Energy storage device

Abstract

The present invention provides an energy storage device that suppresses stress concentration at the periphery of the connection point with the terminal in the busbar. [Solution] The energy storage device comprises a first energy storage element and a second energy storage element, and a busbar 6 connecting the first and second energy storage elements, wherein the first and second energy storage elements are aligned in a first direction X, the first energy storage element includes a first terminal at its end in a second direction intersecting the first direction, the second energy storage element includes a second terminal at its end in the second direction, the busbar has a first joint portion 611W joined to the first terminal and a second joint portion 621W joined to the second terminal, and the busbar includes a through portion 65 between the first and second joint portions that penetrates the busbar in the second direction.

Description

Technical Field

[0001] The present invention relates to a power storage device including a power storage element.

Background Art

[0002] Patent Document 1 discloses an assembled battery 100 including a laminate 110 in which battery cells 111 having terminals 112 and separators 113 are alternately arranged, and a bus bar 115 connecting the terminals 112 of adjacent battery cells 111 (see FIG. 12).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a plurality of battery cells connected by a bus bar relatively move due to vibration or the like, stress may concentrate on the periphery of the joint portion of the bus bar with the terminal. When stress concentrates on the periphery of the joint portion, there may be a problem in the joint between the bus bar and the terminal.

[0005] An object of the present embodiment is to provide a power storage device in which stress concentration at the periphery of the joint portion of the bus bar with the terminal is suppressed.

Means for Solving the Problems

[0006] The power storage device of the present embodiment includes a first power storage element and a second power storage element, and [[ID=五十]]a bus bar connecting the first power storage element and the second power storage element, and is provided with the first power storage element and the second power storage element are arranged in a first direction, the first power storage element includes a first terminal at an end in a second direction intersecting the first direction, The second energy storage element includes a second terminal at the end in the second direction. The busbar has a first joint that is connected to the first terminal and a second joint that is connected to the second terminal. The busbar includes a through portion between the first joint and the second joint that penetrates the busbar in the second direction. [Effects of the Invention]

[0007] According to this embodiment, it is possible to provide an energy storage device in which stress concentration at the periphery of the connection between the busbar and the terminal is suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of the energy storage device according to this embodiment. [Figure 2] Figure 2 is an exploded perspective view of the laminated structure of the energy storage device. [Figure 3] Figure 3 is an exploded perspective view of the restraint portion of the energy storage device. [Figure 4] Figure 4 is a perspective view of the busbars of the aforementioned energy storage device. [Figure 5] Figure 5 is a view of the busbar from the Z-axis direction. [Figure 6] Figure 6 is a cross-sectional view taken at the VI-VI position in Figure 5. [Figure 7] Figure 7 is a cross-sectional view taken at position VII-VII in Figure 5. [Figure 8] Figure 8 shows a busbar according to another embodiment, viewed from the Z-axis direction. [Figure 9] Figure 9 is a view of a busbar according to another embodiment, as seen from the Z-axis direction. [Figure 10] Figure 10 is a view of a busbar according to another embodiment, as seen from the Z-axis direction. [Figure 11] Figure 11 is a view of a busbar according to another embodiment, as seen from the Z-axis direction. [Figure 12] Figure 12 is a plan view of a conventional battery pack with some components omitted.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] (1) The power storage device according to one embodiment of the present invention includes a first power storage element and a second power storage element, and a bus bar connecting the first power storage element and the second power storage element. The first power storage element and the second power storage element are arranged side by side in a first direction. The first power storage element includes a first terminal at an end in a second direction intersecting the first direction. The second power storage element includes a second terminal at an end in the second direction. The bus bar has a first joint portion joined to the first terminal and a second joint portion connected to the second terminal. The bus bar includes a through portion penetrating the bus bar in the second direction between the first joint portion and the second joint portion.

[0010] According to the power storage device according to one embodiment of the present invention, when the first power storage element and the second power storage element arranged side by side in the first direction relatively move, the bus bar is likely to deform outside the peripheries of the first joint portion and the second joint portion, and stress concentration at at least one of the peripheries of the first joint portion and the second joint portion is suppressed.

[0011] (2) In the power storage device described in (1) above, the through portion includes a first through portion and a second through portion. The first through portion and the second through portion may be arranged at intervals in the first direction.

[0012] According to the power storage device described in (2) above, the first through portion and the second through portion are provided corresponding to the first joint portion and the second joint portion, and when the first power storage element and the second power storage element relatively move, portions (peripheries of each through portion) close to each joint portion in the bus bar are deformed respectively, so that stress concentration at the peripheries of the first joint portion and the second joint portion is preferably suppressed.

[0013] (3) In the power storage device described in (2) above, The first through portion and the second through portion are slit-shaped, extending in a third direction that intersects the first direction and the second direction, such that, when viewed from the second direction, they intersect with an imaginary line connecting the first joint portion and the second joint portion. The first penetrating portion includes the first end which is the end in the third direction, The second penetration portion includes the second end, which is the end in the third direction. The distance between the first penetration portion and the second penetration portion in the first direction at the position of the imaginary line may be smaller than the distance between the first end and the second end in the first direction.

[0014] According to the energy storage device described in (3) above, the areas around the first and second penetrations in the busbar become more easily deformable, so that stress concentration at the periphery of the first and second joints when the first and second energy storage elements, which are aligned in the first direction, move relative to each other is more effectively suppressed.

[0015] (4) In the energy storage device described in (3) above, The first end or the second end may include a bent portion that curves away from the imaginary line in the third direction.

[0016] According to the energy storage device described in (4) above, when the area around the first or second penetration portion deforms due to the relative movement of the first and second energy storage elements aligned in the first direction, stress concentration at the end of the penetration portion is suppressed.

[0017] Hereinafter, one embodiment of the present invention will be described with reference to Figures 1 to 7. The names of each component (each element) in this embodiment are those of this embodiment and may differ from the names of each component (each element) in the background art.

[0018] As shown in Figures 1 and 2, the energy storage device 1 according to this embodiment includes two energy storage elements 3 (first energy storage element 3A and second energy storage element 3B) arranged in a first direction, and a busbar 6 connecting these two energy storage elements 3. In this energy storage device 1, each of the two energy storage elements 3 includes a terminal 34 at the end in a second direction intersecting the first direction. The energy storage device 1 will now be described in detail.

[0019] The energy storage device 1 comprises a laminate 2 on which energy storage elements 3 are stacked, and a restraining part 5 that restrains the laminate 2. The energy storage device 1 has a plurality of busbars 6 that connect the energy storage elements 3 to each other.

[0020] The laminate 2 has a plurality of energy storage elements 3 and a plurality of separators 4. In this laminate 2, the energy storage elements 3 and separators 4 are arranged alternately in the stacking direction.

[0021] Each of the multiple energy storage elements 3 is a primary battery, a secondary battery, a capacitor, etc. The energy storage element 3 in this embodiment is a rechargeable non-aqueous electrolyte secondary battery. More specifically, the energy storage element 3 is a lithium-ion secondary battery that utilizes electron transfer that occurs with the movement of lithium ions.

[0022] Specifically, each energy storage element 3 comprises an electrode body, a case 31 that houses the electrode body together with an electrolyte, terminals 34 (positive electrode terminal 34a, negative electrode terminal 34b) with at least a portion exposed to the outside of the case 31, and a current collector that electrically connects (makes conductive) the electrode body and the terminals 34.

[0023] Terminal 34 is a metal component that guides the electricity stored in the electrode body to the external space of the energy storage element 3, and also introduces electricity into the internal space of the energy storage element 3 in order to store electricity in the electrode body. Terminal 34 is made of aluminum, aluminum alloy, copper, copper alloy, or the like.

[0024] In the electrode body, positive and negative electrodes are stacked alternately with a separator in between. In this electrode body, lithium ions move between the positive and negative electrodes, causing the energy storage element 3 to charge and discharge.

[0025] Case 31 has a case body 32 having an opening and a plate-shaped cover portion 33 that closes the opening of the case body 32 (see Figure 2). In this embodiment, the case body 32 is a bottomed rectangular tube, and case 31 is a rectangular parallelepiped (hexagonal) shape. In this embodiment, case 31 is a flat rectangular parallelepiped shape, and multiple energy storage elements 3 are arranged in a line in the laminate 2 with the wide surfaces (walls) of case 31 (case body 32) facing each other via separators 4.

[0026] In the following explanation, the stacking direction of the multiple energy storage elements 3 (first direction) is defined as the X-axis direction in the Cartesian coordinate system, the normal direction of the cover portion 33 (second direction) is defined as the Z-axis direction in the Cartesian coordinate system, and the directions perpendicular to the X-axis direction and the Z-axis direction are defined as the Y-axis direction in the Cartesian coordinate system.

[0027] Each of the multiple separators 4 has electrical insulation properties and is placed between energy storage elements 3 aligned in the X-axis direction, or between an energy storage element 3 and a member aligned in the X-axis direction relative to the energy storage element 3 (in this embodiment, a part of the restraining portion 5 (end member) 51: see Figure 1). This electrically insulates adjacent energy storage elements 3 and between the energy storage elements 3 and the end member 51. Each separator 4 has a shape that corresponds to the energy storage element 3 when viewed from the X-axis direction (in this embodiment, a rectangular shape that is elongated in the Y-axis direction).

[0028] The restraining portion 5 surrounds the laminate 2, thereby restraining the laminate 2 in a compressed state in the X-axis direction. Specifically, as shown in Figure 3, the restraining portion 5 includes a pair of end members 51 arranged on both sides of the laminate 2 (a plurality of energy storage elements 3 arranged in the X-axis direction), a pair of side members 52 connecting the pair of end members 51, and a plurality of connecting members 53 connecting the end members 51 and the side members 52.

[0029] Each of the pair of end members 51 is a plate-shaped member positioned to sandwich a separator 4 between itself and the energy storage element 3 located at the X-axis end (outermost part) of the laminate 2. The end members 51 are rectangular in shape, corresponding in size to the energy storage element 3 when viewed from the X-axis direction. Specifically, the end members 51 are rectangular in shape, elongated in the Y-axis direction. The end members 51 have connecting recesses 511 at both ends in the Y-axis direction that are recessed inward in the Y-axis direction and extend in the Z-axis direction. The end members 51 have a plurality of first connecting holes 512 at both ends in the Y-axis direction, spaced apart in the Z-axis direction.

[0030] The pair of side members 52 are positioned on both sides of the laminate 2 in the Y-axis direction and extend along the laminate 2 in the X-axis direction. The side members 52 are rectangular in shape and are the same size as the laminate 2 when viewed from the Y-axis direction. Specifically, the side member 52 has a rectangular side member body 521 that is elongated in the X-axis direction, and a pair of connecting protrusions 522 that extend from both ends of the side member body 521 in the X-axis direction toward the inside in the Y-axis direction (towards the center of the laminate 2 in the Y-axis direction).

[0031] Each of the pair of connecting protrusions 522 fits into the corresponding connecting recess 511 of the end member 51. The connecting protrusions 522 have a plurality of second connecting holes 523 that are spaced apart in the Z-axis direction. Each second connecting hole 523 overlaps with the corresponding first connecting hole 512 of the end member 51 when viewed from the X-axis direction.

[0032] Each of the multiple connecting members 53 connects the end member 51 and the side member 52 by being inserted into the first connecting hole 512 of the end member 51 and the second connecting hole 523 of the side member 52 (connecting projection 522).

[0033] The busbar 6 is a conductive plate-shaped member made of metal or the like. The busbar 6 connects the terminals 34 of multiple energy storage elements 3 electrically. The multiple busbars 6 in this embodiment connect (connect) the multiple energy storage elements 3 included in the energy storage device 1 in series.

[0034] In this embodiment, the busbar 6 connects (makes conductive) the corresponding terminals 34 of two adjacent energy storage elements 3 in the X-axis direction. Hereinafter, one of the two energy storage elements 3 connected by the busbar 6 will be referred to as the first energy storage element 3A, and the other of the two energy storage elements 3 will be referred to as the second energy storage element 3B (see Figure 1). When the positive terminal 34a of the first energy storage element 3A is referred to as the first terminal, the negative terminal (the terminal corresponding to the first terminal) 34b of the second energy storage element 3B will be referred to as the second terminal. Furthermore, when the negative terminal 34b of the first energy storage element 3A is referred to as the first terminal, the positive terminal (the terminal corresponding to the first terminal) 34a of the second energy storage element 3B will be referred to as the second terminal.

[0035] As shown in Figures 4 to 7, the busbar 6 has a first joint portion 611W that is connected to the first terminal 34a and a second joint portion 621W that is connected to the second terminal 34b. Between the first joint portion 611W and the second joint portion 621W, the busbar 6 includes a through portion 65 that penetrates the busbar 6 in the Z-axis direction. In this embodiment, the through portion 65 includes a first through portion 66 and a second through portion 67.

[0036] Specifically, the busbar 6 is a conductive, rectangular plate-shaped member when viewed from the Z-axis direction. This busbar 6 has a first plate-shaped portion 61 and a second plate-shaped portion 62 that are spaced apart in the X-axis direction, and a busbar projection 63 that connects the first plate-shaped portion 61 and the second plate-shaped portion 62.

[0037] The first plate-like portion 61 is a plate-like part that extends in a plane direction perpendicular to the Z-axis direction and includes the first joining region 611. The first plate-like portion 61 has a first through-hole 611a that penetrates in the Z-axis direction, located near one end in the Y-axis direction (the upper end in Figure 5). The first through-hole 611a in this embodiment is a circular through-hole. In the first plate-like portion 61, the region including the first through-hole 611a is the first joining region 611. Within this first joining region 611, the portion welded to the first terminal 34a is the first joint portion 611W.

[0038] The first joining region 611 in this embodiment is a rectangular area (region) that extends in a plane direction perpendicular to the Z-axis direction and has a first through hole 611a in its approximate center (the region enclosed by the dashed line of reference numeral 611 in Figures 4 and 5). The first joining region 611 in this embodiment is the part that is joined to the first terminal 34a by welding. The entire area of ​​the first joining region 611 does not have to be joined (welded, etc.) to the first terminal 34a. In this example, within the first joining region 611, the first through hole 611a is approximately centered and welded to the first terminal 34a in an annular shape (see reference numeral 611W in Figure 5), and this annular welded area constitutes the first joint 611W.

[0039] The second plate-like portion 62 is a plate-like part that extends in a plane direction perpendicular to the Z-axis direction and includes the second joining region 621. The second plate-like portion 62 has a second through-hole 621a that penetrates in the Z-axis direction at a position closer to one end in the Y-axis direction. In this embodiment, the second through-hole 621a is a circular through-hole. In the second plate-like portion 62, the region including the second through-hole 621a is the second joining region 621. Within this second joining region 621, the portion welded to the second terminal 34b is the second joining portion 621W.

[0040] The second joining region 621 in this embodiment is a rectangular area (region) that extends in a plane direction perpendicular to the Z-axis direction and has a second through hole 621a in its approximate center (the region enclosed by the dashed line of reference numeral 621 in Figures 4 and 5). The second joining region 621 in this embodiment is joined to the second terminal 34b by welding. The entire area of ​​the second joining region 621 does not have to be welded to the second terminal 34b. In this example, within the second joining region 621, the second through hole 621a is approximately centered and welded to the second terminal 34b in an annular shape (see reference numeral 621W in Figure 5), and this annular welded area constitutes the second joint 621W.

[0041] The busbar protrusion 63 is a portion that protrudes from the center of the busbar 6 in the X-axis direction, on one side in the Z-axis direction (away from the energy storage element 3), and is a portion that absorbs (relieves) stress when the first plate-like portion 61 and the second plate-like portion 62 are displaced relative to each other in the X-axis direction.

[0042] Specifically, the busbar projection 63 has a first upright portion 631 that rises in the Z-axis direction from the edge of the first plate-like portion 61 closest to the second plate-like portion 62, a second upright portion 632 that rises in the Z-axis direction from the edge of the second plate-like portion 62 closest to the first plate-like portion 61, and a connecting portion 633 that connects the tip of the first upright portion 631 and the tip of the second upright portion 632. This connecting portion 633 is plate-shaped, extending in a plane direction perpendicular to the Z-axis direction, that is, it is plate-shaped parallel to or substantially parallel to the first plate-like portion 61 and the second plate-like portion 62 (see Figure 6).

[0043] The through-section 65 is positioned between the first joint 611W and the second joint 621W and penetrates the busbar 6 in the Z-axis direction. In this embodiment, the through-section 65 includes two through-sections (first through-section 66 and second through-section 67).

[0044] The first through-hole 66 and the second through-hole 67 are spaced apart in the X-axis direction. The first through-hole 66 and the second through-hole 67 are slit-shaped holes that extend in the Y-axis direction so as to intersect with the first imaginary line K1 (see Figure 5) connecting the first joint 611W and the second joint 621W when viewed from the Z-axis direction, or more specifically, with the first imaginary line K1 connecting the center of the first through-hole 611a and the center of the second through-hole 621a.

[0045] In the busbar 6 of this embodiment, the first through portion 66 is formed at a position spanning the first plate-like portion 61 and the busbar protrusion 63, and the second through portion 67 is formed at a position spanning the second plate-like portion 62 and the busbar protrusion 63.

[0046] Specifically, the first through portion 66 has a first portion 661 extending along the Y-axis, a second portion 662 extending from one end of the first portion 661 in a direction away from the second through portion 67 in the X-axis direction, and a third portion 663 extending from the other end of the first portion 661 in a direction away from the second through portion 67 in the X-axis direction.

[0047] The first portion 661 extends in the Y-axis direction at the connecting portion 633, while the second portion 662 and the third portion 663 each extend from the connecting portion 633 through the first upright portion 631 to the first plate-like portion 61. The boundary between the first portion 661 and the second portion 662 is arc-shaped, and the boundary between the first portion 661 and the third portion 663 is also arc-shaped.

[0048] This first penetrating portion 66 has first ends 665a and 665b at both ends (i.e., the tip of the second portion 662 and the tip of the third portion 663).

[0049] Each first end portion 665a, 665b includes a portion (bent portion) that curves away from the first virtual line K1 in the Y-axis direction. In other words, the first end portions 665a, 665b of this embodiment are composed of bent portions. At these first end portions 665a, 665b, the edges 666a, 666b that are farther from the second penetration portion 67 in the X-axis direction are in the shape of an arc that bulges away from the second penetration portion 67 in the X-axis direction (see enlarged view of Figure 5).

[0050] When the first terminal 34a and the second terminal 34b are displaced relative to each other in the Z-axis direction, a torsional force is applied to these arc-shaped edges 666a and 666b as the busbar protrusion 63 moves in the Z-axis direction while the Z-axis position of the first joint 611W (first joint region 611) is maintained. However, because the curve is small (a gently curved arc) compared to a configuration without a bend, stress concentration is reduced compared to an arc-shaped edge with a large curvature and no bend.

[0051] The second through-section 67, when viewed from the Z-axis direction, has a shape symmetric to the first through-section 66 when the axis of symmetry is the second imaginary line K2 (see Figure 5), which extends in the Y-axis direction at the central position in the X-axis direction of the busbar 6. Specifically, the second through-section 67 has a fourth portion 671 extending along the Y-axis direction, a fifth portion 672 extending from one end of the fourth portion 671 in a direction away from the first through-section 66 in the X-axis direction, and a sixth portion 673 extending from the other end of the fourth portion 671 in a direction away from the first through-section 66 in the X-axis direction.

[0052] The fourth portion 671 extends in the Y-axis direction at the connecting portion 633, and the fifth portion 672 and the sixth portion 673 each extend from the connecting portion 633 through the second upright portion 632 to the second plate-like portion 62. The boundary between the fourth portion 671 and the fifth portion 672 is arc-shaped, and the boundary between the fourth portion 671 and the sixth portion 673 is also arc-shaped.

[0053] This second penetrating portion 67 has second ends 675a ​​and 675b at both ends (i.e., the tip of the fifth portion 672 and the tip of the sixth portion 673).

[0054] Specifically, each second end portion 675a, 675b includes a portion (bent portion) that is curved away from the first virtual line K1 in the Y-axis direction. In other words, the second end portions 675a, 675b of this embodiment are composed of bent portions. At the second end portions 675a, 675b, the edges 676a, 676b that are farther from the first through portion 66 in the X-axis direction are in the shape of an arc that bulges away from the first through portion 66 in the X-axis direction.

[0055] When the first terminal 34a and the second terminal 34b are displaced relative to each other in the Z-axis direction, the busbar protrusion 63 moves in the Z-axis direction while the Z-axis position of the second joint 621W (second joint region 621) is maintained, thereby applying a torsional force to these arc-shaped edges 676a and 676b. However, because the curve is a small arc shape (a gently curved arc shape) compared to a configuration without a bend, stress concentration is reduced compared to an arc-shaped edge with a large curvature and no bend.

[0056] With the busbar 6 described above, when the first energy storage element 3A and the second energy storage element 3B, which have a first terminal 34a and a second terminal 34b connected by the busbar 6, undergo relative displacement, stress concentration at the periphery of the first junction region 611 (specifically, the first junction 611W) and the periphery of the second junction region 621 (specifically, the second junction 621W) is suppressed. In particular, the effect of suppressing stress concentration at the periphery of the first junction 611W and the periphery of the second junction 621W when the first energy storage element 3A and the second energy storage element 3B undergo relative displacement in the Z-axis direction is remarkable. Details are as follows.

[0057] When the first energy storage element 3A is displaced relative to the second energy storage element 3B to one side in the Z-axis direction, as shown by arrows A1 and A2 in Figure 6, the formation of the first penetration portion 66 and the second penetration portion 67 prevents the edge 611E of the first joint region 611 closest to the second joint region 621 from being pulled to one side in the Z-axis direction (upper side in Figure 6), and prevents the edge 621E of the second joint region 621 closest to the first joint region 611 from being pushed to the other side in the Z-axis direction (lower side in Figure 6). As a result, it becomes difficult for forces in the Z-axis direction to be applied to the periphery of each joint region 611, 621 (more specifically, each joint portion 611W, 621W), and as a result, stress concentration at the periphery of each joint portion 611W, 621W is effectively suppressed.

[0058] When the first energy storage element 3A and the second energy storage element 3B are subjected to relative displacement in the Z-axis direction, a torsional force is applied to the periphery of each end of the first penetration portion 66 and the second penetration portion 67 (first end portions 665a and 665b, second end portions 675a ​​and 675b), making it easy for stress to concentrate at the periphery of these ends.

[0059] However, as described above, since the ends 665a, 665b, 675a, and 675b of the first penetration section 66 and the second penetration section 67 are formed by bends, the edges 666a, 666b, 676a, and 676b are in the shape of a small arc, which widens the area where stress is concentrated around these ends 665a, 665b, 675a, and 675b. As a result, the stress in that area is dispersed, and consequently, the stress in that area is suppressed.

[0060] The energy storage device 1 described above comprises a first energy storage element 3A and a second energy storage element 3B, and a busbar 6 connecting the first energy storage element 3A and the second energy storage element 3B. The first energy storage element 3A and the second energy storage element 3B are aligned in the X-axis direction (first direction), the first energy storage element 3A includes a first terminal 34a at one end (upper side in Figure 2) in the Z-axis direction (second direction) intersecting the X-axis direction, the second energy storage element 3B includes a second terminal 34b at one end in the Z-axis direction, the busbar 6 has a first joint portion 611W connected to the first terminal 34a and a second joint portion 621W connected to the second terminal 34b, and the busbar 6 includes a through portion 65 between the first joint portion 611W and the second joint portion 621W that penetrates the busbar 6 in the Z-axis direction.

[0061] With this configuration, when the first energy storage element 3A and the second energy storage element 3B move relative to each other in the X-axis direction, the busbar 6 is more easily deformed at locations other than the periphery of the first joint 611W and the periphery of the second joint 621W, thereby suppressing stress concentration at at least one of the periphery of the first joint 611W and the periphery of the second joint 621W.

[0062] In the energy storage device 1 of this embodiment, the through-hole 65 includes a first through-hole 66 and a second through-hole 67, and the first through-hole 66 and the second through-hole 67 are spaced apart in the X-axis direction (first direction).

[0063] With this configuration, a first through-hole 66 and a second through-hole 67 are provided corresponding to the first joint 611W and the second joint 621W, and when the first energy storage element 3A and the second energy storage element 3B move relative to each other, the parts of the busbar 6 near each joint 611W and 621W (around the first through-hole 66 and the second through-hole 67) deform, respectively, thereby effectively suppressing stress concentration at the periphery of the first joint 611W and the periphery of the second joint 621W.

[0064] In the energy storage device 1 of this embodiment, the first penetration portion 66 and the second penetration portion 67 are slit-shaped extensions in the Y-axis direction (third direction) so as to intersect with the first imaginary line (imaginary line) K1 connecting the first joint portion 611W and the second joint portion 621W when viewed from the Z-axis direction (second direction). The first penetration portion 66 includes first ends 665a and 665b, which are the ends in the Y-axis direction, and the second penetration portion 67 includes second ends 675a ​​and 675b, which are the ends in the Y-axis direction. The distance between the first penetration portion 66 and the second penetration portion 67 in the X-axis direction (first direction) at the position of the first imaginary line K1 is smaller than the distance between the first ends 665a and 665b and the second ends 675a ​​and 675b in the X-axis direction.

[0065] With this configuration, the areas around the first penetration portion 66 and the second penetration portion 67 of the busbar 6 become more easily deformable, so that stress concentration at the periphery of the first joint portion 611W and the periphery of the second joint portion 621W when the first energy storage element 3A and the second energy storage element 3B, which are aligned in the X-axis direction, move relative to each other is more effectively suppressed.

[0066] In the energy storage device 1 of this embodiment, the first end portion 665a, 665b or the second end portion 675a, 675b includes a bent portion that curves away from the first virtual line (virtual line) K1 in the Y-axis direction (third direction).

[0067] With this configuration, when the area around the first penetration portion 66 or the second penetration portion 67 deforms due to the relative movement of the first energy storage element 3A and the second energy storage element 3B, which are aligned in the X-axis direction, stress concentration at the ends of the first penetration portion 66 and the ends of the second penetration portion 67 is suppressed.

[0068] It should be noted that the energy storage device of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0069] In the above embodiment, the X-axis direction (first direction), the Y-axis direction (third direction), and the Z-axis direction (second direction) are orthogonal to each other, but they do not have to be orthogonal. That is, the X-axis direction, the Y-axis direction, and the Z-axis direction only need to intersect.

[0070] In the above embodiment, the first through portion 66 of the busbar 6 extends in a direction in which the second portion 662 and the third portion 663 intersect with respect to the first portion 661 which extends in the Y-axis direction, and the second through portion 67 extends in a direction in which the fifth portion 672 and the sixth portion 673 intersect with respect to the fourth portion 671 which extends in the Y-axis direction, but the configuration is not limited to this.

[0071] As shown in Figure 8, the first through-hole 66A and the second through-hole 67A may each be arc-shaped or the like.

[0072] In the first through-hole 66 and second through-hole 67 of the above embodiment, the shape of the hole periphery near the center of the busbar 6 in the X-axis direction is substantially the same as the shape of the hole periphery far from the center when viewed from the Z-axis direction, but the configuration is not limited to this. For example, as shown in Figure 9, in the first through-hole 66B and second through-hole 67B, the shape of the hole periphery near the center of the busbar 6 in the X-axis direction may be different from the shape of the hole periphery far from the center.

[0073] In the above embodiment, the width of the holes in the first through-hole 66 and the second through-hole 67 is substantially constant, but the configuration is not limited to this. As shown in Figure 10, in the first through-hole 66C, the widths of the first portion 661C, the second portion 662C, and the third portion 663C may be different. Also, in the second through-hole 67C, the widths of the fourth portion 671C, the fifth portion 672C, and the sixth portion 673C may be different. Furthermore, the widths of the second portion 662C and the third portion 663C may be different, and the widths of the fifth portion 672C and the sixth portion 673C may be different.

[0074] In the busbar 6 of the above embodiment, the first through-section 66 and the second through-section 67 have a symmetrical shape with respect to the second imaginary line K2 as the axis of symmetry, but the configuration is not limited to this. As shown in Figure 11, the first through-section 66D and the second through-section 67D do not have to have a symmetrical shape with respect to the second imaginary line K2 as the axis of symmetry.

[0075] In the above embodiment, the busbar 6 has a busbar projection 63 formed in the center in the X-axis direction, but the configuration is not limited to this. The busbar 6 may be flat (i.e., without the busbar projection 63).

[0076] In the busbar 6 of the above embodiment, the through portion 65 includes a first through portion 66 and a second through portion 67, and the first through portion 66 and the second through portion 67 are spaced apart in the X-axis direction, but the configuration is not limited to this. The through portion 65 may include only one through portion, or it may include three or more through portions. Also, the direction in which the first through portion 66 and the second through portion 67 are aligned is not limited to the X-axis direction. The first through portion 66 and the second through portion 67 may be aligned in a direction other than the X-axis direction.

[0077] In the above embodiment, the first through-hole 66 and the second through-hole 67 are slit-shaped and extend in the Y-axis direction, but the configuration is not limited to this. The first through-hole 66 and the second through-hole 67 may extend in directions other than the Y-axis direction. Also, the first through-hole 66 and the second through-hole 67 may have shapes other than slits.

[0078] In the busbar 6 of the above embodiment, the distance between the first through portion 66 and the second through portion 67 in the X-axis direction at the position of the first virtual line K1 is smaller than the distance between the first ends 665a, 665b and the second ends 675a, 675b in the X-axis direction, but the configuration is not limited to this. The distance between the first through portion 66 and the second through portion 67 in the X-axis direction at the position of the first virtual line K1 may be the same as the distance between the first ends 665a, 665b and the second ends 675a, 675b in the X-axis direction, or it may be larger than the distance between the first ends 665a, 665b and the second ends 675a, 675b in the X-axis direction.

[0079] The first ends 665a and 665b of the first through-hole 66 in the above embodiment include a bent portion that curves away from the first virtual line K1 in the Y-axis direction, but it does not have to include a bent portion. The second ends 675a ​​and 675b of the second through-hole 67 in the above embodiment include a bent portion that curves away from the first virtual line K1 in the Y-axis direction, but it does not have to include a bent portion. [Explanation of Symbols]

[0080] 1...Energy storage device, 2...Laminate, 3...Energy storage element, 3A...First energy storage element (energy storage element), 3B...Second energy storage element (energy storage element), 31...Case, 32...Case body, 33...Cover part, 34...Terminal, 34a...Positive terminal (first terminal), 34b...Negative terminal (second terminal), 4...Separator, 5...Restraining part, 51...End member, 511...Connection recess, 512...First connecting hole, 52...Side member, 521... Side member body, 522...connecting projection, 523...second connecting hole, 53...connecting member, 6...busbar, 61...first plate-like part, 611...first joining region, 611E...edge near the second joining region, 611W...first joining part, 611a...first through hole, 62...second plate-like part, 621...second joining region, 621E...edge near the first joining region, 621W...second joining part, 621a...second through hole, 63...busbar projection , 631...First standing part, 632...Second standing part, 633...Connection part, 65...Penetration part, 66, 66A, 66B, 66C, 66D...First penetration part, 661, 661C...First part, 662, 662C ...Second part, 663, 663C...Third part, 665a, 665b...First end, 666a, 666b...Edge, 67, 67A, 67B, 67C, 67D...Second penetration part, 671, 671C...Fourth Part, 672, 672C... Fifth part, 673, 673C... Sixth part, 675a, 675b... Second end, 676a, 676b... Edge, 100... Battery pack, 110... Laminate, 111, 111a, 111b... Battery cell, 112... Terminal, 112n... Negative terminal, 112p... Positive terminal, 113... Separator, 115... Busbar, A1, A2... Direction of movement, K1... First virtual line, K2... Second virtual line

Claims

1. First energy storage element and second energy storage element, The system comprises a busbar connecting the first energy storage element and the second energy storage element, The first energy storage element and the second energy storage element are arranged in the first direction, The first energy storage element includes a first terminal at the end in a second direction intersecting the first direction. The second energy storage element includes a second terminal at the end in the second direction. The busbar has a first joint that is connected to the first terminal and a second joint that is connected to the second terminal. The busbar is a power storage device in which a through portion is provided between the first joint and the second joint, and the busbar penetrates the busbar in the second direction.

2. The aforementioned through portion includes a first through portion and a second through portion, The energy storage device according to claim 1, wherein the first penetration portion and the second penetration portion are arranged with an interval between them in the first direction.

3. The first through portion and the second through portion are slit-shaped, extending in a third direction that intersects the first direction and the second direction, such that, when viewed from the second direction, they intersect with an imaginary line connecting the first joint portion and the second joint portion. The first penetrating portion includes the first end which is the end in the third direction, The second penetration portion includes the second end, which is the end in the third direction. The energy storage device according to claim 2, wherein the distance between the first penetration portion and the second penetration portion in the first direction at the position of the virtual line is smaller than the distance between the first end and the second end in the first direction.

4. The energy storage device according to claim 3, wherein the first end or the second end includes a bent portion that bends away from the imaginary line in the third direction.

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