Battery pack and bus bar

Abstract

The invention relates to a battery pack and a bus bar. Each of a first battery cell and a second battery cell constituting the battery pack includes an electrode terminal, a first bus bar includes a belt-shaped connection portion having two parallel side edges extending in an X-axis direction, and the connection portion has a through hole for welding connection with the electrode terminal. The through-hole has a hexagonal shape formed by sequentially connecting a first corner, a second corner, a third corner, a fourth corner, a fifth corner, and a sixth corner, and an imaginary straight line connecting the first corner and the fourth corner is perpendicular to both sides.

Description

Technical Field

[0001] The invention relates to a battery pack and a bus bar. Background Art

[0002] Japanese Patent Application Laid-Open No. 2022-013957 discloses an invention of a bus bar and a battery module, disclosing a structure in which a circular through hole is provided in the bus bar and a cutout hole extending outward is provided in the through hole at a position offset from the center.

[0003] Japanese Patent Application Laid-Open No. 2021-163629 discloses an invention related to a power supply device, a vehicle including the power supply device, and a power storage device, and discloses a structure in which a through hole is provided in the center of an elliptical thin-walled region of a busbar.

[0004] Japanese Patent Application Publication No. 2019-160727 discloses an invention related to an electric storage device, which discloses a structure in which a circular through-hole is provided in a busbar and a cutout hole extending outward from a center position is provided in the through-hole. Summary of the invention

[0005] A cell-to-pack structure is being developed in which a stack including a plurality of battery cells is directly housed in a case without using end plates and restraining bars (module structure) for restraining a plurality of battery cells.

[0006] In a structure in which a bus bar module modularized by accommodating a plurality of bus bars in a plate member is mounted on a stack of a plurality of battery cells, the bus bars are used when connecting adjacent battery cells in the same stack of the plurality of battery cells.

[0007] The busbars and the battery cells are electrically connected by welding in a state where the electrodes of the battery cells are exposed from through holes provided in the busbars. After welding, image analysis of the welded portion is performed to confirm whether the welding is properly performed.

[0008] The shape of the busbar varies depending on the location where it is used, but when there are three sides of the busbar around the through hole, even if the shape of the through hole is deformed after welding, the position of the weld can be estimated and detected based on the edges (corners of the plate thickness) of each of the three sides. As a result, it is possible to confirm whether welding is performed properly through image analysis.

[0009] On the other hand, when there are only two sides instead of three sides of the busbar around the through hole, the position of the weld cannot be estimated and detected based on the two edge positions. As a result, it is impossible to confirm whether welding is properly performed by image analysis.

[0010] An object of the present invention is to provide a battery pack and a bus bar having a system capable of identifying welding locations between a bus bar and a battery cell by image analysis regardless of the shape of the bus bar.

[0011] The present invention provides the following battery pack and bus bar.

[0012] [1] A battery pack, wherein the battery pack comprises: a first stack including a plurality of first battery cells arranged in a first direction; a second stack adjacent to the first stack in a second direction orthogonal to the first direction, including a plurality of second battery cells arranged in the first direction; a housing having side walls facing the first stack and the second stack from the first direction and accommodating the first stack and the second stack; a first bus bar and a first bus bar module, wherein the first bus bar electrically connects the plurality of first battery cells, the first bus bar module accommodating the first bus bar and being arranged on the first stack; and a second bus bar and a second bus bar module, wherein the second bus bar electrically connects the plurality of second battery cells, the second bus bar module accommodating the second bus bar and being arranged on the second stack. On the stack; and a third busbar, which is configured to bridge the first busbar module and the second busbar module along the second direction, electrically connecting one of the first battery cells selected from the first stack and one of the second battery cells selected from the second stack, the first battery cell and the second battery cell both include electrode terminals, the first busbar, the second busbar and the third busbar include a strip-shaped plate portion having two parallel side edges extending in the second direction, the plate portion having a through hole for welding with the electrode terminal, the through hole is a hexagonal shape formed by connecting the first corner, the second corner, the third corner, the fourth corner, the fifth corner and the sixth corner in sequence, and an imaginary straight line connecting the first corner and the fourth corner is perpendicular to the two side edges.

[0013] [2] In the battery pack described in [1], the hexagonal shape is a regular hexagon.

[0014] [3] In the battery pack described in [1] or [2], the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary straight line.

[0015] [4] In the battery pack described in any one of [1] to [3], the third bus bar includes: a first region electrically connected to the first battery cell and located on the first bus bar module side; a second region electrically connected to the second battery cell and located on the second bus bar module side; and a third region arranged at a position bridging the first bus bar module and the second bus bar module, connecting the first region with the second region, and the through hole is arranged in the first region and the second region.

[0016] [5] A busbar comprising a plurality of battery cells including electrode terminals arranged in an arranged configuration, the busbar being used to electrically connect the electrode terminals of adjacent battery cells, wherein the busbar comprises a strip-shaped plate portion having two parallel sides extending in one direction, the plate portion having a through hole for welding to the electrode terminal, the through hole being in a hexagonal shape formed by sequentially connecting a first corner portion, a second corner portion, a third corner portion, a fourth corner portion, a fifth corner portion and a sixth corner portion, and an imaginary straight line connecting the first corner portion and the fourth corner portion is perpendicular to the two side sides.

[0017] [6] In the busbar described in [5], the above-mentioned hexagonal shape is a regular hexagon.

[0018] [7] In the busbar described in [5] or [6], the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary straight line.

[0019] The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is an exploded perspective view of the battery pack according to the embodiment.

[0021] Figure 2 It is a perspective view of a battery cell according to the embodiment.

[0022] Figure 3 It is a plan view of a plate member of a busbar module according to the embodiment.

[0023] Figure 4 It is a perspective view showing the structure around the busbars of the busbar module according to the embodiment.

[0024] Figure 5 It is a perspective view of the first bus bar and the second bus bar according to the embodiment.

[0025] Figure 6 It is a plan view of the first bus bar and the second bus bar according to the embodiment.

[0026] Figure 7 It is a plan view of a first bus bar and a second bus bar according to another mode of the embodiment.

[0027] Figure 8 It is a perspective view of the third busbar in the embodiment.

[0028] Fig. 9 It is a plan view of the third busbar of the embodiment.

[0029] Fig.10It is a partially enlarged plan view of a bus bar arranged in a bus bar module according to an embodiment.

[0030] Fig.11 This is a partially enlarged view of a third busbar module of a busbar according to another aspect of the embodiment.

[0031] Fig.12 This is a perspective view of a busbar according to another embodiment.

[0032] Fig.13 It is a plan view of a busbar according to another embodiment of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, an embodiment of the present invention will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0034] In the embodiments described below, when the number, quantity, etc. are mentioned, except for the cases specifically described, the scope of the present invention is not necessarily limited to the number, quantity, etc. In addition, in the following embodiments, each component is not necessarily essential to the present invention except for the cases specifically described. In addition, the present invention is not necessarily limited to achieving all the effects mentioned in the present embodiments.

[0035] In addition, in this specification, the descriptions of “comprise”, “include”, and “have” are open-ended. That is, when a certain structure is included, other structures other than the structure may be included or other structures other than the structure may not be included.

[0036] In addition, in this specification, when geometric terms and terms indicating position and direction relationships, such as "parallel", "orthogonal", "oblique 45°", "coaxial", "along", etc., are used, these terms allow for manufacturing errors or slight changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be flipped or rotated to any angle by the setting direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0037] In this specification, "battery" is not limited to lithium-ion batteries, and can include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "battery pack" can be installed in hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) and electric vehicles (BEV). However, the use of "battery cells" is not limited to vehicle use.

[0038] Figure 1 1 is an exploded perspective view of the battery pack 1. Figure 1 As shown, the battery pack 1 includes: a plurality of battery cells 100 (see Figure 2 ) of a stacked body 10; a housing 20 for housing the stacked body 10; and a busbar module 30 disposed on the stacked body 10.

[0039] The stacked body 10 includes a first stacked body 10A, a second stacked body 10B, and a third stacked body 10C. The first stacked body 10A and the second stacked body 10B are adjacent to each other in the X-axis direction (second direction). The second stacked body 10B and the third stacked body 10C are adjacent to each other in the X-axis direction.

[0040] The housing 20 has a side wall 21 facing the first stack 10A, the second stack 10B, and the third stack 10C in the Y-axis direction. The side wall 21 directly supports the first stack 10A, the second stack 10B, and the third stack 10C from both sides in the Y-axis direction. In this way, the battery pack 1 of this embodiment is a battery pack adopting a Cell-to-Pack structure in which the stack 10 including a plurality of battery cells 100 is directly accommodated in the housing.

[0041] The busbar module 30 includes: a first busbar module 30A disposed on the first stack 10A; a second busbar module 30B disposed on the second stack 10B; and a third busbar module 30C disposed on the third stack 10C. In the present embodiment, the first busbar module 30A, the second busbar module 30B, and the third busbar module 30C have the same form, but may also have different forms.

[0042] Figure 2 1 is a perspective view showing the structure of the battery cell 100 constituting the first stack 10A, the second stack 10B, and the third stack 10C. Figure 2 As shown, the battery cell 100 has a square shape and includes an electrode terminal 110 , a frame 120 , and a gas exhaust valve 130 .

[0043] The electrode terminal 110 is formed on the frame 120. The electrode terminal 110 includes a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 arranged along the X-axis direction (second direction) orthogonal to the Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are provided to be separated from each other in the X-axis direction.

[0044] The frame 120 has a substantially rectangular parallelepiped shape. An electrode assembly and an electrolyte solution (not shown) are accommodated in the frame 120. The frame 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and a third side surface 125.

[0045] The upper surface 121 is a plane perpendicular to the Z-axis direction. The electrode terminal 110 is arranged on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction (third direction) perpendicular to the Y-axis direction (first direction) and the X-axis direction (second direction).

[0046] Each of the first side surface 123 and the second side surface 124 is formed of a plane orthogonal to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the frame body 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape in which the X-axis direction is the long side direction and the Z-axis direction is the short side direction when viewed in the Y-axis direction.

[0047] The plurality of battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. Thus, the positive terminals 111 and the negative terminals 112 are alternately arranged in the Y-axis direction.

[0048] The gas discharge valve 130 is provided on the upper surface 121 . When the internal pressure of the housing 120 increases to a predetermined value or more due to the gas generated inside the housing 120 , the gas discharge valve 130 opens and discharges the gas to the outside of the housing 120 .

[0049] Next, use Figure 3 and Figure 4 , the basic structure of the busbar module 30 is described. Figure 3 is a top view of a plate member 310 included in the busbar module 30, Figure 4 This is a perspective view showing the structure of the busbar and its surroundings in the busbar module.

[0050] The first busbar module 30A, the second busbar module 30B and the third busbar module 30C respectively include Figure 3 The plate member 310 is shown. Figure 3 As shown, the plate member 310 includes: an end face 311 located at the end in the Y-axis direction; an end face 312 located at the end in the X-axis direction; a through hole 313 formed at a position corresponding to the gas exhaust valve 130 of the battery cell 100; and a wall portion 314 that divides the space on the plate member 310 into multiple parts.

[0051] like Figure 4 As shown, in the first busbar module 30A, busbars 320 (first busbars) are stored in each space separated by the wall portion 314. The busbar 320 (first busbar) is composed of a conductor (typically a metal member). The busbar 320 (first busbar) electrically connects the electrode terminals 110 of multiple battery cells 100 to each other. The busbar 320 (first busbar) includes a root portion 321 extending in the Y-axis direction and a pair of connecting portions 322 (first connecting portion, second connecting portion) protruding from the root portion 321 in the X-axis direction. The connecting portions 322 are respectively connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0052] The busbar 320 is connected to the wiring 410. The wiring 410 is fixed to the busbar 320 (first busbar) by screws 420. The wiring 410 and the screws 420 are not limited to Figure 4 In the structure shown, for example, wiring can be formed by a flexible wiring substrate.

[0053] The electrode terminal 110 of the battery cell 100 and the bus bar 320 (first bus bar) are positioned relative to each other in the X-axis direction and the Y-axis direction and then welded together. By accurately positioning the electrode terminal 110 and the bus bar 320 (first bus bar), the welding process can be performed efficiently and with high quality. The through hole 322h1 provided in the bus bar 320 is used for welding.

[0054] like Figure 4 As shown, in the second busbar module 30B, similarly to the first busbar module 30A, busbars 320 (second busbars) are stored in respective spaces partitioned by the wall portion 314. The structure and function of the busbar 320 (second busbar) are the same as those of the busbar 320 (first busbar).

[0055] like Figure 4 As shown, a bus bar 500 (third bus bar) is provided, and the bus bar 500 (third bus bar) is provided to bridge between the first bus bar module 30A and the second bus bar module 30B along the X-axis direction, and electrically connects one battery cell 100 (first battery cell) selected from the first stack 10A and one battery cell 100 (second battery cell) selected from the second stack 10B. Although not shown in the figure, the bus bar 500 is also provided between the second bus bar module 30B and the third bus bar module 30C.

[0056] The busbar 500 is connected to the wiring 410. The wiring 410 is fixed to the busbar 500 by screws 420. The wiring 410 and the screws 420 are not limited to Figure 4 In the structure shown, for example, wiring can be formed by a flexible wiring substrate.

[0057] In the present embodiment, one battery cell 100 (first battery cell) selected from the first stack 10A is a battery cell located at the endmost position (the endmost end in the Y-axis direction) facing the side wall 21, and one battery cell 100 (second battery cell) selected from the second stack 10B is a battery cell located on the same side (the endmost end in the Y-axis direction, adjacent in the X-axis direction) as one battery cell 100 (first battery cell) selected from the first stack 10A. In addition, the position where the busbar 500 is provided is not limited to the position shown in the figure.

[0058] Below, refer to Figures 5 to 8 , the specific structure of the busbar is explained. Figure 5 is a stereogram of busbar 320 (first busbar, second busbar), Figure 6 is a plan view of busbar 320, Figure 7 is a plan view of the busbar 320 in other ways, Figure 8 This is a three-dimensional diagram of busbar 500 (third busbar). Fig. 9 is a plan view of the busbar 500 .

[0059] Reference Figure 5 and Figure 6 , the specific shape of the busbar 320 is described. As described above, the busbar 320 is composed of a conductor (typically a metal member). The busbar 320 electrically connects the electrode terminals 110 of multiple battery cells 100 to each other. The busbar 320 has a substantially U-shaped shape when viewed from above, including a root portion 321 extending in the Y-axis direction and a first connecting portion 322 and a second connecting portion 323 protruding from the root portion 321 in the X-axis direction. The connecting portions 322 are respectively connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0060] A through hole 323h2 is provided on the connecting portion 323 side of the root portion 321. The root portion 321 and the second connecting portion 323 are provided at different heights in the Z-axis direction. Figure 5 In the embodiment, the root portion 321 is arranged to be higher than the connecting portion 322 .

[0061] Each of the connection parts 322 is formed of a strip-shaped plate having two parallel sides 322p extending in the X-axis direction. The through hole 322h1 provided in the connection part 322 is used for welding and joining with the electrode terminal 110. Figure 6As shown, the through hole 322h1 is a hexagonal shape formed by sequentially connecting the first corner E1, the second corner E2, the third corner E3, the fourth corner E4, the fifth corner E5 and the sixth corner E6. In addition, the imaginary straight line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the two side edges 322p.

[0062] Here, the corners do not necessarily need to be acute corners, and may be slightly rounded corners. In the present embodiment, the hexagonal shape is a shape that is line-symmetrical about the imaginary straight line L1, but, for example, as shown in FIG. 7 , the through hole 322h1 may also be a regular hexagonal shape in which the lengths of the sides between the corners are equal.

[0063] Even if the through hole 322h1 is deformed by welding to the electrode terminal 110 of the battery cell 100, the first corner E1 and the fourth corner E4 need to remain for reasons described below. Therefore, the first corner E1 and the fourth corner E4 are preferably spaced apart.

[0064] Below, refer to Figure 8 and Fig. 9 , the specific shape of the busbar 500 is described. The busbar 500 is composed of a conductor (typically a metal member) similarly to the busbar 320. As described above, the busbar 500 is provided to bridge between the first busbar module 30A and the second busbar module 30B, and electrically connects one battery cell 100 (first battery cell) selected from the first stack 10A and one battery cell 100 (second battery cell) selected from the second stack 10B.

[0065] The busbar 500 includes: a first region 510 electrically connected to the battery cell 100 (first battery cell) and located on the first busbar module 30A side; a second region 520 electrically connected to the battery cell 100 (second battery cell) and located on the second busbar module 30B side; and a third region 530 arranged at a position bridging the first busbar module 30A and the second busbar module 30B and connecting the first region 510 with the second region 520.

[0066] Furthermore, when observing the busbar 500 along the Z-axis direction (third direction) which is orthogonal to the Y-axis direction (first direction) and the X-axis direction (second direction), the third region 530 has a convex shape located above the first region 510 and the second region 520 .

[0067] Specifically, the third region 530 includes a top surface portion 500 a and a pair of first side wall portions 500 b extending downward on both sides of the top surface portion 500 a in the X-axis direction.

[0068] The first region 510 includes a bottom portion 500c, a second side wall portion 500d extending upward from one end of the bottom portion 500c, and an extension portion 500e extending from the upper end of the second side wall portion 500d in parallel with the bottom portion 500c. The bottom portion 500c is provided with a hexagonal through hole 500h1, and the extension portion 500e is provided with a circular through hole 500h2.

[0069] The second region 520 has, similarly to the first region 510, a bottom portion 500c, a second side wall portion 500d extending upward from one end of the bottom portion 500c, and an extension portion 500e extending from the upper end of the second side wall portion 500d in parallel with the bottom portion 500c. The bottom portion 500c is provided with a hexagonal through hole 500h1, and the extension portion 500e is provided with a circular through hole 500h2.

[0070] The through hole 500h1 is used when the electrode terminal 110 of the battery cell 100 is welded to the bottom surface portion 500c. The through hole 500h2 is used to fasten the wiring 410 with the screw 420.

[0071] The bus bar 500 in the present embodiment is provided with an extension portion 500 e at a height position between the bottom surface portion 500 c and the top surface portion 500 a when viewed in the Z-axis direction (third direction).

[0072] The first region 510, the second region 520, and the third region 530 are formed integrally and are composed of a strip-shaped plate portion having two parallel sides 500p extending in the X-axis direction. The through hole 500h1 provided in the bottom portion 500c is used for welding and joining with the electrode terminal 110. Fig. 9 As shown, the through hole 500h1 is a hexagonal shape formed by sequentially connecting the first corner E1, the second corner E2, the third corner E3, the fourth corner E4, the fifth corner E5 and the sixth corner E6. In addition, the imaginary straight line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the two side edges 500p.

[0073] Here, the corners do not necessarily need to be acute angles, but may be slightly rounded corners. In this embodiment, the hexagonal shape is a shape that is line-symmetrical about the imaginary straight line L1, but for example, the through hole 500h1 may be a regular hexagonal shape with equal lengths of sides between the corners.

[0074] Even if the through hole 500h1 is deformed by welding to the electrode terminal 110 of the battery cell 100, the first corner E1 and the fourth corner E4 need to remain for reasons described below. Therefore, the first corner E1 and the fourth corner E4 are preferably spaced apart.

[0075] Below, refer to Fig.10 , the effects of the through hole 322h1 provided in the bus bar 320 and the through hole 500h1 provided in the bus bar 500 are described. Fig.10 It is a partially enlarged plan view of the busbar 320 and the busbar 500 arranged in the second busbar module 30B.

[0076] The through hole 322h1 and the through hole 500h1 are arranged in the Y-axis direction. Although not shown in the figure, the electrode terminal 110 of the battery cell 100 and the connecting portion 322 are electrically connected by welding via the through hole 322h1. Similarly, the electrode terminal 110 of the battery cell 100 and the bottom portion 500c are electrically connected by welding via the through hole 500h1. After welding, the shapes of the through hole 322h1 and the through hole 500h1 are deformed, and the hexagonal shape is often no longer recognizable.

[0077] Here, during welding, the welding is performed in such a way that the first corner E1 and the fourth corner E4 are not damaged by welding in the hexagonal hole. Thus, it is possible to obtain an imaginary straight line L1 that can identify the first corner E1 and the fourth corner E4 through image recognition after welding. As a result, in the case of the busbar 320, the position of the welding part can be inferred based on the position of the two side edges 322p arranged in parallel and the position of the imaginary straight line L1, and image recognition of the welding part can be performed. Similarly, in the case of the busbar 500, the position of the welding part can be inferred based on the position of the two side edges 500p arranged in parallel and the position of the imaginary straight line L1, and image recognition of the welding part can be performed.

[0078] As described above, according to the busbar of this embodiment, the welding position between the busbar and the battery cell can be identified by image analysis regardless of the shape of the busbar. In addition, by setting the through hole for the welding position to a hexagonal shape, even if there are many positions to be confirmed by image recognition, the confirmation work can be made efficient by using image processing technology.

[0079] (Other busbars)

[0080] Reference Fig.12 and Fig.13 , another embodiment of a bus bar 600 provided with hexagonal through holes for welding will be described. Fig.11 is a partial enlarged view of the third busbar module 30C of the busbar 600 using other methods, Fig.12 This is a three-dimensional diagram of a busbar 600 of another type. Fig.13 It is a plan view of a busbar 600 in another embodiment.

[0081] The busbar 600 is connected to the wiring 410 at one end by a screw 420, and is fastened to an external plate terminal 700 at the other end by a bolt B2. The busbar 600 has a concave shape in the axial direction, and has: a bottom portion 600a; a pair of side wall portions 600b extending upward from both sides of the bottom portion 600a; and a pair of extension portions 600c extending from the upper ends of the pair of side wall portions 600b in the X-axis direction. An enlarged portion 600d extending in the Y-axis direction is provided on one of the extension portions 600c.

[0082] A hexagonal through hole 600h1 is provided in the bottom portion 600a, and a circular through hole 600h2 is provided in the extending portion 600c.

[0083] The through hole 600h1 is used when welding and joining the electrode terminal 110 of the battery cell 100 to the bottom surface portion 600a. The through hole 600h2 is used for fastening the wiring 410 with the screw 420 or fastening the plate terminal 700 with the bolt B2.

[0084] The busbar 600 is formed integrally and is composed of a strip-shaped plate portion having two parallel sides 600p extending in the X-axis direction. The through hole 600h1 provided in the bottom portion 600a is used for welding and joining with the electrode terminal 110. Fig.13 As shown, the through hole 600h1 is a hexagonal shape formed by sequentially connecting the first corner E1, the second corner E2, the third corner E3, the fourth corner E4, the fifth corner E5 and the sixth corner E6. In addition, the imaginary straight line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the two side edges 600p.

[0085] Here, the corners do not necessarily need to be acute corners, and may be slightly rounded corners. In the present embodiment, the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary straight line L1, but for example Figure 7 Similar to the busbar shown, the through hole 600h1 may be in the form of a regular hexagon in which the lengths of the sides between the corners are equal.

[0086] The bus bar 600 having this structure can also obtain the same effects as those of the bus bar 320 and the bus bar 500 described above.

[0087] The above-mentioned busbar configuration in which the hexagonal through-holes for welding are provided is merely an example and is not limited to the above-mentioned busbar configuration, and the hexagonal through-holes for welding can be applied to various busbar configurations.

[0088] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery pack, wherein: The battery pack has: A first stack including a plurality of first battery cells arranged in a first direction; a second stacked body adjacent to the first stacked body in a second direction orthogonal to the first direction, and including a plurality of second battery cells arranged in the first direction; a housing having side walls facing the first stack and the second stack from the first direction and accommodating the first stack and the second stack; a first bus bar and a first bus bar module, wherein the first bus bar electrically connects the plurality of the first battery cells, and the first bus bar module receives the first bus bar and is disposed on the first stack; a second bus bar and a second bus bar module, wherein the second bus bar electrically connects the plurality of second battery cells, and the second bus bar module accommodates the second bus bar and is disposed on the second stack; and a third bus bar configured to bridge the first bus bar module and the second bus bar module along the second direction, and electrically connect one of the first battery cells selected from the first stack with one of the second battery cells selected from the second stack; The first battery cell and the second battery cell each include an electrode terminal, The first busbar, the second busbar and the third busbar each include a strip-shaped plate portion having two parallel sides extending in the second direction, The plate portion has a through hole for welding and joining with the electrode terminal. The through hole is a hexagonal shape formed by sequentially connecting the first corner, the second corner, the third corner, the fourth corner, the fifth corner and the sixth corner, and an imaginary straight line connecting the first corner and the fourth corner is perpendicular to the two side edges.

2. The battery pack according to claim 1, wherein: The hexagonal shape is a regular hexagon.

3. The battery pack according to claim 1, wherein: The hexagonal shape is a shape that is line-symmetrical with respect to the imaginary straight line.

4. The battery pack according to claim 1, wherein: The third busbar comprises: A first region, which is electrically connected to the first battery cell and is located on the first busbar module side; a second region, which is electrically connected to the second battery cell and is located on the second bus bar module side; and The third area is arranged at a position bridging the first busbar module and the second busbar module, connecting the first area with the second area. The through holes are provided in the first region and the second region.

5. A busbar, a plurality of battery cells including electrode terminals arranged in an array, the busbar being used to electrically connect the electrode terminals of adjacent battery cells, wherein: The busbar includes a strip-shaped plate portion having two parallel sides extending in one direction, The plate portion has a through hole for welding and joining with the electrode terminal. The through hole is a hexagonal shape formed by sequentially connecting the first corner, the second corner, the third corner, the fourth corner, the fifth corner and the sixth corner, and an imaginary straight line connecting the first corner and the fourth corner is perpendicular to the two side edges.

6. The busbar according to claim 5, wherein: The hexagonal shape is a regular hexagon.

7. The busbar according to claim 5, wherein: The hexagonal shape is a shape that is line-symmetrical with respect to the imaginary straight line.

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