Battery packs and bus bars

Abstract

To provide a battery pack having configuration that enables a welded portion between a bus bar and a battery cell to be recognized by image analysis, regardless of the shape of the bus bar, and to provide the bus bar.SOLUTION: Each of a first battery cell and a second battery cell that constitutes a battery pack, includes an electrode terminal, and a first bus bar 320 includes a band-shaped connecting portion 322 having parallel side edges 322p extending in the X-axis direction, and has a through-hole 322h1 used for welding the connecting portion 322 to the electrode terminal, and the through-hole 322h1 has a hexagonal shape formed by connecting a first corner E1, a second corner E2, a third corner E3, a fourth corner E4, a fifth corner E5, and a sixth corner E6 in order, and a virtual straight line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the side edges 322p.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present technology relates to a battery pack and a bus bar. [Background technology]

[0002] Japanese Patent Publication No. 2022-013957 (Patent Document 1) discloses an invention of a bus bar and a battery module, in which a circular through hole is provided in the bus bar, and a notch hole extending outward is provided at a position offset from the center in this through hole.

[0003] Patent Publication No. 2021-163629 (Patent Document 2) discloses an invention relating to a power supply unit, a vehicle equipped with the same, and a storage device, and discloses a configuration in which a through hole is provided in the center of an elliptical thin-walled area of ​​the bus bar.

[0004] Japanese Patent Application Laid-Open Publication No. 2019-160727 (Patent Document 3) discloses an invention relating to an energy storage device, in which a bus bar has a circular through hole, and this through hole has a notch hole extending outward from the center position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-013957 [Patent Document 2] Japanese Patent Publication No. 2021-163629 [Patent Document 3] Japanese Patent Application Publication No. 2019-160727 Summary of the Invention [Problem to be solved by the invention]

[0006] Development is underway on a cell-to-pack structure in which a stack containing multiple battery cells is housed directly in a case, without using end plates and bind bars (module structure) that constrain multiple battery cells.

[0007] In a structure in which a busbar module, which is formed by housing multiple busbars in a plate member and modularizing the busbar module, is mounted on a stack of multiple battery cells, the busbars are used to connect adjacent battery cells within the same stack, including the multiple battery cells.

[0008] To electrically connect the busbar to the battery cells, welding is performed with the battery cell electrodes exposed through through-holes in the busbar. After welding, image analysis of the welded area is used to check whether the welding was performed properly.

[0009] The shape of a busbar varies depending on where it is used, but if there are three sides of the busbar around the through hole, even if the through hole becomes irregular after welding, it is possible to estimate and detect the position of the weld from the three edge positions based on the edges (corners of the plate thickness) of each of the three sides.As a result, it is possible to confirm whether the welding was performed properly using image analysis.

[0010] On the other hand, if the busbar has only two sides around the through hole, instead of three, it is not possible to estimate and detect the position of the weld from the positions of the two edges, making it impossible to verify whether the welding was performed properly through image analysis.

[0011] An object of the present technology is to provide a battery pack and a bus bar having a configuration that allows the welded portions between the bus bar and the battery cells to be recognized by image analysis, regardless of the shape of the bus bar. [Means for solving the problem]

[0012] The present technology provides the following battery packs and bus bars: [1] 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 perpendicular to the first direction and including a plurality of second battery cells arranged in the first direction; a case having side walls facing the first stack and the second stack in the first direction and housing the first stack and the second stack; a first bus bar electrically connecting the plurality of first battery cells, a first bus bar module housing the first bus bar and disposed on the first stack; a second bus bar electrically connecting the plurality of second battery cells, a second bus bar module housing the second bus bar and disposed on the second stack; and a first bus bar module and a second bus bar module disposed on the second stack along the second direction. and a third bus bar arranged to bridge between the first stack and the second stack and electrically connects one of the first battery cells selected from the first stack and one of the second battery cells selected from the second stack, wherein the first battery cell and the second battery cell each include an electrode terminal, the first bus bar, the second bus bar, and the third bus bar each include a strip-shaped plate portion having parallel side edges extending in the second direction, the plate portion has a through hole used for welding to the electrode terminal, the through hole has a hexagonal shape formed by connecting a first corner, a second corner, a third corner, a fourth corner, a fifth corner, and a sixth corner in that order, and an imaginary line connecting the first corner and the fourth corner is perpendicular to the side edges.

[0013] [2] The battery pack according to [1], wherein the hexagonal shape is a regular hexagon. [3] The battery pack according to [1] or [2], wherein the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary line.

[0014] [4] The battery pack according to any one of [1] to [3], wherein the third busbar includes: a first region electrically connected to the first battery cell and located on the first busbar module side; a second region electrically connected to the second battery cell and located on the second busbar module side; and a third region located at a position bridging between the first busbar module and the second busbar module and communicating between the first region and the second region; and the through hole is provided in the first region and the second region.

[0015] [5] A busbar for electrically connecting the electrode terminals of adjacent battery cells arranged with a plurality of battery cells each including an electrode terminal, the busbar including a band-shaped plate portion having parallel opposite sides extending in one direction, the plate portion having a through hole used for welding to the electrode terminal, the through hole having a hexagonal shape formed by connecting a first corner, a second corner, a third corner, a fourth corner, a fifth corner, and a sixth corner in order, and an imaginary line connecting the first corner and the fourth corner perpendicular to the opposite sides.

[0016] [6] The busbar according to [5], wherein the hexagonal shape is a regular hexagon. [7] The busbar according to [5] or [6], wherein the hexagonal shape is a shape that is line-symmetrical with respect to the virtual straight line. [Effects of the Invention]

[0017] According to the present technology, it is possible to provide a battery pack bus bar having a configuration that allows the welded portions between the bus bar and the battery cells to be recognized by image analysis, regardless of the shape of the bus bar. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is an exploded perspective view of the battery pack according to the embodiment. [Figure 2] FIG. 2 is a perspective view of a battery cell according to an embodiment. [Figure 3]FIG. 2 is a top view of a plate member of the bus bar module according to the embodiment. [Figure 4] FIG. 2 is a perspective view illustrating a structure around a bus bar of the bus bar module according to the embodiment. [Figure 5] FIG. 2 is a perspective view of a first bus bar and a second bus bar according to the embodiment. [Figure 6] FIG. 2 is a plan view of a first bus bar and a second bus bar according to the embodiment. [Figure 7] 10 is a plan view of a first bus bar and a second bus bar according to another embodiment. FIG. [Figure 8] FIG. 4 is a perspective view of a third bus bar according to the embodiment. [Figure 9] FIG. 10 is a plan view of a third bus bar according to the embodiment. [Figure 10] FIG. 2 is a partially enlarged plan view of a bus bar arranged in the bus bar module according to the embodiment. [Figure 11] FIG. 10 is a partially enlarged view of a third bus bar module employing bus bars according to another embodiment. [Figure 12] FIG. 10 is a perspective view of a bus bar according to another embodiment of the present invention. [Figure 13] FIG. 10 is a plan view of a bus bar according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0020] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects mentioned in the present embodiments.

[0021] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0022] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0023] In this specification, "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "battery packs" can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "battery cells" is not limited to in-vehicle use.

[0024] Fig. 1 is an exploded perspective view of a battery pack 1. As shown in Fig. 1, the battery pack 1 includes a stack 10 including a plurality of battery cells 100 (see Fig. 2) arranged in the Y-axis direction (first direction), a case 20 that houses the stack 10, and a bus bar module 30 arranged on the stack 10.

[0025] The laminate 10 includes a first laminate 10A, a second laminate 10B, and a third laminate 10C. What is , 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.

[0026] The case 20 has side walls 21 that face the first stack 10A, the second stack 10B, and the third stack 10C in the Y-axis direction. The side walls 21 directly support 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 according to this embodiment employs a cell-to-pack structure in which the stack 10, which includes a plurality of battery cells 100, is housed directly in the case.

[0027] The busbar module 30 includes a first busbar module 30A arranged on the first laminate 10A, a second busbar module 30B arranged on the second laminate 10B, and a third busbar module 30C arranged on the third laminate 10C. In the present embodiment, the first busbar module 30A, the second busbar module 30B, and the third busbar module 30C have the same shape, but may have different shapes.

[0028] 2 is a perspective view showing the configuration of the battery cells 100 that make up the first stack 10A, the second stack 10B, and the third stack 10C. As shown in FIG. 2, the battery cells 100 have a rectangular shape. The battery cells 100 have electrode terminals 110, a housing 120, and a gas release valve 130.

[0029] The electrode terminals 110 are formed on the housing 120. The electrode terminals 110 include a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 aligned along an X-axis direction (second direction) perpendicular to a Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are spaced apart from each other in the X-axis direction.

[0030] The housing 120 has a substantially rectangular parallelepiped shape. An electrode assembly and an electrolyte (not shown) are housed in the housing 120. The housing 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.

[0031] The upper surface 121 is a plane perpendicular to the Z-axis direction. The electrode terminals 110 are disposed 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).

[0032] Each of the first side surface 123 and the second side surface 124 is made of a plane perpendicular 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 housing 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 when viewed in the Y-axis direction, with the X-axis direction being the longitudinal direction and the Z-axis direction being the lateral direction.

[0033] The multiple 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. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0034] Gas exhaust valve 130 is provided on top surface 121. When the internal pressure of housing 120 rises to a predetermined value or higher due to gas generated inside housing 120, gas exhaust valve 130 opens and exhausts the gas to the outside of housing 120.

[0035] Next, the basic configuration of the busbar module 30 will be described with reference to Figures 3 and 4. Figure 3 is a top view of a plate member 310 included in the busbar module 30, and Figure 4 is a perspective view showing the structure around the busbars in the busbar module.

[0036] The first busbar module 30A, the second busbar module 30B, and the third busbar module 30C each include a plate member 310 shown in Fig. 3. As shown in Fig. 3, 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, through-holes 313 formed at positions corresponding to the gas release valves 130 of the battery cells 100, and wall portions 314 that divide the space on the plate member 310 into multiple sections.

[0037] As shown in FIG. 4 , in the first busbar module 30A, busbars 320 (first busbars) are housed in each space partitioned by the wall portions 314. The busbars 320 (first busbars) are made of a conductor (typically, a metal member). The busbars 320 (first busbars) electrically connect the electrode terminals 110 of the multiple battery cells 100 to one another. The busbars 320 (first busbars) include a root portion 321 extending in the Y-axis direction and a pair of connection portions 322 (first connection portion and second connection portion) protruding from the root portion 321 in the X-axis direction. The connection portions 322 are each connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0038] Bus bar 320 is connected to wiring 410. Wiring 410 is fixed to bus bar 320 (first bus bar) by screws 420. The configuration of wiring 410 and screws 420 is not limited to that shown in Fig. 4, and the wiring may be formed by, for example, a flexible wiring board.

[0039] The electrode terminal 110 of the battery cell 100 and the bus bar 320 (first bus bar) are welded together after being positioned relative to each other in the X-axis direction and the Y-axis direction. By performing this positioning accurately, the welding process between the electrode terminal 110 and the bus bar 320 (first bus bar) can be carried out with high efficiency and quality. For the welding, a through hole 322h1 provided in the bus bar 320 is used.

[0040] 4, in the second busbar module 30B, similarly to the first busbar module 30A, busbars 320 (second busbars) are housed in the respective spaces partitioned by the wall portions 314. The configuration and function of the busbars 320 (second busbars) are the same as those of the busbars 320 (first busbars).

[0041] 4, a bus bar 500 (third bus bar) is provided along the X-axis direction so as to bridge between the first bus bar module 30A and the second bus bar 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. Although not shown in the figure, a bus bar 500 is also provided between the second bus bar module 30B and the third bus bar module 30C.

[0042] Bus bar 500 is connected to wiring 410. Wiring 410 is fixed to bus bar 500 by screws 420. The configuration of wiring 410 and screws 420 is not limited to that shown in Fig. 4, and the wiring may be formed by, for example, a flexible wiring board.

[0043] In this embodiment, one battery cell 100 (first battery cell) selected from the first stack 10A is the battery cell located at the end (the extreme 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 the battery cell located on the same side (the extreme end in the Y-axis direction and adjacent in the X-axis direction) as the one battery cell 100 (first battery cell) selected from the first stack 10A. Note that the position at which the bus bar 500 is provided is not limited to the position shown in the figure.

[0044] Next, specific configurations of the busbars will be described with reference to Fig. 5 to Fig. 8. Fig. 5 is a perspective view of busbar 320 (first busbar, second busbar), Fig. 6 is a plan view of busbar 320, Fig. 7 is a plan view of busbar 320 in another embodiment, Fig. 8 is a perspective view of busbar 500 (third busbar), and Fig. 9 is a plan view of busbar 500.

[0045] 5 and 6, the specific shape of the busbar 320 will be described. As described above, the busbar 320 is made 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 configuration in a plan view, and includes a root portion 321 extending in the Y-axis direction, and connection portions 322 (first connection portion) and 323 (second connection portion) protruding from the root portion 321 in the X-axis direction. The connection portions 322 are each connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0046] A through-hole 323h2 is provided on the connecting portion 323 side of the base portion 321. The base portion 321 and the connecting portion 322 are provided to have different heights in the Z-axis direction. In FIG. 5, the base portion 321 is provided to be higher than the connecting portion 322.

[0047] The connecting portion 322 is composed of a strip-shaped plate portion having parallel side edges 322p extending in the X-axis direction. A through hole 322h1 provided in the connecting portion 322 is used for welding to the electrode terminal 110. As shown in FIG. 6, the through hole 322h1 has a hexagonal shape formed by connecting a first corner E1, a second corner E2, a third corner E3, a fourth corner E4, a fifth corner E5, and a sixth corner E6 in this order. Furthermore, an imaginary line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the side edges 322p.

[0048] Here, the corners do not necessarily have to be acute corners, and may be slightly rounded corners. In this embodiment, the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary line L1, but for example, as shown in Fig. 7, the shape of the through hole 322h1 may be a regular hexagon with sides of equal lengths between the corners.

[0049] Furthermore, even if the shape of the through hole 322h1 becomes distorted due to the welding connection with the electrode terminal 110 of the battery cell 100, the first corner E1 and the fourth corner E4 must remain for reasons described below, so it is preferable that the distance between the first corner E1 and the fourth corner E4 is large.

[0050] Next, the specific shape of the busbar 500 will be described with reference to Figures 8 and 9. The busbar 500 is made of a conductor (typically, a metal member) like the busbar 320. As described above, the busbar 500 is provided so as 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.

[0051] This 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 located at a position bridging the gap between the first busbar module 30A and the second busbar module 30B and connecting the first region 510 and the second region 520.

[0052] Furthermore, when this busbar 500 is viewed along the Z-axis direction (third direction) perpendicular 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.

[0053] Specifically, the third region 530 has a top surface portion 500a and a pair of first sidewall portions 500b extending downward on both sides of the top surface portion 500a in the X-axis direction.

[0054] The first region 510 has a bottom surface 500c, a second side wall 500d extending upward from one end of the bottom surface 500c, and an extension 500e extending parallel to the bottom surface 500c from the upper end of the second side wall 500d. A hexagonal through-hole 500h1 is provided in the bottom surface 500c, and a circular through-hole 500h2 is provided in the extension 500e.

[0055] Similar to the first region 510, the second region 520 has a bottom surface 500c, a second side wall 500d extending upward from one end of the bottom surface 500c, and an extension 500e extending parallel to the bottom surface 500c from the upper end of the second side wall 500d. A hexagonal through-hole 500h1 is provided in the bottom surface 500c, and a circular through-hole 500h2 is provided in the extension 500e.

[0056] The through-holes 500h1 are used when welding the electrode terminals 110 of the battery cells 100 to the bottom surface portion 500c. The through-holes 500h2 are used when fastening the wiring 410 using screws 420.

[0057] When viewed along the Z-axis direction (third direction), bus bar 500 in this embodiment has extension portion 500e provided at a height position between bottom surface portion 500c and top surface portion 500a.

[0058] The first region 510, the second region 520, and the third region 530 are integrally formed and comprise a band-shaped plate portion having parallel side edges 500p extending in the X-axis direction. A through hole 500h1 provided in the bottom surface portion 500c is used for welding to the electrode terminal 110. As shown in FIG. 9, the through hole 500h1 has a hexagonal shape formed by sequentially connecting a first corner E1, a second corner E2, a third corner E3, a fourth corner E4, a fifth corner E5, and a sixth corner E6. Furthermore, an imaginary line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the side edges 500p.

[0059] Here, the corners do not necessarily have to be acute corners, and may be somewhat rounded corners. In this embodiment, the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary line L1, but for example, as shown in Fig. 9, the shape of the through hole 500h1 may be a regular hexagon with sides of equal lengths between the corners.

[0060] Furthermore, even if the shape of the through hole 500h1 becomes distorted due to the welding connection with the electrode terminal 110 of the battery cell 100, the first corner E1 and the fourth corner E4 must remain for reasons described below, so it is preferable that the distance between the first corner E1 and the fourth corner E4 is large.

[0061] Next, the effects of through hole 322h1 provided in bus bar 320 and through hole 500h1 provided in bus bar 500 will be described with reference to Fig. 10. Fig. 10 is a partially enlarged plan view of bus bar 320 and bus bar 500 arranged in second bus bar module 30B.

[0062] The through holes 322h1 and 500h1 are aligned in the Y-axis direction. Although not shown in the figure, the electrode terminals 110 of the battery cell 100 are electrically connected to the connection portions 322 via the through holes 322h1 by welding. Similarly, the electrode terminals 110 of the battery cell 100 are electrically connected to the bottom surface portion 500c via the through holes 500h1 by welding. After welding, the shapes of the through holes 322h1 and 500h1 become distorted, and the hexagonal shape is often no longer recognizable.

[0063] Here, welding is performed so that the first corner E1 and the fourth corner E4 of the hexagonal hole are not crushed by welding. As a result, image recognition after welding can obtain an imaginary straight line L1 that allows the first corner E1 and the fourth corner E4 to be recognized. As a result, for busbar 320, the positions of the welded points can be estimated from the positions of both parallel sides 322p and the imaginary straight line L1, and image recognition of the welded points can be performed. Similarly, for busbar 500, the positions of the welded points can be estimated from the positions of both parallel sides 500p and the imaginary straight line L1, and image recognition of the welded points can be performed.

[0064] As described above, the busbar according to this embodiment enables the welded portions between the busbar and the battery cells to be recognized by image analysis, regardless of the shape of the busbar. Furthermore, by making the through holes used for the welded portions hexagonal in this way, it is possible to use image processing technology to improve the efficiency of the checking work, even when there are many locations where the welded state needs to be checked using image recognition.

[0065] (Other types of busbars) Another embodiment of a busbar 600 having hexagonal through holes for use in welding will be described with reference to Figures 12 and 13. Figure 11 is a partially enlarged view of a third busbar module 30C employing another embodiment of a busbar 600, Figure 12 is a perspective view of the another embodiment of a busbar 600, and Figure 13 is a plan view of the another embodiment of a busbar 600.

[0066] For example, one end of bus bar 600 is connected to wiring 410 with screw 420, and the other end is fastened to an external plate terminal 700 with bolt B2. Bus bar 600 has a concave shape in the Z-axis direction and has a bottom surface 600a, a pair of side wall portions 600b extending upward from both sides of bottom surface 600a, and a pair of extending portions 600c extending in the X-axis direction from the upper ends of pair of side wall portions 600b. One of extending portions 600c is provided with an enlarged portion 600d extending in the Y-axis direction.

[0067] The bottom surface portion 600a is provided with a hexagonal through-hole 600h1, and the extending portion 600c is provided with a circular through-hole 600h2.

[0068] The through-hole 600h1 is used when welding the electrode terminal 110 of the battery cell 100 to the bottom surface portion 600a. The through-hole 600h2 is used to fasten the wiring 410 using the screw 420 or the plate terminal 700 using the bolt B2.

[0069] The bus bar 600 is composed of a strip-shaped plate portion formed integrally and having parallel side edges 600p extending in the X-axis direction. A through hole 600h1 provided in the bottom surface portion 600a is used for welding to the electrode terminal 110. As shown in FIG. 13 , the through hole 600h1 has a hexagonal shape formed by sequentially connecting a first corner E1, a second corner E2, a third corner E3, a fourth corner E4, a fifth corner E5, and a sixth corner E6. Furthermore, an imaginary line L1 connecting the first corner E1 and the fourth corner E4 is perpendicular to the side edges 600p.

[0070] Here, the corners do not necessarily have to be acute corners, and may be slightly rounded corners. In this embodiment, the hexagonal shape is a shape that is line-symmetrical with respect to the imaginary line L1, but for example, like the bus bar shown in FIG. 7, the shape of the through hole 600h1 may be a regular hexagon with sides of equal length between the corners.

[0071] Bus bar 600 having this configuration can also achieve the same effects as bus bar 320 and bus bar 500 described above.

[0072] The above-described bus bar shape having a hexagonal through hole used for welding is merely one example, and is not limited to the above-described bus bar shape. The hexagonal through hole used for welding can be applied to various bus bar shapes.

[0073] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0074] 1 battery pack, 10 laminate, 10A first laminate, 10B second laminate, 10C third laminate, 20 case, 21 side wall, 30 busbar module, 30A first busbar module, 30B second busbar module, 30C third busbar module, 100 battery cell, 110 electrode terminal, 111 positive terminal, 112 negative terminal, 120 housing, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130 gas release valve, 310 plate member, 311, 312 end surface, 313, 322h1, 323h2, 500h1, 500h2, 600h1, 600h2 through hole, 314 wall portion, 320, 500, 600 busbar, 321 Base part, 32 2 connections connection portion, 322p, 500p, 600p both sides, 410 wiring, 420 screw, 500a top surface portion, 500b first side wall portion, 500c, 600a bottom surface portion, 500d second side wall portion, 500e, 600c extension portion, 510 first region, 520 second region, 530 third region, 600b side wall portion, 600d enlarged portion, 700 plate terminal, E1 first corner portion, E2 second corner portion, E3 third corner portion, E4 fourth corner portion, E5 fifth corner portion, E6 sixth corner portion, L1 imaginary straight line.

Claims

1. 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 perpendicular to the first direction and including a plurality of second battery cells aligned in the first direction; a case having side walls facing the first stack and the second stack in the first direction, the case housing the first stack and the second stack; a first bus bar that electrically connects the plurality of first battery cells, and a first bus bar module that houses the first bus bar and is disposed on the first stack; a second bus bar that electrically connects the plurality of second battery cells, and a second bus bar module that houses the second bus bar and is disposed on the second stack; a third bus bar that is provided along the second direction so as to bridge between the first bus bar module and the second bus bar module, and that electrically connects one of the first battery cells selected from the first stack and one of the second battery cells selected from the second stack; and Equipped with each of the first battery cell and the second battery cell includes an electrode terminal; each of the first bus bar, the second bus bar, and the third bus bar includes a strip-shaped plate portion having parallel opposite sides extending in the second direction; the plate portion has a through hole used for welding to the electrode terminal, the through hole has a hexagonal shape formed by connecting a first corner, a second corner, a third corner, a fourth corner, a fifth corner, and a sixth corner in order, and an imaginary line connecting the first corner and the fourth corner is perpendicular to both side edges; the first corner portion and the fourth corner portion are not used when joining the electrode terminal by welding; The first corner, the fourth corner, and the both side edges are used in image recognition after the welding joint to estimate the position of the welding point based on a relationship in which the virtual line connecting the first corner and the fourth corner edge is perpendicular to the both side edges. Battery pack.

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

3. The hexagonal shape is a shape that is line-symmetric with respect to the virtual straight line. The battery pack according to claim 1 .

4. The third bus bar is 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; a third region provided at a position bridging the gap between the first bus bar module and the second bus bar module, the third region communicating with the first region and the second region, The through-hole is provided in the first region and the second region. The battery pack according to claim 1 .

5. A bus bar is provided for electrically connecting a plurality of battery cells, each including an electrode terminal, adjacent battery cells to each other, the bus bar comprising: the bus bar includes a strip-shaped plate portion having parallel opposite sides extending in one direction, the plate portion has a through hole used for welding to the electrode terminal, the through hole has a hexagonal shape formed by connecting a first corner, a second corner, a third corner, a fourth corner, a fifth corner, and a sixth corner in order, and an imaginary line connecting the first corner and the fourth corner is perpendicular to both side edges; the first corner portion and the fourth corner portion are not used when joining the electrode terminal by welding; The first corner, the fourth corner, and the both side edges are used in image recognition after the welding joint to estimate the position of the welding point based on a relationship in which the virtual line connecting the first corner and the fourth corner edge is perpendicular to the both side edges. Busbar.

6. The hexagonal shape is a regular hexagon. The bus bar according to claim 5 .

7. The hexagonal shape is a shape that is line-symmetric with respect to the virtual straight line. The bus bar according to claim 5 .

Images