Film capacitor

This application is a U.S. national stage application of the PCT International Application No. PCT/JP2015/004121 filed on Aug. 19, 2015, which claims the benefit of foreign priority of Japanese patent application No. 2014-168149 filed on Aug. 21, 2014, the contents all of which are incorporated herein by reference.

The present invention relates to a film capacitor used for various kinds of electronic equipment, electric equipment, industrial equipment, automobiles or the like (hereinafter referred to as “external equipment”), and particular to a film capacitor which is most appropriate for smoothing, for a filter, for a snubber, or the like of a motor driving inverter circuit of a hybrid vehicle or the like.

A film capacitor incorporated in external equipment is mechanically and electrically connected with the external equipment via an external connection terminal of the film capacitor.

FIG. 14 is an exploded perspective view showing a configuration of a conventional film capacitor before resin molding, and FIG. 15 is an enlarged perspective view of a main part in FIG. 14 .

As shown in FIG. 14 , the film capacitor includes capacitor element 91 , a pair of bus bars 92 formed of a copper plate or the like, holding member 93 having insulation, and resin case 99 .

At one end of bus bar 92 , element connection part 928 is connected to metallikon electrode 911 of capacitor element 91 by soldering, resistance welding, or the like. Further, bus bar 92 is bent into an L-shape so as to be directed to an upper side (an opening) of case 99 , and another end of bus bar 92 is provided with external connection terminal 929 partially protruding from case 99 . This external connection terminal 929 is mechanically and electrically connected to external equipment (not shown). In order to facilitate this connection work, relative positions of respective external connection terminals 929 , 929 provided at the pair of bus bars 92 , 92 are extremely important.

Accordingly, the conventional film capacitor shown in FIG. 14 has the following configuration.

The pair of bus bars 92 , 92 facing each other has overlapping parts 927 which overlap in a facing direction (a Y direction). Resin holding member 93 is provided with protrusion 93 F on a surface of holding member 93 , and overlapping part 927 of bus bar 92 is formed with hole 92 F at a position corresponding to protrusion 93 F. Also, by fitting protrusion 93 F of this holding member 93 and hole 92 F provided at overlapping part 927 , the relative positions of external connection terminals 929 of the pair of bus bars 92 are temporarily fixed, and the positions of the pair of bus bars 92 and the holding member 93 are temporarily fixed.

Such film capacitor having protrusion 93 F and hole 92 F is, for example, disclosed in PTL 1.

According to a technique disclosed in PTL 1, bus bar 92 can be certainly positioned relative to holding member 93 in an X direction and a Z direction by fitting protrusion 93 F into hole 92 F. However, bus bar 92 cannot be positioned relative to holding member 93 in the Y direction (an insertion direction of protrusion 93 F into hole 92 F).

Accordingly, when bus bar 92 is connected to metallikon electrode 911 of capacitor element 91 by soldering, resistance welding, or the like, it is necessary to use a positioning jig which regulates a positional shift in the Y direction. Also, when a positive electrode bus bar is connected to a positive metallikon electrode, it is necessary to use a positive electrode positioning jig which regulates a positional shift in a plus Y direction. Moreover, when a negative electrode bus bar is connected to a negative metallikon electrode, it is necessary to use a negative electrode positioning jig which regulates a positional shift in a minus Y direction. In bus bar mounting/connecting processes, steps of positioning (a positive electrode), connecting (the positive electrode), positioning (a negative electrode), and connecting (the negative electrode) must be sequentially performed, and the connecting process becomes complex/complicated.

Further, even when bus bar 92 is temporarily fixed by using the positioning jig, a relative position in the Y direction of bus bar 92 with respect to holding member 93 may be shifted by completion of the connection. This is because holding member 93 and bus bar 92 are not unmovably fixed to each other, and holding member 93 and bus bar 92 are only indirectly and temporarily fixed via the positioning jig.

In other words, a film capacitor capable of improving relative mounting accuracy (positioning accuracy) of positive and negative electrode bus bars and capable of easily connecting the bus bars to a capacitor element is required.

Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2010-251400

A first invention of the present application is a film capacitor including: a capacitor element in which a metallikon electrode is formed at an end; a bus bar connected to the metallikon electrode; and a holding member having a slit into which the bus bar is inserted, the slit being formed with protrusions. The bus bar inserted into the slit is press-contacted with the protrusions, and as a result, the bus bar is held by the holding member.

According to the first invention of the present application, relative mounting accuracy (positioning accuracy) of a positive electrode bus bar and the holding member can be improved, and further, relative mounting accuracy (positioning accuracy) of a negative electrode bus bar and the holding member can be also improved. As a result, relative mounting accuracy (positioning accuracy) of the positive electrode bas bar and the negative electrode bus bar can be improved. Further, a film capacitor capable of easily connecting the bus bars to the capacitor elements can be provided.

A second invention of the present application is a film capacitor including: a capacitor element in which a metallikon electrode is formed at an end; a bus bar connected to the metallikon electrode and having a locked part; and a holding member having a slit into which the bus bar is inserted, an abutting part, and a locking protrusion. When an extending direction of the slit is a first direction, a direction vertical to the first direction and parallel to a principal surface of the holding member is a second direction, and a direction vertical to the first direction and the second direction, respectively, is a third direction, the bus bar is sandwiched between the slits in the second direction and is sandwiched between the slits in the third direction, and the bus bar is abutted by the abutting part from one side in the first direction and is locked by the locking protrusion from another side in the first direction.

According to the second invention of the present application, relative mounting accuracy (positioning accuracy) of a positive electrode bus bar and the holding member can be improved, and further, relative mounting accuracy (positioning accuracy) of a negative electrode bus bar and the holding member can be also improved. As a result, relative mounting accuracy (positioning accuracy) of the positive electrode bas bar and the negative electrode bus bar can be improved. Further, a film capacitor capable of easily connecting the bus bars to the capacitor elements can be provided.

FIG. 1 is a perspective view of a main part of a film capacitor in a first exemplary embodiment of the present invention.

FIG. 2 is an exploded perspective view of the main part of the film capacitor in the first exemplary embodiment of the present invention.

FIG. 3 is a partial sectional view of a vicinity of a slit part of the film capacitor in the first exemplary embodiment of the present invention.

FIG. 4 is a perspective view of a main part of a film capacitor in a second exemplary embodiment of the present invention.

FIG. 5 is an exploded perspective view of the main part of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 6 is a perspective view of a positive electrode bus bar of the film capacitor in the first and second exemplary embodiments of the present invention.

FIG. 7 is a perspective view of a holding member of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 8 is a sectional view of the main part of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 9 is a sectional view explaining locking operation of one locked part of the positive electrode bus bar and a locking protrusion of the holding member of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 10 is a sectional view explaining locking operation of another locked part of the positive electrode bus bar and a locking protrusion of the holding member of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 11 is a partial perspective view of a vicinity of one locked part of a negative electrode bus bar and a locking protrusion of the holding member of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 12 is a partial perspective view of a vicinity of another locking protrusion of the negative electrode bus bar and a locked part of the holding member of the film capacitor in the second exemplary embodiment of the present invention.

FIG. 13 is a sectional view explaining another locked state of a locking protrusion and a locked part in the second exemplary embodiment of the present invention.

FIG. 14 is an exploded perspective view of a conventional film capacitor.

FIG. 15 is a perspective view of a main part of the conventional film capacitor.

Hereinafter, a configuration of a film capacitor and a method for manufacturing the film capacitor in exemplary embodiments of the present invention are described with reference to the drawings.

First Exemplary Embodiment

FIG. 1 is a perspective view of a main part (capacitor elements/a holding member mounted with bus bars) of a film capacitor excluding a case and a sealing resin layer according to a first exemplary embodiment. FIG. 2 is an exploded perspective view of the main part of the film capacitor.

As shown in FIG. 1 , the film capacitor in the first exemplary embodiment includes three capacitor elements 1 .

A configuration of capacitor element 1 is described below. Capacitor element 1 has two end surfaces and a side surface connecting these two end surfaces. Capacitor element 1 is formed in a flat shape (a shape having two flat surfaces and two curved surfaces), as viewed from the end surface. Further, capacitor element 1 includes a pair of metallized films. The metallized film is a film in which a vapor-deposited metal layer (a vapor-deposited electrode) is formed by vapor-depositing aluminum on at least one surface of surfaces of a dielectric film formed of polypropylene (hereinafter referred to as “PP”) or the like. Then, this pair of metallized films is overlapped and wound around, thereby forming a winding body. Further, metallikon electrode 11 formed of zinc is formed on both end surfaces of this winding body. The vapor-deposited metal layer having a positive electrode is connected with the metallikon electrode having a positive electrode, and the vapor-deposited metal layer having a negative electrode is connected with the metallikon electrode having a negative electrode.

As shown in FIGS. 1 and 2 , metal bus bar 2 formed of, for example, copper is configured with positive electrode bus bar 2 A and negative electrode bus bar 2 B. FIG. 6 is a perspective view of positive electrode bus bar 2 A used in the first exemplary embodiment and the second exemplary embodiment, which will be described below. As shown in FIG. 6 , positive electrode bus bar 2 A is configured by integrally connecting first portion 2 A 1 , second portion 2 A 2 , and third portion 2 A 3 . Second portion 2 A 2 is a portion bent by 90 degrees relative to first portion 2 A 1 , and third portion 2 A 3 is a portion bent by 90 degrees relative to second portion 2 A 2 . It should be noted that positive electrode bus bar 2 A is one example of a first bus bar and that negative electrode bus bar 2 B is one example of a second bus bar.

First portion 2 A 1 has a substantially rectangular shape, and includes external connection terminal 2 A 9 on one end side in a longitudinal direction (an end side in a minus X direction). External connection terminal 2 A 9 protrudes from a sealing resin layer (not shown) in a state in which capacitor elements 1 are sealed by a case (not shown) and the sealing resin layer, and is mechanically and electrically connected to external equipment (not shown). Third portion 2 A 3 is provided with three element connection parts 2 A 8 , each of which is connected to metallikon electrode 11 by soldering, resistance welding, or the like.

As shown in FIG. 2 , negative electrode bus bar 2 B also includes first portion 2 B 1 , second portion 2 B 2 , and third portion 2 B 3 as with positive electrode bus bar 2 A. Second portion 2 B 2 is a portion bent by 90 degrees relative to first portion 2 B 1 , and third portion 2 B 3 is a portion bent by 90 degrees relative to second portion 2 B 2 .

First portion 2 B 1 has a substantially rectangular shape, and includes external connection terminal 2 B 9 on another end side in the longitudinal direction (an end side in a plus X direction). External connection terminal 2 B 9 protrudes from the sealing resin layer (not shown) in a state in which capacitor elements 1 are sealed by the case (not shown) and the sealing resin layer, and is mechanically and electrically connected to the external equipment (not shown). Third portion 2 B 3 is provided with three element connection parts 2 B 8 , each of which is connected to metallikon electrode 11 by soldering, resistance welding, or the like. Further, a length in a Y direction of second portion 2 B 2 of negative electrode bus bar 2 B is larger than a length in the Y direction of second portion 2 A 2 of positive electrode bus bar 2 A.

Both a principal surface of positive electrode bus bar 2 A and a principal surface of negative electrode bus bar 2 B face flat plate 31 of holding member 3 , which will be described below.

Holding member 3 is formed of an insulating resin, and has substantially rectangular flat plate 31 as shown in FIG. 2 . Slit 3 S for fixing positive electrode bus bar 2 A is provided at each end in the longitudinal direction (the X direction) of a first principal surface (a plus Y direction side) of flat plate 31 . Slit 3 S for fixing negative electrode bus bar 2 B is provided at each end in the longitudinal direction (the X direction) of a second principal surface (a minus Y direction side) on a side opposite to the first principal surface.

FIG. 3 is a partial sectional view taken along a cutting line I-I in FIG. 1 . Vertical wall 3 S 1 and parallel wall 3 S 2 are sequentially connected to respective ends on the first principal surface side and the second principal surface side of flat plate 31 , and a space surrounded by a surface of flat plate 31 , inner surface 3 S 11 of vertical wall 3 S 1 , and inner surface 3 S 21 of parallel wall 3 S 2 configures slit 3 S. Further, protrusion 3 A linearly extending along an extending direction (a Z direction) of the slit is formed on the surface of flat plate 31 and inner surface 3 S 21 of parallel wall 3 S 2 , which face slit 3 S, respectively. It should be noted that slit 3 S formed at a plus X side end of holding member 3 also has the same configuration as the configuration in FIG. 3 .

A position in the X direction of positive electrode bus bar 2 A inserted into slit 3 S is regulated by one or both of inner surface 3 S 11 of vertical wall 3 S 1 of slit 3 S on a minus X side and inner surface 3 S 11 of vertical wall 3 S 1 of slit 3 S on the plus X side. The same applies to a position in the X direction of negative electrode bus bar 2 B inserted into slit 3 S.

End 2 A 4 of positive electrode bus bar 2 A inserted into slit 3 S is press-contacted with protrusions 3 A in the minus Y direction and in the plus Y direction, thereby regulating a position in the Y direction of positive electrode bus bar 2 A. The same applies to a position in the Y direction of negative electrode bus bar 2 B inserted into slit 3 S.

Also, protrusions 3 A press-contact positive electrode bus bar 2 A and negative electrode bus bar 2 B, thereby fixing relative positions of positive electrode bus bar 2 A, negative electrode bus bar 2 B, and holding member 3 in the three directions of X, Y, Z.

Further, in the present exemplary embodiment, on each of the first principal surface side and the second principal surface side of flat plate 31 of holding member 3 , two slits 3 S in total are respectively provided at both ends in an arrangement direction (i.e., the X direction) of the capacitor elements. Accordingly, press-contacting force (an added value) between ends 2 A 4 , 2 B 4 of bus bars 2 A, 2 B and protrusions 3 A of slits 3 S becomes large, positive electrode bus bar 2 A, negative electrode bus bar 2 B, and holding member 3 can be more reliably fixed to each other, and relative mounting accuracy of these three members can be improved.

Further, first portion 2 A 1 of positive electrode bus bar 2 A and first portion 2 B 1 of negative electrode bus bar 2 B face via holding member 3 , and positive electrode bus bar 2 A and negative electrode bus bar 2 B have overlapping parts which overlap each other in a facing direction (the Y direction). Since directions of currents which respectively flow in first portion 2 A 1 of positive electrode bus bar 2 A and first portion 2 B 1 of negative electrode bus bar 2 B are reversed, mutual inductance can be lowered. In other words, the holding member has the first principal surface and the second principal surface on the side opposite to the first principal surface, and the positive electrode bus bar is held on the first principal surface and the negative electrode bus bar is held on the second principal surface. Accordingly, the mutual inductance can be lowered.

(Manufacturing Method)

A method for manufacturing the film capacitor of the present exemplary embodiment is described below.

(Capacitor Element Forming Process)

Capacitor element 1 is manufactured in a capacitor element forming process. First, aluminum is vapor-deposited on one surface of the dielectric film formed of PP, thereby forming the metallized film formed with the vapor-deposited metal layer (the vapor-deposited electrode). It should be noted that aluminum is used as the vapor-deposited metal in the present exemplary embodiment. However, zinc, magnesium, or a combination of these metals may be used other than aluminum.

Next, the metalized film for a positive electrode and the metalized film for a negative electrode are overlapped and wound around in a state in which ends in a width direction are slightly shifted. Moreover, the PP protection film is wound about ten times to manufacture the cylindrical winding body. Then, a curved outer peripheral surface of this winding body is pressed from both sides in a radial direction of the winding body to machine the winding body into the flat shape (the shape having the two flat surfaces and the two curved surfaces). Moreover, metallikon electrode 11 is formed by thermally spraying zinc on the two end surfaces that face each other of the winding body machined into the flat shape. With this configuration, film capacitor element 1 , in which the vapor-deposited metal layers that face via the dielectric film are connected to the metallikon electrode, is completed.

(Bus Bar Mounting Process)

Positive electrode bus bar 2 A and negative electrode bus bar 2 B are mounted on holding member 3 in a bus bar mounting process. First, positive electrode bus bar 2 A, negative electrode bus bar 2 B, holding member 3 , and a mounting jig are prepared. Next, holding member 3 is mounted on a mounting surface of the mounting jig and holds the mounting jig. Then, ends 2 A 4 of positive electrode bus bar 2 A are inserted into slits 3 S provided at both ends in the longitudinal direction (the X direction) of the first principal surface (the plus Y direction side) of flat plate 31 along a direction of arrow AR 1 in FIG. 2 . Further, ends 2 B 4 of negative electrode bus bar 2 B are inserted into slits 3 S provided at both ends in the longitudinal direction (the X direction) of the second principal surface (the minus Y direction side) of flat plate 31 along a direction of arrow AR 2 in FIG. 2 . Then, lower surfaces of positive electrode bus bar 2 A and negative electrode bus bar 2 B abut on the mounting surface of the mounting jig, thereby finishing the insertion of positive electrode bus bar 2 A and negative electrode bus bar 2 B. The bus bar mounting process is completed by removing the holding member 3 mounted with positive electrode bus bar 2 A and negative electrode bus bar 2 B from the mounting jig.

The positions in the X direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B can be regulated by inner surfaces 3 S 11 of vertical walls 3 S 1 configuring slits 3 S. Further, the positions in the Y direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B can be regulated by protrusions 3 A provided on flat plate 31 and parallel walls 3 S 2 . Also, positions in the Z direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B can be regulated by the mounting surface of the mounting jig.

Since positive electrode bus bar 2 A and negative electrode bus bar 2 B are respectively pressed and held by protrusions 3 A provided on flat plate 31 and parallel walls 3 S 2 , mutual relative positional relations in three directions (X, Y, Z) of positive electrode bus bar 2 A, negative electrode bus bar 2 B, and holding member 3 are fixed. In other words, positioning is completed, and the relative positional relations in the three directions are not changed even after holding member 3 is removed from the mounting jig. As compared with the conventional technique where the relative positional relation between capacitor element 91 and bus bar 92 is fixed only after capacitor element 91 and bus bar 92 are connected, relative mounting accuracy (positioning accuracy) of positive electrode bus bar 2 A and negative electrode bus bar 2 B is improved in the configuration of the present exemplary embodiment. Further, since it is easy to handle the holding member mounted with the bus bars in a connecting process, which will be described below, work in the connecting process is facilitated.

(Connecting Process)

Bus bars 2 mounted on holding member 3 and capacitor elements 1 are connected in the connecting process. Three capacitor elements 1 are inserted between third portion 2 A 3 of bus bar 2 A and third portion 2 B 3 of bus bar 2 B so that element connection parts 2 A 8 , 2 B 8 of bus bars 2 A, 2 B, respectively, are disposed at predetermined positions of metallikon electrodes 11 of capacitor elements 1 . Next, element connection part 2 A 8 for a positive electrode and metallikon electrode 11 are connected by soldering, resistance welding, or the like, and element connection part 2 B 8 for a negative electrode and metallikon electrode 11 are connected by soldering, resistance welding, or the like. With this configuration, the capacitor elements/the holding member mounted with the bus bars, as shown in FIG. 1 and serving as a main part of the film capacitor, are completed.

In the bus bar mounting/connecting processes of the conventional technique, steps of positioning (a positive electrode), connecting (the positive electrode), positioning (a negative electrode), and connecting (the negative electrode) must be sequentially performed, and the connecting process becomes complex/complicated. However, in the bus bar mounting process and the connecting process of the present exemplary embodiment, since only steps of positioning (the positive electrode, the negative electrode), connecting (the positive electrode), and connecting (the negative electrode) are required, the processes from the bus bar mounting to the connection become simple.

Further, as mentioned above, the relative positions of positive electrode bus bar 2 A negative electrode bus bar 2 B, and holding member 3 configuring the holding member mounted with the bus bars are fixed in the three directions of X/Y/Z by the single holding member mounted with the bus bars and without using the mounting jig. Accordingly, handling is easy, and there is no possibility that the relative positions of the holding member and the bus bars in one direction (the Y direction) are shifted for a period after the positioning (temporary fixing) until the connection as with the conventional technique.

(Sealing Process)

Capacitor elements 1 are sealed in the sealing process, and the film capacitor is completed. First, a top open type resin case (not shown) having a recess is prepared. Next, the capacitor elements/the holding member mounted with the bus bars are housed in the recess of the case. It should be noted that external connection terminals 2 A 9 , 2 B 9 of respective bus bars 2 A, 2 B protrude from the recess of the case to the outside. Next, an opening of the recess of the case is filled with insulating resin liquid of high temperature. After the filling, the insulating resin liquid is cooled and solidified, thereby forming a sealed resin layer. Accordingly, the film capacitor of the present exemplary embodiment is completed.

Second Exemplary Embodiment

In the first exemplary embodiment, bus bar 2 is fixed to holding member 3 by protrusions 3 A provided at slit 3 S. A second exemplary embodiment is different from the first exemplary embodiment only in that bus bar 2 is fixed to holding member 3 by locking of a locked part with a locking protrusion and without providing protrusions 3 A. The other items in the second exemplary embodiment are identical to the items in the first exemplary embodiment. Accordingly, differences between the first and second exemplary embodiments are mainly described, and description of common items is omitted or simplified. Further, the same reference marks as the reference marks in the first exemplary embodiment are assigned to the same members and parts as the members and parts of the first exemplary embodiment.

FIG. 4 is a perspective view of a main part (capacitor elements/a holding member mounted with bus bars) of a film capacitor excluding a case and a sealing resin layer according to the second exemplary embodiment. FIG. 5 is an exploded perspective of the main part of the film capacitor.

As shown in FIG. 4 , the film capacitor in the second exemplary embodiment includes three capacitor elements 1 .

FIG. 6 is a perspective view of positive electrode bus bar 2 A used in the second exemplary embodiment. As mentioned above, positive electrode bus bar 2 A is the same as positive electrode bus bar 2 A used in the first exemplary embodiment. Locked part 2 A 5 is provided at a minus X side end of third portion 2 A 3 , and locked part 2 A 5 is also provided at a plus X side end of second portion 2 A 2 .

FIG. 11 is a partial perspective view of the plus X side end and FIG. 12 is a partial perspective view of the minus X side end, when the main part of the film capacitor is viewed from a second principal surface side (a minus Y side) of flat plate 31 of holding member 3 . Further, negative electrode bus bar 2 B, though not described with reference to a single drawing, is also the same as negative electrode bus bar 2 B used in the first exemplary embodiment. As shown in FIG. 11 , locked part 2 B 5 and cut-away part 2 B 6 are provided at the plus X side end of second portion 2 B 2 . As shown in FIG. 12 , locked part 2 B 5 and cut-away part 2 B 6 are provided at the minus X side end of second portion 2 B 2 .

FIG. 7 is a perspective view of holding member 3 of the present exemplary embodiment. Holding member 3 is formed of an insulating resin and includes four slits 3 S as with the first exemplary embodiment. However, protrusion 3 A provided in the first exemplary embodiment is not formed on flat plate 31 or parallel wall 3 S 2 . Also, locking protrusion 3 C is provided on each of outer surfaces 3 S 22 of four parallel walls 3 S 2 . Each locking protrusion 3 C has arm 3 C 1 and pawl 3 C 2 provided at an end of arm 3 C 1 . Further, abutting part 3 B is integrally connected to lower parts of two principal surfaces of flat plate 31 . An upper surface of each abutting part 3 B is vertical to an extending direction (a Z direction) of slit 3 S, that is, parallel to an X direction and a Y direction.

FIG. 8 is a sectional view taken along a cutting line II-II in FIG. 4 . Positive electrode bus bar 2 A and negative electrode bus bar 2 B are fitted into slits 3 S of holding member 3 . Further, as shown in FIG. 8 , a lower surface of second portion 2 A 2 of positive electrode bus bar 2 A and a lower surface of second portion 2 B 2 of negative electrode bus bar 2 B abut on the upper surface of abutting part 3 B. Bus bars 2 A, 2 B are fitted into slits 3 S, thereby regulating in the X direction and the Y direction. Bus bars 2 A, 2 B abut on abutting part 3 B, thereby regulating movement in a minus Z direction.

As shown in FIGS. 4, 11, and 12 , since locked parts 2 A 5 , 2 B 5 of respective bus bars 2 A, 2 B are locked by pawls 3 C 2 of locking protrusions 3 C of holding member 3 , movement in a plus Z direction of bus bars 2 A, 2 B is regulated.

In other words, positive electrode bus bar 2 A and negative electrode bus bar 2 B are abutted by abutting part 3 B from a minus Z side, and are locked from a plus Z side by locking protrusions 3 C. With this configuration, positions in the Z direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B are regulated.

Further, positive electrode bus bar 2 A and negative electrode bus bar 2 B are sandwiched between two slits 3 S in the X direction. More specifically, positive electrode bus bar 2 A and negative electrode bus bar 2 B are brought into contact with two slits 3 S, that is, with inner surfaces 3 S 11 of vertical walls 3 S 1 from both the sides in the X direction (the plus X side, the minus X side). With this configuration, positions in the X direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B are regulated.

Further, positive electrode bus bar 2 A and negative electrode bus bar 2 B are sandwiched between two slits 3 S in the Y direction. More specifically, positive electrode bus bar 2 A and negative electrode bus bar 2 B are brought into contact with surfaces of flat plate 31 and inner surfaces 3 S 21 of parallel walls 3 S 2 in the respective two slits from both sides in the Y direction (a plus Y side, a minus Y side). With this configuration, positions in the Y direction of positive electrode bus bar 2 A and negative electrode bus bar 2 B are regulated.

It should be noted that the X direction is an example of a second direction, the Y direction is an example of a third direction, and the Z direction is an example of a first direction. In other words, the second direction is vertical to the first direction, and the third direction is vertical to the first direction and the second direction, respectively. Further, the minus Z side is an example of one side in the first direction, and the plus Z side is an example of another side in the first direction. More specifically, in the aforementioned exemplary embodiment, a direction in which slit 3 S extends is the first direction, a direction which is vertical to the first direction and parallel to principal surfaces of bus bars 2 (parallel to a first principal surface, a second principal surface of flat plate 31 of holding member 3 ) is the second direction, and a direction which is vertical to the first direction and the second direction, respectively, is the third direction.

In this way movement in the three directions of X, Y, Z of bus bars 2 A, 2 B relative to holding member 3 is regulated, and mutual relative positions of positive electrode bus bar 2 A, negative electrode bus bar 2 B, and holding member 3 are fixed.

(Manufacturing Method)

A method for manufacturing the film capacitor of the present exemplary embodiment is described below. It should be noted that since a capacitor element forming process and a sealing process are the same as the capacitor element forming process and the sealing process in the first exemplary embodiment, the description is omitted.

(Bus Bar Mounting Process)

A bus bar mounting process is described with reference to FIG. 5 . Positive electrode bus bar 2 A and negative electrode bus bar 2 B are mounted on holding member 3 in the bus bar mounting process. Ends 2 A 4 of positive electrode bus bar 2 A are inserted into slits 3 S provided at both ends in a longitudinal direction (the X direction) of the first principal surface (a plus Y direction side) of flat plate 31 along a direction of arrow AR 1 in FIG. 5 . Further, ends 2 B 4 of negative electrode bus bar 2 B are inserted into slits 3 S provided at both ends in the longitudinal direction (the X direction) of the second principal surface (a minus Y direction side) of flat plate 31 along a direction of arrow AR 2 in FIG. 5 . Then, as shown in FIG. 8 , the lower surfaces of second portion 2 A 2 of positive electrode bus bar 2 A and second portion 2 B 2 of negative electrode bus bar 2 B abut on the upper surface of abutting part 3 B of holding member 3 . Accordingly the insertion of positive electrode bus bar 2 A and negative electrode bus bar 2 B is finished, and the bus bar mounting process is completed.

FIG. 9 is a view explaining locking operation between locking protrusion 3 C provided at the minus X side end on the first principal surface side of holding member 3 and locked part 2 A 5 to be locked with locking protrusion 3 C. FIG. 9 is a sectional view in which locking protrusion 3 C and locked part 2 A 5 are taken along a cutting line which passes through a center in a width direction (the X direction) of arm 3 C 1 of locking protrusion 3 C. Pawl 3 C 2 has inclined surface 3 C 21 connected to arm 3 C 1 , vertex 3 C 22 , and locking surface 3 C 23 for locking locked part 2 A 5 . Further, locked part 2 A 5 has rushing side end 2 A 51 on a side rushing into pawl 3 C 2 and locked end 2 A 52 to be locked by locking surface 3 C 23 of pawl 3 C 2 .

When positive electrode bus bar 2 A is inserted into slit 3 S, locked part 2 A 5 moves toward locking protrusion 3 C as shown in FIG. 9( a ) . When positive electrode bus bar 2 A is further inserted, locked part 2 A 5 moves in the minus Z direction while rushing side end 2 A 51 of locked part 2 A 5 makes contact with inclined surface 3 C 21 of pawl 3 C 2 of locking protrusion 3 C. At this time, as shown by an arrow in FIG. 9( b ) , arm 3 C 1 is warped, and locking protrusion 3 C is pressed down toward the minus Y direction side.

When the insertion is further performed, rushing side end 2 A 51 of locked part 2 A 5 passes vertex 3 C 22 of pawl 3 C 2 , and further, locked end 2 A 52 of locked part 2 A 5 also passes vertex 3 C 22 of pawl 3 C 2 . Also, when the lower surface of second portion 2 A 2 of positive electrode bus bar 2 A abuts on the upper surface of abutting part 3 B of holding part 3 , as shown in FIG. 9( c ) , locked end 2 A 52 of locked part 2 A 5 and locking surface 3 C 23 of pawl 3 C 2 are in contact with each other. A force that arm 3 C 1 tends to restore from the warp acts on locked end 2 A 52 of locked part 2 A 5 toward the plus Y side. Accordingly, locked part 2 A 5 can no longer move in the plus Z direction.

FIG. 10 is a view explaining locking operation between locking protrusion 3 C provided at the plus X side end on the first principal surface side of holding member 3 and locked part 2 A 5 to be locked with locking protrusion 3 C. FIG. 10 is a sectional view in which locking protrusion 3 C and locked part 2 A 5 are taken along a cutting line which passes through a center in a width direction (the Y direction) of arm 3 C 1 of locking protrusion 3 C. Pawl 3 C 2 has inclined surface 3 C 21 connected to arm 3 C 1 , vertex 3 C 22 , and locking surface 3 C 23 for locking locked part 2 A 5 . Further, locked part 2 A 5 has rushing side end 2 A 51 on a side rushing into pawl 3 C 2 and locked end 2 A 52 to be locked by locking surface 3 C 23 of pawl 3 C 2 .

When positive electrode bus bar 2 A is inserted into slit 3 S, locked part 2 A 5 moves toward locking protrusion 3 C as shown in FIG. 10( a ) . When positive electrode bus bar 2 A is further inserted, locked part 2 A 5 moves in the minus Z direction while rushing side end 2 A 51 of locked part 2 A 5 makes contact with inclined surface 3 C 21 of pawl 3 C 2 of locking protrusion 3 C. At this time, as shown by an arrow in FIG. 10( b ) , arm 3 C 1 is warped, and locking protrusion 3 C is pressed down toward the plus X direction side.

When the insertion is further performed, rushing side end 2 A 51 of locked part 2 A 5 passes vertex 3 C 22 of pawl 3 C 2 , and further, locked end 2 A 52 of locked part 2 A 5 also passes vertex 3 C 22 of pawl 3 C 2 . Also, when the lower surface of second portion 2 A 2 of positive electrode bus bar 2 A abuts on the upper surface of abutting part 3 B of holding part 3 , as shown in FIG. 10( c ) , locked end 2 A 52 of locked part 2 A 5 and locking surface 3 C 23 of pawl 3 C 2 are in contact with each other. A force that arm 3 C 1 tends to restore from the warp acts on locked end 2 A 52 of locked part 2 A 5 toward the minus X side. Accordingly, locked part 2 A 5 can no longer move in the plus Z direction.

In other words, as shown in FIG. 9 and FIG. 10 , positive electrode bus bar 2 A is locked by locked ends 2 A 52 from the plus Z side.

It should be noted that since locking operation between locking protrusions 3 C of holding member 3 and locked parts 2 B 5 of negative electrode bus bar 2 B is the same as the locking operation between locking protrusions 3 C of holding member 3 and locked parts 2 A 5 of positive electrode bus bar 2 A, description of the locking operation is omitted.

Locking protrusions 3 C and locked parts 2 A 5 , 2 B 5 configure so-called snap-fit in which locked parts 2 A 5 , 2 B 5 are locked by pawls 3 C 2 . Since locking protrusions 3 C and locked parts 2 A 5 , 2 B 5 are snap-fit connected, movement of locked part 2 A 5 in a direction (the Z direction) opposite to a moving direction (the minus Z direction) of locked part 2 A 5 can be effectively prevented by utilizing the warp and restoration of arm 3 C 1 .

As mentioned above, by performing the present processes, locked parts 2 A 5 and 2 B 5 , i.e., positive electrode bus bar 2 A and negative electrode bus bar 2 B, are regulated both in the minus Z direction and the plus Z direction, and cannot be moved. Further, movement in the X direction and the Y direction is also regulated by the insertion into the slits, and positive electrode bus bar 2 A and negative electrode bus bar 2 B cannot be moved in the X direction and the Y direction.

The present exemplary embodiment has an advantageous effect in that the relative positions in the Z direction of bus bar 2 and holding member 3 can be easily set only by inserting bus bar 2 into slits 3 S of holding member 3 and by abutting bus bar 2 on abutting part 3 B, without using the mounting jig used in the first exemplary embodiment.

(Connecting Process)

Bus bars 2 mounted on the holding member and capacitor elements 1 are connected in a connecting process. Three capacitor elements 1 are inserted between third portion 2 A 3 of bus bar 2 A and third portion 2 B 3 of bus bar 2 B so that element connection parts 2 A 8 , 2 B 8 of bus bars 2 A, 2 B, respectively, are disposed at predetermined positions of metallikon electrodes 11 of capacitor elements 1 . Next, element connection part 2 A 8 for a positive electrode and metallikon electrode 11 are connected by soldering, resistance welding, or the like, and element connection part 2 B 8 for a negative electrode and metallikon electrode 11 are connected by soldering, resistance welding, or the like. With this configuration, the capacitor elements/the holding member mounted with the bus bars, as shown in FIG. 4 and serving as a main part of the film capacitor, are completed.

In the bus bar mounting/connecting processes of the conventional technique, steps of positioning (the positive electrode), connecting (the positive electrode), positioning (the negative electrode), and connecting (the negative electrode) must be sequentially performed, and the connecting process becomes complex/complicated. However, in the bus bar mounting process and the connecting process of the present exemplary embodiment, positioning is not required, and only steps of inserting (the positive electrode, the negative electrode), connecting (the positive electrode), and connecting (the negative electrode) are required. Accordingly, the processes from the bus bar mounting to the connection are further simpler than the processes in the first exemplary embodiment, not to mention the processes in the conventional technique.

Further, as with the first exemplary embodiment, the relative positions of positive electrode bus bar 2 A, negative electrode bus bar 2 B, and holding member 3 configuring the holding member mounted with the bus bars are fixed in the three directions of X/Y/Z by the single holding member mounted with the bus bars and without using the mounting jig. Accordingly handling is easy, and there is no possibility that the relative positions of the holding member and the bus bars in one direction (the Y direction) are shifted for a period after the positioning (temporary fixing) until the connection as with the conventional technique.

In the first and second exemplary embodiments, positive electrode bus bar 2 A and negative electrode bus bar 2 B having different shapes are used. However, the present invention is not limited to these shapes. For example, positive electrode bus bar 2 A and negative electrode bus bar 2 B may be shared by making the lengths in the Y direction of the second portions equal.

Further, in the second exemplary embodiment, on each of the first principal surface side and the second principal surface side of flat plate 31 of holding member 3 , two snap-fit structures in total are respectively provided at both ends in the direction vertical to the extending direction of the slits. But a configuration provided with only one snap-fit structure can be made. However, in order to prevent movement in the plus Z direction of locked parts 2 A 5 , 2 B 5 more reliably and set relative positions of external connection terminals 2 A 9 , 2 B 9 to desirable positions, it is more preferable that the two snap-fit structures in total be provided on each principal surface side as with the second exemplary embodiment.

A form of locking protrusion 3 C of holding part 3 or locked part 2 A 5 of bus bar 2 shown in the second exemplary embodiment is an illustration, and the form of locking protrusion 3 C or locked part 2 A 5 is not limited to this form. For example, instead of the configuration shown in FIG. 9 , configurations shown in FIG. 13 may be provided. FIG. 13 shows states in which locking is completed as with FIG. 9( c ) . It should be noted that reference marks of parts identical to the parts in FIG. 9 are omitted in FIG. 13 except otherwise specified.

In an aspect of FIG. 13( a ) , through-hole 2 A 53 is formed at locked part 2 A 5 of positive electrode bus bar 2 A. Lower end 2 A 54 of through-hole 2 A 53 is locked by locking surface 3 C 23 of pawl 3 C 2 , and locked part 2 A 5 , i.e., positive electrode bus bar 2 A, cannot be moved due to regulation of movement in a Z direction. It should be noted that a cross-sectional surface of through-hole 2 A 53 can have an arbitrary shape, such as a rectangle, a circle, or an oval.

Here, locking operation is briefly described. When positive electrode bus bar 2 A is inserted into slit 3 S, rushing side end 2 A 51 of locked part 2 A 5 passes vertex 3 C 22 of pawl 3 C 2 . Further, when locked part 2 A 5 moves in a minus Z direction, lower end 2 A 54 of through-hole 2 A 53 starts making contact with locking surface 3 C 23 of pawl 3 C 2 . When insertion of positive electrode bus bar 2 A into slit 3 S is completed, the locking operation is in the state shown in FIG. 13( a ) .

In an aspect of FIG. 13( b ) , recess 2 A 55 is formed at locked part 2 A 5 of positive electrode bus bar 2 A. Lower end 2 A 56 of recess 2 A 55 is locked by locking surface 3 C 23 of pawl 3 C 2 , and locked part 2 A 5 , i.e., positive electrode bus bar 2 A, cannot move due to regulation of movement in a Z direction. It should be noted that a cross-sectional surface of recess 2 A 55 can have an arbitrary shape, such as a rectangle, a circle, or an oval. Since locking operation is the same as the locking operation of through-hole 2 A 53 in FIG. 13( a ) , description of the locking operation is omitted.

In an aspect of FIG. 13( c ) , only a shape of locking protrusion 3 C is different as compared with the aspect of FIG. 9 . More specifically, locking surface 3 C 2 of pawl 3 C is formed substantially vertical to a moving direction (a Z direction) of locked part 2 A 5 , and locked end 2 A 52 of locked part 2 A 5 is locked by locking surface 3 C 23 of pawl 3 C 2 . Locking surfaces 3 C 23 described in FIG. 9 , FIG. 10 , and (a) and (b) of FIG. 13 form an angle of 45 degrees to the moving directions of locked parts 2 A 5 . In the aspect of FIG. 13( c ) , locking surface 3 C 23 is substantially vertical to the moving direction. Accordingly, the movement of locked part 2 A 5 in a plus Z direction can be reliably prevented. It should be noted that, since locking operation is the same as the locking operation described in (a) and (b) of FIG. 9 , description of the locking operation is omitted.

As shown in FIG. 13 , positive electrode bus bar 2 A is locked from the plus Z side by lower ends 2 A 54 , 2 A 56 , and locked end 2 A 52 , respectively.

In the second exemplary embodiment, a protrusion is not provided at slit 3 S unlike the first exemplary embodiment. However, a configuration provided with protrusions 3 A can also be made. By having this configuration, an area where bus bar 2 and holding member 3 are in contact with each other becomes small, and bus bar 2 can be easily inserted into slit 3 S of holding member 3 .

It is possible to provide a film capacitor capable of improving relative mounting accuracy (positioning accuracy) of positive and negative electrode bus bars, and further, capable of easily connecting the bus bars to capacitor elements.