Battery pack

Abstract

To suppress deformation of a frame member or busbar in a busbar module.SOLUTION: An electrical device 50 is fixed to a case 20. A plate member 40 is fixed to the electrical device 50 and forms part of a path electrically connecting a laminate 10 and the electrical device 50. A resin frame member 300 has a main body portion 301 and an extension portion 302. The extension portion 302 extends from the main body portion 301 in a second direction. A bus bar 310 is electrically connected to the laminate 10 and is positioned on the extension portion 302. The plate member 40 has higher rigidity than the bus bar 310. The bus bar 310 and the plate member 40 are screw-fastened together by a fastening member 70 on the extension portion 302.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present technology relates to battery packs. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2016-046234 (Patent Document 1) is a prior art document that discloses the configuration of a battery system. The battery system described in Patent Document 1 comprises an insulating holder, an output line, and an output plate. The insulating holder is fixed to an end plate. A locking portion is provided on the insulating holder. The output line connects the battery cell to a motor or the like. The output plate is held in place by the locking portion. The output line is connected to the electrode terminal of the battery cell via the output plate. The output line is fixed to the output plate by screws. The locking portion of the insulating holder prevents the output plate from shifting position due to rotational torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-046234 Summary of the Invention [Problem to be solved by the invention]

[0004] When using the battery system structure described in Patent Document 1, the busbars connected to the battery cells and the conductive members connected to the electrical equipment are fastened together with screws on the frame members of the busbar module. In this case, stress generated when the screws are fastened may cause deformation of the frame members or the busbars.

[0005] The present technology has been made to solve the above-described problems, and has an object to provide a battery pack that can suppress deformation of frame members or bus bars in a bus bar module. [Means for solving the problem]

[0006] The present technology provides the following battery pack.

[0007] [1] a stack including a plurality of battery cells arranged in a first direction; a case that houses the stack and includes a pair of side walls that support the stack from both sides in the first direction; a bus bar module disposed on the laminate; an electrical device fixed to the case; a plate member fixed to the electrical device and constituting a part of a path electrically connecting the laminate and the electrical device; The busbar module includes: a resin frame member having a main body and an extension extending from the main body in a second direction perpendicular to the first direction; a bus bar electrically connected to the laminate and disposed on the extension portion, the plate member has higher rigidity than the bus bar, The bus bar and the plate member are fastened to each other by a fastening member on the extension portion.

[0008] [2] The battery pack according to [1], wherein the plate member has at least one bent portion.

[0009] [3] The battery pack according to [1] or [2], wherein the plate member is thicker than the bus bar.

[0010] [4] The battery pack according to any one of [1] to [3], wherein the bus bar is joined to the laminate by a welded portion.

[0011] [5] the electrical device has an exterior body made of resin having a higher hardness than the frame member, The plate member is fixed to the exterior body. The battery pack according to any one of [1] to [4].

[0012] [6] The battery pack according to any one of [1] to [5], wherein the plate member is fastened to the electrical device with a screw. [Effects of the Invention]

[0013] According to the present technology, it is possible to suppress deformation of the frame members or bus bars in the bus bar module. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a configuration of a battery pack according to an embodiment of the present technology; [Figure 2] 1 is a perspective view showing an internal structure of a battery pack according to an embodiment of the present technology; [Figure 3] 1 is a perspective view showing a configuration of a battery cell according to an embodiment of the present technology; [Figure 4] 1 is a perspective view showing an electrical connection structure between a first laminate and an electrical device according to an embodiment of the present technology. [Figure 5] 5 is a cross-sectional view of the electrical connection structure between the first laminate and the electrical device of FIG. 4, as viewed from the direction of the arrow VV line. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] 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 and advantages mentioned in the present embodiments.

[0017] 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.

[0018] 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).

[0019] In this specification, the term "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, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0020] Furthermore, the "battery pack" in this specification can be mounted in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), etc. However, the use of the "battery pack" in this specification is not limited to vehicle use.

[0021] In the drawings, the direction in which the extension portion of the busbar module extends is the X direction as the second direction, the direction in which the multiple battery cells are arranged is the Y direction as the first direction, and the direction in which the laminate and the busbar module are arranged is the Z direction.

[0022] Fig. 1 is a perspective view showing a configuration of a battery pack according to an embodiment of the present technology, and Fig. 2 is a perspective view showing an internal structure of the battery pack according to an embodiment of the present technology.

[0023] As shown in FIGS. 1 and 2, a battery pack 1 in this embodiment includes a laminate 10, a case 20, a bus bar module 30, a plate member 40, and an electric device 50.

[0024] The laminate 10 includes a first laminate 10A, a second laminate 10B, and a third laminate 10C. The first laminate 10A includes a plurality of first battery cells arranged in a first direction (Y direction). The second laminate 10B includes a plurality of second battery cells arranged in the first direction (Y direction). The third laminate 10C includes a plurality of third battery cells arranged in the first direction (Y direction). Each of the plurality of first battery cells, the plurality of second battery cells, and the plurality of third battery cells is a battery cell 100 (see FIG. 3) described below.

[0025] The first stack 10A has a first end 11 and a second end 12 in a first direction (Y direction). The second stack 10B and the third stack 10C are aligned with the first stack 10A in a second direction (X direction) perpendicular to the first direction.

[0026] The case 20 accommodates the first stack 10A, the second stack 10B, the third stack 10C, the plate member 40, and the electric device 50.

[0027] The case 20 includes a pair of side walls 21. The pair of side walls 21 extend in the second direction (X direction). The pair of side walls 21 has one side wall 22 and the other side wall 23. The one side wall 22 and the other side wall 23 face each other in the first direction (Y direction). The one side wall 22 is located on the first end 11 side of the first stack 10A. The other side wall 23 is located on the second end 12 side.

[0028] The pair of side walls 21 support the first stack 10A, the second stack 10B, and the third stack 10C from both sides in the first direction (Y direction). In the present embodiment, one side wall 22 and the other side wall 23 directly support the first stack 10A, the second stack 10B, and the third stack 10C from both sides in the Y direction. In this way, the battery pack 1 according to the present embodiment employs a cell-to-pack structure in which the stack 10 including the multiple battery cells 100 is housed directly in the case 20.

[0029] The bus bar module 30 is disposed on the stack 10. The bus bar module 30 insulates the stack 10 from other components disposed on the stack 10. The bus bar module 30 electrically connects the multiple battery cells 100 in the stack 10 together via inter-cell bus bars (not shown).

[0030] The busbar module 30 includes a first busbar module 30A, a second busbar module 30B, and a third busbar module 30C. The first busbar module 30A is arranged on the first laminate 10A. The second busbar module 30B is arranged on the second laminate 10B. The third busbar module 30C is arranged on the third laminate 10C.

[0031] The plate member 40 is a conductive member and is provided to electrically connect the laminates to each other, and to electrically connect the laminate 10 to the electrical device 50. The plate member 40 is made of, for example, an aluminum alloy.

[0032] The plate member 40 includes a first plate member 400 , a second plate member 410 , a third plate member 420 , and a fourth plate member 430 .

[0033] The first plate member 400 is disposed adjacent to one side wall 22 of the pair of side walls 21. The first plate member 400 forms part of a path that electrically connects the first stack 10A and the electric device 50.

[0034] The second plate member 410 is disposed adjacent to the other side wall 23 of the pair of side walls 21. The second plate member 410 extends in the second direction (X direction). The second plate member 410 electrically connects the first stacked body 10A and the second stacked body 10B.

[0035] The third plate member 420 is disposed adjacent to one side wall 22 of the pair of side walls 21. The third plate member 420 extends in the second direction (X direction). The third plate member 420 electrically connects the second stacked body 10B and the third stacked body 10C.

[0036] The fourth plate member 430 is disposed adjacent to the other side wall 23 of the pair of side walls 21. The fourth plate member 430 extends along the second direction (X direction) while bending. The fourth plate member 430 electrically connects the third laminate 10C and the electric device 50. In the Z direction, the second plate member 410 and the fourth plate member 430 overlap each other.

[0037] The electric device 50 is, for example, a junction box for electrically connecting the stack 10 and an external device (not shown) of the battery pack 1. The electric device 50 is electrically connected to the first stack 10A, the second stack 10B, and the third stack 10C. The electric device 50 is fixed to the case 20. In this embodiment, the electric device 50 is fixed to the bottom surface of the case 20.

[0038] In the battery pack 1, electricity can be applied in the following order: electrical device 50, first plate member 400, first stack 10A, second plate member 410, second stack 10B, third plate member 420, third stack 10C, fourth plate member 430, and electrical device 50.

[0039] 3 is a perspective view showing a configuration of a battery cell according to an embodiment of the present technology. As shown in FIG. 3, the battery cell 100 according to the present embodiment includes an electrode terminal 110, a housing 120, and a gas release valve 130.

[0040] The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112. The positive electrode terminal 111 and the negative electrode terminal 112 are arranged side by side in the X direction.

[0041] The housing 120 is a container that houses an electrode assembly and an electrolyte (not shown). The housing 120 has a substantially rectangular parallelepiped shape. The housing 120 is made of aluminum, an aluminum alloy, iron, or an iron alloy such as stainless steel.

[0042] The housing 120 has a sealing plate 121, a bottom surface 122, a pair of long side walls 123, and a pair of short side walls .

[0043] The sealing plate 121 forms the upper surface of the housing 120. The electrode terminals 110 are arranged on the sealing plate 121. The bottom surface 122 faces the sealing plate 121 in the Z direction.

[0044] The pair of long side walls 123 and the pair of short side walls 124 form the side surfaces of the housing 120. The pair of long side walls 123 and the pair of short side walls 124 intersect with the sealing plate 121 and the bottom surface 122, respectively. The pair of long side walls 123 face each other in the Y direction with the electrode body therebetween. The pair of short side walls 124 face each other in the X direction with the electrode body therebetween. Each of the pair of long side walls 123 has a larger area than each of the pair of short side walls 124.

[0045] The gas exhaust valve 130 breaks when the pressure inside the housing 120 reaches or exceeds a predetermined value, thereby allowing the gas inside the housing 120 to be exhausted to the outside of the housing 120.

[0046] Hereinafter, the electrical connection between the first laminate 10A and the electric device 50 will be described in detail. Fig. 4 is a perspective view showing an electrical connection structure between the first laminate and the electric device according to an embodiment of the present technology. Fig. 4 is a perspective view of the battery pack 1 as seen from the direction of arrow IV in Fig. 1. In Fig. 4, configurations such as a part of a cover member 320 (described later) in the first bus bar module 30A are omitted.

[0047] As shown in FIG. 4, the first bus bar module 30A includes a frame member 300, a bus bar 310, and a cover member 320.

[0048] The frame member 300 is disposed on the first stack 10 A. On the frame member 300, bus bars 310, inter-cell bus bars, and the like are disposed.

[0049] The frame member 300 is made of resin. For example, the frame member 300 is made of polypropylene (PP). In order to apply a structure that elastically deforms a member, such as a snap-fit ​​structure, when assembling the frame member 300 with the cover member 320, it is desirable that the frame member 300 be made of a material with a relatively low hardness.

[0050] The frame member 300 has a main body portion 301 and an extending portion 302. The main body portion 301 extends on the XY plane. The main body portion 301 overlaps the first stacked body 10A in the Z direction so as to cover the entire surface of the first stacked body 10A.

[0051] The extension portion 302 extends from the main body portion 301 in a second direction (X direction) perpendicular to the first direction (Y direction). The extension portion 302 extends in the second direction (X direction) from the end of the main body portion 301 in the first direction (Y direction) toward the electrical device 50. By positioning the extension portion 302 on the end side of the main body portion 301 in the first direction (Y direction), it is possible to make the extension portion 302 less likely to come into contact with other components of the battery pack 1.

[0052] The bus bar 310 is electrically connected to the battery cells 100 of the first stack 10A. The bus bar 310 forms part of a path that electrically connects the first stack 10A and the electrical device 50. The bus bar 310 is made of, for example, an aluminum alloy.

[0053] In the present embodiment, bus bar 310 is joined to first laminate 10A by welded portion 311. Welded portion 311 is formed by, for example, laser welding. Bus bar 310 may also be joined by other connection methods, such as screw fastening.

[0054] Bus bar 310 extends in a second direction (X direction). Bus bar 310 is disposed on extending portion 302. Note that bus bar 310 is not limited to a configuration extending only in the second direction (X direction), and may be configured to bend from the second direction (X direction) on extending portion 302 and extend in a first direction (Y direction).

[0055] Cover member 320 covers bus bar 310, inter-cell bus bars, etc. Cover member 320 is made of, for example, polypropylene.

[0056] The electric device 50 has an exterior body 500. The exterior body 500 protects the electrical system of the electric device 50. The exterior body 500 is made of resin. The exterior body 500 has a higher hardness than the frame member 300. The exterior body 500 is made of, for example, polybutylene terephthalate (PBT).

[0057] The first plate member 400 is fixed to the electric device 50. In this embodiment, the first plate member 400 is fixed to the exterior body 500. The first plate member 400 is fixed to the exterior body 500 at the fixing portion 60. In this embodiment, the first plate member 400 is fastened to the electric device 50 with screws. In the Z direction, the position at which the first plate member 400 is fixed to the electric device 50 is lower than the upper surface of the extension portion 302.

[0058] First plate member 400 has higher rigidity than bus bar 310. In the present embodiment, first plate member 400 is thicker than bus bar 310, and therefore first plate member 400 has higher rigidity than bus bar 310. Note that first plate member 400 only needs to have higher rigidity than bus bar 310, and first plate member 400 and bus bar 310 may have the same thickness but different widths or materials, thereby causing first plate member 400 to have higher rigidity than bus bar 310.

[0059] The first plate member 400 has at least one bent portion. The first plate member 400 in this embodiment has a first bent portion 401, a second bent portion 402, and a third bent portion 403.

[0060] The first bent portion 401 bends the portion of the first plate member 400 that extends in the X direction so that it is inclined in the Z direction. The second bent portion 402 bends the portion of the first plate member 400 that is inclined in the Z direction in the X direction. The third bent portion 403 bends the portion of the first plate member 400 that extends in the X direction in the Y direction.

[0061] 5 is a cross-sectional view of the electrical connection structure between the first laminate and an electrical device in FIG. 4, as viewed from the direction of the arrow VV line.

[0062] 5, bus bar 310 is provided with through-hole 312. First plate member 400 is provided with through-hole 404.

[0063] The bus bar 310 and the first plate member 400 are fastened together by a fastening member 70 on the extending portion 302. Specifically, the fastening member 70 has a bolt member 71 and a nut member 72. The bolt member 71 is inserted into the through holes 312, 404. The bolt member 71 and the nut member 72 are threadedly engaged with each other, thereby fastening the bus bar 310 and the first plate member 400 together by the fastening member 70 on the extending portion 302. As a result, the first stack 10A and the electric device 50 are electrically connected via the bus bar 310 and the first plate member 400. The bolt member 71 fits into a recess 303 provided in the extending portion 302 so as to open in the Z direction. As a result, the fastening member 70 is fixed to the extending portion 302.

[0064] 4 and 5, when fastening member 70 is fastened by the screw, stress (direction R1 in FIG. 4) is generated by rotational torque. The stress is transmitted from fastening member 70 to bus bar 310, first plate member 400, and extending portion 302. At this time, first plate member 400 has higher rigidity than lead wires and the like, and first plate member 400 is fixed to electrical device 50. As a result, first plate member 400 is the portion that receives most of the stress, and therefore the stress is applied mainly to first plate member 400. As a result, the stress can be prevented from being applied to bus bar 310 or extending portion 302, and deformation of bus bar 310 or extending portion 302 can be prevented.

[0065] In the Z direction, the first plate member 400, the bus bar 310, and the extending portion 302 are arranged in this order so that the first plate member 400 abuts against the nut member 72. The rotational torque generated when the nut member 72 is tightened onto the bolt member 71 is mainly applied to the first plate member 400. This suppresses deformation of the bus bar 310 or the extending portion 302 compared to when the bus bar 310 abuts against the nut member 72 and is fastened by the screw.

[0066] The bus bar 310 is shorter than the first plate member 400. This reduces the portion of the bus bar 310 that can deform, thereby suppressing deformation of the bus bar 310. It is desirable that the length of the bus bar 310 be, for example, one-third or less of the path electrically connecting the first laminate 10A and the electric device 50.

[0067] In the process of assembling the first laminate 10A and the electric device 50, after the first laminate 10A and the electric device 50 are housed in the case 20, the first plate member 400 is placed on the bus bar 310 on the extending portion 302. Next, the first plate member 400 is fixed to the electric device 50 by the fixing portion 60. After that, the bus bar 310, the first plate member 400, and the extending portion 302 are screwed together by the fastening member 70. Because the first plate member 400 is fixed to the electric device 50, stress generated when the bus bar 310, the first plate member 400, and the extending portion 302 are screwed together acts mainly on the first plate member 400.

[0068] In a battery pack 1 according to an embodiment of the present technology, the bus bar 310 and the first plate member 400 are screwed together on the extending portion 302 by fastening members 70. Stress is generated by the rotational torque of the screw fastening. Because the first plate member 400 is fixed to the electric device 50 while having higher rigidity than the bus bar 310, the first plate member 400 is the portion that receives most of the stress. Because the stress is mainly applied to the first plate member 400, the stress applied to the bus bar 310 or the extending portion 302 can be reduced. As a result, deformation of the frame member 300 or the bus bar 310 in the bus bar module 30 can be suppressed. Consequently, the insulating function of the frame member 300 or the conductive function of the bus bar 310 can be prevented from being impaired, and a highly reliable battery pack 1 can be provided.

[0069] In battery pack 1 according to an embodiment of the present technology, first plate member 400 is provided with at least one bent portion, so that even if stress is applied to first plate member 400 when fastening screws with fastening members 70, first plate member 400 acts like a leaf spring and can absorb the stress applied when fastening screws. This reduces the stress applied to bus bar 310 and extension portion 302, and can suppress deformation of frame member 300 or bus bar 310.

[0070] In the battery pack 1 according to the embodiment of the present technology, the first plate member 400 is thicker than the bus bar 310, and therefore the first plate member 400 having higher rigidity than the bus bar 310 can be easily configured.

[0071] In the battery pack 1 according to the embodiment of the present technology, stress from screw fastening of the fastening members 70 is mainly applied to the first plate member 400, and therefore, even when the bus bar 310 is joined to the first stack 10A by the welded portion 311, it is possible to prevent stress from being applied to the welded portion 311. This makes it possible to prevent cracks and the like from occurring in the welded portion 311.

[0072] In the battery pack 1 according to an embodiment of the present technology, the first plate member 400 is firmly fixed to the electric device 50 by fixing the first plate member 400 to the exterior body 500 having a higher hardness than the frame member 300. This makes it easier for stress generated during screw fastening to be transmitted to the first plate member 400, thereby making it possible to further reduce the effect of the stress on the frame member 300 or the bus bar 310.

[0073] In the battery pack 1 according to an embodiment of the present technology, the first plate member 400 is fastened to the electric device 50 with screws, so that the first plate member 400 can be fixed to the electric device 50 without the need for accurate positioning of the first plate member 400 relative to the electric device 50. As a result, when electrically connecting the first stack 10A and the electric device 50, even if there is misalignment of components due to manufacturing tolerances, the first plate member 400 can be reliably connected to the electric device 50.

[0074] 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]

[0075] 1 battery pack, 10 laminate, 10A first laminate, 10B second laminate, 10C third laminate, 11 first end, 12 second end, 20 case, 21 pair of side walls, 22 one side wall, 23 other side wall, 30 bus bar module, 30A first bus bar module, 30B second bus bar module, 30C third bus bar module, 40 plate member, 50 electrical equipment, 60 fixing portion, 70 fastening member, 71 bolt member, 72 nut member, 100 battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 121 sealing plate, 122 bottom surface, 123 long side wall, 124 short side wall, 130 gas release valve, 300 frame member, 301 main body portion, 302 extension portion, 303 Recess, 310 bus bar, 311 welded portion, 312, 404 through hole, 320 cover member, 400 first plate member, 401 first bent portion, 402 second bent portion, 403 third bent portion, 410 second plate member, 420 third plate member, 430 fourth plate member, 500 exterior body.

Claims

1. a stack including a plurality of battery cells arranged in a first direction; a case that houses the stack and includes a pair of side walls that support the stack from both sides in the first direction; a bus bar module disposed on the laminate; an electrical device fixed to the case; a plate member fixed to the electrical device and constituting a part of a path electrically connecting the laminate and the electrical device; The busbar module includes: a resin frame member having a main body and an extension extending from the main body in a second direction perpendicular to the first direction; a bus bar electrically connected to the laminate and disposed on the extension portion, the plate member has higher rigidity than the bus bar, The bus bar and the plate member are fastened to each other by a fastening member on the extension portion.

2. The battery pack according to claim 1 , wherein the plate member has at least one bent portion.

3. The battery pack according to claim 1 or 2, wherein the plate member is thicker than the bus bar.

4. The battery pack according to claim 1 or 2, wherein the bus bar is joined to the laminate by a weld.

5. the electrical device has an exterior body made of resin having a higher hardness than the frame member, The plate member is fixed to the exterior body. The battery pack according to claim 1 or 2.

6. 3. The battery pack according to claim 1, wherein the plate member is fastened to the electrical device by screws.

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