Battery module

Abstract

To provide a battery module capable of securing an electrical insulation between a strong electric part and a housing.SOLUTION: A battery module 1 comprises: a battery laminate 20; an insulating cooling member 40 which is in contact with tabs 211a1-211b2 extending from a plurality of battery cells 21 and cools the tabs; a lightweight member 50 which is in contact with the cooling member; a housing 10 in which the battery laminate, the cooling member and the lightweight member are stored; and terminal bus bars 30a and 30b which are joined to the tabs and exposed outside of the housing. Heat conductivity of the cooling member is larger than heat conductivity of the lightweight member, and a specific weight of the lightweight member is smaller than a specific weight of the cooling member. The lightweight member includes: main body parts 51 and 52 which are interposed between the housing and the cooling member in an extension direction of the tabs; and a wall part 54 which is connected to the main body parts and interposed between the terminal bus bars and the housing, thereby electrically insulating the terminal bus bars and the housing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] There is known an electric storage device having a cell stack in which electric storage cells are stacked, a bus bar connected to the tabs of the electric storage cells, and a tubular flow path formed along the bus bar (for example, see Patent Document 1). In this electric storage device, the bus bar is cooled by circulating a heat medium through the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-24886 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the storage cells of the above-mentioned conventional technology, the cooling flow path is in linear contact with the bus bar of the storage cell, and the thermal conduction efficiency between the flow path and the bus bar is poor, which reduces the cooling efficiency of the battery cell.

[0005] Therefore, if a cooling resin that can come into planar contact with the bus bars is used, the cooling resin has a relatively large mass, which increases the mass of the battery module. Therefore, it is conceivable to reduce the amount of cooling resin used by placing a member lighter than the cooling resin inside the housing.

[0006] In this case, there is a problem in that it is necessary to ensure electrical insulation between the high-voltage portion of the battery module and the housing.

[0007] The problem to be solved by the present invention is to provide a battery module that can ensure electrical insulation between a high-voltage section and a housing. [Means for solving the problem]

[0008] The present invention solves the above problem by providing a wall portion in the lightweight member that is interposed between the terminal bus bar and the housing, thereby electrically insulating the terminal bus bar from the housing. [Effects of the Invention]

[0009] According to the present invention, electrical insulation between the high-voltage section and the housing can be ensured. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1(a) is a first exploded perspective view showing an example of a battery module in an embodiment of the present invention, and FIG. 1(b) is a second exploded perspective view showing the example of a battery module viewed from the opposite side to the first exploded perspective view. [Figure 2] FIG. 2(a) is a cross-sectional view taken along the XY plane near the tab of a battery module according to an embodiment of the present invention, and FIG. 2(b) is a cross-sectional view taken along the YZ plane near the tab of a battery module according to an embodiment of the present invention. [Figure 3] FIG. 3 is an enlarged perspective view showing the vicinity of the tab in the first exploded perspective view according to the embodiment of the present invention. [Figure 4] FIG. 4 is a first perspective view showing an example of a lightweight member according to an embodiment of the present invention. [Figure 5] FIG. 5 is an enlarged perspective view of the vicinity of the cutout of the top plate in the embodiment of the present invention. [Figure 6] FIG. 6(a) is a second perspective view showing an example of a lightweight member in an embodiment of the present invention, and FIG. 6(b) is an exploded perspective view showing an example of a lightweight member in an embodiment of the present invention. [Figure 7] FIG. 7 is a third perspective view showing a modified example of the lightweight member in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1(a) is a first exploded perspective view showing an example of a battery module 1 according to the present embodiment, and FIG. 1(b) is a second exploded perspective view showing the example of the battery module 1 as viewed from the opposite side to the first exploded perspective view. FIG. 2(a) is a cross-sectional view along the XY plane of the vicinity of tabs 211a1-211b2 of the battery module 1 according to the present embodiment, and FIG. 2(b) is a cross-sectional view along the YZ plane of the vicinity of tabs 211a1-211b2 of the battery module 1 according to the embodiment of the present invention. FIG. 3 is an enlarged perspective view of the vicinity of tabs 211a1-211b2 in the first exploded perspective view according to the present embodiment. Note that the cooling member 40 is not shown in FIG. 3.

[0013] 1, the battery module 1 in this embodiment constitutes, for example, a part of an in-vehicle battery, although it is not particularly limited thereto. This battery is mounted under the vehicle (for example, under the cabin floor), although not particularly limited thereto, and includes at least, for example, a plurality of battery modules 1, a battery case for storing these, and a BMS (battery management system) for controlling the battery modules 1.

[0014] The battery module 1 in this embodiment includes a housing 10, a battery stack 20, a pair of terminal bus bars 30a and 30b, a pair of cooling members 40, and a pair of lightweight members 50.

[0015] The housing 10 is a box member that houses the battery stack 20, the cooling member 40, and the lightweight member 50. In this embodiment, the housing 10 has a hollow rectangular parallelepiped shape and is made up of six metal plates. The metal that makes up these metal plates is not particularly limited, but examples include stainless steel.

[0016] The housing 10 includes a bottom plate 11, a pair of side plates 12, a pair of end plates 13, and a top plate 14. The bottom plate 11 in this embodiment corresponds to an example of a "bottom" in the present invention, the pair of side plates 12 and the pair of end plates 13 in this embodiment correspond to an example of a "side" in the present invention, and the top plate 14 in this embodiment corresponds to an example of a "lid" in the present invention.

[0017] The bottom plate 11 is provided in the housing 10 in the −Z direction in the figure, and forms the bottom of the housing 10. On the top surface of this bottom plate 11, the battery stack 20, cooling member 40, and lightweight member 50 are placed.

[0018] The pair of side plates 12 are provided in the housing 10 in the ±Y directions in the figure, and stand on the bottom plate 11. As shown in FIGS. 2(a) and 2(b), the side plates 12 are in contact with the lightweight member 50.

[0019] The pair of end plates 13 are provided in the housing 10 in the ±X directions in the figure, and stand on the bottom plate 11. As shown in FIG. 2(a), the end plates 13 are in contact with the battery stack 20 in the stacking direction of the battery cells 21 (the ±X directions in the figure).

[0020] 1(a) and 1(b), the top plate 14 is provided in the housing 10 in the +Z direction in the drawings, and constitutes a lid for the housing 10. The top plate 14 includes an injection port 140. The injection port 140 is used when filling the inside of the housing 10 with a material that constitutes the cooling member 40, which will be described later.

[0021] The top plate 14 also includes a pair of cutouts 141. The pair of cutouts 141 expose the terminal bus bars 30a and 30b to the outside of the housing 10. The cutouts 141 in this embodiment correspond to an example of a "first opening" in the present invention. In order to expose the terminal bus bars 30a and 30b, a through-hole penetrating the top plate 14 may be used instead of the cutouts.

[0022] A battery stack 20 is housed in this housing 10. The battery stack 20 includes a plurality of battery cells 21. The number of battery cells 21 included in the battery stack 20 may be any number as long as it is two or more.

[0023] As shown in Fig. 2(a), each battery cell 21 has a flat shape. The battery cells 21 are not particularly limited, but may be secondary batteries such as lithium-ion secondary batteries. The multiple battery cells 21 are stacked one on top of the other along the X direction in the figure.

[0024] The positive electrode tab 211a1 of the battery cell 21 located at one end (the end on the -X direction side) in the stacking direction of the battery stack 20 (the X direction in the figure) is connected to the terminal bus bar 30a. This positive electrode tab 211a1 is not connected to the negative electrode tab 211b2. In contrast, the negative electrode tab 211b1 of the battery cell 21 located at the other end (the end on the +X direction side) in the stacking direction of the battery stack 20 is connected to the terminal bus bar 30b. This negative electrode tab 211b1 is not connected to the positive electrode tab 211a2.

[0025] Meanwhile, in the battery stack 20, the positive electrode tab 211a2 of a battery cell 21 that is not located at an end in the stacking direction is electrically connected to the negative electrode tab 211b2 of an adjacent battery cell 21. In other words, the battery stack 20 includes multiple tab pairs 25, each consisting of a pair of positive and negative electrode tabs 211a, 211b that face each other in adjacent battery cells 21 and are electrically connected to each other. Note that, although the present embodiment includes eight tab pairs 25 in the battery stack 20, this is not limiting. The number of tab pairs 25 included in the battery stack 20 may be any number greater than or equal to one.

[0026] In this embodiment, the positive and negative electrode tabs have a flat plate shape, but are not limited to this. For example, the positive and negative electrode tabs may be, but are not limited to, columnar. In addition, in the tab pair 25 in this embodiment, the positive and negative electrode tabs are directly joined by welding or the like, but are not limited to this. The positive and negative electrode tabs may be electrically connected by a bus bar or the like.

[0027] 2(a), 2(b), and 3, the terminal bus bars 30a and 30b are terminals for electrically connecting the battery module 1 to another battery module or electronic device. In this embodiment, one end of the terminal bus bar 30a is joined to the positive electrode tab 211a1, and one end of the terminal bus bar 30b is joined to the negative electrode tab 211b1. Meanwhile, the other ends of the terminal bus bars 30a and 30b are exposed to the outside of the housing 10 through the notch 141 of the top plate 14.

[0028] 2(a) and 2(b), the cooling member 40 is in surface contact with the positive electrode tabs 211a1 and 211a2 and the negative electrode tabs 211b1 and 211b2 inside the casing 10. As a result, the positive electrode tabs 211a1 and 211a2 and the negative electrode tabs 211b1 and 211b2 are embedded in the cooling member 40.

[0029] The cooling member 40 is made of a material that is electrically insulating and has high thermal conductivity, and electrically insulates these tabs from each other and cools them (removes heat). The thermal conductivity of the cooling member 40 is greater than that of the lightweight member 50. For example, the thermal conductivity of the cooling member 40 is not particularly limited, but may be 1 to 10 W / mK.

[0030] The cooling member 40 can be formed, without any particular limitation, by placing the battery stack 20 and lightweight member 50 inside the housing 10 and then pouring the material (fluid) that makes up the cooling member 40 through the injection port 140 in the top plate into the space between the battery stack 20 and the lightweight member 50 to fill it. Alternatively, the cooling member 40 can be formed by immersing the positive and negative electrode tabs and tab pairs of the battery stack 20 in the material that makes up the cooling member 40 and then hardening the material.

[0031] The material constituting the cooling member 40 is not particularly limited, but examples thereof include a high thermal conductivity resin material obtained by mixing and curing two components, a high thermal conductivity resin material obtained by curing one component, a latent heat storage material, an insulating refrigerant, sand, etc. An example of a high thermal conductivity resin material is not particularly limited, but may be a resin containing a filler, etc. An example of this filler is fibrous or particulate silicon, etc.

[0032] In this embodiment, the cooling member 40 has a comb-like shape in plan view that fits into the comb-like shape of the lightweight member 50. As a result, the cooling member 40 fills the space formed between the battery stack 20 and the lightweight member 50 inside the housing 10.

[0033] The cooling member 40 has one end portion 41, the other end portion 42, and a plurality of intervening portions 43. The one end portion 41 is provided on one end side (the −X direction side) of the cooling member 40. The one end portion 41 covers the entire surface (main surface, side surface, and tip surface) of the positive electrode tab 211a1. The one end portion 41 fills the space between the positive electrode tab 211a1 and the lightweight member 50 and the space between the positive electrode tab 211a1 and the casing 10. The one end portion 41 is connected to the adjacent intervening portion 43 and is formed integrally with the intervening portion 43.

[0034] On the other hand, the other end 42 is provided on the other end side (+X direction side) of the cooling member 40. This other end 42 covers the entire surface of the negative electrode tab 211b1. The other end 42 fills the space between the negative electrode tab 211b1 and the lightweight member 50 and the space between the negative electrode tab 211b1 and the casing 10. This other end 42 is connected to the adjacent intervening part 43 and is formed integrally with the intervening part 43.

[0035] The plurality of intervening portions 43 are provided between one end 41 and the other end 42. The plurality of intervening portions 43 are connected to adjacent intervening portions 43 and are formed integrally with the adjacent intervening portions 43. Each intervening portion 43 is provided between partition plates 53 of the lightweight member 50 described below, and covers the entire surface of the tab pair 25. More specifically, the intervening portion 43 fills the space between the positive electrode tab 211a2 and the negative electrode tab 211b2 of the tab pair 25, and also fills the space between the tab pair 25 and the lightweight member 50. The number of intervening portions 43 can be changed depending on the number of tab pairs 25.

[0036] As described above, one end 41, the other end 42, and the intervening portion 43 are integrally formed, and in this embodiment, they are connected to each other near the tip surface 53a (end surface on the -Y side) of the partition plate 53 shown in Figure 2(a) and near the bottom surface 53b (end surface on the -Z side) of the partition plate 53 shown in Figure 2(b).

[0037] A lightweight member 50 is interposed between the cooling member 40 and the housing 10, and the lightweight member 50 is in contact with the inner surface of the housing 10 and the cooling member 40. While the cooling member 40 is formed inside the housing 10 by filling, the lightweight member 50 in this embodiment is placed inside the housing 10 in a pre-formed state. The specific gravity of the lightweight member 50 is smaller than that of the cooling member 40.

[0038] As described above, the cooling member 40 is formed by filling the interior of the housing 10, but by previously disposing the lightweight member 50, which has a lower specific gravity than the cooling member, inside the housing 10, the amount of cooling member 40 to be filled can be reduced, and the volume of the cooling member 40 can be prevented from becoming larger than necessary. This makes it possible to reduce the increase in mass of the battery module 1. Furthermore, reducing the volume of the cooling member 40 can also reduce costs.

[0039] The lightweight member 50 is made of an electrically insulating material. The material that makes up the lightweight member 50 is not particularly limited, but examples thereof include resin, rubber, ceramic, etc. As the resin, it is preferable to use a material with a specific gravity of 1 or less, and an example of such a material is polypropylene (PP).

[0040] Fig. 4 is a first perspective view showing an example of the lightweight member 50 in this embodiment. As shown in Fig. 4, the lightweight member 50 includes a bottom portion 51, an upright portion 52, a plurality of partition plates 53, and a wall portion 54. The bottom portion 51 and the upright portion 52 in this embodiment correspond to an example of the "main body portion" in the present invention.

[0041] 2(b), the bottom 51 is placed on the bottom plate 11 and faces the battery stack 20 and the side plate 12. As a result, the bottom 51 fills the lower region of the space between the battery stack 20 and the side plate 12.

[0042] 4, the bottom 51 includes a contact surface 512 that comes into contact with the battery stack 20. Because this contact surface 512 comes into contact with the ends (compression pads) of the battery cells 21, the cooling member 40 does not enter below the battery stack 20 (between the battery stack 20 and the bottom plate 11), which reduces the increase in the volume of the cooling member 40.

[0043] 2(a), 2(b), and 4, the standing portion 52 stands on the upper surface 511 of the bottom portion 51. The standing portion 52 is in contact with the inner surface of the side plate 12 and is provided along the inner surface of the side plate 12. The height of the standing portion 52 is higher than the height of the positive and negative electrode tabs 211a1, 211a2, 211b1, and 211b2. Note that the height here refers to the height from the bottom plate 11.

[0044] The standing portions 52 are interposed between the positive and negative electrode tabs 211a1, 211a2, 211b1, and 211b2 and the inner surface of the side plate 12 of the housing 10, insulating them from each other. The standing portions 52 eliminate the need to attach an insulating material such as an insulating film to the inner surface of the housing 10 (functional integration). In other words, the standing portions 52 can ensure insulation between the battery cells 21 and the housing 10 while controlling the amount of cooling member 40 filled.

[0045] A plurality of partition plates 53 are provided on the surface of the upright portion 52 facing the positive and negative electrode tabs 211a1, 211a2, 211b1, and 211b2, and are aligned in a row along the stacking direction (X direction) of the battery stack 20. These partition plates 53 are embedded in the interposition portion 43 and electrically insulate the plurality of tab pairs 25 from each other. The partition plates 53 ensure insulation between adjacent tabs. The number of partition plates 53 can be changed depending on the number of positive and negative electrode tabs 211a1, 211a2, 211b1, and 211b2.

[0046] 4, the wall portion 54 is formed around the main body portion (the bottom portion 51 and the standing portion 52). The wall portion 54 includes a first portion 55 extending from the main body portion in the +Z direction, and a pair of second portions 56 that sandwich the main body portion in the X direction.

[0047] Fig. 5 is an enlarged perspective view of the vicinity of the cutout 141 of the top plate 14 in this embodiment. As shown in Fig. 4 and Fig. 5, the first portion 55 is formed on the upper part of the standing portion 52. This first portion 55 includes a pair of protrusions 551a, 551b.

[0048] 5, a pair of protrusions 551a, 551b are provided at positions corresponding to cutout 141 of top plate 14. Protrusions 551a, 551b are plate-like portions that protrude in the +Z direction in the figure, and face terminal bus bars 30a, 30b at cutout 141. Protrusions 551a, 551b are interposed between exposed portions of terminal bus bars 30a, 30b and side plate 12 in the extension direction of the tabs (Y direction in the figure), thereby electrically insulating the exposed portions from side plate 12.

[0049] The shape of the convex portion may be a flat plate shape without bends like convex portion 551a in this embodiment, or may be a bent shape like convex portion 551b. In this way, with first portion 55 in this embodiment, the insulation distance (clear distance and creepage distance) can be adjusted by the shapes of convex portions 551a and 551b.

[0050] As shown in Figures 2(b) and 4, the second portion 56 is interposed between the end plate 13 and the terminal bus bars 30a, 30b in the stacking direction of the multiple battery cells 21 (X direction in the figures), thereby electrically insulating the end plate 13 from the terminal bus bars 30a, 30b.

[0051] FIG. 6(a) is a second perspective view showing an example of the lightweight member 50 in this embodiment, and FIG. 6(b) is an exploded perspective view showing an example of the lightweight member 50 in this embodiment.

[0052] As shown in Figures 6(a) and 6(b), the main body of the lightweight member 50 includes a flow path 57 through which a coolant can flow. In this embodiment, the flow path 57 has a pair of second openings 571 on the lower surface 513 of the bottom 51. The pair of second openings 571 are used as coolant supply ports or discharge ports. Such flow paths 57 can improve the cooling efficiency of the battery stack 20.

[0053] Furthermore, as in this embodiment, the flow paths 57 may be formed not only in the main body portion but also inside the partition plate 53. Such flow paths 57 can further improve the cooling efficiency of the positive and negative electrode tabs 211a1 to 211b2.

[0054] Furthermore, the lightweight member 50 in this embodiment is fixed to the side plate 12. Specifically, as shown in FIG. 3, the lightweight member 50 is crimped to the side plate 12 by a plurality of crimping portions 521 provided on the back surface of the standing portion 52. This allows the lightweight member 50 and the housing 10 to be integrated together. Although the lightweight member 50 and the housing 10 may be fixed by double-sided tape or adhesive, it is preferable to fix them by the crimping portions 521 because this reduces the number of parts. Furthermore, the crimping portions 521 allow the relative positions of the lightweight member 50 and the housing 10 to be set to predetermined positions (positioning).

[0055] The battery module 1 further includes a first seal member 60 and a second seal member 65 between the lightweight member 50 and the housing 10. The materials constituting the first and second seal members 60, 65 are not particularly limited, but examples thereof include elastic bodies capable of sealing out liquids, such as closed-cell foam material, rubber, and elastomer. The first and second seal members 60, 65 are fixed to the lightweight member 50 and the housing 10 with, but are not particularly limited to, double-sided tape or the like.

[0056] 4, 6(a), and 6(b), the first sealing member 60 is disposed between the corner of the lightweight member 50 and the inner surface of the housing 10. The housing 10 in this embodiment has a through hole corresponding to the crimped portion 521 described above and a third opening 111 (see FIG. 3) corresponding to the second opening 571 of the flow path 57, and the first sealing member 60 can prevent the resin paste used to form the cooling member 40 described above from leaking out from these holes.

[0057] The second sealing member 65 is interposed between the second opening 571 formed in the lower surface 513 of the bottom 51 and the third opening 111 (see FIG. 3) of the bottom plate 11. The second sealing member 65 also makes it possible to prevent the resin paste used to form the cooling member 40 from leaking out from these holes.

[0058] In the battery module 1 of the present embodiment as described above, the cooling member 40 is formed by filling the interior of the housing 10, but the amount of cooling member 40 filled can be reduced by using the lightweight member 50, which has a lower specific gravity than the cooling member 40. This makes it possible to reduce the increase in mass of the battery module 1. Furthermore, reducing the volume of the cooling member 40 also reduces costs.

[0059] In this way, the lightweight member 50 can reduce the amount of cooling member 40 filled, while ensuring electrical insulation between the housing 10 and the high-voltage parts (tabs and terminal bus bars). In particular, when assembling the battery module 1, the cooling member 40 may not be formed before the battery stack 20 is housed in the housing 10. This could lead to contact between the housing 10 and the high-voltage parts of the battery stack 20, resulting in a short circuit. However, the wall 54 of the lightweight member 50 in this embodiment can prevent a short circuit during assembly of the battery module 1.

[0060] The lightweight member 50 may have the following modified configurations: Fig. 7 is a third perspective view showing a modified lightweight member in the embodiment of the present invention.

[0061] In this modification, the contact surface 512 includes a plurality of grooves 514. The ends of the battery cells 21 are positioned inside these grooves 514. This allows the battery cells 21 to be aligned accurately when the battery stack 20 is assembled. It also prevents the battery cells 21 from shifting position when the battery module 1 is subjected to vibration. This reduces variation in the positions of the positive and negative electrode tabs, and therefore reduces variation in the cooling effect of the cooling member on the positive and negative electrode tabs.

[0062] Furthermore, the top surface 511 of the bottom 51 in this modification includes a first inclined surface 511a and a second inclined surface 511b. The first inclined surface 511a in this modification is inclined so that its height gradually decreases from the -X direction toward the +X direction in the figure. Meanwhile, the second inclined surface 511b is inclined so that its height gradually decreases from the +X direction toward the -X direction in the figure. In other words, the top surface 511 includes an inclined surface that is recessed toward the center of the stacking direction of the battery stack 20.

[0063] In this way, since the upper surface 511 includes an inclined surface, when the material constituting the cooling member 40 flows onto the bottom portion 51, the material flows more easily due to the inclined surface. Therefore, the material is less likely to become unevenly distributed and spreads evenly on the bottom portion 51. Therefore, even when a highly viscous material is used, for example, the cooling member 40 can be formed evenly with a single filling port (injection port 140).

[0064] The inclination direction of the inclined surface can be changed as appropriate depending on the position of the injection port 140, etc. For example, the upper surface 511 may include an inclined surface that protrudes toward the center of the stacking direction of the battery stack 20. Alternatively, the upper surface 511 may be inclined in only one direction. For example, the upper surface 511 may be inclined in one direction so that the height of the entire upper surface 511 gradually decreases from the −X direction side to the +X direction side in the figure, or the upper surface 511 may be inclined in one direction so that the height of the entire upper surface 511 gradually decreases from the +X direction side to the −X direction side in the figure.

[0065] Furthermore, a lower surface 53b of the partition plate 53 is spaced apart from an upper surface 511 of the bottom portion 51. That is, the partition plate 53 and the bottom portion 51 are spaced apart, and a gap is formed between the partition plate 53 and the bottom portion 51. As a result, when the material constituting the cooling member 40 is filled, the material spreads uniformly through the gap, and therefore the cooling member 40 can be formed uniformly with a small number of injection ports 140.

[0066] The distance between the partition plates 53 increases toward the center of the row of partition plates 53. In this embodiment, the width of the partition plates 53 in the X direction decreases toward the center of the row of partition plates 53, thereby increasing the distance between the partition plates 53.

[0067] This allows the width of the interposition portion 43 in the X direction to increase as it approaches the center of the cooling member 40. Because the tabs of battery cells 21 closer to the center of the battery stack 20 tend to reach higher temperatures, increasing the width of the interposition portion 43 closer to the center of the cooling member 40 can suppress unevenness in the tab temperature. In other words, it is possible to make the tab temperature uniform. [Explanation of symbols]

[0068] 1...Battery module 10...Housing 20...Battery stack 21...Battery cell 211a1, 211a2...Positive electrode tab 211b1, 211b2...Negative electrode tab 25... Tab vs. 30a, 30b...Terminal bus bar 40...Cooling member 50...Lightweight materials 51...bottom 52...Upright section 521...Crimped part 53...Partition board 54...Wall part 55…Part 1 551a, 551b...Convex part 56…Second part 57...Flow path 571...Second opening 60...First seal member 65...Second seal member

Claims

1. a battery stack including a plurality of battery cells stacked on top of one another; an insulating cooling member that contacts tabs extending from the plurality of battery cells and cools the tabs; a lightweight member in contact with the cooling member; a housing that houses the battery stack, the cooling member, and the lightweight member; a terminal bus bar joined to the tab and exposed to the outside of the housing, the thermal conductivity of the cooling member is greater than the thermal conductivity of the lightweight member, The specific gravity of the lightweight member is smaller than the specific gravity of the cooling member, The lightweight member is a main body portion interposed between the housing and the cooling member in the extending direction of the tab; a wall portion connected to the main body portion and interposed between the terminal bus bar and the housing to electrically insulate the terminal bus bar from the housing.

2. The battery module according to claim 1, The housing includes: a bottom portion on which the battery stack is placed; a side portion that stands on the bottom and surrounds the battery stack, the cooling member, and the lightweight member; a cover having a first opening that exposes the terminal bus bar and that covers the battery stack, the cooling member, and the lightweight member from the side opposite the bottom, The wall portion includes a first portion that is interposed between the side portion and the exposed portion of the terminal bus bar in the first opening, thereby electrically insulating the side portion and the exposed portion.

3. The battery module according to claim 2, The side portion is an end plate that faces the battery stack in the stacking direction of the plurality of battery cells; a side plate facing the lightweight member in the extending direction of the tab, The first portion is a battery module interposed between the side plate and the exposed portion in the first opening.

4. The battery module according to claim 1, The housing includes: a bottom portion on which the battery stack is placed; a side portion that is erected on the bottom portion and surrounds the battery stack, the cooling member, and the lightweight member; The side portion is an end plate that faces the battery stack in the stacking direction of the plurality of battery cells; a side plate facing the lightweight member in the extending direction of the tab, the wall portion includes a second portion that is interposed between the end plate and the terminal bus bar in the stacking direction of the plurality of battery cells, thereby electrically insulating the end plate and the terminal bus bar.

5. The battery module according to claim 1, The battery module further includes a first sealing member interposed between the lightweight member and an inner surface of the housing.

6. The battery module according to claim 1, The main body of the battery module further includes a flow path through which a coolant flows.

7. The battery module according to claim 6, the flow path further includes a second opening formed in a surface of the body portion; the housing includes a third opening opposite the second opening, The battery module further includes a second sealing member interposed between the second and third openings.

8. The battery module according to any one of claims 1 to 7, The lightweight member is a battery module fixed to the housing.

Images