell portion of the negative electrode subunit, and the centroid 922 of the unit cell portion of the positive electrode subunit comprised by such individual unit cell member 504 , as projected onto an imaginary plane 924 that is orthogonal to the stacking direction D. In the case of a separation distance S D between negative and positive electrode active material layers 911 , 923 the centroid separation distance S D for an individual member of the population of unit cells 504 is the absolute value of the distance between the centroid 911 of the unit cell portion of the negative electrode active material layer 132 , and the centroid 923 of the unit cell portion of the positive electrode active material layer 138 comprised by such individual unit cell member 504 , as projected onto an imaginary plane 924 that is orthogonal to the stacking direction Y (e.g., the stacking direction Y as shown in FIGS. 1 and 2A ). Furthermore, in the embodiment as shown in FIG. 42 , the centroid 911 of the unit cell portion of the electrode active material layer 132 is coincident with the centroid 911 of the negative electrode subunit 900 , however the centroids may also be different. A separation distance S D can also be calculated as to two negative electrode subunits and/or two positive electrode subunits in different unit cells 504 a , 504 b , as well as for two negative electrode active material layers in different unit cells 504 a , 504 b and/or two negative electrode active material layers in different unit cells 504 a , 504 b , by taking the absolute value of the distance between the centroids of the structures of interest, as projected onto an imaginary plane 924 that is orthogonal to the stacking direction Y.

Referring to FIGS. 43A-B , which depicts a stacked population 925 of unit cells 504 comprising negative electrode active material layers 132 , separator layers 130 and positive electrode active material layers 138 , it can be seen that a centroid separation distance between the negative electrode active material layer 132 and positive electrode active material layer 138 on either side of the separator layer 130 (i.e., in the same unit cell 504 ) (or similarly, the negative electrode subunit 900 and positive electrode subunit 902 ), can be projected onto an imaginary plane 924 orthogonal to the stacking direction Y. FIG. 43B further depicts negative electrode active material layers 132 and positive electrode active material layers 138 (or alternatively, unit cell portions of the negative electrode subunit 900 and positive electrode subunit 902 ) stacked in the stacking direction Y and having centroids 910 , 922 , where the centroid separation distance S D1 for a first unit cell 504 a (as shown in FIG. 43B ) is shown as projected onto a first imaginary plane 924 a (coincident with a plane of a layer of negative electrode active material as depicted), and the centroid separation distance S D2 for a first unit cell 504 b (as shown in FIG. 43B ) is shown as projected onto a second imaginary plane 924 b (coincident with a plane of a layer of negative electrode active material as depicted). That is, according to certain embodiments, the separation distance S D can be understood to be the absolute value of the distance between the centroids 910 , 922 of each of the respective negative electrode subunit portion and positive electrode subunit portion (or, between the centroids of the negative electrode and positive electrode active material layers) in a given unit cell 504 , as projected onto an XZ plane that is orthogonal to the stacking direction Y (i.e., not including a component of the distance between centroids in the stacking direction). FIG. 43C further depicts an embodiment of a plot of the centroid separation distances S D1 , S D2 and S D3 for first, second, and third unit cells 504 a , 504 b , 504 c , showing examples of the magnitude of the centroid separation distances for each unit cell 504 . In a case where S D is 0, then the entroids of the respective structures project to a point that is coincident on the XZ plane. In a case where S D is non-zero (greater than 0, since S D is the absolute value of the distance, the centroids for the respective structures are offset from one another.

According to certain aspects, the centroid separation distances are maintained within a predetermined limit that provides a suitable alignment of the negative electrode subunit and positive electrode subunit portions in a unit cell, such as alignment of the negative electrode active material layer and positive electrode active material layers 132 , 138 , with any member of the unit cell population. According to yet another embodiment, the centroid separation distances are maintained within a predetermined limit that provides suitable alignment of positive electrode subunits and/or positive electrode active material layers between different unit cell members, and/or suitable alignment of negative electrode subunits and/or negative electrode active material layers between different unit cell members 504 . An average centroid separation distance S D for a predetermined number of unit cells 504 within the electrode assembly, and/or among different unit cells 504 within the electrode assembly, may also be maintained within a certain predetermined limit. For example, the stacking of the negative electrode subunits 900 and the positive electrode subunits 902 may be performed in such a way so as to provide an alignment of the negative electrode and positive electrode subunits and/or active material layers with respect to one another, with this relative alignment and/or positioning being reflected via relative alignment of the centroids of these structures with respect to one another, within a predetermined limit.

›DETAILED DESCRIPTION · 9 of 58

In one embodiment, the centroid separation distance for an individual member of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative electrode structure in the member (i.e., electrode subunit and/or active material layer) is less than 500 microns, then the predetermined limit is less than 2% of that largest dimension. That is, in the case where a largest dimension of the individual member is less than 25 mm, the centroid separation distance is less than 2% of the largest dimension, and otherwise the centroid separation distance is less than 500 microns. In another embodiment, the centroid separation distance between first and second members of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative or positive electrode structure in either of the members (i.e., electrode subunit and/or active material layer) is less than 500 microns, then the predetermined limit is less than 2% of that largest dimension of the larger negative or positive electrode structure in either of the members. That is, in the case where a largest dimension of the individual member is less than 25 mm, the centroid separation distance is less than 2% of the largest dimension, and otherwise the centroid separation distance is less than 500 microns.

The largest dimension of the negative electrode active material 132 in each unit cell (or negative electrode active material layers 132 in first and second unit cells), may be, for example, the larger of either the length L E that corresponds to the Feret diameter as measured in the transverse direction X between first and second opposing transverse end surfaces 502 a,b of the electrode active material layer (see, e.g., FIG. 26A ) and/or a height H E that corresponds to the Feret diameter of the negative electrode active material layer as measured in the vertical direction between first and second opposing vertical end surfaces 500 a,b of the negative electrode active material layer 132 (see, e.g., FIG. 30 ), as is described further hereinbelow. The largest dimension of a positive electrode active material layer 138 in each unit cell, or in first and second unit cells, if the larger of the length or height that corresponds to the Feret diameter in the same manner as determined for the electrode active material layer. Furthermore, the largest dimension of either the negative electrode subunit and/or positive electrode subunit, either in the same unit cell, or first and second unit cells may also correspond to the larger of the L Sub that corresponds to the Feret diameter of the negative and/or positive electrode subunit as measured in the X direction between first and second opposing transverse end surfaces 992 a,b of the negative electrode subunit and/or the height H Sub that corresponds to the Feret diameter of the negative electrode subunit and/or positive electrode subunit as measured in the Z direction between first and second opposing end surfaces 994 a,b of the negative electrode active material layer 132 (see, e.g., FIG. 42 ).

In one embodiment, the stacked population has an average centroid separation distance that is within the predetermined limit across at least 5 unit cells in the stacked population. That is, according to one aspect the average across 5 unit cells of the centroid separation distances between structures within in each unit cell may be within the predetermined limit. According to yet another aspect, the average across 5 unit cells of the centroid separation distances between structures in first and second unit cells may be within the predetermined limit. According to yet another embodiment, the stacked population has an average centroid separation distance that is within the predetermined limit for at least 10 unit cells, at least 15 unit cells, at least 20 unit cells, and/or at least 25 unit cells in the stacked population, again either for structures within the same unit cell or structures in different unit cells. According to yet another embodiment, the stacked population can comprise the average centroid separation distance that is within the predetermined limit for at least 75%, at least 80%, at least 90% and/or at least 95% of the unit cell members 504 of the stacked population of unit cells, either for structures within the same unit cell or structures in different unit cells. That is, the average centroid separation distance for positive and negative electrode structures in the same unit cell (e.g., negative and positive electrode subunits in the same unit cell, or positive and negative electrode active material layers in the same unit cell), may be within the predetermined limit for at least 75%, at least 80%, at least 90% and/or at least 95% of the unit cell members 504 of the stacked population of unit cells. Also, the average of the centroid separation distance between unit cells, for positive and negative electrode structures (e.g., negative electrode subunits in the different unit cells, negative electrode active material layers in different unit cells, positive electrode subunits in the different unit cells, or positive electrode active material layers in different unit cells), may be within the predetermined limit for at least 75%, at least 80%, at least 90% and/or at least 95% of the unit cell members 504 of the stacked population of unit cells. Furthermore, in a case where a negative electrode subunit does not have electrode active material (for example when negative electrode active material is formed in situ in a formation process), an area of a negative electrode subunit (e.g., negative electrode current collector) that is geometrically opposing an positive-electrode active material layer in the same unit cell can be treated as an electrode active area, and the separation distance of a centroid of this electrode active area to other structures in the stacked population can be calculated as for the negative electrode active material herein (e.g., generally the separation distance will be zero between the electrode active area and the positive electrode active material layer in the same unit cell).

›DETAILED DESCRIPTION · 10 of 58

Referring to FIGS. 44A and 44B , a further illustration showing an embodiment of the centroid separation distance S D is depicted, with the centroids 910 , 922 of negative electrode active material layer 132 and positive electrode active material layer 138 in a unit cell 504 being shown as superimposed on a surface of the positive electrode active material layer 138 (separators and current collectors are omitted from the figures for ease of illustration). In the embodiment shown in FIG. 44A , the geometric centers of the negative electrode active material layer 132 and positive electrode active material layer 138 in a unit cell 504 are more or less aligned in the unit cell 504 , such that a separation distance S D between the centroids is close to or even effectively zero. In the embodiment shown in FIG. 44B , the geometric centers of the layers in the unit cell 504 are slightly offset, such that the separation distance S D as measured between the centroids 910 and 920 of the layers 132 , 138 has a non-zero value, due to a negative electrode active material layer 132 that has a geometric center of mass that is slightly offset in the X-direction from the geometric center of mass of the positive electrode active material layer 138 , as shown in the figure. As discussed above, in certain embodiments, the layers 132 , 138 in a unit cell 504 of the stacked population are aligned such that the separation distance between the respective centroids 910 , 922 is within a predetermined limit. Maintaining the centroid alignment within the predetermined limit can provide for improved manufacture of the electrode assembly 106 with improved energy density, and even reduced incidence of shorting between negative electrodes and positive electrodes in the electrode assembly. Furthermore, by providing the centroid alignment within the predetermined limit, offsets between the edges of negative and positive electrode active material layers can be controlled, as is described further herein, which can be critical to provide improved current distribution in the electrode assembly. That is, as further described hereinbelow, maintaining the negative and positive electrode edge offsets in the Z and X directions can be critical to maximize the performance, energy density and safety of the electrode assembly.

Returning to FIG. 38 , an embodiment of an electrode assembly manufacturing apparatus 1000 is shown, by which further embodiments of the method of manufacture are described. In one embodiment, as shown in FIG. 38 , the apparatus 1000 comprises a plurality of rolls 1002 a - d of continuous webs of electrode assembly components, such that the negative electrode sheet 906 , separator sheet 912 and/or positive electrode sheet 918 may comprise a continuous web having the negative electrode, separator and/or positive electrode subunits formed therein. In one embodiment, a negative electrode sheet continuous web 926 is provided that has one or more negative electrode sheets 906 (e.g., as shown in FIG. 39A , B) each having the negative electrode subunits 900 formed therein. Furthermore, a separator sheet continuous web 928 can be provided that has one or more separator sheets 912 (e.g., as shown in FIG. 39A , B) each having the separator layer subunits 904 formed therein. Furthermore, a positive electrode continuous web 930 can be provided that has one or more positive electrode sheets 918 (e.g., as shown in FIG. 39A , B) each having the positive electrode subunits 902 formed therein. In further embodiments, as an alternative or in addition to continuous webs, one or a plurality of discrete sheets that are separated from each other, and that contain one or more subunits or other structures, may also be provided. Accordingly, processes and/or devices using the continuous webs described herein may also be performed and/or operated with individual and discrete sheets having the subunits formed therein, in certain embodiments. The continuous web can further comprise a plurality of each type of subunit (e.g., negative electrode, separator and positive electrode sheets) e.g., with each type separated from each other along a web feeding direction F, and/or the continuous web can comprise a single type of the subunit therein.

The continuous webs 930 and/or sheets may be patterned to provide the subunit structures therein, as is described in further detail herein. For example, the continuous webs may be patterned prior to forming the rolls of the continuous webs, or may be patterned as a part of the process as the webs are being fed from the rolls to the processing stations of the apparatus 1000 . The continuous webs are patterned to form weakened regions therein, as described below. Methods of patterning the webs can include using laser energy or heat to form a pattern of weakened regions in the webs, by cutting the patterns into the webs, or by other methods that are capable of forming a region that is susceptible separation under certain predetermined conditions, as is discussed further herein. For example, the pattern may be formed by stamping, laser cutting, or other means of material removal.

In the embodiment as shown in FIG. 38 , a plurality of continuous webs and/or sheets are fed in a feeding direction F from separate rolls 1002 a,b,c,d comprising each of the continuous webs and/or sheets, to a merging station 932 where the webs are aligned and merged in a continuous fashion, prior to removal of the subunits from the sheets. For example, a negative electrode sheet continuous web 926 , a positive electrode continuous web 930 , and at least one separator continuous web 928 (in the embodiment shown in FIG. 38 , two separator sheet continuous webs 928 ), each of which are separated from one another in a vertical direction in the embodiment as shown, are fed to a merging station 932 of the apparatus 1000 , where the continuous webs are layered one on top of another to form a merged web stack and/or merged sheet stack of the continuous webs and/or sheets (4-layer merged web stack in the embodiment shown in FIG. 38 ). In the embodiment as shown, the roller 933 may cooperate with an opposing surface to merge the incoming sheets and/or webs on top of one another to form a merged stack and/or merged web. Furthermore, according to one aspect, the apparatus 1000 can comprise at least one registration station 935 with at least one registration device 934 that is provided to register and align the continuous webs and/or sheets with respect to one another before and/or after merging, for example by engagement and/or interaction with alignment features 936 formed in the continuous webs and/or sheets (see, e.g., FIG. 39 ). That is, the continuous webs can comprise alignment features 936 formed therein that can allow for alignment of each of the webs and/or sheets with respect to one another, such as by mechanical and/or optical alignment means.

›DETAILED DESCRIPTION · 11 of 58

In the embodiment as shown in FIGS. 39A and 39B , the alignment features 936 comprise apertures 938 formed in the plurality of continuous webs and/or sheets, at predetermined positions, such as at positions corresponding to alignment of the subunits therein with subunits in the other webs. For example, the alignment features 936 can be formed so as to provide alignment of the individual negative electrode subunits, positive electrode subunits, and separator layer subunits in each of the layers of the merged web and/or stack. According to one aspect, the alignment features 938 can comprise a plurality of apertures 938 that extend through the thickness of at least one and even the entire stack of merged webs and/or sheets (e.g., in the web and/or sheet thickness S T dimension, as shown in FIGS. 39A and 39B , which is orthogonal to the web and/or sheet length dimension S L , and also orthogonal to the web and/or sheet width dimension S W ). The plurality of apertures may further be formed in a plurality of positions along the dimension S L , which may be along a direction of a web and/or sheet feeding direction F, to provide for continuous registration and/or alignment thereof as the web and/or sheet is fed in the feeding direction F (see, e.g., FIGS. 39A and 39B ). The plurality of apertures 938 may further be formed in a peripheral region 940 and/or edge margin 907 , 919 , 913 of the webs and/or sheets that is outside an outer boundary 909 , 915 , 921 defining the subunits 900 , 904 , 902 formed in each web.

Alternatively, according to certain aspects, the plurality of webs and/or sheets may be aligned without providing separate alignment features, such as by optically or mechanically detecting edges of the webs and/or sheets, such that the edges serve as integrated alignment features. In yet another embodiment, the subunit alignment features 970 that are at least partially within the boundaries of the subunits may be used for the web and/or sheet alignment (in addition to subunit alignment, discussed in more detail hereinbelow), without requiring separate alignment features 936 . Furthermore, according to certain aspects, processing may proceed without a separate step of alignment of the continuous webs and/or sheets, such as for example where a roll comprising a single pre-merged sheet is provided for the manufacturing process, where webs and/or sheets of different types are processed individually, or where the process otherwise does not require alignment of the webs and/or sheets. According to certain embodiments, alignment of the apertures 938 in each web and/or sheet (e.g., negative electrode sheet continuous web 930 , positive electrode sheet continuous web 930 , and/or separator sheet continuous web 928 ) with respect to one another in the merged web and/or merged sheet, can thus provide for a predetermined positioning and alignment of the subunits in each web and/or sheet with respect to each other.

In the embodiment shown in FIG. 38 , the apparatus 1000 comprises a registration device 934 including a mechanical sprocket wheel 942 with teeth 944 that are capable of engaging the apertures 938 in each web and/or sheet, as the webs and/or sheets are fed to the wheel from a feeding roller 933 at the merging station 932 . Furthermore, in one embodiment, merging and registration may happen substantially simultaneously, such that alignment of the webs and/or sheets occurs as they are merged. In the embodiment as shown the webs and/or sheets are merged just before registering and/or alignment. In addition to the sprocket wheel with teeth to engage the apertures 938 as shown, alternatively and/or additionally, the registration device 943 can comprise a device that is capable of optically determining registration and/or alignment of the webs and/or sheets, such as by detecting optical features, and/or other mechanical alignment means other than that specifically shown can be provided, such as mechanical alignment with alignment features comprising protrusions, tabs, bumps, indentations, or other features in the web. Furthermore, while alignment of continuous webs is exemplified herein, the registration device and/or web alignment features may similarly be applied to alignment of individual sheets having the subunits therein, regardless of whether said sheets form a part of a continuous web, or comprise a plurality of separate sheets having the subunits formed therein. Additionally, while the embodiment of FIG. 38 depicts merging and alignment of 4 continuous webs with respect to each other, it is also possible to merge and align only two continuous webs, or 3 or even 5 or more continuous webs with one another, each of the webs comprising the subunits for forming the stacked population. In yet another embodiment, one or more of the continuous webs and/or sheets may optionally comprise a backing layer (not shown) that provides structural support for the continuous web and/or sheet, and which can be rolled out with the web and/or sheet and removed before a processing stage, such as before merging of the continuous webs and/or sheets.

Furthermore, while only one merging station 932 and registration station 935 are shown for the apparatus 1000 as shown in FIG. 38 , it may also be possible for the apparatus 1000 to comprise a plurality of feeding lines 972 a,b,c , that each run a line of continuous webs for processing as shown in FIGS. 47A and 47B . For example, the apparatus may comprise an array of feeding lines along a direction A orthogonal to the feeding direction F, and which feed in the same feeding direction F, or in other embodiments the feeding lines may be set up along varying orientations with respect to each other. According to certain embodiments, for an apparatus 1000 having multiple feeding lines 972 a,b,c , individual merging stations 932 , registration stations 935 , and other processing stations and devices described herein, may be provided for each feeding line, and/or shared between feeding lines (such as by advancing a device between feeding lines), to process the continuous webs and/or sheets being fed along the feeding lines.

›DETAILED DESCRIPTION · 12 of 58

In yet another embodiment, the apparatus 1000 and/or method may provide for sequential alignment and/or merging of the continuous webs and/or sheets, such as merging and/or alignment of a first set of continuous webs and/or sheets at a first merging and/or registration station, followed by merging and/or registration at a subsequent merging and/or registration station, such as in a same feeding line, or by moving between feeding lines. Also, the merging and registration of the webs and/or sheets can proceed simultaneously, and/or the continuous webs and/or sheets may be merged before alignment thereof, or some combination thereof. Even further, in one embodiment, the continuous webs and/or sheets may be individually fed from the rolls 1002 of the continuous webs and/or sheets, in the feeding direction F, for further processing, without merging the continuous webs and/or sheets with respect to one another, and/or without aligning the continuous webs and/or sheets with respect to one another. For example, in a case where the subunits 900 , 902 , 904 are to be removed individually from the continuous webs and/or sheets, to sequentially form the stacked population of unit cells 504 , each continuous web and/or sheet containing the individual subunit ( 900 , 902 and/or 904 ) may be fed in the feeding direction F for removal of the subunit therefrom, without pre-merging of the webs and/or sheets and/or pre-alignment of the subunits therein. FIG. 47B shows an embodiment where separate continuous webs comprising negative electrode sheets 906 , separator sheet 912 and positive electrode sheet 918 are fed separately along separate feeding lines 972 a,b,c , in the feeding direction F with processing of the continuous webs being performed separately for each continuous web, and without merging of the webs.

Referring to FIGS. 39A and 39B and 41B , the sheets 906 , 912 , 918 (which may form a part of the continuous webs described herein, or may be separate sheets), are described in further detail. Each of the negative electrode sheet 906 , positive electrode sheet 918 , and separator layer sheet 912 may have a similar configuration as shown in FIGS. 39A and 39B , with each sheet having a plurality of subunits 900 , 902 , 904 (negative electrode, positive electrode, and/or separator layer) formed therein. In one embodiment, each sheet comprises a same type of unit, i.e. the separator sheet comprises only separator layer subunits, the negative electrode sheet comprises only negative electrode subunits, and the positive electrode sheet comprises only positive electrode subunits. In another embodiment, each sheet can comprise two or more different types of subunits. In the embodiments shown in FIGS. 39A and 39B , the sheet comprises a plurality of such subunits formed along the dimension S L (i.e., length direction of the sheet), which also corresponds to the feeding direction F of the sheet (and/or continuous web). The sheet can also comprise a plurality of subunits formed in an orthogonal direction S W in a direction of the width of the sheet (and/or continuous web). In the embodiment shown, the sheet comprises two columns separated from each other in the S W direction, with each column having a plurality of subunits extending along the S L direction of the sheet (and/or web). Alternatively, only a single column, or more than two columns separated from one another in the S W direction can be provided. Further orientations and/or configurations of the subunits in the sheet can also be provided, such as different combinations of rows and columns of the subunits. In one aspect, as discussed above, the sheets 906 , 912 , 918 can also comprise web and/or sheet alignment features 936 that provide for alignment of the web and/or sheets with respect to one another. As discussed herein, the subunits may comprise a single layer of material, such as a single layer of separator material, or may comprise a multi-layer subunit. In yet another and/or alternative embodiment, the alignment features 936 may provide for alignment of the sheet and/or web in a predetermined position such that subunits can be removed from the sheets at the predetermined sheet position, as discussed in further detail below. That is, the alignment features 936 can allow for the alignment of subunits in a first sheet and/or web to be aligned with subunits in a second sheet and/or web, and/or the subunits in a plurality of further sheets and/or webs.

In the embodiment as shown in FIGS. 39A and 39B , the sheets (and/or continuous webs) comprise edge margins 907 , 913 , 919 and an outer edge perimeter 948 that extends about the outer boundary and/or edges of the sheet, and the least one weakened region 908 , 914 , 920 that is internal to the edge margins 907 , 913 , 919 (and thus also the outer sheet perimeter 948 ). The at least one weakened region at least partially defines boundaries 909 , 915 , 921 of the subunit 900 , 404 , 902 within the sheet, and in certain aspects may even entirely define the subunit. The at least one weakened region is a region of the sheet that has been weakened with respect to the rest of the sheet, such that the subunit having the boundary that is at least partially defined by the at least one weakened region can be removed therefrom, leaving a remaining portion of the sheet behind (e.g., the edge margins 907 , 913 , 919 ). That is, according to certain embodiments, the weakened region may be a region where release of the subunit from the sheet occurs upon application of electrical, mechanical or thermal energy. According to certain embodiments, the weakened region can comprise one or more of a region comprising perforations and/or cuts in the sheet, and/or a region where the material of the sheet has been thinned or indented with respect to other regions of the sheet, and/or a region comprising a thinner cross-section as compared to other regions of the sheet, and/or a region where the material of the sheet has in some other way been compromised, such that the weakened region gives way upon application of a removal force to the subunit and/or sheet, such as by applying a tensioning force to one or more parts of the sheet to tear the subunit away from the sheet. According to other embodiments, the weakened region may be constructed such that application of heat or electrical energy separates the subunit from the sheet. For example, the weakened region may be a separated region that is held together with a low-melting point adhesive, such that application of heat energy melts the adhesive and causes the subunit to separate from the sheet. The weakened region may also comprise a region having a thin cross-section in the S T dimension (thickness dimension), such that application of electrical energy to a subunit that is electrically conducting causes the subunit to separate from the sheet at the weakened region. According to certain embodiments, the sheet margin 954 adjacent the outer perimeter 948 may remain when the plurality of subunits have been removed from the sheet.

›DETAILED DESCRIPTION · 13 of 58

In the embodiment as shown in FIG. 39A , the boundaries of the subunits are at least partially defined by first and second weakened regions 952 a , 952 b comprising perforated regions extending in the S L direction on opposing sides of the subunits, and are further defined by weakened regions comprising separated regions 950 a , 950 b extending in the S W direction on opposing sides of the subunits, the separated regions 950 , 950 b being regions where portions of the subunits have been completely removed from the sheet, such as by cutting the subunits from the sheet, or other separation method. According to other aspects, the weakened regions may completely define the subunits, such as by completely surrounding a perimeter of the subunits. While at least a portion of the weakened region is internal to the edge margin of the sheet, in certain aspects at least a portion of the weakened region may extend to reach the outer perimeter 948 , or alternatively the at least one weakened region defining the subunit may be entirely internal to the outer perimeter, meaning that no portion extends to the outer perimeter. Furthermore, while the weakened region is depicted in FIG. 39A as comprising straight lines in the S L and S W directions, the weakened region may also and/or alternatively comprise other shapes, as is discussed in further detail below. In FIG. 39B , the weakened regions 908 , 920 are depicted for negative electrode and/or positive electrode subunits 900 , 902 . The weakened regions in this embodiment likewise comprise first and second weakened regions 952 a , 952 b comprising perforated regions extending in the S L direction on opposing sides of the subunits, and are further defined by weakened regions comprising separated regions 950 a , 950 b extending in the S W direction on opposing sides of the subunits, the separated regions 950 , 950 b being regions where a portion of the subunits have been completely removed from the sheet. FIG. 39B further shows an embodiment of a multi-layer positive or negative electrode subunit, with negative electrode active material 132 , 138 forming a layer towards an interior region of the subunit, and current collector material forming a layer 136 , 140 towards the ends of the subunit in the S W direction. That is, the current collector layers 136 , 140 may be exposed at the ends of the subunit, while the active material layer covers the current collector layer in the interior region of the subunit. Furthermore, in the embodiment as shown in FIG. 39B , the sheet comprises weakened regions 908 , 920 for separating the subunits from the sheet, and further comprises subunit weakened regions 986 that are internal to the subunits, and which are described in further detail below. Furthermore, while weakened regions 908 , 920 are exemplified for the negative electrode and/or positive electrode subunits 900 , 902 in FIG. 39B , the separator subunit can also comprise such weakened regions as shown and described, and can further comprise weakened regions 986 that are internal to separator layer subunits, as described for the negative and/or positive electrode subunits. That is, the description herein of the weakened regions, whether at least partially defining or internal to the subunits, may be applicable to subunits in any of the negative electrode, positive electrode, and/or separator subunits.

According to embodiments herein, the negative electrode subunit 900 and positive electrode subunit 902 are processed form negative and positive electrodes of an electrode assembly 106 for an energy storage device, such as for example the electrode structure 110 and counter-electrode structure 112 of the electrode assembly 106 , as described herein. Accordingly, the negative electrode subunit 900 and positive electrode subunit 902 may have dimensions and ratios of dimensions in S W , S L and S T , that are the same as and/or similar to those described for the electrode and counter-electrode structures 110 , 112 in X, Y and Z, as shown for example in FIG. 2A . That is, the negative electrode subunit may have the same and/or similar width dimension S W as described herein for the length of the electrode structure 110 in the X direction, the same and/or similar dimension S L as described herein for the width of electrode structure 110 in the Y direction, and the same and/or similar dimension S T as described herein for the height of the electrode structure 110 in the Z direction. Similarly, the positive electrode subunit may have the same and/or similar width dimension S W as described herein for the length of the counter-electrode structure 112 in the X direction, the same and/or similar dimension S L as described herein for the width of the counter-electrode structure 112 in the Y direction, and the same and/or similar dimension S T as described herein for the height of the counter-electrode structure 112 in the Z direction.

The dimensions of the negative electrode active material layer and/or the positive electrode active material layer in the subunits in the dimensions S T , S W and S L may also be the same and/or similar to those of the electrode active material layer and/or the counter-electrode active material layer in the electrode assembly 106 in Z, X and Y dimensions. Furthermore, the ratios of the S T , S W and S L dimensions of the negative electrode subunits with respect to one another may be the same and/or similar to the ratios of the electrode length L E , height H E and width W E with respect to each other, and/or the ratios of the S T , S W and S L dimensions of the positive electrode subunits with respect to one another may be the same and/or similar to the ratios of the counter-electrode length L CE , height H CE and width W CE with respect to each other, as is described further herein, and the relative ratios of the dimensions of the negative electrode active material layer and positive electrode active material layer may also be similar to and/or the same as the relative ratios of the dimensions of the electrode and counter-electrode active material layers, respectively.

›DETAILED DESCRIPTION · 14 of 58

Referring again to FIG. 38 , in one embodiment the apparatus 1000 comprises a subunit removal station 956 that is capable of removing the subunits from the sheets, or removing a plurality of subunits from a plurality of stacked sheets (or stacked continuous webs). As shown in the embodiment shown in FIG. 38 , the sheets can be fed in the F direction from the layering station 932 and/or alignment device 934 to the removal station 956 . In the embodiment as shown, the removal station 956 comprises a punch head 958 that is capable of exerting a force on the subunits in the direction S T that is orthogonal to both the length direction S L and width direction S W of the sheet and/or web, such that at least one subunit is removed from the sheet. Other methods of removing the subunits may also be provided, such as by pulling the subunits away from the sheets and/or webs, and/or by pushing the subunits in the opposing direction along S T , or by using other means of separating the subunits from the sheets at the weakened regions. In one embodiment, the removal station 956 may be capable of removing only one subunit each time a force is exerted (e.g., the punch head 958 may be capable of punching out a single subunit at a time), or alternatively the removal station may be capable of simultaneously removing a plurality of subunits spaced apart along S W and/or S L each time a force is exerted (e.g., the punch head 958 may be capable of punching out a plurality of subunits at a time). As discussed above, the sheet may comprise a part of a merged stack of such sheets, and/or merged continuous webs, such as a stack comprising a negative electrode sheet, positive electrode sheet and/or separator sheet 912 , 906 , 918 , in which case the removal station 956 may be capable of removing a plurality of subunits in the stack, such as the negative electrode subunits 900 , the positive electrode subunits 902 , and/or the separator layer subunits 904 . For example, as shown in FIG. 38 , the continuous webs comprising the negative electrode sheet 906 , positive-electrode sheet 918 , and two alternating separator sheets 912 , are fed into the removal station 956 , such that the subunits in each sheet can be simultaneously removed. That is, the removal station 956 may simultaneously remove from the merged sheets and/or webs, a stacked population 925 comprising the multi-layer negative electrode subunits 900 , the multi-layer positive electrode subunits 902 , and the two separator layer subunits 904 , as shown in FIG. 38 . In another embodiment, the removal station 956 removes one or more subunits at a time from just a single sheet of a first type (e.g., negative electrode sheet), followed by removal of one or more subunits at a time from a subsequent sheet of a second type (e.g., positive electrode sheet), to provide for sequential subunit removal. Other sequences of subunit removal from the sheets may also be possible. The sheet margins and/or other portions of the sheet remaining after removal of the subunits may be fed along the feeding line 972 as advanced by post-removal advancing sprocket 996 , optionally with teeth configured to engage the alignment features remaining in the sheets following removal of the subunits, and/or with an end of line roller 997 .

Furthermore, while the embodiment of FIG. 38 depicts advancement of the continuous web or sheet in the feeding direction F, in yet another embodiment, the continuous web and/or sheet feeding direction may also be reversed, and/or the web and/or sheet may be advanced in alternating directions, so as to allow for removal of predetermined subunits from the sheet. According to one embodiment, the web and or sheet is advanced to the removal station 956 a sufficient distance to allow for the removal of a predetermined number of subunits at the removal station and at a feeding position corresponding to the position of the removal station 956 , without further advancing of the web and/or sheet, such as 1, 2, 3, 4, 5, 8 and/or 10 subunits, after which the web and/or sheet is advanced sufficiently far to allow for a subsequent predetermined number of subunits to be removed. The predetermined number of subunits may be removed simultaneously or sequentially, or some combination thereof, while the web and/or sheet is maintained in position at the removal station. Alternatively, the web and/or sheet may be continuously advanced through the removal station at a rate that allows for removal of the subunits from the moving web and/or sheet. According to yet another embodiment, the punching head or other removal device may alternate between feeding lines as shown for example in FIGS. 47A and 47B , to provide for the sequential removal of subunits from different feeding lines 972 a, b,c , and/or may advance in a direction forwards or backwards along a single feeding line to remove subunits that are along the feeding direction of the line.

Referring to FIGS. 41A-41C , in one embodiment, the apparatus 1000 comprises a removal alignment station 962 where the one or more sheets and/or webs can be aligned for removal of the subunits therefrom by the removal station 956 , such as for example by punch-out of the subunits from their respective sheets. In the embodiment shown in FIG. 41A , the removal alignment station 962 comprises a plate 964 having a central opening 965 that is sized to allow the subunits to pass therethrough upon removal of the subunits from the sheets. The plate 964 further provides one or more registration features 966 to align the one or more sheets over the plate and provide proper alignment therefor prior to removal of the one or more subunits, such as alignment of the subunits and/or sheets and/or webs with respect to the punching head 958 or other removal device. In the embodiment as shown in FIGS. 41A and 41C , the registration features 966 comprise a plurality of registration teeth that are capable of engaging the one or more alignment features 936 formed in the sheets and/or webs, and/or may also be capable of advancing the sheets and/or webs either forward in the feeding direction F or backwards. The alignment features 936 formed in the sheets may be the same as those used by the registration device 934 upstream of the pre-removal alignment station 962 , such as for example the apertures 938 , and/or the alignment features may comprise features other than those used by the registration device 934 . Also, as described with respect to the registration device 934 , according to certain aspects, it may be possible to align without providing any alignment features on the sheet, and/or the subunit alignment features 970 that are formed in the subunits may serve as alignment features. Furthermore, in certain embodiment, the sheets and/or webs may comprise a single set of alignment features 936 and/or may comprise two or more sets of alignment features, to provide alignment and one or more stations via different alignment mechanisms. In yet another embodiment, the removal alignment station 962 may comprise an alignment device, such as plate 964 as shown in FIG. 41 A, that aligns one or more of the sheets and/or continuous webs with respect to one another using mechanical or non-mechanical means. As for the alignment device, the removal alignment station 962 may be capable of aligning the sheets in one or more of the S W and S L direction with respect to the removal station 956 , and/or with respect to one another, so that the sheets are properly aligned for removal of the subunits therefrom.

›DETAILED DESCRIPTION · 15 of 58

In the embodiment as shown in FIG. 41C , the one or more sheets having alignment features 936 comprising apertures 938 , as shown in FIG. 41B , is fed onto the plate 964 with the registration features 966 engaging the apertures 938 to provide proper alignment of the one or more sheets on the plate. One or more of the subunits can then be removed from the one or more sheets by exerting a force on the one or more subunits such that the at least one weakened region in each subunit in each sheet gives way, and the one or more subunits pass through the opening 965 , leaving the sheet margins remaining as retained by the plate and registration features 966 . The removal alignment station 962 may operate with the removal station 956 to substantially provide alignment of the sheets and/or webs at the proper positioning for removal of the subunits via the removal station 956 , for example by aligning for removal immediately before removal is executed, or even substantially simultaneously with removal of the subunits. In certain embodiments where the removal station 956 advances in a direction along the feeding line, or moves to separate feeding lines, the removal alignment station 962 may even move in concert with the removal station to provide alignment of the sheets for the removal of the subunits.

In one embodiment, a plurality of removal stations 956 and/or removal alignment stations 962 are provided, for example to remove a plurality of subunits from one or more sheets in a same sheet feeding line 972 along the feeding direction F of the sheets (e.g., as in FIG. 38 ), or to remove a plurality of subunits from a plurality of sheets in separate sheet feeding lines 972 a,b,c , such as an array of sheet feeding lines in a direction A that is orthogonal to F (e.g., as shown in FIGS. 47A and 47B ). In yet another embodiment, the removal station 965 may be capable of moving to a plurality of different positions in the feeding direction F, and/or in other directions or positions co-located with separate feeding lines, to remove multiple subunits in a same sheet feeding line or in adjacent sheet feeding lines. Alternatively, the sheet feeding lines may themselves be re-positioned to process different sheets, or individual sheets may be fed to different removal 965 and/or alignment stations 962 in the feeding direction F, as well as on other feeding lines. In the embodiment as shown in FIG. 38 , a single removal station 956 is provided that is capable of simultaneously removing two subunits and/or subunit stacks (in the case of a merged sheet) from a sheet, the subunits being separated from one another in the S W direction as shown in FIG. 39 . Following removal of the subunits, the sheet is advanced in the S L direction (feeding direction F), to allow for removal of the next set of subunits and/or subunit stacks in the S W direction, and the process is iterated. In the embodiment as shown, the subunits that are removed in a single removal execution at the removal station 956 can include a subunit stack comprising a negative electrode subunit, two separator layer subunits, and a positive electrode subunit, removed from a merged sheet comprising a negative electrode sheet, two separator layer sheets, and a positive electrode sheet, although other configurations of subunits can also be removed. The removal process can be repeated with further subunits from the sheets, until a stacked population 925 having a predetermined number of unit cells 504 is achieved.

Referring again to FIG. 38 , the apparatus 1000 further comprises a receiving unit 960 that is configured to receive subunits removed from the sheets, to form the stacked population 925 of unit cells 504 . In one embodiment, the receiving unit 960 is configured to engage with one or more stacking alignment features 970 formed in the subunits to provide a stacked population having an alignment of at least a portion of the unit cells in the stacked population, such as an alignment of centroids of negative electrode subunits and/or active material layers and positive electrodes subunits and/or active material layers in the unit cells 504 , as described above. Referring to FIGS. 39A and B and FIG. 41 , the stacking alignment features 970 may be formed internally to the sheet and/or web alignment features 936 , such that the alignment features are retained by the subunits even after removal of the subunits from the sheets and/or web. The stacking alignment features 970 may also be at least partially and even entirely within the boundary of the subunits 900 , 902 , 904 . In certain embodiments, the stacking alignment features 970 can comprise holes or apertures formed through a thickness of at least a portion of the subunit S T , and may even extend through all of the layers in a merged stack in the thickness direction. Further description of the stacking alignment features 970 is described below. The receiving unit 960 may be capable of receiving the subunits separated from the sheets and/or webs by the removal station 956 , such as subunits separated from the sheets and/or webs by the punching head 958 above the pre-removal alignment station. In the embodiments as shown in FIGS. 40A-40C and 41 D, the receiving unit 960 comprises one or more alignment pins 977 extending from a base 961 , that are configured to engage with the stacking alignment features 970 , to allow for stacking of the subunits removed at the removal station 956 . That is, in certain embodiments, the alignment pins 977 may be spaced apart from each other a distance that corresponds to the distance in S W between the stacking alignment features 970 in the subunits. A length of the alignment pins may be selected to allow for the stacking of multiple subunits to form a stacked population 925 having a predetermined number of unit cells. A dimension of the alignment pins in the S W and SL directions may also be selected to accommodate the features 970 , such as a dimension that is slightly smaller or roughly the same size as the features. Further description of alignment pin shapes and sizes, and complementary features 970 , is provided below.

›DETAILED DESCRIPTION · 16 of 58

Referring to FIGS. 40A-40C , an embodiment of a subunit removal and stacking process is described. In FIG. 40A , a plurality of continuous webs 912 , 918 and 906 can be fed to the removal station 956 , where subunits can be removed from the webs. In an embodiment of a first removal and stacking iteration, the subunits that are removed and formed into the stack include, in a stacking direction Y starting from a first end of the stack, a first end plate 974 a , a negative electrode subunit 900 comprising a single layer of negative electrode material 132 on a side of a negative electrode current collector 136 that is opposite a side of the negative electrode current collector facing the first end plate 974 a , a separator layer subunit 904 , a positive electrode subunit 918 having positive electrode active material layers 138 on opposing sides of a positive electrode current collector 140 , and a subsequent separator layer subunit 904 . The first removal and stacking iteration thus starts a first end of the stack with the end plate 974 a , a negative electrode subunit 900 having only one layer of negative electrode active material on a side of the subunit facing the rest of the stack, and positive electrode subunit 918 and separator layer subunits 904 .

In one embodiment, the first end plate 974 a is a part of a continuous web having end plate subunits therein, which is merged with a continuous web comprising the negative electrode subunit 900 with the single layer of negative electrode active material, a continuous web comprising the separator layer subunit 94 , and a continuous web comprising the positive electrode subunit 918 . The first end plate 974 a subunits, the negative electrode subunits 900 with the single electrode active material layer, the separator layer subunits 904 , and positive electrode subunits 918 are aligned with each other within the merged web, to provide for a stack of the subunits upon removal of the subunits at the removal station 956 . For example as shown in FIG. 47A , in one embodiment a first feeding line 972 can comprise a line on which a first merged web 975 a and/or merged sheets are fed in the feeding direction F to the removal station 956 . The first merged web 975 a and/or merged sheets can comprise the subunits for the first removal and stacking iteration, such as the first end plate subunits 974 a , and the negative and positive electrode subunits and separator layer subunits. Alternatively, the first end plate 974 a can be stacked on the receiving unit 960 separately from the other subunits. In the embodiment as shown in FIG. 47A , the first merged web 975 a has been pre-merged into a first roll 1002 a , which feeds the merged web into the first feeding line 972 . Alternatively, the first merged web 975 a can be formed by merging separate continuous webs and/or sheets each corresponding to the separate subunits, such as from separate rolls, to a merging station 932 , as shown for example in FIG. 38 , after which the subunits can be removed from the merged web and stacked in the first removal and stacking operation. Furthermore, in the embodiment as shown in FIG. 47A , second and third feeding lines 972 a,b,c can also be provided to feed merged layers for subsequent removal and stacking iterations, as described in further detail below. The first, second, and third feeding lines 972 a,b,c in FIG. 47A may form an array of feeding lines that are separated from one another in a direction A (array direction), such as a direction that is orthogonal to the feeding direction F.

In yet another embodiment, the subunits making up the first iteration in the stacked population may be provided from separate continuous webs and/or sheets on a plurality of different feed lines, as shown in FIG. 47B . For example, separate feed lines 972 a - 972 e may be arranged in a direction orthogonal to the feeding direction F, such as in an array direction A. Each of the feed lines may comprise a separate continuous web with a type of subunit, such as for example a negative electrode sheet 906 , separator sheet 912 and/or positive electrode sheet 918 . In the case where the first iteration of the subunit stack is being formed, each feedline can comprise, for example, a sheet comprising the first base plates, a sheet comprising the negative electrode subunits with just a single layer of negative electrode active material, and separator sheets 912 . The receiving unit 960 can move in the array direction A to the different feedlines to provide for stacking of subunits from each of the sheets.

Furthermore, in alternative embodiments, the first removal and stacking iteration can comprise removal and stacking of different subunits other than those specifically exemplified (such as a positive electrode subunit having only a single positive electrode active material layer in place of the negative electrode subunit having the single layer of negative electrode active material layer), and including negative and positive electrode subunits and separator layer subunits without an end plate, only one or two of the subunits, and/or only a single separator layer subunit. According to certain aspects, the first iteration is performed to provide any subunits and/or structures on which the remaining stacked population can be built. Also, while the first removal and stacking iteration can be performed before further removal and stacking operations, alternatively the removal and stacking iteration shown in FIG. 40A can be performed at a subsequent stage, such as after a stacked population of predetermined subunits has be formed, as a final removal and stacking operation. The top right-hand side figure of FIG. 40A depicts the sheet having subunits for removal as viewed from a direction S T of the sheet, the second figure from the top on the right hand side of FIG. 40A and the bottom figure from the top on the right hand side of FIG. 40A depict the stacked population 925 after the first iteration as viewed from a direction S L of the sheets, which corresponds to a direction Z of the electrode assembly 106 as described herein, and the figure third from the top on the right hand side of FIG. 40A depicts a view of the stacked population as viewed from a direction S T of the sheet.

›DETAILED DESCRIPTION · 17 of 58

An embodiment of a subsequent removal and stacking iteration is shown in FIG. 40B . In this embodiment, the subunits that are removed and formed into the stack include, in a stacking direction Y starting from a first end of the stack where the first end plate 974 a is located, a negative electrode subunit 900 comprising two layers of negative electrode material 132 , one on each of opposing sides of a negative electrode current collector 136 , a separator layer subunit 904 , a positive electrode subunit 918 having two positive electrode active material layers 138 , one on each of opposing sides of a positive electrode current collector 140 , and a subsequent separator layer subunit 904 . The subsequent removal and stacking iteration thus adds on to the subunits removed and stacked in the first removal and stacking iteration, as shown in the bottom of FIG. 40B . Furthermore, the subsequent removal and stacking iteration can be repeatedly performed a predetermined number of times, to achieve a predetermined number of unit cells 504 in the stacked population 925 .

Similarly to the first iteration described above, in the subsequent removal and stacking iteration (e.g., the primary stacking process) a merged web can be provided that is formed from a continuous web comprising the negative electrode subunit 900 with both layers of negative electrode active material on the opposing sides of the negative electrode current collector, two continuous webs comprising the separator layer subunits 904 , and a continuous web comprising the positive electrode subunit 918 with positive electrode active material layers on opposing sides of the positive electrode current collector. The negative electrode subunits 900 , the separator layer subunits 904 , and the positive electrode subunits 918 are aligned with each other within the merged web, to provide for a stack of the subunits upon removal of the subunits at the removal station 956 . For example as shown in FIG. 47A , in one embodiment a second feeding line 972 b can comprise a line on which a second merged web 975 b and/or merged sheets are fed in the feeding direction F to the removal station 956 . The second merged web 975 b and/or merged sheets can comprise the subunits for the subsequent removal and stacking iteration, such as the negative and positive electrode subunits and separator layer subunits. In the embodiment as shown in FIG. 47A , the second merged web 975 b has been pre-merged into a second roll 1002 b , which feeds the merged web into the second feeding line 972 b . Alternatively, the second merged web 975 b can be formed by merging separate continuous webs and/or sheets each corresponding to the separate subunits, such as from separate rolls, to a merging station 932 , as shown for example in FIG. 38 , after which the subunits can be removed from the merged web and stacked in the primary removal and stacking operation. Referring to FIG. 47A , in one embodiment the receiving unit 960 and/or removal station 956 may be capable of moving in an array direction A between the first and second feeding lines to provide for the first iteration of removal and stacking at the first feed line, followed by the second iteration of removal and stacking at the second feed line.

In yet another embodiment, the subunits making up the subsequent iteration (the primary stacking process) to form the stacked population may be provided from separate continuous webs and/or sheets on a plurality of different feed lines, as shown in FIG. 47B . For example, separate feed lines 972 a - 972 e may be arranged in a direction orthogonal to the feeding direction F, such as in an array direction A. Each of the feed lines may comprise a separate continuous web with a type of subunit, such as for example a negative electrode sheet 906 , separator sheet 912 and/or positive electrode sheet 918 . In the case where the subsequent iteration of the removal and stacking process is performed, each feedline can comprise, for example, a sheet comprising the negative electrode subunits with layers of negative electrode active material on opposing sides of a negative electrode current collector, a sheet comprising the positive electrode subunits with layers of positive electrode active material on opposing sides of a positive electrode current collector, and sheets comprising separator layer subunits. The receiving unit 960 can move in the array direction A between the separate feed lines 972 a - 972 e to form the stacked population from the subunits in each sheet.

Furthermore, in alternative embodiments, the subsequent removal and stacking iteration can comprise removal and stacking of different subunits other than those specifically exemplified. Also, while the subsequent removal and stacking iteration can be performed before after the initial removal and stacking iteration, alternatively the removal and stacking iteration shown in FIG. 40B can be performed first, with the subsequent processes being performed to provide end plates and/or otherwise complete the electrode assembly 106 . The top figure of FIG. 40B depicts the sheet having subunits for removal as viewed from a direction S T of the sheet, the second figure from the top and the bottom figure of FIG. 40B depict the stacked population 925 after a subsequent iteration following the first iteration, as viewed from a direction S L of the sheets, which corresponds to a direction Z of the electrode assembly 106 as described herein, and the figure third from the top side of FIG. 40B depicts a view of the stacked population as viewed from a direction S T of the sheet. In the second figure from the top in FIG. 40B , and embodiment of the stacked subunits for just a single subsequent iteration are shown, and in this embodiment comprises just 4 subunits. In the bottom figure of FIG. 40B , an embodiment of a stacked population having several subsequent stacking iterations is shown.

FIG. 40C depicts an embodiment of a final removal and stacking iteration. In the embodiment as shown, the subunits that are removed and formed into the stack include, in a stacking direction Y starting from the first end of the stack and the first end plate 974 a , a negative electrode subunit 900 and a second end plate 974 b , wherein the negative electrode subunit comprises a single electrode active material layer 134 on a side of a negative electrode current collector 136 that is opposite a side of the negative electrode current collector facing the second end plate 974 b . The final removal and stacking iteration may thus complete the stacked population 925 by providing the second end plate 974 b at the second end of the stack opposing the end with the first end plate 974 a.

›DETAILED DESCRIPTION · 18 of 58

In one embodiment, the second end plate 974 b is a part of a continuous web having end plate subunits therein, which is merged with a continuous web comprising the negative electrode subunit 900 with the single layer of negative electrode active material. The second end plate 974 b subunits, and the negative electrode subunits 900 with the single electrode active material layer, are aligned with each other within the merged web, to provide for a stack of the subunits upon removal of the subunits at the removal station 956 . For example as shown in FIG. 47A , in one embodiment a third feeding line 972 c can comprise a line on which a third merged web 975 c and/or merged sheets are fed in the feeding direction F to the removal station 956 . The third merged web 975 c and/or merged sheets can comprise the subunits for the final removal and stacking iteration, such as the second end plate subunits 974 b , and the negative electrode subunits. Alternatively, the second end plate 974 b can be stacked on the receiving unit 960 separately from the other subunits. In the embodiment as shown in FIG. 47A , the third merged web 975 c has been pre-merged into a third roll 1002 c , which feeds the merged web into the third feeding line 972 c . Alternatively, the third merged web 975 c can be formed by merging separate continuous webs and/or sheets each corresponding to the separate subunits, such as from separate rolls, to a merging station 932 , as shown for example in FIG. 38 , after which the subunits can be removed from the merged web and stacked in the final removal and stacking operation. Furthermore, in the embodiment as shown in FIG. 47A , second and third feeding lines 972 a,b,c can also be provided to feed merged layers for subsequent removal and stacking iterations, as described in further detail below. The first, second, and third feeding lines 972 a,b,c in FIG. 47A may form an array of feeding lines that are separated from one another in a direction A (array direction) that is orthogonal to the feeding direction F.

In yet another embodiment, the subunits making up the final iteration in the stacked population may be provided from separate continuous webs and/or sheets on a plurality of different feed lines, as shown in FIG. 47B . For example, separate feed lines 972 a - 972 e may be arranged in a direction orthogonal to the feeding direction F, such as in an array direction A. Each of the feed lines may comprise a separate continuous web with a type of subunit, such as for example a negative electrode sheet 906 , separator sheet 912 and/or positive electrode sheet 918 . In the case where the final iteration of the subunit stack is being formed, each feedline can comprise, for example, a sheet comprising the second end plates, and a sheet comprising the negative electrode subunits with just a single layer of negative electrode active material. The receiving unit 960 can move in the array direction A to the different feedlines to provide for stacking of subunits from each of the sheets.

Furthermore, in alternative embodiments, the final removal and stacking iteration can comprise removal and stacking of different subunits other than those specifically exemplified (such as a positive electrode subunit having only a single positive electrode active material layer in place of the negative electrode subunit having the single layer of negative electrode active material layer), and including negative and positive electrode subunits and separator layer subunits without an end plate, only one or two of the subunits, and/or only a single separator layer subunit. According to certain aspects, the final iteration is performed to provide any subunits and/or structures to complete the stacked population 925 . However, while the final removal and stacking iteration can be performed after prior removal and stacking operations have been performed, alternatively the removal and stacking iteration shown in FIG. 40C can be performed at an earlier stage, with the stacked layers of the final iteration being joined to the other stacked layers once they are formed. The top figure of FIG. 40C depicts the sheet having subunits for removal as viewed from a direction S T of the sheet, the second figure from the top of FIG. 40C and the bottom figure from the top of FIG. 40C depict the stacked population 925 after the final iteration as viewed from a direction S L of the sheets, which corresponds to a direction Z of the electrode assembly 106 as described herein, and the figure third from the top of FIG. 40C depicts a view of the stacked population as viewed from a direction S T of the sheet.

In yet a further embodiment, the method can comprise removing at least a portion 988 of one or more of the subunits that has been removed from the sheets and stacked in the stacked population 925 , to provide a final subunit structure for the stacked population. For example, at least a portion 988 of a negative electrode subunit 900 and/or positive electrode subunit 902 may be removed to provide for connection of current collectors therein to a busbar 600 , 602 , as is described in further detail hereinbelow. For example, the portion 988 may be removed to provide for free and/or exposed positive electrode and/or negative electrode current collector ends 606 , 604 that can be electrically connected to a positive and/or negative electrode busbar 600 , 602 (electrode or counter-electrode busbar 600 , 602 ), as shown in any of FIGS. 27A-27F herein, or via another suitable connection method and/or structure. Referring to FIG. 45A , according to one embodiment, the negative electrode subunit 900 has a first set of two opposing end surfaces 978 a,b , and opposing end margins 980 a,b adjacent each of the first set of opposing end surfaces, (ii) the positive electrode subunit 902 has a second set of opposing end surfaces 982 a,b , and opposing end margins 984 a,b adjacent each of the second set of opposing end surfaces 982 a,b , (iii) one or more of the negative electrode subunit and positive electrode subunit have at least one subunit weakened region 986 in at least one of the opposing end margins thereof. According to embodiments of the method, a tensioning force is applied to at least one of the opposing end margins of one or more of the negative electrode subunit 900 and positive electrode subunit 902 in a tensioning direction, to remove a portion 988 of one or more of the negative electrode subunit 900 and positive electrode subunit 902 that is adjacent the weakened region 986 in the at least one opposing end margin, such that one or more of the first set of opposing end surfaces 978 a , 978 b of the negative electrode subunit 900 and the second set of opposing end surfaces 982 a,b of the positive electrode subunit 902 comprise at least one end surface 990 exposed by removal of the portion 980 , as shown for example in FIGS. 46A-46C . That is, the tensioning force T is applied to pull or otherwise tear the portion 988 from the negative electrode and/or positive electrode subunit 900 , 902 , to provide a new structure shape. In the embodiment as shown in FIG. 45A , the portion may be removed to expose current collector ends 604 , 606 on opposing sides of the negative electrode and positive electrode subunits 900 , 902 , respectively. In one embodiment, the tensioning force T may be in a direction that is parallel to the length of the subunit. FIG. 45B shows another embodiment where the positive and negative electrode subunits 900 , 902 have the subunit weakened regions 986 where the portions 988 can be separated from the subunits by application of tension to the end margins.

›DETAILED DESCRIPTION · 19 of 58

FIGS. 45D and 45E show cross-sections of FIG. 45C , where the end margin 980 a is formed in a negative electrode current collector layer 136 ( FIG. 45D ), and/or in a sacrificial layer 905 that is layered between layers 136 a,b of negative electrode current collector ( FIG. 45E ). In the embodiment shown in FIG. 45D , the end margin 980 corresponds to an end region of a negative electrode current collector layer 136 that extends beyond the electrode active material layers, and the weakened region 986 that is formed in the margin provides for exposure of the current collector end upon removal of the portion 988 from the subunit. In the embodiment shown in FIG. 45E , the end margin 980 corresponds to an end region of the sacrificial layer 905 , in a section of the layer that extends out from between layers 136 a,b of negative electrode current collector. The weakened region 986 is formed in the margin 980 of the sacrificial layer, and the portion 988 can be separated from the subunit at the weakened region, leaving an end surface of the sacrificial layer exposed, along with the ends of current collector layers that are adjacent to the sacrificial layer. Similarly, while not shown, a positive electrode subunit 902 can comprise positive electrode active material layers 132 on either side of the positive electrode current collector layer 136 , with the end margin 980 a having a weakened region 986 formed in the positive electrode current collector layer and/or a sacrificial layer sandwiched in between layers of positive electrode current collector. Accordingly, by removing the portion of the subunit via the weakened region, the ends of current collectors for the negative electrode and/or positive electrode subunits can be exposed to allow for electrical connection thereof. Also, by forming the weakened region at a predetermined position corresponding to a resulting subunit shape, subunits having a predetermined dimension in S W (and optionally S L may be formed). That is, in certain embodiments, negative and/or positive electrode units having predetermined dimensions may be formed, by removing the portion 988 to leave a unit of the predetermined size. In one embodiment, the at least one portion 988 is removed by exerting a tension via one or more alignment pins 977 engaging the alignment features 970 , as is discussed in more detail below. That is, in one embodiment, the alignment pins 977 engaged in alignment features 970 on opposing ends of the subunits can be pulled apart from one another in the tensioning direction, to cause the weakened region to release the at least one portion from the subunit.

Furthermore, according to one embodiment, in the stacked population 925 , the subunits may be stacked such that the opposing end margins of the negative electrode subunit 900 and the positive electrode subunit 902 at least partially overlie one another (e.g., as shown in FIGS. 40A-40C ). According to aspects herein, following removal of the portion 980 of one or more of the negative electrode subunit 900 and the positive electrode subunit 902 , at least a portion of one or more of the opposing end surfaces 978 a,b in the first set of opposing end surfaces 978 a,b of the negative electrode subunit 900 are offset relative to at least a portion of one or more of the opposing end surfaces 982 a,b in the second set of opposing end surfaces 982 a,b of the positive electrode subunit 902 , in one or more of the tensioning direction and a third direction orthogonal to both the tensioning direction T and the stacking direction. For example, referring to FIG. 45F which shows an negative electrode subunit 900 with negative electrode active material layers 132 and negative electrode current collector 136 , and positive electrode subunit 902 with positive electrode active material layers 138 and positive electrode current collector 140 , the first opposing end 978 a of the negative electrode subunit, following removal of the portion, is internally offset with respect to the first opposing end 982 a of the positive electrode subunit, and the second opposing end 978 b of the negative electrode subunit, following removal of the portion, is externally offset with respect to the second opposing end 982 b of the positive electrode subunit. In FIG. 45F , the offsets are in the tensioning direction, which is also corresponds to a dimension S W of the electrode subunits and the components thereof, and also corresponds to the direction X as shown (the coordinate system of the electrode assembly in FIG. 2A ). However, the offsets may also be in another direction orthogonal to the stacking direction, such as in dimension S L and/or the Z direction that corresponds to a height dimension of the electrode subunits and components thereof. According to one embodiment, by providing an offset between the subunits and/or current collector layers, the positive and negative electrode current collector ends may be able to be individually accessed such that the negative electrode current collector ends can be collected and electrically connected to their respective busbar separately from the positive electrode current collector ends (e.g., as shown in FIGS. 27A-27F herein), and/or the offset may inhibit any shortening between the negative and positive electrode current collector ends.

According to yet another embodiment, in the stacked population, an interior portion 998 of the negative electrode subunit 900 and an interior portion 999 of the positive electrode subunit 902 are aligned with respect to each other in a tensioning direction X that is orthogonal to the stacking direction Y, and further comprising maintaining an alignment of the stacked population 925 while the tension is applied. According to one aspect, an interior portion of a subunit that is internal to the end margins, such as an interior portion that is interior to the portion 988 that is to be removed, is aligned with the interior portion of other subunits, and this alignment is maintained while tension is applied, to provide a stacked population having proper alignment following removal of the portion 988 . In one embodiment, the alignment is maintained by applying a tension at the opposing margins that is sufficiently balanced to maintain alignment. In yet another embodiment, the alignment is maintained by clamping the subunits in the stacked population into a fixed position with respect to each other, such as for example with the first and second end plates 974 a,b . Alternatively, in one embodiment, the alignment is maintained by separately fixing and holding the subunits, such as by individually clamping and holding each subunit in place. In another embodiment, the alignment is maintained by adhering the subunits to one another with an adhesive or by otherwise bonding the subunits together. In yet another embodiment, separate alignment pins may be provided to engage first alignment features 70 a that are internal to weakened regions, while second alignment features 70 b are used to remove the portion (see, e.g., FIG. 48M ).

›DETAILED DESCRIPTION · 20 of 58

In yet another embodiment, as shown in FIG. 41E , the alignment is maintained by affixing a structure to one or more of the subunits in the S T S W plane (corresponding to the XY plane of FIG. 2A ). That is, the edges of the subunits along the dimension S L (corresponding to the Z dimension) may be affixed to a structure, such as the first and second secondary growth constraints 158 , 160 described herein, to maintain alignment of the subunits with respect to each other while tension is applied to the ends of the subunits in the S W dimension (X direction). In the embodiment as shown, the end plates 974 a,b used to clamp and compress the first and second ends of the stacked population correspond to the first and second primary growth constraints 154 , 164 , and in combination with the secondary growth constraints 158 , 160 , serve to fix the positions of the subunits with respect to each other during processing to remove one or more of the end portions therefrom. According to certain aspects, each subunit in the stacked population may be affixed to the first and second secondary growth constraints. In another aspect, only a few of the subunits are affixed, with the remaining optionally being affixed at a later processing point. In certain aspects, the current collectors of the subunits may be affixed to the constraints. In the embodiment as shown, pulling the alignment pins 977 apart from one another in the X direction (tensioning direction) results in removal of the portion while keeping the rest of the stacked population in the predetermined alignment. That is, according to one embodiment, the alignment may be maintained by attaching a plurality of the negative electrode current collectors and/or positive electrode current collectors in the stacked population to one or more constraint members on a face of the stacked population that is in a plane of the stacking direction. According to one embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, each positive electrode subunit in the stacked population comprises a predetermined position with respect to the other positive electrode subunits in the tensioning direction and the third direction, and/or each negative electrode subunit in the negative electrode sheet comprises a predetermined position with respect to the other negative electrode sheets in the tensioning direction and the third direction. According to another embodiment, following removal of the portion of one or more of the negative electrode subunit and the positive electrode subunit, each negative electrode subunit in the stacked population comprises a predetermined position with respect to each positive electrode subunit in the stacked population in the tensioning direction.

According to one embodiment, the centroid separation distances between structures in a same unit cell (such as the unit cell portion of the negative electrode unit and unit cell portion of the positive electrode unit, and/or the unit cell portion of the negative electrode active material layer and unit cell portion of the positive electrode active material layer), and/or the centroid separation distances between structures in different unit cells (such as negative electrode units and/or negative electrode active material layers in different unit cells, or positive electrode units and/or positive electrode active material layers in different unit cells), as defined above, may be within the predetermined limits defined above following removal of the at least one portion, to provide a stacked population with proper alignment between the structures. For example in one embodiment, following removal of the portion of the one or more of the positive electrode subunit and the negative electrode subunit, the centroid separation distance between a positive electrode subunit centroid and a negative electrode subunit centroid is within a predetermined limit. In another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, for a centroid separation distance for each unit cell member of the population that is the distance between a centroid of the negative electrode active material layer and a centroid of the positive electrode active material layer comprised by such individual member projected onto an imaginary plane that is orthogonal to the stacking direction, the centroid distance is within a predetermined limit. According to yet another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, for a centroid separation distance for each unit cell member of the population that is the absolute value of the distance between a centroid of the negative electrode subunit and a centroid of the positive electrode subunit comprised by such individual member projected onto an imaginary plane that is orthogonal to the stacking direction, the centroid distance is within a predetermined limit. According to yet another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the members of the stacked population of unit cells have a centroid separation distance between either or both of negative electrode active material layers and/or positive electrode active material layers of first and second members, and wherein the centroid separation distance between first and second members of the population is the absolute value of the distance between the centroid of the unit cell portion of the negative electrode active material layer of the first member and the centroid of the unit cell portion of the negative electrode active material layer of the second member, and/or the absolute value of the distance between the centroid of the unit cell portion of the positive electrode active material layer of the first member and the centroid of the unit cell portion of the positive electrode active material layer of the second member, and the centroid distance is within a predetermined limit.

›DETAILED DESCRIPTION · 21 of 58

According to one embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the absolute value of the centroid separation distance for unit cell portions of negative electrode and positive electrode subunits in an individual member of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative electrode subunit is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the negative electrode subunit. According to yet another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the absolute value of the centroid separation distance for unit cell portions of negative electrode and positive electrode active material layers in an individual member of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative electrode active material layer is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the negative electrode active material layer. According to yet another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the absolute value of the centroid separation distance for unit cell portions of negative electrode subunits in first and second members of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative electrode subunit in either of the members is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the largest negative electrode subunit in the first and second members, and wherein the absolute value of the centroid separation distance for unit cell portions of positive electrode subunits in first and second members of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the positive electrode subunit in either of the members is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the largest positive electrode subunit in the first and second members. According to one embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the absolute value of the centroid separation distance for unit cell portions of negative electrode active material layers in first and second members of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the negative electrode active material in either of the members is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the largest negative electrode active material layer in the first and second members, and wherein the absolute value of the centroid separation distance for unit cell portions of positive electrode active material layers in first and second members of the population S D is within a predetermined limit corresponding to either less than 500 microns, or in a case where 2% of the largest dimension of the positive electrode active material layer in either of the members is less than 500 microns, then within a predetermined limit of less than 2% of the largest dimension of the largest positive electrode active material layer in the first and second members.

In one embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, an average centroid separation distance for at least 5 unit cells in the stacked population is within the predetermined limit. In another embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the average centroid separation distance is within the predetermined limit for at least 10 unit cells, at least 15 unit cells, at least 20 unit cells, and/or at least 25 unit cells in the stacked population. In one embodiment, following removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, the average centroid separation distance is within the predetermined limit for at least 75%, at least 80%, at least 90% and/or at least 95% of the unit cell members of the stacked population of unit cells.

The positive electrode, negative electrode, and separator sub-units may have one or more alignment features (for example, 970 in FIG. 41C ) in order to enable aligning each of the subunits to required tolerances upon stacking. In many cases, the subunit stacking alignment features are created on the sheet level prior to stacking onto a receiving unit 960 ( FIG. 38 ) onto alignment pins ( FIGS. 41D, 41E ). However, in some embodiments, the subunit alignment features can also be created during the stacking process by puncturing the sheets during a stacking process. Referring now to FIG. 50A , the subunit stacking alignment features 970 can be created in various shapes such as circles, triangles, squares, indented circles etc. In certain aspects, the design of the alignment features 90 may depends on, and is co-designed with, the shape of the alignment pins 977 in order to achieve a certain tolerance, and ease of assembly. It is also possible to have alignment features 977 with clearance as shown in FIG. 50B . A strategically designed clearance in the subunit alignment features paired with a corresponding alignment pin shape can provide benefits in stacking efficiency by causing less binding on the alignment pins 977 during the stacking operation. In one embodiment, the alignment feature has a five-sided shape with a narrow triangular end as shown in FIG. 50B . The alignment pins 977 in this case could be positioned along the wider square area which enables less binding during stacking.

›DETAILED DESCRIPTION · 22 of 58

The subunit alignment features (e.g. 970 in FIG. 41C ) may be positioned along different points on the sheet subunits ( 908 , 914 , 920 in FIG. 41C ) in order to provide alignment of the subunits in the stacks. In a preferred embodiment, the alignment features are positioned towards the middle of the subunit in the height direction (for example, the direction of height H E along the electrode subunit) and towards each end of the subunit along the length direction (for example, the direction of length L E along the electrode subunit) as shown in FIG. 39 . Once the stack has been formed by stacking the negative electrode, separator, positive electrode sheets in alternating fashion onto the receiving unit 960 by utilizing the alignment pins 977 , a subsequent fine alignment step can be performed by tensioning the stack by moving the alignment pins away from each other along the electrode length L E direction. In an arrangement where the subunit alignment features 970 have a five-sided shape with a triangular end ( FIG. 50B ), and the triangular portions of the five-sided shapes in the alignment features are facing away from each other, the post-stacking tensioning step can move the alignment pins toward the narrow areas, thereby providing tension to the different components of the stack and resulting in tighter alignment between layers.

In other embodiments, subunit alignment features 970 in combinations with alignment pin shape and dimensions can be used to tailor alignments along different directions as shown in FIG. 49 . For example, a slot along the X-direction in FIG. 49 can be used to align sheets in a Z-direction, which a slot along the Z-direction can be used to align sheets in an X-direction. Combinations of slots, holes, and other shapes can be used in conjunction with alignment pins to achieve required alignment tolerances along a X, Z, and Θ direction.

In certain embodiments, the subunits themselves have weakened regions 986 therein, in order to enable removal of subunit alignment features 970 after the stack has been aligned and stack alignment has been fixed by utilizing an alignment fixing processes as described elsewhere herein. While in certain embodiments the subunit alignment features 970 can be left intact by removing the alignment pins 977 after fixing the stack alignment; extra volume occupied by the alignment features 970 in the battery can in certain instances negatively impact volumetric and gravimetric energy density. In an embodiment as in FIG. 48I , the positive and negative electrode subunits (and the separator in between the positive and negative electrode subunits, not shown) each have two alignment features 970 , one each towards each end of the subunit sheet along the X-direction. The positive and negative electrode sheets also have two weakened regions 986 , one each towards each end of the subunit sheet along the X-direction, with both weakened regions in each sheet inboard of the alignment features along the X-direction (closer to each other). Once stacking is complete and alignment is fixed, the areas marked by X in FIG. 48I can be removed by removing the negative and positive electrodes (and the separators, not shown) by applying a force to remove the alignment feature pieces from the stack.

Referring now to FIG. 48A thru 48 J, various combinations of subunit alignment features 970 and weakened regions 986 can be used to achieve different alignments and offsets for the stacks as determined by device design requirements. In each figure in this sequence, the piece that gets removed from the final device is marked with the letter X. The separator sheet is not shown in these series of images, but the separator sheet can have similar features to one of the positive or negative electrodes and can be treated as an extension of the electrode for excess material removal purposes. In certain embodiments, such as for safety and shorting prevention reasons, the separator may be the widest material remaining in the device. In FIG. 48A , the positive electrode subunit 900 has a hole as an alignment feature 970 in the near edge and a weakened region 986 close to the hole and inboard of the hole towards the center of the positive electrode subunit. The negative electrode subunit 902 has a slot along the near edge in the X-direction and does not have a weakened region in the subunit internal to the perimeter. In this arrangement, according to certain embodiments, the stacking can be done using one alignment pin 977 until all the layers are stacked, and then a subsequent alignment could be done by aligning the far edge of the sheets by pushing the edges together while allowing the stack to rotate along the alignment holes and slots on the near edge. Once the alignment is fixed, the far edge can be held in place by holding on to the sheets from the edges with a mechanism such as clamping, and the alignment pin in the near edge can be moved away from the center of the electrode subunit along the length direction, thereby removing a portion of the positive electrode sheet along its weakened region. Embodiments may provide a stack with the negative electrode unit overhanging the positive electrode along the near side of the stack, which could then potentially be used for electrical connections or mechanical reinforcements. Alternatively, referring to FIG. 48B , embodiments may provide a negative electrode subunit overhang on the far side, away from the alignment features.

Referring to FIGS. 48C and 48D , in certain embodiments no overhang of the positive and negative electrode subunits may result if the weakened regions 986 are aligned along the same length with respect to each other. According to certain aspects, it may be possible to provide an overlap of either one of the negative or positive electrode subunit by tailoring the location of the weakened regions 986 relative to one another. Referring to FIG. 48E , in certain embodiments the removal of the portion at the weakened region 986 may result in a device that has the positive electrode subunit 900 overhang on the far side and a negative electrode subunit 902 overhang on the near side, and would allow for electrical connections of like electrode current collectors on opposite sides along the X-direction. FIGS. 48F through 48J show further embodiments of weakened region and alignment feature configurations, which may result in differing orientations and offsets of the negative electrode subunit with respect to the positive electrode subunit.

›DETAILED DESCRIPTION · 23 of 58

According to certain embodiments, the alignment features 970 can be used to apply mechanical forces along the X-direction (along the length direction of the subunits) to preferentially leave behind the desired subunit shapes and dimensions. However, other methods can be utilized to remove the weakened regions as well. Mechanical, electrical, and thermal methods can be used to separate the two features along the weakened area. For example, a laser beam could be directed along the weakened area to heat, melt, and separate the two regions. High current could be applied between the two sections and utilize resistance melting to remove the two pieces. Combination of electrical, thermal, and mechanical processes can be used as well. Additionally, the weakened regions 986 can be fabricated and/or correspond to any of the configurations and/or methods described herein, such as the sheet weakened regions 908 , 914 , 920 . That is, the sheet weakened regions 908 , 914 , 920 may comprise the same and or similar types of regions, and/or may be formed in the same or similar fashion, as the weakened regions 986 , and thus the disclosure herein with respect to the sheet weakened regions 908 , 914 , 920 should also be understood as applying to the weakened regions of the subunits.

Referring to FIG. 57A , an embodiment of a negative electrode sheet 906 process flow is shown. According to this embodiment, the raw materials for the negative electrode consisting of the negative electrode active material (such as carbon, silicon, silicon oxides, tin, tin oxides, lithium titanium oxide), binders (such as polyimide, PAA, CMC/SBR, PVDF), and conductive aids (such as carbon black, acetylene black, graphite, carbon nanotubes) are mixed with a solvent (such as NMP, water or other organic liquid) to form a paste.

The mixing process can follow multiple paths such as: mixing all the dry ingredients first, followed by mixing with the solvent; adding each of the dry ingredients in a particular sequence to the solvent followed by interim mixing; and/or mixing a portion of the dry ingredients together such as the active material and conductive agent first and then adding the components in a specific order followed by interim mixing.

The mixing process can be done in electrode batch slurry mixing equipment or with a continuous flow mixing process where the raw materials are fed in and the mixed slurry is continuously fed to the coating equipment. The temperature of the mixing process can be controlled to a specified setting or varied to multiple settings at different points in the process. The atmosphere in contact with the slurry being mixed can be ambient air, inert with controlled humidity or a vacuum.

Once the mixing process is complete, the next step in this embodiment is coating the slurry onto a negative electrode current collector 136 , typically within a specified time after the mixing is complete. According to embodiments herein, the current collector material can be a metal foil of specified thickness (between 0.5 um and 30 um) and made of Cu, Ni or stainless steel or a mixture of these. The current collector can also be a mesh made of the above materials. The current collector can also be a laminated foil where the core and the surface are made of different materials.

The coating process according to one embodiment can involve laying down a uniform layer of the slurry in a specified pattern on the current collector. Examples of coating processes include slot die, reverse roll, inkjet, spray coat, dip coat, screen and stencil print. Only one side of the current collector may be coated or both sides. When both sides of the current collector are coated, it can be done concurrently or sequentially. After the coating process is complete, the solvent may be evaporated off. This can be done with the assistance of higher temperature, increased airflow or lower air pressure or with a combination of these.

Optionally, in a next step, the negative electrode sheet 906 can be calendared to a specified thickness and porosity with a calendar mill. The surface of the calendar mill can be smooth, rough or with a specified pattern that leaves portions of the electrode at different thicknesses and porosities.

According to certain embodiments, an alternate negative electrode sheet process could be performed for a metal anode such as Li, Na, Mg. In this case, a single foil of the negative electrode material can serve as both the negative electrode active material and the negative electrode current collector. Alternately, the negative electrode active material can be laminated (or deposited with other means such as CVD, plating, evaporation, sputtering, etc.) onto a backing layer to provide further support to the subunit. The backing layer could be comprised of an organic material, a ceramic or ceramic composite, or another metal or metal alloy.

According to embodiments herein, the next steps in the method can be mixed and matched from the following to make a patterned negative electrode sheet. (1) Clear the negative electrode active material off the negative electrode current collector with a specific pattern to define parts of the negative electrode active material layer and electrode tab geometries (e.g., the geometry of the area occupied by the negative electrode active material and that of negative electrode current collector and current collector end that is to be connected to the negative electrode busbar 600 ). This clearing can be done with a laser or with a mechanical process. Care may be taken minimize damage to the underlying negative electrode current collector layer as well as to the remaining electrode active material layer. In addition, accumulation of debris on the surface of the negative electrode active material layer or negative electrode current collector should typically be minimized. (2) Define and add primary and secondary alignment features 936 , 970 (e.g., web and/or sheet alignment features and/or subunit alignment features). This can involve making marks or through holes in the negative electrode current collector layer and/or negative electrode active material layer at specified locations, and with a specified pattern and geometry. This can be accomplished with a laser or with a mechanical process. (3) Define and add weakened regions 908 , 938 (e.g., weakened regions defining negative electrode subunits, and weakened regions within the subunit for removal of a portion therefrom). The weakened regions can be generated by removing or thinning a specified geometry of the negative electrode current collector layer, or even both the negative electrode current collector and negative electrode active material layer, for example such that when a tensional force is applied later in the process, stress is increased in the weakened region. Alternatively, the weakened regions may be formed by, following removal of parts of the negative electrode current collector layer and/or negative electrode active material layer, applying weaker materials (such as organic films) to the regions where removal occurred to at least partially rejoin the parts, including electrically or thermally fusible materials. The weaker material may add enough structural rigidity to allow subsequent processing with high yield. (3) Add spacer layers 909 a,b to the margins. The spacer layer can include, for example, a layer of organic or inorganic material, and can be applied to portions of either or both the active and inactive surfaces. The spacer layers 909 a , 909 b can also comprise a material that is the same as an electrode active material layer and/or separator layer, as is described in further detail hereinbelow. The thickness of the spacer layer can be well controlled such that when the stack is assembled, the spacer layer increases the distance between adjacent layers in the stack by a specified amount. The spacer layer can later be removed as part of the battery manufacturing process, or portions of it can be left behind.

›DETAILED DESCRIPTION · 24 of 58

Referring to FIG. 57B , an embodiment of a process flow for a separator sheet 912 is described. According to the embodiment, the separator layer 130 is formed by mixing an insulating particulate material with a binder in a liquid medium to make a slurry. The liquid medium can be water or an organic solvent. The slurry is then applied to a backing material to a consistent thickness. The method of application can be casting, spray coating, dip coating, slot die coating, reverse roll coating, inkjet printing, stencil or screen printing. After the coating process is complete, the solvent may be evaporated off. This can be done with the assistance of higher temperature, increased airflow or lower air pressure or with a combination of these.

According to one embodiment, a next step may be to optionally calendar the separator layer 130 to a specified thickness and porosity with a calendar mill. The surface of the calendar mill can be smooth, rough or with a specified pattern that leaves portions of the separator at different thicknesses and porosities. The backing layer could be optionally removed at this stage or left on to be removed later to provide structural support for the separator layer. An alternate option according to certain embodiments is to obtain the separator as a sheet from another source and integrate into the process.

Another alternate option according to certain embodiments is to obtain the separator sheet 912 from another source, and add a layer from a suspension or a slurry. The suspension or slurry can contain a particulate material or materials in a liquid medium. The method of application can be casting, spray coating, dip coating, slot die coating, reverse roll coating, inkjet printing, stencil or screen printing. After the coating process is complete, the liquid may be evaporated off. This can be done with the assistance of higher temperature, increased airflow or lower air pressure or with a combination of these. The additional layer may, according to certain aspects add additional functionality to the separator. Examples of this added functionality may be increase in puncture resistance, increase in elastomeric properties, or reduction of defects or combinations of these. In addition to thickness, porosity, tortuosity, defect density and ionic conductance which may be parameters measured for the separator, the separator may also be controlled to provide these same parameters under applied pressures between 0 and 20 MPa. Furthermore, according to certain embodiments, in order for the separator to maintain a minimum ionic conductance under increasing pressure, the materials and construction of the separator may be engineered such that the pores in the separator do not generally collapse.

According to certain embodiments, the next steps can be mixed and matched to make the patterned separator sheet 912 . (1) Define and add primary and secondary alignment features ( 936 , 970 ). This can involve making marks or through holes in the separator layer 130 at specified locations and with a specified pattern and geometry. This can be accomplished with a laser or with a mechanical process. (2) Define and add weakened regions 914 , 986 . The weakened regions can be generated by removing or thinning a specified geometry of the separator layer, for example such that when a tensional force is applied later in the process, stress is increased in the weakened region. Alternatively, the weakened regions may be formed by, following removal of parts of the separator layer 130 , applying weaker materials (such as organic films) to the regions where removal occurred to at least partially rejoin the parts, including electrically or thermally fusible materials. (3) Add spacer layers to the margins 909 a,b . The spacer layer can comprise a layer of organic or inorganic material, and can be applied to portions of the separator layer. The thickness of the spacer layer should be well controlled such that when the stack is assembled, the spacer layer increases the distance between adjacent layers in the stack by a specified amount. The spacer layer can later be removed as part of the battery manufacturing process, or portions of it can be left behind.

Referring to FIG. 57C , an embodiment of a process flow for preparing a positive electrode sheet 918 is described. According to this embodiment, the raw materials for the positive electrode can include the active material (such as LCO, NCA, NCM, FePO 4 ), binders (such as polyimide, PAA, CMC/SBR, PVDF), and conductive aids (such as carbon black, acetylene black, graphite, carbon nanotubes) are mixed with a solvent (such as NMP, water or other organic liquid) to form a paste. The mixing process can follow multiple paths such as: mixing all the dry ingredients first, followed by mixing with the solvent; adding each of the dry ingredients in a particular sequence to the solvent followed by interim mixing; and/or mixing a portion of the dry ingredients together such as the active material and conductive agent first and then adding the components in a specific order followed by interim mixing.

The mixing process can be done in a battery electrode batch slurry mixing equipment or with a continuous flow mixing process where the raw materials are fed in and the mixed slurry is continuously fed to the coating equipment. The temperature of the mixing process can be controlled to a specified setting or varied to multiple settings at different points in the process. The atmosphere in contact with the slurry being mixed can be ambient air, inert with controlled humidity or a vacuum.

Once the mixing process is complete, the next step according to certain embodiments is coating the slurry onto a positive electrode current collector 140 which should be completed within a specified time after the mixing is complete. The positive electrode current collector material can, for example, be a metal foil of specified thickness (between 0.5 um and 30 um) and made of Al. The positive electrode current collector can also be a mesh made of the above material. The positive electrode current collector can also be a laminated foil where the core and the surface are made of different materials.

›DETAILED DESCRIPTION · 25 of 58

According to certain embodiment, the coating process can involve laying down a uniform layer of the slurry in a specified pattern on the positive electrode current collector. Examples of coating processes include slot die, reverse roll, inkjet, spray coat, dip coat, screen and stencil print. Only one side of the positive electrode current collector may be coated, or both sides can be coated. When both sides of the positive electrode current collector are coated, it may be done concurrently or sequentially. After the coating process is complete, the solvent may be evaporated off. This can be done with the assistance of higher temperature, increased airflow or lower air pressure or with a combination of these.

The next step, according to certain embodiments, may be to optionally calendar the positive electrode sheet 918 to a specified thickness and porosity with a calendar mill. The surface of the calendar mill can be smooth, rough or with a specified pattern that leaves portions of the positive electrode at different thicknesses and porosities. The next steps can be mixed and matched to make the patterned positive electrode sheet 918 . (1) Clear the positive electrode active material off the positive electrode current collector with a specific pattern to define parts of the positive electrode active material layer and positive electrode tab geometries (e.g., the geometry of the area occupied by the positive electrode active material and that of the positive electrode current collector and positive electrode current collector end that is to be connected to the positive electrode busbar 602 ). This clearing can be done with a laser or with a mechanical process. Care is typically taken to minimize damage to the underlying current collector as well as to the remaining electrode. In addition, accumulation of debris on the surface of the electrode or current collector is typically minimized. (2) Define and add primary and secondary alignment features 936 , 970 . This can involve making marks or through holes in the positive electrode current collector and/or positive electrode active material layer at specified locations and with a specified pattern and geometry. This can be accomplished with a laser or with a mechanical process. (3) Define and add weakened regions 920 , 986 . The weakened regions can be generated by removing or thinning a specified geometry of the positive electrode current collector and/or positive electrode current collector and positive electrode active material layer, for example such that when a tensional force is applied later in the process, stress is increased in the weakened region. Alternatively, the weakened regions may be formed by, following removal of parts of the positive electrode current collector and/or positive electrode active material layer, applying weaker materials (such as organic films) to the regions where removal occurred to at least partially rejoin the parts, including electrically or thermally fusible materials. The weaker material may add enough structural rigidity to allow subsequent processing with high yield. (4) Add spacer layers 909 a,b to the margins. The spacer layer can comprise a layer of organic or inorganic material, and can be applied to portions of either or both the active and inactive surfaces. The thickness of the spacer layer may be controlled such that when the stack is assembled, the spacer layer increases the distance between adjacent layers in the stack by a specified amount. The spacer layer can later be removed as part of the battery manufacturing process, or portions of it can be left behind.

Referring to FIG. 57D , an embodiment of a stacking process is described. According to this embodiment, separate feeds of the patterned separator sheet 912 , the patterned positive electrode sheet 918 , another patterned separator sheet 912 and the patterned negative electrode sheet 906 are brought together to roughly align the sheets to their respective final positions in the stack with the aid of alignment features 936 on the sheets, thereby forming a pre-aligned set of sheets. The feeds of the electrode and separator sheets can originate from a roll of each or directly fed from the tool that patterns each sheet respectively, or from combinations of the two.

According to this embodiment, the starting stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture (e.g., receiving unit 960 ). According to another embodiment, additional electrodes and separators could be added, such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

According to the embodiment, the pre-aligned sheets that have been roughly aligned in the alignment process are then fed into the stacking area (e.g., subunit removal station 956 ) where four pieces (two electrodes and two separators) are removed from their respective sheets by detaching through the weakened area. The weakened area could be, for example, mechanically, electrically or thermally weakened, or a combination of these. The detached electrodes and separators are then fed into the stacking fixture such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer to their respective final positions with respect to each electrode and separator centroid.

According to the embodiment, the roughly aligned sheets advance to another position where another four pieces (two electrodes and two separators) are removed from their respective sheets by detaching through the weakened area. The weakened area could be mechanically, electrically or thermally weakened or a combination of these. The detached electrodes and separators are then fed into the stacking fixture such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer their respective final positions with respect to each electrode and/or separator centroid. This process is repeated until the required number of electrodes and separators are inserted into the stacking fixture.

›DETAILED DESCRIPTION · 26 of 58

According to the embodiment, the ending stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. A further option would be add additional electrodes and separators such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

Upon completion, the completed electrode and separator stack and stacking fixture are removed from the stacking tool.

Referring to FIG. 57E , a further embodiment of a stacking process is described. According to this embodiment, separate feeds of the patterned separator sheet 912 and the patterned positive electrode sheet 918 , are brought together to roughly align the sheets to their respective final positions in the stack with the aid of alignment features on the sheets, and form a first set of pre-aligned sheets. Furthermore, separate feeds of another patterned separator sheet 912 and the patterned negative electrode sheet 906 are brought together to roughly align the sheets to their respective final positions in the stack with the aid of alignment features on the sheets, and form a second set of pre-aligned sheets. The feeds of the electrode and separator sheets can originate from a roll of each or directly fed from the tool that patterns each sheet respectively, or from combinations of the two.

According to the embodiment, the first and second set of pre-aligned sheets are fed to one or more stacking areas (e.g., removal stations 956 ) for stacking of the electrodes and separators from the sets of sheet. According to one embodiment, the second set of pre-aligned sheets are fed into a second stacking area where two pieces in the second set (the negative electrode and separator) are removed from their respective sheets by detaching through the weakened area. The weakened area could be, for example, mechanically, electrically or thermally weakened, or a combination of these. A stacking fixture is provided in the second stacking area to receive and further align the pieces removed from the second set of pre-aligned sheets. Furthermore, as the negative electrode and separators enter the stacking fixture they are further aligned to be closer to their respective final positions with respect to each negative electrode and separator centroid. Similarly, according to one embodiment, the first set of pre-aligned sheets are fed into a first stacking area where two pieces in the second set (the positive electrode and separator) are removed from their respective sheets by detaching through the weakened area. The weakened area could be, for example, mechanically, electrically or thermally weakened, or a combination of these. A stacking fixture is provided in the first stacking area to receive and further align the pieces removed from the first set of pre-aligned sheets.

According to one embodiment, the stacking fixture is configured to move between first and second stacking areas, to provide for alternating stacking of the negative electrode and separator in the second set of pre-aligned sheets, and the positive electrode and separator in the first set of pre-aligned sheets. That is, the stacking fixture may alternate between the first and second stacking areas so as to stack each set with each other in an alternating fashion. For example, in a case where the first and second stacking areas are in separate first and second feeding lines 971 a,b , the stacking fixture may alternate between two lines. Each of the pieces in the sets of sheets can be removed from their respective sheets by detaching through the weakened area. The weakened area could be mechanically, electrically or thermally weakened or a combination of these. The first and second (and optionally more) sets of detached electrodes and separators are fed into the stacking fixture, in an alternating fashion, such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer their respective final positions with respect to each electrode and/or separator centroid. This process is repeated until the required number of electrodes and separators are inserted into the stacking fixture.

According to yet another embodiment, the stacking fixture is configured to separately receive the first set of pre-aligned sheets and the second set of pre-aligned sheets at a same stacking area (e.g., in the same feeding line), with the first and second set being fed separately in an alternating fashion to the stacking area, such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer their respective final positions with respect to each electrode and separator's centroid. This process is repeated until the required number of electrodes and separators are inserted into the stacking fixture.

According to the embodiment, the ending stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. A further option would be to add additional electrodes and separators, such as from the first and second pre-aligned sheets above, such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

Upon completion, the completed electrode and separator stack and stacking fixture are removed from the stacking tool.

›DETAILED DESCRIPTION · 27 of 58

Referring to FIG. 57F , a further embodiment of a stacking process is described. According to this embodiment, separate feeds of the patterned separator sheets 912 , the patterned positive electrode sheet 918 , and the negative electrode sheet 906 are each individually fed into a stacking area (e.g., removal station 956 ). That is, according to certain aspects, the separate feeds may be brought to an area for stacking, substantially without preforming a step to pre-align the sheets with respect to each other. The feeds of the electrode and separator sheets can originate from a roll of each, or be directly fed from the tool that patterns each sheet respectively, or any combination of the two.

According to this embodiment, the starting stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. According to another embodiment, additional electrodes and separators could be added, such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

According to the embodiment, the separate feeds may be fed to separate stacking areas (e.g., via separate feeding lines) for individual stacking of the pieces from each sheet and/or the separate feeds may be individually fed to the same stacking area (e.g., via a shared feeding line), but stacking is alternated between each feed. For example, according to one embodiment, a stacking fixture may alternate between different stacking areas for each separate feed, and/or may receive the separate feed individually at a same stacking area. According to one aspect, each of the patterned separator feeds, the patterned positive electrode sheet and the patterned negative electrode sheet are each fed to a separate stacking area, and the stacking fixture may alternate between each of the separate stacking areas to provide for individual stacking of the features removed from the sheets in the separate feeds. According to another aspect, each of the patterned separator feeds, the patterned positive electrode sheet and the patterned negative electrode sheet, are each fed to a same stacking area in an alternating fashion, such that the stacking fixture at the same stacking area receives the pieces removed from the sheets in the separate feeds in an alternating fashion. According to one embodiment the pieces removed from each separate feed (e.g., separator, positive electrode, and negative electrode) are removed from their respective sheets by detaching through the weakened area. The weakened area could be, for example, mechanically, electrically or thermally weakened, or a combination of these. Furthermore, as the electrodes and separators enter the stacking fixture they are further aligned to be closer to their respective final positions with respect to each electrode and/or separator centroid. The detached pieces removed from the sheets of each feed (separator, positive electrode, negative electrode) are fed onto the stacking fixture, in an alternating fashion, such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. This process is repeated until the required number of electrodes and separators are inserted into the stacking fixture

According to the embodiment, the ending stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. A further option would be to add additional electrodes and separators, such as from the first and second pre-aligned sheets above, such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

Upon completion, the completed electrode and separator stack and stacking fixture are removed from the stacking tool.

Referring to FIG. 57G , a further embodiment of a stacking process is described. According to this embodiment, separate multi-sheet feeds are brought together to roughly align each of the multi-sheet feeds to their respective final positions in the stack with the aid of alignment features on the sheets of the multi-sheet feeds. For example, each of the multi-sheet feeds can comprise layered sheets of patterned negative electrode 906 , patterned separator 912 , patterned positive electrode 918 , and another patterned separator sheet 912 that have been patterned and then roughly pre-aligned with respect to one another. By aligning each of the multi-sheet feeds (4 multi-sheet feeds as shown), a stacking feed can be provided having a plurality of the multi-sheet feeds aligned together therein. That is, a stacking feed having more than just a single stacking iteration of negative electrode/separator/positive electrode/separator can be provided, with multiple iterations corresponding to each multi-sheet feed that is aligned together to form the stacking feed. The multi-sheet feeds can originate from a roll of each or directly fed from the tool that patterns each sheet respectively, or from combinations of the two.

According to this embodiment, the starting stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. According to another embodiment, additional electrodes and separators could be added, such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

According to the embodiment, the stacking feed comprising the pre-aligned multi-sheet that have been roughly aligned with respect to each other are then fed into the stacking area (e.g., removal station 956 ) where the pieces (electrodes and separators of each multilayer sheet) are removed from their respective sheets and the stacking feed, by detaching through the weakened area in each sheet. The weakened area could be, for example, mechanically, electrically or thermally weakened, or a combination of these. The detached electrodes and separators are then fed into the stacking fixture such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer to their respective final positions with respect to each electrode and separator centroid.

›DETAILED DESCRIPTION · 28 of 58

According to the embodiment, the stacking feed may then be advanced to another position where another set of pieces (electrodes and separators) are removed from each of the multi-layer sheets stacked together in the stacking feed by detaching through the weakened area. The weakened area could be mechanically, electrically or thermally weakened or a combination of these. The detached electrodes and separators are then fed into the stacking fixture such that a sequence of negative electrode/separator/positive electrode/separator is maintained through the stack. As the electrodes and separators enter the stacking fixture they are further aligned to be closer their respective final positions with respect to each electrode and/or separator centroid. This process is repeated until the required number of electrodes and separators are inserted into the stacking fixture.

According to the embodiment, the ending stack materials comprised of an end plate, a single-sided electrode facing away from the end plate and optionally a layer of separator are fed into the stacking fixture. A further option would be to add additional electrodes and separators such that a sequence of negative electrode/separator/positive electrode/separator is maintained.

Upon completion, the completed electrode and separator stack and stacking fixture can be removed from the stacking tool.

Referring to FIG. 57H , an embodiment of a post stack battery fabrication process is described. According to this embodiment, the completed stack in its stacking fixture (such as any in FIGS. 57D-57G above) is fed into the final alignment tool. The final alignment of each negative electrode subunits, positive electrode subunits and separator layer subunits with respect to the target location of the centroid for the subunits may be achieved by using alignment features 970 on one or more element. According to this embodiment, the alignment of each element of the stack can be then fixed by either gluing the elements together, melting a portion of the negative electrode, positive electrode or separator, or by heat laminating the structure.

According to this embodiment, a final alignment structure can be bonded in place. Furthermore, according to certain aspects, fixing the alignment of each element and bonding the final alignment structure can be achieved as one step. According to certain aspects, the stacking fixture, and optionally, the secondary alignment features are removed. This can be done removing the secondary alignment features 970 along a weakened region 986 in the negative electrode subunit, positive electrode subunit or separator layers. The weakened area could be mechanically, electrically or thermally weakened or a combination of these.

According to this embodiment, a next step of the process is to connect current carrying tabs (e.g., busbars 600 , 602 ) to the ends of the negative electrode current collectors and the positive electrode current collectors, separately. The other end of the negative electrode tab and positive electrode tab can, in a further step, be brought outside the package of the battery and serve as the positive and negative terminals of the battery. The connection process of the current carrying tabs to the negative electrode current collectors and positive electrode current collectors can involve laser, resistance or ultrasonic welding, gluing, or pressure connections.

According to the embodiment, the battery stack may then be inserted into a soft pouch. The pouch material can be made of standard battery aluminized pouch foil material. Furthermore, a liquid electrolyte may optionally be injected into the package, and the package sealed by laminating the edges of the pouch material together. After the sealing is complete, the positive and negative current carrying tabs may be visible outside of the pouch with the laminated pouch seals around each tab.

Referring to FIG. 57I , another embodiment of a post stack battery fabrication process is described. According to this embodiment, the completed stack in its stacking fixture (such as any in FIGS. 57D-G above) is fed into the final alignment tool. The final alignment of each negative electrode subunit, positive electrode subunit and separator layer subunit with respect to the target location of the centroid for one or more of the subunits can be achieved by using alignment features 970 the subunits. According to this embodiment, the alignment of each element of the stack can be then fixed by either gluing the elements together, melting a portion of the negative electrode, positive electrode or separator, or by heat laminating the structure.

According to this embodiment, the stacking fixture, and optionally, the secondary alignment features 970 are removed. This can be done removing the secondary alignment features 970 along a weakened region 986 in the negative electrode current collector and/or negative electrode active material layer, positive electrode current collector and/or positive electrode active material layer, or separator layer. The weakened area could be mechanically, electrically or thermally weakened or a combination of these. According to certain embodiments, a next step of the process can be to connect current carrying tabs (e.g., negative electrode busbar 600 and positive electrode busbar 602 ) to the ends of the negative electrode current collectors and the positive electrode current collectors, separately. The other end of the negative electrode tab and positive electrode tab can in a later step be brought outside the package of the battery and serve as the positive and negative terminals of the battery. The connection process of the current carrying tabs to the negative electrodes and positive electrodes can involve laser, resistance or ultrasonic welding, gluing, or pressure connections.

According to certain embodiments, the battery stack may then be inserted into a soft pouch. The pouch material can be made of standard battery aluminized pouch foil material. Furthermore, a liquid electrolyte may optionally be injected into the package, and the package sealed by laminating the edges of the pouch material together. After the sealing is complete, the positive and negative current carrying tabs may be visible outside of the pouch with the laminated pouch seals around each tab.

›DETAILED DESCRIPTION · 29 of 58

Furthermore, processes for manufacturing the secondary battery, energy storage device and/or electrode assembly described herein may also incorporate combinations of steps in any of FIGS. 57A-57I above, and/or combinations of the entire process flows as described with reference to any of FIGS. 57A-57I above, as well as any other suitable steps and/or processes.

Returning to FIGS. 48A-48M and 46A-46C , in one embodiment the negative electrode subunit 900 has the at least one weakened location 986 in an opposing end margin thereof, and tension may be applied to the opposing end margin of the negative electrode subunit having the weakened region to remove the portion of the negative electrode subunit, such that the first set of opposing end surfaces of the negative electrode subunit comprise the at least one end surface exposed by removal of the portion, as shown in FIGS. 48A-48B and 46A . In another embodiment, the positive electrode subunit 902 has the at least one weakened location 986 in at least one opposing end margin thereof, and tension may be applied to the opposing end margin having the weakened region of the positive electrode subunit to remove the portion of the positive electrode subunit, such that the second set of opposing end surfaces of the negative electrode subunit comprise the at least one end surface exposed by removal of the portion, as shown in FIGS. 48G-48H . Furthermore, in one embodiment, both the negative electrode subunit 900 and the positive electrode subunit 902 have the at least one weakened region 986 in at least one opposing end margin thereof, such that tension may be applied to the opposing end margins having the at least one weakened region of the negative electrode and positive electrode subunits to remove the portions of the negative electrode subunit and positive electrode subunit, such that both the first set of opposing end surfaces of the negative electrode subunit and the second set of opposing end surfaces of the positive electrode subunit comprise at least one end surface exposed by removal of the portions therefrom, as shown in FIGS. 48C-48D . Furthermore, in one embodiment, the opposing end margin having the at least one weakened region of the negative electrode subunit 900 is on a same side in the tensioning direction as the opposing margin having the at least one weakened region of the positive electrode subunit, as shown in FIGS. 48C-48D . In yet another embodiment, the opposing end margin having the at least one weakened region of the negative electrode subunit is on an opposing side in the tensioning direction as the opposing margin having the at least one weakened region of the positive electrode subunit, as shown in FIG. 48E . According to yet another embodiment, at least one of the negative electrode subunit and positive electrode subunit comprises weakened end regions at both opposing end margins thereof, as shown in FIG. 48I . In a further embodiment, both the negative electrode subunit and the positive electrode subunit comprise weakened end regions at both opposing end margins thereof, as shown in FIG. 48J .

Furthermore, while embodiments herein have described forming the complete stack population 925 before removing the portions from the negative electrode and positive electrode subunits, in further embodiments it may be possible to form a portion of the stacked population prior to removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit, and wherein the removal of the portion of one or more of the positive electrode subunit and the negative electrode subunit is followed by stacking further members of one or more of the negative electrode subunit population, the separator layer subunit population, and the positive electrode subunit population to form the stacked population. Alternating steps of stacking and end margin portion removal may also be performed.

According to one embodiment, the stacked population 925 is formed by stacking a plurality of negative electrode subunits and positive electrode subunits, optionally with a plurality of separator sheets, to form at least one unit cell, at least two unit cells, at least three unit cells, at least four unit cells, at least 5 unit cells, at least 6 unit cells, at least 7 unit cells, at least 8 unit cells, at least 9 unit cells, at least 10 unit cells, at least 11 unit cells, at least 12 unit cells, at least 13 unit cells, at least 14 unit cells, at least 15 unit cells and/or at least 16 unit cells of a battery. In another embodiment, the stacked population is formed by stacking at least 1 negative electrode subunit and at least 1 positive electrode subunit, stacking at least 2 negative electrode subunits and at least 2 positive electrode subunits, stacking at least 3 negative electrode subunits and at least 3 positive electrode subunits, stacking at least 4 negative electrode subunits and at least 4 positive electrode subunits, stacking at least 5 negative electrode subunits and at least 5 positive electrode subunits, stacking at least 6 negative electrode subunits and at least 6 positive electrode subunits, stacking at least 7 negative electrode subunits and at least 7 positive electrode subunits, stacking at least 8 negative electrode subunits and at least 8 positive electrode subunits, stacking at least 9 negative electrode subunits and at least 9 positive electrode subunits, stacking at least 10 negative electrode subunits and at least 10 positive electrode subunits, stacking at least 11 negative electrode subunits and at least 11 positive electrode subunits, stacking at least 12 negative electrode subunits and at least 12 positive electrode subunits, stacking at least 13 negative electrode subunits and at least 13 positive electrode subunits, stacking at least 14 negative electrode subunits and at least 14 positive electrode subunits, stacking at least 15 negative electrode subunits and at least 15 positive electrode subunits, and/or stacking at least 16 negative electrode subunits and at least 16 positive electrode subunits.

›DETAILED DESCRIPTION · 30 of 58

Furthermore, according to embodiments herein, the at least one subunit weakened region may be formed in a negative electrode current collector layer of a negative electrode subunit, and/or the at least one subunit weakened region may be formed in a positive electrode current collector layer of a positive electrode subunit. The at least one weakened region may also be formed in a sacrificial layer. Furthermore, the at least one weakened region may also be formed in a negative electrode active material layer of a negative electrode subunit, and/or in a positive electrode active material layer of a positive electrode subunit. The at least one weakened layer may also be formed in a separator layer. In one embodiment, the weakened region is formed through multiple layers of the subunit. In another embodiment the at least one subunit weakened region extends through a thickness of the subunit in the stacking direction.

Referring to FIGS. 51A-51E , in one embodiment, the at least one weakened region traverses at least a portion of height of the positive electrode and/or negative electrode subunit in the Z direction orthogonal to the stacking direction Y and the tensioning direction, between first and second opposing surfaces thereof. In another embodiment, the at least one weakened region traverses at least a portion of a substantially straight line between first and second opposing surfaces of the negative electrode subunit and/or positive electrode subunit in the third direction, as shown in FIG. 51A . In another embodiment, the at least one weakened region traverses at least a portion of a diagonal line between first and second opposing surfaces of the negative electrode subunit and/or positive electrode subunit in the third direction, as shown in FIG. 51B . In another embodiment, the at least one weakened region traverses at least a portion of a curved line between first and second opposing surfaces of the negative electrode subunit and/or positive electrode subunit in the third direction, as in FIG. 51C . In yet another embodiment, the at least one subunit weakened region comprises a combination of weakened features, as in FIGS. 51D-51E . In one embodiment, the negative electrode subunit and/or positive electrode subunit comprises one or more separated regions, with one or more regions where the negative electrode subunit and/or positive electrode subunit comprises perforations and/or thinning of the subunit in the stacking direction, as shown in FIGS. 51D-51E .

According to one embodiment, the at least one weakened region at least partially traces a current collector end feature 700 of the negative electrode subunit and/or positive electrode subunit, as shown for example in FIGS. 48K-48L and 53A-53D . In one embodiment, the at least one subunit weakened region at least partially traces a current collector end protrusion 701 of the negative subunit and/or positive electrode subunit, as shown in FIGS. 53A, 53C and 48K-48L . In another embodiment, the at least one weakened region at least partially traces one or more current collector end protrusions 701 and a current collector end indentation 702 of the negative electrode subunit and/or positive electrode subunit, as shown in FIG. 53B . In yet another embodiment, the at least one weakened region at least partially traces a current collector end that extends in a Z direction from the electrode active material, for example as shown in FIG. 53D , and wherein the negative electrode subunit and positive electrode subunit may have current collectors that extend in opposing directions in Z. According to one embodiment, the at least one subunit weakened region at least partially traces a hook-shaped current collector end protrusion 701 of the negative electrode subunit and/or positive electrode subunit, as shown for example in FIG. 55 . Furthermore, as shown in FIG. 48K , in one embodiment, the at least one weakened traces current collector protrusions 701 on the negative and positive electrode subunits that are on a same side in the X direction of the subunits, but that are offset in the Z direction from each other. According to yet another embodiment, the at least one weakened region in the negative electrode subunit at least partially traces one or more current collector end protrusions in the negative electrode subunit, and the at least one weakened region in the positive electrode subunit at least partially traces one or more current collector protrusions in the positive electrode subunit, and wherein the one or more negative electrode current collector ends are offset from the one or more positive-electrode current collector ends in one or more of the tensioning and Z directions, as shown in FIG. 45F . In yet another embodiment, the one or more negative electrode current collector ends are on a first side of the negative electrode subunit, and the one or more positive electrode current collector ends are on a second side of the positive electrode subunit, the first side opposing the second side in the tensioning direction. According to yet another embodiment, the one or more negative electrode current collector ends are on a same side as the one or more positive electrode current collector ends in the tensioning direction, and the one or more negative electrode current collector ends comprise at least a portion thereof that is offset in the Z direction from at least a portion of the one or more positive electrode current collector ends.

In one embodiment, to remove the at least one portion, tension is simultaneously applied to both opposing end margins on both sides of the negative electrode subunit and/or positive electrode subunit, to remove portions of the negative electrode and/or positive electrode subunits adjacent the weakened regions at both opposing end margins, for example as shown in FIG. 46B . According to yet another embodiment, to remove the at least one portion, a tension may be applied, sequentially, to a first end margin on a first side of the negative electrode subunit and/or positive electrode subunit, followed by applying tension to a second end margin on a second side of the negative electrode subunit and/or positive electrode subunit, to remove portions of the negative electrode subunit and/or positive electrode subunits adjacent the weakened regions at both opposing end margins, as shown for example in FIG. 46C . Furthermore, in certain embodiments, the weakened region formed in a first opposing end margin may be weaker than a weakened region formed in a second opposing end margin, such that the portion in the first end margin releases at a lower tensioning force than the portion in the second end margin, as shown in FIG. 46D with two weakened regions, one being more highly perforated than the other. In another embodiment, as shown in FIG. 46A , tension is applied to both opposing end margins, to remove just one portion on one side of the positive and/or negative electrode subunit. Furthermore, according to one embodiment, a method can comprise, while maintaining the alignment of the interior portions of the negative electrode subunit and positive electrode subunit with respect to one another in the tensioning direction, simultaneously applying tension to a first opposing end margin on a first side of the negative electrode subunit, and applying tension to a second opposing end margin on a second side of the positive electrode subunit, to remove a portion of the negative electrode subunit at the first end margin on the first side and a portion of the positive electrode subunit at the second end margin at the second side. In another embodiment, a method can comprise, while maintaining the alignment of the interior portions of the negative electrode subunit and positive electrode subunit with respect to one another in the tensioning direction, sequentially, applying tension to a first opposing end margin on a first side of the negative electrode subunit, followed by applying tension to a second opposing end margin on a second side of the positive electrode subunit, to remove a portion of the negative electrode subunit at the first end margin on the first side and a portion of the positive electrode subunit at the second end margin at the second side. In yet another embodiment, a methods can comprise, while maintaining the alignment of the interior portions of the negative electrode subunit and positive electrode subunit with respect to one another in the tensioning direction, sequentially, applying tension to a first opposing end margin on a first side of the positive electrode subunit, followed by applying tension to a second opposing end margin on a second side of the negative electrode subunit, to remove a portion of the positive electrode subunit at the first end margin on the first side and a portion of the negative electrode subunit at the second end margin at the second side.

›DETAILED DESCRIPTION · 31 of 58

As described herein, according to one embodiment, at least one of the negative electrode subunit and positive electrode subunit comprise an alignment feature formed in at least one of the opposing end margins thereof, as shown for example in FIGS. 48A-48M . In one embodiment, at least one of the negative electrode subunit and the positive electrode subunit comprise alignment features formed in both opposing end margins thereof, as shown in FIG. 48F . In yet another embodiment, both the negative electrode subunit and the positive electrode subunit comprise alignment features formed in at least one of the opposing end margins thereof, as shown for example in FIGS. 48A-48B . In yet another embodiment, both the negative electrode subunit and the positive electrode subunit comprise alignment features formed in both opposing end margins thereof. In a further embodiment, the tensioning force is applied to remove the portion of the negative electrode subunit and/or positive electrode subunit adjacent the weakened region in the at least one end margin, by pulling the at least one alignment pin placed in an alignment feature at one end of the negative electrode subunit and/or positive electrode subunit, in the tensioning direction and away from the second end of the negative electrode subunit and/or positive electrode subunit. In another embodiment, the tensioning force is applied to remove the portion of the negative electrode subunit and/or positive electrode subunit adjacent the weakened region in the at least one end margin, by simultaneously pulling alignment pins in alignment features on opposing ends of the negative electrode subunit and/or positive electrode subunit in opposing directions in the tensioning direction. In one embodiment, the alignment feature is formed in an opposing end margin that is removed upon application of the tension, as shown in FIG. 48A . In another embodiment, the alignment feature is formed in an end margin that opposes an end margin where a portion adjacent a subunit weakened region is removed, as shown in FIG. 48B .

According to one embodiment, the negative electrode subunit and positive electrode subunit both comprise alignment features in at least one end margin thereof, and an alignment feature in at least one of the negative electrode subunit and positive electrode subunit comprises a slot having a translation dimension in the tensioning direction, as shown in FIG. 48A , such that when an alignment pin inserted into the alignment features of the negative electrode subunit and positive electrode subunit on a first side is pulled outwardly in a tensioning direction away from the second side of the negative electrode subunit and positive electrode subunit, the alignment pin applies a tension to the end margin of the negative electrode subunit and/or positive-electrode subunit having the smaller dimension of the alignment feature via tension applied to the negative electrode subunit alignment feature, while the alignment pin translates through the translation dimension of the slot in the tensioning direction in the other of the negative electrode subunit and/or positive electrode subunit. According to yet another embodiment, the alignment feature of the negative electrode subunit and/or positive electrode subunit is formed in the same end margin as the at least one weakened region, and applying tension via the alignment pin results in removal of the portion of the end margin comprising the alignment feature in the negative electrode subunit and/or positive electrode subunit, as shown in FIG. 48A . In another embodiment, the alignment feature of the negative electrode subunit and/or positive electrode subunit is formed in an end margin opposing an end margin where at least one subunit weakened region is formed, and applying tension via the alignment pin results in removal of the portion of the end margin of the negative electrode subunit and/or positive electrode subunit opposing the end margin where the alignment feature is located, as shown in FIG. 48B . In yet another embodiment, alignment features are formed in end margins having the at least one subunit weakened region on a same side of both the negative electrode subunit and the positive electrode subunit, and applying tension via the alignment pin results in removal of the portions of the end margins comprising the alignment features on the same sides in the negative electrode subunits and positive electrode subunits, as shown in FIG. 48C . In another embodiment, alignment features are formed in end margins on a same side of both the negative electrode subunit and the positive electrode subunit that oppose end margins where the at least one weakened region is formed in each negative electrode subunit and positive electrode subunit, and applying tension via the alignment pin results in removal of the portions of the end margins of the negative electrode subunits and positive electrode subunits opposing the end margins where the alignment features are located, as shown in FIG. 48D .

In yet another embodiment, both the negative electrode subunit and positive electrode subunit comprise alignment features at opposing end margins of each sheet thereof, and at least one of the negative electrode subunit and positive electrode subunit comprise an alignment feature formed in an end margin comprising the at least one weakened region therein, and the other of the negative electrode subunit and positive electrode subunit comprise an alignment feature comprising a slot having a translation dimension in the tensioning direction that is greater than that of the alignment feature in the other of the negative electrode subunit and/or positive electrode subunit, the alignment feature comprising the slot being on a same side as the alignment feature formed in the end margin having the at least one subset weakened region. Applying of tension via insertion of a set of alignment pins into the alignment features on both sides of the stacked population results in removal of the portion of the negative electrode and/or positive electrode subunit in the end margin having the subset weakened region, and translation of the pin in the translation dimension of the alignment feature comprising the slot of the other of the negative electrode subunit and/or positive electrode subunit, as shown in FIG. 48F .

›DETAILED DESCRIPTION · 32 of 58

In yet a further embodiment, the stacked population comprises alignment features in both opposing end margins of each of the negative electrode subunit and positive electrode subunit, and alignment features on a first side of the negative electrode subunit and second opposing side of the positive electrode subunit are in end margins comprising the at least one subunit weakened region therein, and alignment features formed on a second side of the negative electrode subunit and a first side of the positive electrode subunit comprise slots having translation dimensions in the tensioning direction that are greater than that of the alignment features formed in the other of the negative electrode subunit and positive electrode subunit on the same respective side. Applying of tension via insertion of a set of alignment pins into the alignment features on both sides of the stacked population results in removal of the portion of the negative electrode and positive electrode subunit in the end margin having the subset weakened region, and translation of the pin in the translation dimension of the alignment features comprising the slots in the other opposing end margins, as shown in FIG. 48G .

In yet another embodiment, the stacked population comprises alignment features in both opposing end margins of each of the negative electrode subunit and positive electrode subunit, and alignment features are formed in the end margin of a first side of the negative electrode subunit having at least one subunit weakened region, and the end margin of a first side of the positive electrode subunit having at least one subunit weakened region on the same side. Applying of tension via insertion of a set of alignment pins into the alignment features on both sides of the negative electrode subunit and positive electrode subunit results in removal of the portion of the negative electrode and positive electrode subunit in the end margins on the same side having the weakened region, as shown in FIG. 48H . According to another embodiment, the stacked population comprises alignment features in both opposing end margins of each of the negative electrode subunit and the positive electrode subunit, and alignment features on a first side of the negative electrode subunit and same first side of the positive electrode subunit are in end margins comprising the at least one weakened region therein. The alignment feature on the second opposing side of either the negative electrode subunit or positive electrode subunit is in an end margin comprising at least one subunit weakened region therein, and the alignment features formed on a second opposing side of the other of the negative electrode subunit and positive electrode subunit comprises a slot having translation dimensions in the tensioning direction that is greater than that of the alignment feature formed in the other of the negative electrode and positive electrode subunits on the same respective side. Applying of tension via insertion of a set of alignment pins into the alignment features on both sides of the stacked population results in removal of the portion of the negative electrode and positive electrode subunit in the end margin on the first side having the weakened region, removal of the portion of the negative electrode subunit or positive electrode subunit in the end margin on the second side having the weakened region, and translation of the pin in the translation dimension of the alignment feature comprising the slots in the end margin on the second side of the other of the negative electrode subunit or positive electrode subunit, as shown in FIG. 48I . According to yet another embodiment, the stacked population comprises alignment features in both opposing end margins of each of the negative electrode subunit and positive electrode subunit, and alignment features on both first and second sides of the negative electrode subunit and the positive electrode subunit are in end margins comprising the at least one subset weakened region therein. Applying of tension via insertion of a set of alignment pins into the alignment features on both sides of the stacked population results in removal of the portions of the negative electrode and positive electrode subunit in the end margins on the first side and second sides having the weakened regions, as shown in FIG. 48J .

In one embodiment, the stacked population comprises alignment features in end margins on a same side of each of the negative electrode subunit and the positive electrode subunit, and the alignment feature of one of the negative electrode subunit and positive electrode subunit is formed in an end margin of a first side comprising the at least one subunit weakened region therein, and the alignment feature on the other of the negative electrode subunit or positive electrode subunit is in an end margin on the first side that is opposing a second side having an end margin with the at least one subunit weakened region therein. Applying of tension via insertion of a set of alignment pins into the alignment features on the same side of the stacked population results in removal of the portion of the negative electrode subunit and/or positive electrode subunit in the end margin on the first side having the subunit weakened region, and removal of the portion of the negative electrode subunit or positive electrode subunit in the end margin on the second side having the subset weakened region that is opposing the first end with the end margins where the alignment features are formed, as shown in FIG. 48I .

According to one embodiment, the alignment features on one or more of the negative electrode subunits and/or positive electrode units comprise a slot with a translation dimension in the tensioning direction, as shown in FIG. 49 . In another embodiment, the subunit alignment features on each of the negative electrode subunit and/or positive electrode subunit comprise a slot with a translation dimension in the Z direction orthogonal to the tensioning direction and stacking direction, as shown in FIG. 49 . In one embodiment, the subunit alignment features on each of the negative electrode subunits and/or positive electrode subunits comprise round apertures sized to allow an alignment pin to pass therethrough, and may be further sized to provide for a tensioning force to be exerted via the alignment feature upon exerting a tensioning force with the alignment pin, as shown for example in FIGS. 49 and 50B . In a further embodiment, the subunit alignment features comprise a combination of slots with translation dimensions, and round apertures. In another embodiment, the subunit alignment features comprise a first set of apertures 970 a to provide for stacking and alignment of the negative electrode subunits and positive electrode subunits, and the negative electrode and/or positive electrode subunits further comprise second set of apertures 970 b through which pins can be inserted to exert a tensioning force on one or more of the stacked negative electrode and positive electrode subunits, as shown in FIG. 48M . In one embodiment, the second set of apertures 970 b comprise holes in end margins having at least one weakened region, and slots having a translation dimension on one opposing side of each of the negative electrode subunit and positive electrode subunit. Applying tension results in removal of portions of the negative electrode subunit and positive electrode subunit on opposing sides thereof, at the subunit weakened locations, as shown in FIG. 48M . In one embodiment, the alignment features comprise apertures having an opening with a cross-section that is any one or more of rounded, triangular, square, oblong, oval, and rectangular, as shown in FIG. 50A . In another embodiment, the alignment features comprise apertures with inwardly protruding engagement portions about a circumference thereof to engage the alignment pins, as shown in FIG. 50B . According to yet another embodiment, the alignment features comprise apertures having an opening with a cross-section that is larger at a first side of the opening proximate to the end of the negative electrode subunit and/or positive electrode subunit, and is narrower at a second side of the opening that is distal to the end of the negative electrode subunit and/or positive electrode subunit, as shown in FIG. 50B .

›DETAILED DESCRIPTION · 33 of 58

In one embodiment, the receiving station is configured to receive the one or more subunits at a stacking position in the sheet feeding direction and sheet width direction that coincide with a removal position where the one or more subunits are separated from the one or more sheets at the removal station. Furthermore, the receiving station may receive the one or more subunits at a plurality of positions in the sheet feeding direction and/or sheet width direction that correspond to a plurality of separation positions along the sheet feeding direction and/or sheet width direction. In one embodiment, the receiving station is configured to maintain that portion of the stacked population that is stacked thereon in tension in the web width direction.

In yet another embodiment, as shown in FIGS. 52A-52C , weakened regions can be formed according to varying perforation patterns, according to a strength of the weakened region that may be suitable for the subunit.

According to yet another embodiment, as shown in FIG. 54 , a stacked population can be formed with negative electrode units 900 , positive electrode units 902 and separator layers 904 , and stacked on alignment pins 977 to align the stack and optionally provide for removal of a portion of one of the subunits, as has been described herein. However, further, at least one of the subunits may be provided with spacers 909 a,b placed at the peripheral edges of the subunits (e.g., in the margins), to space the subunit away from an adjacent layer. The spacers may be provided to the subunit at any point before stacking on the alignment pins, for example the spacers may be provided as a part of the continuous web sheet of which the subunit is a part, or the spacers may be applied to the subunit immediately before removal of the subunit and stacking on the receiving unit. The spacers may be provided to a negative electrode unit, a positive electrode unit and/or a separator unit, and only one or a plurality of the units may have the spacers. In one embodiment, the spacers are placed in the edge margins on the subunits, exterior to the weakened regions, such that they are removed with the end portions of the subunits when the at least one portion is removed, for example by applying the tensioning force to the subunit.

Furthermore, FIG. 56A gives an example of an embodiment where the stacked population is formed by stacking and aligning the negative electrode subunit 900 and positive electrode subunit 902 , but no portion of the end margins of either of the subunits are removed. That is, the alignment features 970 using to align the subunits are simply maintained as a part of the stack. FIG. 56B provides yet another example of a method of alignment. In this embodiment, the alignment features 970 comprise open divots and/or groove type features formed in the negative electrode and positive electrode subunits. The divots can be formed in either or both of the X direction, to align the subunits along X, or along Y to align the subunits along Y. A pin or other engagement feature can be used to engage the feature and push the divot in one subunit until the edge of the other subunit is reached, on both opposing sides, indicating alignment.

Furthermore, according to one embodiment, an energy storage device (e.g., a secondary battery) having an electrode assembly is provided, the energy storage device comprising, in a stacked arrangement, a negative electrode subunit, a separator layer, and a positive electrode subunit. The electrode assembly comprises an electrode stack comprising a population of negative electrode subunits and a population of positive electrode subunits stacked in a stacking direction, each of the stacked negative electrode subunits having a length L E of the negative electrode subunit in a transverse direction that is orthogonal to the stacking direction, and a height H E of the negative electrode subunit in a direction orthogonal to both the transverse direction and stacking directions, wherein (i) each member of the population of negative electrode subunits comprises a first set of two opposing end surfaces that are spaced apart along the transverse direction, (ii) each member of the population of positive electrode subunits comprises a second set of two opposing end surfaces that are spaced apart along the transverse direction. Furthermore, at least one of the opposing end surfaces of the negative electrode subset and/or positive electrode subunit comprises regions 705 about the opposing end surfaces of one or more of the negative electrode subset and positive electrode subunit that exhibit plastic deformation and fracturing oriented in the transverse direction, due to elongation and narrowing of the cross-section of the negative electrode subunit and/or positive electrode subunit. For example, referring to FIG. 55 , the deformation resulting from separation of the removed portion from the subunit can be seen at the area where the current collector attached to the removed portion (i.e., about the weakened region).

According to one aspect, the energy storage device manufactured according to the method described herein comprises a set of electrode constraints such as any of those described in further detail herein. For example, according to one embodiment, the set of electrode constraints 108 comprises a primary constraint system 151 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 (stacking direction), and the at least one primary connecting member connecting the first and second primary growth constraints. The set of electrode constraints 108 may also comprise a secondary constraint system 155 comprising first and second secondary growth constraints and at least one secondary connecting member, the first and second second growth constraints separated from each other in a second direction that is orthogonal to the longitudinal direction (e.g., the Z direction), and the at least one secondary connecting member connecting the first and second secondary growth constraints, to reduce growth in the second direction, In one embodiment, the primary constraint array 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%, where the charged state is at least 75% of a rated capacity of the secondary battery, and the discharged state is less than 25% of the rated capacity of the secondary battery. According to further embodiments, the energy storage device manufactured according to the method herein may even be capable of exhibiting reduced growth, such that 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%, where the charged state is at least 75% of a rated capacity of the secondary battery, and the discharged state is less than 25% of the rated capacity of the secondary battery. Furthermore, aspects of the energy storage device manufactured according to the method as claimed, may allow for an electrode assembly with reduced growth in the longitudinal direction, such that any increase in the Feret diameter of the electrode assembly in the stacking direction over 20 consecutive cycles and/or 50 consecutive cycles of the secondary battery is less than 3% and/or less than 2%, where the charged state is at least 75% of a rated capacity of the secondary battery, and the discharged state is less than 25% of the rated capacity of the secondary battery. The energy storage device manufactured according to embodiments of the method described herein may exhibit the reduced growth in the longitudinal and/or vertical directions, such as with the primary and/or secondary growth constraints, as is further described herein.

›DETAILED DESCRIPTION · 34 of 58

According to another embodiment, the negative electrode subunits and/or positive electrode subunits used to form the energy storage device may have dimensions that are the same as and/or similar to those described herein for electrode structures and/or counter-electrode structures. For example, the negative electrode subunits and/or positive electrode subunits may have a ratio of a length dimension L, to both the height H and width dimensions W of at least 5:1, such as at least 8:1 and even at least 10:1, and have a ratio of H to W in the range of 0.4:1 to 1000:1, such as in the range of 2:1 to 10:1. Furthermore, the energy storage device formed according to the method herein using the subunits may have electrodes and/or counter-electrodes and/or active material layers having the dimensions that are described elsewhere herein for these structures. For example, the energy storage device may comprise negative electrode active material from the negative electrode subunits and/or positive electrode active material from the positive electrode subunits having a ratio of a length dimension L, to both the height H and width dimensions W of at least 5:1, such as at least 8:1 and even at least 10:1, and have a ratio of H to W in the range of 0.4:1 to 1000:1, such as in the range of 2:1 to 10:1.

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 FIGS. 1B and 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 ).

›DETAILED DESCRIPTION · 35 of 58

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 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.

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 % 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.

›DETAILED DESCRIPTION · 36 of 58

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 , X3 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-electrode active material (i.e., at each x position X 1 , X 2 , X3 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)

›DETAILED DESCRIPTION · 37 of 58

In one embodiment, the absolute value of S Z1 may be ≥5 μm, such as ≥10 μm, ≥15 μm, ≥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 Z1 may be s 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 LE 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 , X3 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. 22A-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 , X3 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 ).

›DETAILED DESCRIPTION · 38 of 58

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, ≥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 ).

›DETAILED DESCRIPTION · 39 of 58

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 , Z3 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 −A 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, ≥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.

›DETAILED DESCRIPTION · 40 of 58

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 , Z3 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 TP2 . 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)

›DETAILED DESCRIPTION · 41 of 58

In one embodiment, the absolute value of S X2 may be ≥5 μm, such as ≥10 μm, ≥15 μm, ≥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 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 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.

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 FIGS. 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.

›DETAILED DESCRIPTION · 42 of 58

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.

›DETAILED DESCRIPTION · 43 of 58

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. 25D ), 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.

›DETAILED DESCRIPTION · 44 of 58

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 S 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.

›DETAILED DESCRIPTION · 45 of 58

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.

›DETAILED DESCRIPTION · 46 of 58

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 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.

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.

›DETAILED DESCRIPTION · 47 of 58

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.

›DETAILED DESCRIPTION · 48 of 58

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.

›DETAILED DESCRIPTION · 49 of 58

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 increased 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 busbar 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).

›DETAILED DESCRIPTION · 50 of 58

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 H BB 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.

›DETAILED DESCRIPTION · 51 of 58

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 H C being defined as describe above. For example, in one embodiment, the electrode current collector and/or the 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.

›DETAILED DESCRIPTION · 52 of 58

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 a,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 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. The 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, and/or 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.

›DETAILED DESCRIPTION · 53 of 58

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 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.

›DETAILED DESCRIPTION · 54 of 58

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 E 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 battery enclosure may, in one embodiment, be a sealed enclosure comprising components therein, such as portions of, and even the entire set, of the electrode constraints. The battery enclosure may also contain the electrolyte within the enclosure, and as such an interior surface thereof may be at least partly in contact with the electrolyte within the enclosure. In one embodiment, the battery enclosure comprises a hermetically sealed enclosure that contains the carrier ions, electrode assembly, and any other contents of the secondary battery therein. 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.

›DETAILED DESCRIPTION · 55 of 58

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 504 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 ).

›DETAILED DESCRIPTION · 56 of 58

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 LE 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%, 01%, 0.01%, 0.001%, and/or 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 |, and/or (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 |.

In yet another embodiment, the carrier ion insulating material layer 674 may 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 (a) in a case where the first transverse end surface of the electrode active material layer is inwardly disposed with respect to the first transverse end surface of the counter-electrode active material, D CC equals 2×W E +|S X1 |, and (b) in a case where 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, D CC equals 2×W E −|S X1 |, and/or (ii) the second transverse end surface of the electrode active material layer, wherein (a) in a case where the second transverse end surface of the electrode active material layer is inwardly disposed with respect to the second transverse end surface of the counter-electrode active material, D CC equals 2×W E +|S X2 |, and (b) in a case where 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, D CC equals 2×W E +|S X2 |, and/or (iii) the first vertical end surface of the electrode active material layer, wherein (a) in a case where the first vertical end surface of the electrode active material layer is inwardly disposed with respect to the first vertical end surface of the counter-electrode active material, D CC equals 2×W E +|S Z1 |, and (b) in a case where 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, D CC equals 2×W E −|S Z1 |, and/or (iv) the second vertical end surface of the electrode active material layer, wherein (a) in a case where the second vertical end surface of the electrode active material layer is inwardly disposed with respect to the second vertical end surface of the counter-electrode active material, D CC equals 2×W E +|S Z2 |, and (b) in a case where 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, D CC equals 2×W E −|S Z1 | wherein D CC equals the sum of 2×W E and |S Z2 |.

›DETAILED DESCRIPTION · 57 of 58

Referring to FIGS. 37A-37B , an embodiment is shown where S X1 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 , S Z1 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 material layer is 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 W C and height H C of the counter-electrode active material layer. Examples of electrode assemblies 106 having such 3D electrodes are depicted in FIGS. 1B and 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 .

›DETAILED DESCRIPTION · 58 of 58

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

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Claims as granted

3 claims

Classifications

14 codes

IPC · International Patent Classification

Section H — Electricity

H01M10/0525
H01M4/66
H01M50/103
H01M4/134
H01M10/0585
H01M10/04
H01M10/0565
H01M4/02
H01M50/46
H01M10/054
H01M4/38
H01M4/48
H01M4/525
H01M50/54

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Osei K Amponsah

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