Battery module

Abstract

A battery module having excellent workability at the time of disassembly is provided. The battery module includes a plurality of battery cells (11) stacked in a predetermined direction and a plurality of bus bars (50) for electrically connecting the plurality of battery cells to each other. The plurality of bus bars includes a first bus bar (51) extending between a first battery cell (11d) and a second battery cell (11a) adjacent in the predetermined direction among the plurality of battery cells. The first bus bar has a first base portion (226) connected to the first battery cell, a second base portion (221) connected to the second battery cell, and a standing portion (231) having a shape standing from the first base portion and the second base portion and connecting between the first base portion and the second base portion. A fragile portion (240) is provided at a root region (236) of the standing portion.

Description

Technical Field

[0001] This invention relates to battery modules. Background Technology

[0002] For example, Japanese Patent Application Publication No. 2017-216095 discloses a battery module comprising: a battery cell stack, wherein multiple battery cells are stacked together; and a plurality of busbars connecting the positive and negative external terminals of adjacent battery cells in the stacking direction. The busbars have weak portions, which are portions with weak compressive strength relative to the stacking direction of the battery cells.

[0003] Furthermore, Japanese Patent Application Publication No. 2012-59451 discloses a busbar module comprising multiple busbars for electrically connecting adjacent energy storage elements, multiple busbar holding portions for holding the multiple busbars, and connecting portions for connecting adjacent busbar holding portions to each other. In the connecting portions, a cutout is provided such that the cross-sectional area of ​​a predetermined portion is smaller than that of a portion adjacent to the predetermined portion.

[0004] Furthermore, Japanese Patent Application Publication No. 2011-253735 discloses a battery pack comprising: a plurality of individual cells, each individual cell having a gas release valve and stacked in a predetermined direction; and a busbar module, the busbar module being used to unitize a plurality of busbars for connecting adjacent individual cells in the predetermined direction. The busbar module is provided with a vulnerable portion capable of thermal melting when gas is released from the gas release valve.

[0005] As disclosed in the aforementioned patent documents, it is known that there are battery modules having multiple battery cells stacked in one direction, in which a busbar is used as a component for electrically connecting the multiple battery cells to each other.

[0006] On the other hand, during battery module maintenance, it is sometimes necessary to disconnect the busbars from multiple battery cells and disassemble the battery module. However, in conventional battery modules, the disassembly of the battery module was not adequately considered in the connection between the busbars and multiple battery cells. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Therefore, the purpose of this invention is to solve the above-mentioned problems and provide a battery module with excellent workability during disassembly.

[0009] The battery module of the present invention includes a plurality of battery cells stacked in a predetermined direction and a plurality of busbars for electrically connecting the plurality of battery cells to each other. The plurality of busbars includes a first busbar extending between adjacent first and second battery cells in the predetermined direction. The first busbar has: a first base connected to a first battery cell; a second base connected to a second battery cell; and an upright portion having a shape that rises from the first and second bases and connects the first and second bases. A vulnerable portion is provided at the root region of the upright portion.

[0010] With this battery module configuration, the operator can detach the connection between the upright portion and the first and second base portions by breaking the weak point, thus separating the first and second battery cells. In this case, the weak point is located in the root region of the upright portion, allowing the operator to easily break it. This improves the workability during battery module disassembly.

[0011] Furthermore, it is preferable that the vulnerable part has a thin-walled structure that locally reduces the thickness of the erected part.

[0012] With this type of battery module, the operator can easily break the weak parts with thin-walled structures.

[0013] Furthermore, it is preferable to apply a constraint force along a predetermined direction to multiple battery cells. The thickness direction of the raised portion at the vulnerable part is parallel to the predetermined direction.

[0014] In this battery module configuration, to break the thin-walled, vulnerable section, the operator applies a force along the thickness direction to the upright section, with this force parallel to the direction of the constraint force applied to the multiple battery cells. Therefore, the constraint force can be used to prevent the first and second battery cells from tilting in the direction of the force applied to the upright section, allowing for more efficient force transmission to the vulnerable section. Consequently, the operator can more easily break the vulnerable section.

[0015] Alternatively, preferably, the vulnerable part is composed of a cut structure or a linear perforation structure, wherein the cut structure has a cut in the width direction of the erected part orthogonal to the erection direction and the thickness direction of the erected part, and the linear perforation structure has a cut portion that extends through the thickness direction of the erected part intermittently and linearly.

[0016] With this battery module configuration, the operator can easily break the weak parts formed by the cut structure or the linear perforation structure.

[0017] Furthermore, preferably, the vulnerable portion is disposed overlapping a predetermined plane constituting the boundary of the first battery cell and the second battery cell. The first busbar has a symmetrical shape sandwiching the predetermined plane.

[0018] In this battery module configuration, the first busbar is evenly supported on both sides of the vulnerable section by the first and second battery cells. Therefore, when the operator applies force to the upright section to break the vulnerable section, deformation of the first busbar can be suppressed, and force can be transmitted to the vulnerable section more efficiently. Consequently, the operator can more easily break the vulnerable section.

[0019] Alternatively, preferably, the erecting portion includes a dividing portion that connects the first base portion and the second base portion and can be divided from the first base portion and the second base portion with the weak portion as the boundary.

[0020] With this battery module configuration, the operator can efficiently apply force to the upright portion while holding the segmented part until the weakest part breaks. This makes it easier for the operator to break the weakest part.

[0021] In addition, preferably, the erected portion further includes a first residual portion remaining on the first base side and a second residual portion remaining on the second base side and overlapping with the first residual portion when the dividing portion is cut from the first base and the second base.

[0022] In a battery module constructed in this way, after the connection between the erected portion and the first base and the second base is severed and the first and second battery cells are separated, the disassembled battery module can sometimes be reassembled. Even in such cases, the first base and the second base can be connected by using overlapping first and second residual portions.

[0023] Preferably, the battery module comprises a plurality of battery cells arranged in a predetermined direction and subjected to a constraint force along the predetermined direction. Each battery cell has a plurality of battery cells arranged continuously in the predetermined direction and a holding member integrally holding the plurality of battery cells arranged continuously in the predetermined direction. A first busbar electrically connects adjacent battery cells in the predetermined direction to each other between a first battery cell in the plurality of battery cells and a second battery cell in the plurality of battery cells adjacent to the first battery cell in the predetermined direction. The plurality of busbars also include a second busbar in each battery cell that electrically connects adjacent battery cells in the predetermined direction to each other.

[0024] With this battery module configuration, the first and second battery cells can be easily separated.

[0025] In addition, preferably, the battery cell has an output density of 8000W / L or higher.

[0026] Based on this configuration, the workability during disassembly can be improved in battery modules with individual battery cells having a high output density of 8000W / L or more.

[0027] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description of the invention, which will be understood in conjunction with the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a perspective view illustrating a battery module according to an embodiment of the present invention.

[0029] Figure 2 It is shown Figure 1 A 3D view of the internal structure of the battery module.

[0030] Figure 3 It shows the composition Figure 1 A 3D view of the battery cell unit of the battery module.

[0031] Figure 4 It shows the composition Figure 3 A three-dimensional view of a battery cell unit in the image.

[0032] Figure 5 It is an exploded assembly diagram showing the interconnection structure of multiple battery cells.

[0033] Figure 6 This is a perspective view showing the connection structure of adjacent battery cells.

[0034] Figure 7 It is a perspective view showing the connection structure of the battery cells within a battery cell unit.

[0035] Figure 8 It is shown in Figure 6 The diagram shows the connection structure of a battery cell as observed in the direction indicated by arrow VIII.

[0036] Figure 9 It is shown Figure 6 A three-dimensional diagram showing the first morphological change of the connection structure of the battery cells.

[0037] Figure 10 It is shown in Figure 9 The diagram shows the connection structure of a battery cell as observed in the direction indicated by arrow X.

[0038] Figure 11 It is shown Figure 6 A three-dimensional diagram showing the second morphological change of the connection structure of the battery cells.

[0039] Figure 12 It is shown Figure 8 The diagram shows the first deformation example of the vulnerable part in the figure.

[0040] Figure 13 It is shown Figure 8 The diagram shows the second deformation example of the vulnerable part in the figure.

[0041] Figure 14 It is shown Figure 6 A three-dimensional view of a modified example of the first busbar in the diagram.

[0042] Figure 15 It is shown in Figure 14 The diagram shows the first busbar observed in the direction indicated by arrow XV. Detailed Implementation

[0043] Embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent components are labeled with the same reference numerals.

[0044] Figure 1 This is a perspective view illustrating a battery module according to an embodiment of the present invention. Figure 2 It is shown Figure 1 A 3D view of the internal structure of the battery module. Figure 3 It shows the composition Figure 1 A 3D view of the battery cell unit of the battery module.

[0045] Reference Figures 1 to 3 The battery module 100 is used as a power source for driving vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or battery electric vehicles (BEV).

[0046] In this specification, for the convenience of explaining the structure of the battery module 100, the axis extending parallel to the stacking direction of the plurality of battery cells 11 described later is called the "Y-axis". Based on the "Y-axis", the axis extending in the direction orthogonal to the Y-axis is called the "X-axis", and the axis extending in the direction orthogonal to the Y-axis and X-axis is called the "Z-axis". Figure 1 The upper right direction on the paper is the "+Y axis direction", and the lower left direction is the "-Y axis direction". Figure 1 The right-downward direction on the paper is the "+X-axis direction", and the left-upward direction is the "-X-axis direction". Figure 1 The top direction of the paper is the "+Z axis direction", and the bottom direction is the "-Z axis direction".

[0047] Typically, the battery module 100 is mounted in the vehicle in an orientation in which the +Z axis direction corresponds to the upward direction and the -Z axis direction corresponds to the downward direction.

[0048] First, the overall structure of the battery module 100 will be described. For example... Figure 1 As shown, the battery module 100 has multiple battery cell units 21 (21A, 21B, 21C, 21D, 21E, 21F) and constraint members 41.

[0049] Multiple battery cell units 21 are stacked in the Y-axis direction. Battery cell units 21A, 21B, 21C, 21D, 21E, and 21F are arranged in the listed order from the negative side to the positive side in the Y-axis direction. It should be noted that the number of battery cell units 21 in the battery module 100 is only required to be 2 or more, and there is no particular limitation.

[0050] Multiple battery cell units 21 are integrally held by a constraint member 41. The constraint member 41 applies a constraint force along the Y-axis to the multiple battery cell units 21. The constraint member 41 has a pair of end plates 42 (42P, 42Q), a pair of first constraint bands 43, and a second constraint band (not shown).

[0051] A pair of end plates 42 are respectively disposed on both sides of a plurality of battery cell units 21 stacked in the Y-axis direction. End plate 42P is disposed facing battery cell unit 21A in the Y-axis direction. End plate 42Q is disposed facing battery cell unit 21F in the Y-axis direction. End plates 42 are made of sheet material in the thickness direction of the Y-axis direction.

[0052] A pair of first constraint bands 43 are disposed on both sides of the plurality of battery cell units 21 in the X-axis direction. A second constraint band (not shown) is disposed in the Z-axis direction facing the plurality of battery cell units 21. The first constraint bands 43 and the second constraint band extend along the Y-axis direction. The ends of the first constraint bands 43 and the second constraint band in the Y-axis direction are connected to the end plate 42P. The ends of the first constraint bands 43 and the second constraint band in the Y-axis direction are connected to the end plate 42Q.

[0053] The first constraint band 43 has a plurality of openings 44. The plurality of openings 44 are spaced apart from each other in the Y-axis direction, and each opening 44 is formed by a through hole that passes through the first constraint band 43 in the X-axis direction. The openings 44 are arranged such that the vent 32 provided in the housing 31 described later is exposed.

[0054] The battery module 100 also has a pair of main terminals 91 (91p, 91q), wiring components 92, multiple voltage detection lines 96, and an exhaust pipe 93.

[0055] A pair of main terminals 91 are respectively disposed on both sides of a plurality of battery cell units 21 stacked in the Y-axis direction. The main terminal 91p is disposed at a position overlapping the end plate 42P when viewed from the Z-axis direction. The main terminal 91q is disposed at a position overlapping the end plate 42Q when viewed from the Z-axis direction. The main terminals 91 are terminals used to connect the battery module 100 to external wiring such as cables disposed outside the battery module 100.

[0056] Wiring member 92 is positioned facing multiple battery cell units 21 in the Z-axis direction. The wiring member 92 sandwiches the multiple battery cell units 21 and is arranged on the opposite side of the second constraint band (not shown). The wiring member 92 extends in the Y-axis direction through the central portion of the battery cell unit 21 in the X-axis direction. The wiring member 92 is, for example, made of a flexible printed circuit board. Multiple voltage detection lines 96 extend from the wiring member 92 and are respectively connected to multiple busbars 50 described later.

[0057] The exhaust duct 93 extends in the Y-axis direction. When viewed from the Z-axis direction, the exhaust duct 93 extends at a position overlapping with the wiring component 92. The exhaust duct 93 is disposed in the Z-axis direction between the plurality of battery cell units 21 and the wiring component 92.

[0058] like Figure 2 and Figure 3 As shown, the battery cell unit 21 has a plurality of battery cells 11 and a holding member 30.

[0059] Each battery cell unit 21 has four battery cells 11 (11a, 11b, 11c, 11d). Each battery cell unit 21 has an even number of battery cells 11. It should be noted that the number of battery cells 11 in each battery cell unit 21 only needs to be two or more; there is no particular limitation. The number of battery cells 11 can also be odd.

[0060] In each of the battery cell units 21—21A, 21B, 21C, 21D, 21E, and 21F—multiple battery cells 11 are arranged continuously along the Y-axis. Battery cells 11a, 11b, 11c, and 11d are arranged in the listed order from the negative side to the positive side along the Y-axis.

[0061] The stacking direction of the multiple battery cells 11 in each battery cell unit 21 is the same as the stacking direction of the multiple battery cell units 21. The constraint member 41 applies a constraint force along the Y-axis to the multiple battery cells 11.

[0062] The retaining member 30 integrally holds multiple battery cells 11 (11a, 11b, 11c, 11d). The retaining member 30 has a housing 31. The housing 31 has a cuboid shape. The multiple battery cells 11 are housed in the housing 31.

[0063] The housing 31 is provided with a plurality of vents 32. The plurality of vents 32 are provided on both sides of the housing 31 orthogonal to the X-axis direction. The vents 32 are formed by through holes that penetrate the housing 31 in the X-axis direction. The vents 32 are provided as passages for introducing cooling air into or out of the gap between adjacent battery cells 11 in the Y-axis direction.

[0064] Figure 4 It shows the composition Figure 3 A three-dimensional view of a battery cell unit in the image. Figure 5 It is an exploded assembly diagram showing the interconnection structure of multiple battery cells.

[0065] Reference Figure 4 and Figure 5 The battery cell 11 is a lithium-ion battery. The battery cell 11 has an output density of over 8000 W / L. The battery cell 11 is square, with a thin plate shape resembling a cuboid. Multiple battery cells 11 are stacked with the Y-axis direction being the thickness direction of the battery cell 11.

[0066] The battery cell 11 has an outer casing 12. The outer casing 12 is a rectangular frame that forms the appearance of the battery cell 11. Electrodes and electrolyte are housed within the outer casing 12.

[0067] The outer casing 12 has a first side 13, a second side 14, and a third side 15. The first side 13 and the second side 14 are each formed by a plane orthogonal to the Y-axis. The first side 13 and the second side 14 face opposite directions in the Y-axis direction. The first side 13 and the second side 14 have the largest area among the multiple sides of the outer casing 12. The first side 13 and the second side 14 have a rectangular shape when viewed from the Y-axis direction. The first side 13 and the second side 14 have a rectangular shape with the X-axis as the longer side and the Z-axis as the shorter side when viewed from the Y-axis direction. The third side 15 is formed by a plane orthogonal to the Z-axis. The third side 15 faces the +Z-axis direction.

[0068] The battery cell 11 also has a gas discharge valve 17. The gas discharge valve 17 is located on the third side 15. When the internal pressure of the outer casing 12 exceeds a predetermined value due to gas generated inside the casing 12, the gas discharge valve 17 discharges the gas to the outside of the casing 12. The gas from the gas discharge valve 17... Figure 1The fluid flows through the exhaust pipe 93 and is discharged to the outside of the battery module 100.

[0069] The battery cell 11 also has a pair of electrode terminals 16, namely a positive terminal 16P and a negative terminal 16N. The electrode terminals 16 are made of metal. The electrode terminals 16 are disposed on the third side 15. The positive terminal 16P and the negative terminal 16N are disposed separately from each other in the X-axis direction. The positive terminal 16P and the negative terminal 16N are respectively disposed on both sides of the wiring member 92 and the exhaust pipe 93 in the X-axis direction.

[0070] Multiple battery cells 11 are stacked in the Y-axis direction with their first side 13 facing each other and their second side 14 facing each other. Thus, in the Y-axis direction of the stacked battery cells 11, the positive terminal 16P and the negative terminal 16N are arranged alternately.

[0071] Furthermore, when the number of battery cells 11 in the battery cell unit 21 is odd, the orientation of the battery cell unit 21 between adjacent battery cell units 21 in the Y-axis direction can be reversed by 180° with the Z-axis as the center.

[0072] Next, the connection structure of the multiple battery cells 11 will be described. (Refer to...) Figures 1 to 5 The battery module 100 also has multiple busbars 50. The busbars 50 are made of conductive material. The multiple busbars 50 are provided for electrically connecting the multiple battery cells 11 of the battery module 100 to each other.

[0073] Busbar 50 extends in the Y-axis direction. At each end of the busbar 50 extending in the Y-axis direction, it is connected to adjacent battery cells 11, 11 in the Y-axis direction. The busbar 50 is configured such that the positive terminal 16P and negative terminal 16N, arranged in the Y-axis direction, are connected between adjacent battery cells 11, 11. Multiple battery cells 11 are electrically connected in series with each other through multiple busbars 50.

[0074] Figure 6 This is a perspective view showing the connection structure of adjacent battery cells. Figure 7 It is a perspective view showing the connection structure of the battery cells within a battery cell unit.

[0075] Reference Figures 5 to 7 The plurality of busbars 50 includes one or more first busbars 51 and one or more second busbars 52. In this embodiment, the plurality of busbars 50 includes a plurality of first busbars 51 and a plurality of second busbars 52.

[0076] like Figure 5 and Figure 6As shown, the first busbar 51 extends between a first battery cell 11d and a second battery cell 11a that are adjacent in the Y-axis direction among the plurality of battery cells 11. The first busbar 51 electrically connects the adjacent battery cells 11, 11 in the Y-axis direction between the first battery cell in the plurality of battery cell units 21 and the second battery cell in the plurality of battery cell units 21 that are adjacent to the first battery cell in the Y-axis direction.

[0077] The first busbar 51 has a first base 226, a second base 221, and a standing portion 231. The first base 226 is connected to the first battery cell 11d. The second base 221 is connected to the second battery cell 11a. The standing portion 231 has a shape that rises from the first base 226 and the second base 221. The standing portion 231 connects the first base 226 and the second base 221.

[0078] When Figure 6 When describing the range shown, battery cell unit 21B corresponds to the first battery cell unit, battery cell unit 21C corresponds to the second battery cell unit, battery cell 11d in battery cell unit 21B corresponds to the first battery cell, and battery cell 11a in battery cell unit 21C corresponds to the second battery cell.

[0079] The first base 226 is connected to the negative terminal 16N of battery cell 11d in battery cell unit 21B. The second base 221 is connected to the positive terminal 16P of battery cell 11a in battery cell unit 21C. The first busbar 51 electrically connects the negative terminal 16N of battery cell 11d in battery cell unit 21B to the positive terminal 16P of battery cell 11a in battery cell unit 21C between battery cell unit 21B and battery cell unit 21C.

[0080] like Figure 5 and Figure 7 As shown, the second busbar 52 electrically connects adjacent battery cells 11, 11 in the Y-axis direction within each battery cell unit 21. When... Figure 7 When the range shown is described, the second busbar 52 electrically connects the negative terminal 16N of battery cell 11b to the positive terminal 16P of battery cell 11c in battery cell unit 21C.

[0081] Figure 8 It is shown in Figure 6 The diagram shows the connection structure of the battery cells as observed in the direction indicated by arrow VIII. Below, we will focus on... Figure 6 and Figure 8 The scope shown will be used to explain the more specific construction of the first busbar 51.

[0082] Reference Figure 6 and Figure 8 The first busbar 51 is composed of a first busbar segment 211 and a second busbar segment 212.

[0083] The first busbar splitter 211 and the second busbar splitter 212 are composed of separate conductive bodies (metal plates). The first busbar splitter 211 is connected to the negative terminal 16N of the battery cell 11d in the battery cell unit 21B. The second busbar splitter 212 is connected to the positive terminal 16P of the battery cell 11a in the battery cell unit 21C. The first busbar splitter 211 and the second busbar splitter 212 are joined together by welding.

[0084] When viewed along the Z-axis, the first busbar divider 211 is positioned at an overlap with the battery cell 11d in the battery cell unit 21B. The first busbar divider 211 has a first plate portion 227, a second plate portion 228, a third plate portion 229, and a fourth plate portion 233.

[0085] The first plate portion 227 has a plate shape with its thickness direction along the Z-axis and is arranged parallel to the X-Y axis plane. The first plate portion 227 overlaps with the negative terminal 16N of the battery cell 11d in the battery cell unit 21B in the Z-axis direction. The first plate portion 227 is joined to the negative terminal 16N of the battery cell 11d in the battery cell unit 21B by welding. The second plate portion 228 has a plate shape with its thickness direction along the X-axis and is arranged parallel to the Y-Z axis plane. The second plate portion 228 extends from the end of the first plate portion 227 in the -X-axis direction toward the +Z-axis direction.

[0086] The third plate portion 229 has a plate shape in the Z-axis direction that is the thickness direction, and is arranged parallel to the X-axis-Y-axis plane. The third plate portion 229 extends from the end of the second plate portion 228 in the +Z-axis direction toward the -X-axis direction. The fourth plate portion 233 has a plate shape in the Y-axis direction that is the thickness direction, and is arranged parallel to the X-axis-Z-axis plane. The fourth plate portion 233 extends from the end of the third plate portion 229 in the +Y-axis direction toward the +Z-axis direction.

[0087] When viewed along the Z-axis, the second busbar divider 212 is positioned at an overlap with the battery cell 11a in the battery cell unit 21C. The second busbar divider 212 has a fifth plate portion 222, a sixth plate portion 223, a seventh plate portion 224, and an eighth plate portion 232.

[0088] The fifth plate 222, the sixth plate 223, the seventh plate 224 and the eighth plate 232 each have an X-axis-Z-axis plane that sandwiches the boundary between the battery cell 11d in the battery cell unit 21B and the battery cell 11a in the battery cell unit 21C, and are symmetrical to the first plate 227, the second plate 228, the third plate 229 and the fourth plate 233.

[0089] The fifth plate portion 222 overlaps with the positive terminal 16P of the battery cell 11a in the battery cell unit 21C in the Z-axis direction. The fifth plate portion 222 is joined to the positive terminal 16P of the battery cell 11a in the battery cell unit 21C by welding. The eighth plate portion 232 overlaps with the fourth plate portion 233 in the Y-axis direction. The fourth plate portion 233 and the eighth plate portion 232 are in surface contact with each other in a plane parallel to the X-axis-Z-axis plane. The fourth plate portion 233 and the eighth plate portion 232 are joined together by welding.

[0090] In the first busbar 51 with this structure, the first base 226 is composed of a first plate 227, a second plate 228, and a third plate 229. The first plate 227 of the first base 226 is connected to the negative terminal 16N of the battery cell 11d in the battery cell unit 21B. The second base 221 is composed of a fifth plate 222, a sixth plate 223, and a seventh plate 224. The fifth plate 222 of the second base 221 is connected to the positive terminal 16P of the battery cell 11a in the battery cell unit 21C.

[0091] The upright portion 231 is composed of the overlapping portions of the fourth plate portion 233 and the eighth plate portion 232. The upright portion 231 has a shape that rises from the third plate portion 229 of the first base portion 226 and the seventh plate portion 224 of the second base portion 221 in the +Z axis direction.

[0092] The erecting portion 231 rises from the third plate portion 229 of the first base portion 226 and the seventh plate portion 224 of the second base portion 221 in a +Z axis direction orthogonal to the X-Y axis plane in which the third plate portion 229 and the seventh plate portion 224 are arranged. The erecting portion 231 rises from the first base portion 226 and the second base portion 221 in a direction away from the battery cells 11, 11 connected to these first base portions 226 and the second base portion 221. The erecting portion 231 is located at a position away from the third side surface 15 of the outer casing 12 where the electrode terminals 16 are provided in a +Z axis direction.

[0093] The Z-axis direction of the erected portion 231, which rises from the first base 226 (third plate 229) and the second base 221 (seventh plate 224), corresponds to the erection direction of the erected portion 231. The Y-axis direction of the overlapping fourth plate 233 and eighth plate 232 corresponds to the thickness direction of the erected portion 231. The X-axis direction, which is orthogonal to the erection direction and the thickness direction of the erected portion 231, corresponds to the width direction of the erected portion 231.

[0094] A weak portion 240 is provided in the upright portion 231. The weak portion 240 is provided in the root region 236 of the upright portion 231. The weak portion 240 has less rigidity than the other parts of the upright portion 231 except for the weak portion 240. The weak portion 240 has less rigidity than the top region 237 of the upright portion 231.

[0095] like Figure 8 As shown, the root region 236 of the upright portion 231 is defined on the root side of the upright portion 231, which has an upright shape that rises from the first base 226 and the second base 221. The tip region 237 of the upright portion 231 is defined on the tip side of the upright portion 231, which has an upright shape that rises from the first base 226 and the second base 221.

[0096] More specifically, the erecting portion 231 has a root portion 231j and a tip portion 231k, extending between the root portion 231j and the tip portion 231k. The root portion 231j is located on the side of the first base portion 226 and the second base portion 221 in the erecting direction (Z-axis direction) of the erecting portion 231, and the tip portion 231k is located on the opposite side of the root portion 231j. The root region 236 of the erecting portion 231 corresponds to the region of the erecting portion 231 that is closer to the root portion 231j than the tip portion 231k in the erecting direction. The tip region 237 of the erecting portion 231 corresponds to the region of the erecting portion 231 that is closer to the tip portion 231k than the root portion 231j in the erecting direction.

[0097] The upright portion 231 has an upright length La. In this case, the root region 236 of the upright portion 231 is a range of La / 2 from the root portion 231j toward the +Z axis direction. The top region 237 of the upright portion 231 is a range of La / 2 from the top portion 231k toward the -Z axis direction.

[0098] The vulnerable part 240 is located at a position away from the root 231j in the +Z axis direction. The vulnerable part 240 is located at a position away from the top region 237 of the upright part 231 in the -Z axis direction.

[0099] The vulnerable portion 240 is composed of a thin-walled structure 241 that partially reduces the thickness of the upright portion 231. The upright portion 231, except for the vulnerable portion 240, has a thickness Tb in the Y-axis direction. The vulnerable portion 240 has a thickness Ta (Ta < Tb) in the Y-axis direction that is smaller than the thickness Tb. A groove 242 is provided in the root region 236 of the upright portion 231. The groove 242 is formed in a groove shape that is recessed from the surface of the fourth plate portion 233 facing the -Y-axis direction and the surface of the eighth plate portion 232 facing the +Y-axis direction, and extends towards the +X-axis direction. The thin-walled structure 241 is composed of the groove 242.

[0100] The thickness direction of the upright portion 231 in the vulnerable portion 240 is parallel to the Y-axis direction of the constraint force generated by the constraint member 41 applied to the multiple battery cells 11.

[0101] The vulnerable portion 240 is positioned at a location overlapping the X-axis-Z-axis plane (a predetermined plane) of the boundary between the battery cell 11d in battery cell unit 21B and the battery cell 11a in battery cell unit 21C. The first busbar 51 has a symmetrical shape that sandwiches the X-axis-Z-axis plane of the boundary between the battery cell 11d in battery cell unit 21B and the battery cell 11a in battery cell unit 21C.

[0102] Figure 9 It is shown Figure 6 A three-dimensional diagram showing the first morphological change of the connection structure of the battery cells. Figure 10 It is shown in Figure 9 The diagram shows the connection structure of a battery cell as observed in the direction indicated by arrow X. Figure 11 It is shown Figure 6 A three-dimensional diagram showing the second morphological change of the connection structure of the battery cells.

[0103] Reference Figure 6 and Figures 8 to 11 The upright part 231 has a dividing part 251, a first residual part 252 and a second residual part 253.

[0104] The dividing portion 251 connects the first base portion 226 and the second base portion 221. The dividing portion 251 can divide the first base portion 226 and the second base portion 221 with the weak portion 240 as the boundary. In the state where the dividing portion 251 is divided from the first base portion 226 and the second base portion 221, the first residual portion 252 remains on the first base portion 226 side, and the second residual portion 253 remains on the second base portion 221 side. The first residual portion 252 and the second residual portion 253 overlap each other.

[0105] The dividing portion 251 is connected to the first residual portion 252 and the second residual portion 253 at the vulnerable portion 240. The dividing portion 251 is composed of a fourth plate portion 233 located on the top side of the upright portion 231, which is closer to the vulnerable portion 240, and an eighth plate portion 232 located on the top side of the upright portion 231, which is closer to the vulnerable portion 240. The fourth plate portion 233 and the eighth plate portion 232 are joined together at the dividing portion 251.

[0106] The first residual portion 252 is formed by a fourth plate portion 233 located on the root side of the upright portion 231, which is closer to the weak portion 240. The second residual portion 253 is formed by an eighth plate portion 232 located on the root side of the upright portion 231, which is closer to the weak portion 240. The fourth plate portion 233 and the eighth plate portion 232 are not joined to each other at the first residual portion 252 and the second residual portion 253.

[0107] Sometimes, the battery module 100 needs to be disassembled for maintenance or other purposes. In such cases, the operator uses tools such as pliers to hold the dividing portion 251 in the upright portion 231 while applying force along the Y-axis to the upright portion 231, thereby causing the weak portion 240 to break. This allows the connection between the upright portion 231 and the first base 226 and the second base 221 to be severed, separating adjacent battery cell units 21 from each other. For example, the operator... Figure 11 As shown, the battery cell unit 21C is separated from the battery cell units 21B and 21D on both sides to repair or replace the battery cell 11 in the battery cell unit 21C.

[0108] In this embodiment, the vulnerable part 240 is provided in the root region 236 of the upright part 231. With this structure, the operator can easily grasp the upright part 231 with pliers or the like, or easily apply force to the vulnerable part 240, thus making it easy to break the vulnerable part 240. As a result, the workability during the disassembly of the battery module 100 can be improved.

[0109] Furthermore, in the vulnerable section 240 constructed of thin-walled structure 241, the thickness direction of the upright portion 231 of the vulnerable section 240 is parallel to the Y-axis direction of the stacked multiple battery cells 11 (battery cell units 21). In this case, since a Y-axis constraint force is applied to the multiple battery cells 11 (battery cell units 21) from the constraint member 41, it is possible to prevent the battery cells 11 from tilting in the Y-axis direction when the operator applies a force along the Y-axis direction to the upright portion 231 in order to break the vulnerable section 240. As a result, the force applied to the upright portion 231 can be transmitted to the vulnerable section 240 more efficiently, improving the workability when the operator breaks the vulnerable section 240.

[0110] Furthermore, the vulnerable portion 240 is configured to overlap with the X-axis-Z-axis plane that forms the boundary of the battery cells 11, 11 connected by the first busbar 51, and the first busbar 51 has a symmetrical shape sandwiching this X-axis-Z-axis plane. With this structure, the first busbar 51 sandwiches the vulnerable portion 240, which receives force from the operator, and is evenly supported by the battery cells 11 between the first base 226 side connected to the first battery cell 11d and the second base 221 side connected to the second battery cell 11a. Therefore, when the operator applies a force along the Y-axis direction to the upright portion 231 to break the vulnerable portion 240, elastic deformation of the first busbar 51 can be suppressed. This allows for more efficient transmission of the force applied to the upright portion 231 to the vulnerable portion 240, improving workability when the operator breaks the vulnerable portion 240.

[0111] Furthermore, the erecting portion 231 has a dividing portion 251 that can be separated from the first base portion 226 and the second base portion 221 by the weak portion 240. With such a structure, the operator can hold the dividing portion 251 while continuously applying force to the erecting portion 231 until the weak portion 240 breaks, thus improving the operator's workability when breaking the weak portion 240.

[0112] In addition, the erecting part 231 also has Figure 9 and Figure 10 The first residual portion 252 and the second residual portion 253 are shown. With this structure, when the maintained battery cell unit 21 is assembled into the battery module 100, the first base 226 and the second base 221 of the first busbar 51 can be reconnected by welding the first residual portion 252 and the second residual portion 253.

[0113] Figure 12 It is shown Figure 8 A diagram of the first deformed example of the vulnerable part. (Refer to...) Figure 12 In this modified example, the vulnerable part 240 is composed of a cut structure 243. A cut 244 is provided in the root region 236 of the erected part 231.

[0114] The cut 244 is provided in a manner that cuts the upright portion 231 in the width direction (X-axis direction) of the upright portion 231, which is orthogonal to the uprighting direction (Z-axis direction) and the thickness direction (Y-axis direction) of the upright portion 231. The cut 244 is formed in a cut shape that is recessed from both sides of the upright portion 231 toward the +X-axis direction and -X-axis direction and extends through the upright portion 231 in the Y-axis direction. The width Sa of the upright portion 231 in the vulnerable portion 240 is smaller than the width Sb of the upright portion 231 at other locations except for the vulnerable portion 240 (Sa < Sb).

[0115] Figure 13 It is shown Figure 8 A diagram of the second deformation example of the vulnerable part. (Refer to...) Figure 13 In this modified example, the vulnerable part 240 is composed of a linear perforation structure 246. A cut-off part 247 is provided in the root region 236 of the upright part 231.

[0116] The cutting portion 247 is formed by a through hole that penetrates the upright portion 231 in the thickness direction. The cutting portion 247 is provided discontinuously and linearly. The cutting portion 247 extends in a straight line. The cutting portion 247 extends in the X-axis direction.

[0117] Figure 14 It is shown Figure 6 A three-dimensional view of a modified example of the first busbar in the diagram. Figure 15 It is shown in Figure 14 The diagram shows the first busbar observed in the direction indicated by arrow XV.

[0118] Reference Figure 14 and Figure 15 In this modified example, when viewed along the Z-axis, the first busbar divider 211 is positioned overlapping with the battery cell 11d in the battery cell unit 21B. The first busbar divider 211 has a first plate portion 284 and a second plate portion 283.

[0119] The first plate portion 284 has a plate shape with its thickness direction along the Z-axis and is arranged parallel to the X-Y axis plane. The first plate portion 284 overlaps with the negative terminal 16N of the battery cell 11d in the battery cell unit 21B in the Z-axis direction. The first plate portion 284 is joined to the negative terminal 16N of the battery cell 11d in the battery cell unit 21B by welding. The second plate portion 283 has a plate shape with its thickness direction along the X-axis and is arranged parallel to the Y-Z axis plane. The second plate portion 283 extends from the end of the first plate portion 284 in the -X-axis direction toward the +Z-axis direction.

[0120] When viewed along the Z-axis, the second busbar divider 212 is provided to span the position overlapping with the battery cell 11a in the battery cell unit 21C and the position overlapping with the battery cell 11d in the battery cell unit 21B. The second busbar divider 212 has a third plate portion 262, a fourth plate portion 263, a fifth plate portion 264, an elastic portion 265, a sixth plate portion 266, and a seventh plate portion 282.

[0121] The third plate portion 262 has a plate shape with its thickness direction along the Z-axis and is arranged parallel to the X-Y axis plane. The third plate portion 262 overlaps with the positive terminal 16P of the battery cell 11a in the battery cell unit 21C in the Z-axis direction. The third plate portion 262 is joined to the positive terminal 16P of the battery cell 11a in the battery cell unit 21C by welding. The fourth plate portion 263 has a plate shape with its thickness direction along the X-axis and is arranged parallel to the Y-Z axis plane. The fourth plate portion 263 extends from the end of the third plate portion 262 in the -X-axis direction toward the +Z-axis direction.

[0122] The fifth plate portion 264 and the sixth plate portion 266 each have a plate shape in which the thickness direction is along the Z-axis, and are arranged parallel to the X-Y axis plane. The fifth plate portion 264 extends from the end of the fourth plate portion 263 in the +Z-axis direction toward the -X-axis direction. The sixth plate portion 266 is provided at a position offset from the fifth plate portion 264 in the -Y-axis direction. The fifth plate portion 264 is provided at a position overlapping with the battery cell 11a in the battery cell unit 21C when viewed along the Z-axis direction, and the sixth plate portion 266 is provided at a position overlapping with the battery cell 11d in the battery cell unit 21B when viewed along the Z-axis direction.

[0123] An elastic portion 265 extends between the fifth plate portion 264 and the sixth plate portion 266. Viewed along the Z-axis, the elastic portion 265 is positioned at the boundary overlapping with the battery cell 11a in battery cell unit 21C and the battery cell 11d in battery cell unit 21B. The elastic portion 265 extends from the end of the fifth plate portion 264 in the -Y-axis direction towards the -Z-axis direction and bends, while reversing in the Z-axis direction, and then extends towards the +Z-axis direction to connect with the end of the sixth plate portion 266 in the +Y-axis direction. The elastic portion 265 can elastically deform in a manner that varies with the distance between the fifth plate portion 264 and the sixth plate portion 266 in the Y-axis direction.

[0124] The seventh plate portion 282 has a plate shape in the thickness direction along the X-axis and is arranged parallel to the Y-axis-Z-axis plane. The seventh plate portion 282 extends from the end of the sixth plate portion 266 in the +X-axis direction toward the +Z-axis direction. The seventh plate portion 282 overlaps with the second plate portion 283 in the X-axis direction. The seventh plate portion 282 contacts the surface of the second plate portion 283 in a plane parallel to the Y-axis-Z-axis plane. The second plate portion 283 and the seventh plate portion 282 are joined together by welding.

[0125] In the first busbar 51 with this structure, the first base 226 is composed of a first plate 284. The first plate 284 of the first base 226 is connected to the negative terminal 16N of the battery cell 11d in the battery cell unit 21B. The second base 221 is composed of a third plate 262, a fourth plate 263, a fifth plate 264, an elastic part 265, and a sixth plate 266. The third plate 262 of the second base 221 is connected to the positive terminal 16P of the battery cell 11a in the battery cell unit 21C.

[0126] The upright portion 231 is formed by the overlapping portion of the second plate portion 283 and the seventh plate portion 282. The upright portion 231 is the portion on the positive side in the Z-axis direction relative to the corner of the sixth plate portion 266 and the seventh plate portion 282.

[0127] A vulnerable portion 240 is provided in the root region 236 of the upright portion 231. The upright portion 231 has an upright length Lb. The root region 236 of the upright portion 231 extends from the root 231j of the upright portion 231 towards the +Z axis direction for a length of Lb / 2. The tip region 237 of the upright portion 231 extends from the tip 231k of the upright portion 231 towards the -Z axis direction for a length of Lb / 2.

[0128] The thickness direction of the upright portion 231 in the vulnerable portion 240 is the X-axis direction, which is orthogonal to the Y-axis direction of the constraint force generated by the constraint member 41 applied to the plurality of battery cells 11. The first busbar 51 has an asymmetrical shape by sandwiching the X-axis-Z-axis plane that forms the boundary between the battery cell 11d in the battery cell unit 21B and the battery cell 11a in the battery cell unit 21C.

[0129] When summarizing the structure of the battery module 100 in the embodiments of the present invention described above, the battery module 100 in this embodiment includes: a plurality of battery cells 11 stacked in the Y-axis direction as a predetermined direction, and a plurality of busbars 50 for electrically connecting the plurality of battery cells 11 to each other. The plurality of busbars 50 includes a first busbar 51 extending between a first battery cell 11d and a second battery cell 11a adjacent in the Y-axis direction among the plurality of battery cells 11. The first busbar 51 has: a first base 226 connected to the first battery cell 11d; a second base 221 connected to the second battery cell 11a; and an upright portion 231 having a shape that rises from the first base 226 and the second base 221, connecting the first base 226 and the second base 221. A vulnerable portion 240 is provided in the root region 236 of the upright portion 231.

[0130] According to the battery module 100 of the present invention configured in this way, by providing a vulnerable portion 240 in the root region 236 of the upright portion 231, the operator can easily break the vulnerable portion 240 to separate the first battery cell 11d and the second battery cell 11a adjacent in a predetermined direction. This improves the workability of disassembling the battery module 100.

[0131] In addition to the first busbar 51, the vulnerable part of the present invention may also be provided in the second busbar 52 that connects the battery cells 11, 11 to each other within the battery cell unit 21.

[0132] Embodiments of the present invention have been described, but should be considered illustrative rather than restrictive in all respects. The scope of the invention is set forth in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery module comprising a plurality of battery cells stacked in a predetermined direction, and a plurality of bus bars for electrically connecting the plurality of battery cells to each other, the plurality of bus bars includes a first bus bar extending between first and second battery cells adjacent in the predetermined direction among the plurality of battery cells, the first bus bar has: a first base connected to the first battery cell; a second base connected to the second battery cell; and a standing portion having a shape standing from the first and second bases in a standing direction orthogonal to the predetermined direction, and connecting between the first and second bases, a fragile portion is provided at a root region of the standing portion, the battery cells are square, the fragile portion is constituted by a thin-walled configuration in which a groove portion is recessed in a thickness direction of the standing portion, a cutout configuration provided with a cutout in a width direction of the standing portion orthogonal to the standing direction of the standing portion and the thickness direction of the standing portion, or a linear hole configuration intermittently and linearly provided with a cut portion penetrating in the thickness direction of the standing portion, the standing portion includes a division portion connecting between the first and second bases and capable of being divided from the first and second bases with the fragile portion as a boundary, and a first remaining portion remaining on the first base side and a second remaining portion remaining on the second base side and overlapping the first remaining portion in a state in which the division portion is divided from the first and second bases, a length of the division portion in the standing direction is longer than lengths of the first and second remaining portions in the standing direction.

2. The battery module according to claim 1, wherein a constraint force along the predetermined direction is applied to the plurality of battery cells, a thickness direction of the standing portion at the fragile portion is parallel to the predetermined direction.

3. The battery module according to claim 1 or 2, wherein the fragile portion is provided overlapping a predetermined plane constituting a boundary of the first and second battery cells, the first bus bar has a symmetrical shape sandwiching the predetermined plane.

4. The battery module according to claim 1 or 2, wherein the battery module comprises a plurality of battery cell units arranged in the predetermined direction and to which a constraint force along the predetermined direction is applied, each of the battery cell units has the plurality of battery cells arranged continuously in the predetermined direction, and a holding member integrally holding the plurality of battery cells arranged continuously in the predetermined direction, the first bus bar electrically connects the battery cells adjacent in the predetermined direction to each other between a first battery cell unit among the plurality of battery cell units and a second battery cell unit adjacent in the predetermined direction to the first battery cell unit among the plurality of battery cell units. ​ The plurality of bus bars further include second bus bars electrically connecting the battery cells adjacent to each other in the predetermined direction in each of the battery cell units.

5. The battery module according to claim 1 or 2, wherein The battery cell has an output density of 8000 W / L or more.

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