Battery module

Abstract

To provide a battery module in which a battery cell is deformed less when a laminate-type battery cell is in contact with a connection part for connecting edges of a first wall and a second wall of a case to each other.SOLUTION: The present invention has a curvature radius changing unit in which an inner surface 31 of a connection part 30 for connecting edges of a first wall 24 and a second wall 26 adjacent to each other of a case 15 to each other is a curved surface recessed toward a space and in which at least a part of the curved surface has a curvature radius which gradually becomes smaller from the first wall side to the second wall side, a battery cell 60F located closest to the first wall side having a part in contact with the curvature radius changing unit.SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] Patent Document 1 below discloses a battery module including a battery cell laminate configured by laminating a plurality of laminated battery cells, and a case for housing the battery cell laminate. This case has an upper wall portion, a lower wall portion, and a peripheral wall portion connecting the outer peripheral portions of the upper wall portion and the lower wall portion. Further, the peripheral wall portion includes a pair of first walls and a pair of second walls orthogonal to and connected to the first walls. Each battery cell is arranged along the facing direction of the pair of first walls.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In some cases, the above case may include four connecting portions that connect the ends of adjacent first walls and second walls and project toward the space inside the case. In this case, the longitudinal end of the battery cell facing the first wall may interfere with the connecting portion, and there is a risk that this end will be greatly deformed by contacting the connecting portion.

[0005] In consideration of the above facts, an object of the present invention is to obtain a battery module capable of reducing the amount of deformation of a battery cell when the laminated battery cell contacts a connecting portion connecting the ends of the first wall and the second wall of the case.

Means for Solving the Problems

[0006] The battery module of the first aspect includes a case having a pair of first walls spaced apart in a predetermined first direction, a pair of second walls spaced apart in a second direction orthogonal to the first direction, and four connecting portions connecting the ends of the adjacent first walls and second walls, and a plurality of laminated battery cells arranged in a line along the first direction in a space surrounded by the pair of first walls, the pair of second walls, and each of the connecting portions, and extending along the second direction. The inner surface of the connecting portion is a curved surface convex toward the space when the case is viewed along an orthogonal direction orthogonal to the first direction and the second direction, and at least a part of the curved surface is a curvature changing portion whose radius of curvature gradually decreases from the first wall side toward the second wall side. The battery cell located closest to the first wall side includes a portion that contacts the curvature changing portion when the case is viewed along the orthogonal direction.

[0007] The inner surface of the connecting portion of the battery module of the first aspect is a curved surface convex toward the space when the case is viewed along an orthogonal direction orthogonal to the first direction and the second direction. Further, at least a part of the curved surface is a curvature changing portion whose radius of curvature gradually decreases from the first wall side toward the second wall side. Further, the battery cell located closest to the first wall side includes a portion that contacts the curvature changing portion when the case is viewed along the orthogonal direction. Therefore, the battery module of the first aspect can reduce the amount of deformation of the thickness changing portion when a laminated battery cell contacts the connecting portion of the case. Accordingly, when a laminated battery cell contacts the connecting portion, the amount of deformation of the battery cell is reduced.

[0008] In the battery module of the second aspect, the portion of the battery cell located closest to the first wall side that contacts the curvature changing portion is a thickness changing portion whose thickness decreases toward the second wall side when the case is viewed along the orthogonal direction.

[0009] In the battery module of the second aspect, by making the portion that contacts the curvature changing portion a thickness changing portion, when a laminated battery cell contacts the connecting portion, the amount of deformation of the battery cell is further reduced.

[0010] In the third aspect, in the first aspect, the radius of curvature of the predetermined portion of the curved surface is equal to or greater than the dimension obtained by multiplying the thickness of the portion that contacts the predetermined portion of the battery cell by 0.5.

[0011] According to the battery module of the third aspect, the amount of deformation of the thickness change portion is likely to be small.

[0012] In the fourth aspect, in any one of the first to third aspects, the entire curved surface is the curvature change portion.

[0013] According to the battery module of the fourth aspect, the amount of deformation of the thickness change portion is likely to be small.

Advantages of the Invention

[0014] As described above, the battery module according to the present invention has an excellent effect that the amount of deformation of the battery cell can be reduced when a laminated battery cell contacts the connection portion connecting the ends of the first wall and the second wall of the case.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0016] (Overall Configuration of Vehicle 100) FIG. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in FIG. 1, the vehicle 100 is a battery electric vehicle (BEV) with the battery pack 10 mounted under the floor. In addition, the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle up-down direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction, respectively. When using the front-rear, left-right, and up-down directions to explain, unless otherwise specified, the front and rear in the vehicle front-rear direction, the left and right in the vehicle width direction, and the up and down in the vehicle up-down direction are shown.

[0017] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are arranged on the vehicle front side of the battery pack 10. Further, on the vehicle rear side of the battery pack 10, a motor 108, a gearbox 110, an inverter 112, and a charger 114 are arranged.

[0018] The direct current output from the battery pack 10 is supplied to the electric compressor 104, the PTC heater 106, the inverter 112, etc. after the voltage is adjusted by the DC / DC converter 102. In addition, by supplying power to the motor 108 via the inverter 112, the rear wheels rotate to make the vehicle 100 run.

[0019] A charging port 116 is provided on the right side of the rear part of the vehicle 100. By connecting a charging plug of an external charging facility (not shown) to the charging port 116, power can be stored in the battery pack 10 via the in-vehicle charger 114.

[0020] Note that the arrangement and structure of each component constituting the vehicle 100 are not limited to the above-described configuration. For example, it may be applied to a hybrid vehicle (HV) equipped with an engine or a plug-in hybrid electric vehicle (PHEV). Also, in the present embodiment, the vehicle is a rear-wheel drive vehicle with the motor 108 mounted at the rear of the vehicle, but it is not limited thereto, and it may be a front-wheel drive vehicle with the motor 108 mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, a vehicle equipped with in-wheel motors on each wheel may also be used.

[0021] Here, the battery pack 10 is configured to include a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the vehicle front-rear direction on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the vehicle front-rear direction on the left side of the vehicle 100. Also, each of the battery modules 11 is electrically connected.

[0022] A pair of voltage terminals 12 and connectors 14 are provided at both ends in the vehicle width direction of the battery module 11. A flexible printed circuit board 70 described later is connected to the connector 14. Also, bus bars (not shown) are welded to both ends in the vehicle width direction of the battery module 11.

[0023] As shown in FIGS. 1 and 2, each battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The case 15 constituting the outer shape of the battery module 11 is formed of an aluminum alloy. The case 15 includes a case body 20 and a lid body 50.

[0024] The length MW in the vehicle width direction of the battery module 11 is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

[0025] As shown in FIGS. 3 and 4, the case body 20 is an integrally molded product including a bottom wall portion 21 having a rectangular planar shape, a peripheral wall portion 23 connected to the outer peripheral edge portion of the upper surface of the bottom wall portion 21, and four connecting portions 30, 35, 40, 45. Further, the peripheral wall portion 23 includes a front wall portion (first wall) 24, a rear wall portion (first wall) 25, a left side wall portion (second wall) 26, and a right side wall portion (second wall) 27. In plan view, the front wall portion 24 and the rear wall portion 25 are parallel to the left-right direction (second direction) and face each other in the front-rear direction (first direction). In plan view, the left side wall portion 26 and the right side wall portion 27 are parallel to the front-rear direction (first direction) and face each other in the left-right direction (second direction).

[0026] A connecting portion 30 is provided between the left end portion of the front wall portion 24 and the front end portion of the left side wall portion 26, and a connecting portion 35 is provided between the right end portion of the front wall portion 24 and the front end portion of the right side wall portion 27. Further, a connecting portion 40 is provided between the left end portion of the rear wall portion 25 and the rear end portion of the left side wall portion 26, and a connecting portion 45 is provided between the right end portion of the rear wall portion 25 and the rear end portion of the right side wall portion 27. The lower ends of the connecting portions 30, 35, 40, 45 are connected to the bottom wall portion 21. Further, the upper surfaces of the connecting portions 30, 35, 40, 45 and the upper surface of the peripheral wall portion 23 are planes that are continuous with each other and orthogonal to the vertical direction (orthogonal direction). A plurality of laminated battery cells 60 are housed in the space 29 surrounded by the bottom wall portion 21 and the peripheral wall portion 23.

[0027] The inner surfaces 31, 36, 41, 46, which are the surfaces of the connecting portions 30, 35, 40, 45 facing the space 29, are constituted by convex curved surfaces on the space 29 side when viewed in the vertical direction (orthogonal direction).

[0028] As shown in FIG. 7, the radius of curvature RP centered on the corner 20A where the front wall portion 24 and the left side wall portion 26 intersect when viewed along the vertical direction of the inner surface 31 of the connecting portion 30 gradually decreases from the front wall portion 24 side toward the left side wall portion 26 side. Similarly, the radius of curvature centered on the corner 20B where the front wall portion 24 and the right side wall portion 27 intersect when viewed along the vertical direction of the inner surface 36 of the connecting portion 35 gradually decreases from the front wall portion 24 side toward the right side wall portion 27 side. The radius of curvature centered on the corner 20C where the rear wall portion 25 and the left side wall portion 26 intersect when viewed along the vertical direction of the inner surface 41 of the connecting portion 40 gradually decreases from the rear wall portion 25 side toward the left side wall portion 26 side. The radius of curvature centered on the corner 20D where the rear wall portion 25 and the right side wall portion 27 intersect when viewed along the vertical direction of the inner surface 46 of the connecting portion 45 gradually decreases from the rear wall portion 25 side toward the right side wall portion 27 side. That is, the entire inner surface 31, the entire inner surface 36, the entire inner surface 41, and the entire inner surface 46 are constituted by the curvature changing portions.

[0029] As shown in FIGS. 2 and 3, the lid body 50 is constituted by a rectangular plate material. Through holes 51 are formed at four corners of the lid body 50.

[0030] As shown in FIG. 4, a plurality of battery cells 60 are housed inside the case body 20 in an arranged state. In this embodiment, as an example, 24 battery cells 60 are arranged in the vehicle front-rear direction and adhered to each other (in FIG. 4, only some of the battery cells 60 are shown).

[0031] A flexible printed circuit (FPC) 70 is disposed on the battery cell 60. The flexible printed circuit 70 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and thermistors 75 are provided at both ends of the flexible printed circuit 70, respectively. The thermistors 75 are not adhered to the battery cell 60 and are pressed toward the battery cell 60 side by the lid body 50.

[0032] Also, as shown in FIG. 4, inside the case body 20, a cushioning material 77 facing the inner surface of the front wall portion 24 and a cushioning material 77 facing the inner surface of the rear wall portion 25 are accommodated. The thickness direction of the two cushioning materials 77 coincides with the arrangement direction (lamination direction) of the battery cells 60. For example, the cushioning material 77 is a thin plate-like member that can be elastically deformed.

[0033] FIG. 5 is a schematic view of the battery cells 60 accommodated in the battery module 11 as viewed from the thickness direction of the battery cells 60. As is clear from FIGS. 4 and 5, the battery cells 60 are formed in a substantially rectangular plate shape.

[0034] As shown in FIGS. 5 to 7, the battery cell 60 includes a positive electrode sheet 61, a negative electrode sheet 62, separators 63, 64, and a laminate film 67. The battery cell 60 has a structure in which a laminate including the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63, 64 is covered with a laminate film 67. As shown in FIG. 6, the positive electrode sheet 61 is sandwiched between the separator 63 and the separator 64, and the separator 64 is sandwiched between the positive electrode sheet 61 and the negative electrode sheet 62. The positive electrode sheet 61, the negative electrode sheet 62, and the separators 63, 64 are long strip-shaped flexible members extending along a predetermined direction (the left-right direction in FIG. 6). The positive electrode sheet 61 includes a long strip-shaped positive electrode body and positive electrode active materials coated on both surfaces of the positive electrode body. However, the positive electrode active material is not coated on the positive electrode terminal 61A, which is one end of the positive electrode body. The negative electrode sheet 62 includes a long strip-shaped negative electrode body and negative electrode active materials coated on both surfaces of the negative electrode body. However, the negative electrode active material is not coated on the negative electrode terminal 62A, which is one end of the negative electrode body. The positive electrode terminal 61A and the negative electrode terminal 62A protrude from the ends of the separators 63, 64. Also, the end portion 61B of the positive electrode sheet 61 on the side opposite to the positive electrode terminal 61A is located on the positive electrode terminal 61A side with respect to the end portions of the separators 63, 64 on the negative electrode terminal 62A side. The end portion 62B of the negative electrode sheet 62 on the side opposite to the negative electrode terminal 62A is located on the negative electrode terminal 62A side with respect to the end portions of the separators 63, 64 on the positive electrode terminal 61A side.

[0035] As shown in FIG. 6 here, the region constituted by the positive electrode terminal 61A of the laminate is defined as the first region AR1, the region constituted by the portion on the positive electrode terminal 61A side from the end portions 62B of the separators 63 and 64 is defined as the second region AR2, the region constituted by the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64 is defined as the third region AR3, the region constituted by the portion on the negative electrode terminal 62A side from the end portions 61B of the separators 63 and 64 is defined as the fourth region AR4, and the region constituted by the negative electrode terminal 62A is defined as the fifth region AR5. In this case, the thickness T of the laminate (see FIGS. 6 and 7) has the relationship of the first region AR1, the fifth region AR5 < the second region AR2, the fourth region AR4 < the third region AR3.

[0036] The laminate having the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64 is folded ninety times or wound, and is sealed with a laminate film 67 that covers the laminate in this state from the outer peripheral side. In this embodiment, as an example, by folding and bonding an embossed sheet-like laminate film 67, a housing portion for a portion excluding a part of the positive electrode terminal 61A and a part of the negative electrode terminal 62A of the laminate is formed. Note that both a single cup emboss structure with one embossing and a double cup emboss structure with two embossings can be adopted, but in this embodiment, a single cup emboss structure with a draw depth of about 8 mm to 10 mm is adopted.

[0037] The upper ends at both longitudinal ends of the battery cell 60 are bent, and the corners form the outer shape. Also, the upper end portion of the battery cell 60 is bent, and a fixing tape 78 is wound along the longitudinal direction on the upper end portion of the battery cell 60.

[0038] As shown in FIGS. 5 and 6, a part of the positive electrode terminal 61A and the negative electrode terminal 62A protrudes from both longitudinal ends of the laminate film 67, respectively. In this embodiment, as an example, the positive electrode terminal 61A and the negative electrode terminal 62A are provided at positions offset downward from the center in the vertical direction of the battery cell 60. The positive electrode terminal 61A and the negative electrode terminal 62A are joined to a bus bar (not shown) by laser welding or the like. Further, a region where the positive electrode terminal 61A protrudes from the laminate film 67 in the battery cell 60 is defined as a first region AR1-X, and a region where the negative electrode terminal 62A protrudes from the laminate film 67 is defined as a fifth region AR5-X. Further, a region located between the first region AR1-X and the third region AR3 of the laminate film 67 is defined as a second region AR2-X, a region corresponding to the third region AR3 is defined as a third region AR3-X, and a region located between the fifth region AR5-X and the third region AR3-X is defined as a fourth region AR4-X. In this case, the thicknesses T of the first region AR1-X, the second region AR2-X, the third region AR3-X, the fourth region AR4-X, and the fifth region AR5-X satisfy the relationship of the first region AR1-X, the fifth region AR5-X < the second region AR2-X, the fourth region AR4-X < the third region AR3-X. Further, as shown in FIGS. 5 and 6, a portion corresponding to the second region AR2-X of the battery cell 60 is a thickness change portion 60TG1, and a portion corresponding to the fourth region AR4-X is a thickness change portion 60TG2. The thickness change portion 60TG1 is a portion where the thickness T decreases as it goes toward the left side (positive electrode terminal 61A) side, and the thickness change portion 60TG2 is a portion where the thickness T decreases as it goes toward the right side (negative electrode terminal 62A) side.

[0039] As shown in FIG. 5, the length CW1 in the vehicle width direction of the battery cell 60 is, for example, 530 mm to 600 mm, the length CW2 of the third region AR3 of the laminate is, for example, 500 mm to 520 mm, and the height (width direction dimension) CH of the battery cell 60 is, for example, 80 mm to 110 mm. Further, the thickness of the battery cell 60 is 7.0 mm to 9.0 mm, and the height TH of the positive electrode terminal 61A and the negative electrode terminal 62A is 40 mm to 50 mm.

[0040] As shown in FIG. 2, a lid body 50 is placed on the upper surface of a case body 20 that houses a battery cell 60, a flexible printed circuit board 70, and a fixing tape 78. Screws 80 are inserted into four through holes 51 of the lid body 50 from above, and the male screw grooves of the respective screws 80 are screwed into corresponding female screw holes 32. Therefore, the outer peripheral portion of the lower surface of the lid body 50 is in close contact with the upper end surface of the case body 20.

[0041] As shown in FIG. 4, 24 battery cells 60 are housed side by side in the vehicle front-rear direction inside the case body 20. Further, the 24 battery cells 60 are sandwiched in the front-rear direction by a front buffer material 77 that contacts the inner surface of the front wall portion 24 and a rear buffer material 77 that contacts the inner surface of the rear wall portion 25. Further, the left end portion of each battery cell 60 is located between the connection portions 30 and 40, and the right end portion of each battery cell 60 is located between the connection portions 35 and 45. Further, the thickness change portion 60TG1 of the battery cell 60 located at the most front side contacts the inner surface 31, and the thickness change portion 60TG2 contacts the inner surface 36. Also, the thickness change portion 60TG1 of the battery cell 60 located at the most rear side contacts the inner surface 41, and the thickness change portion 60TG2 contacts the inner surface 46. Therefore, the thickness change portions 60TG1 and 60TG2 of several battery cells 60 located at the front side and the rear side are bent by the connection portions 30, 35, 40, and 45. Here, the battery cell 60 located at the most front among the 24 battery cells 60 is referred to as a battery cell 60F, and the battery cell 60 located at the most rear is referred to as a battery cell 60R. The thickness change portions 60TG1 and 60TG2 of the battery cell 60F are directly pressed by the connection portions 30 and 35, and the thickness change portions 60TG1 and 60TG2 of the battery cell 60R are directly pressed by the connection portions 40 and 45. Therefore, the bending amounts of the thickness change portions 60TG1 and 60TG2 of the battery cells 60F and 60R are larger than those of the other battery cells 60. When the thickness change portions 60TG1 and 60TG2 of the battery cell 60 are bent, forces corresponding to the bending amounts reach the first region AR1, the second region AR2, the fourth region AR4, and the fifth region AR5 of the laminate, respectively. Therefore, it is preferable that the deformation amounts (bending amounts) of the thickness change portions 60TG1 and 60TG2 of the battery cell 60 are small.

[0042] Incidentally, as described above, the thickness T of the thickness change portion 60TG1 of the battery cell 60F when viewed in the vertical direction gradually decreases toward the tip end portion (positive electrode terminal 61A) side. Further, the thickness change portion 60TG1 of the battery cell 60F contacts the inner surface 31 of the connection portion 30. As described above, the radius of curvature RP centered on the corner portion 20A when viewed along the vertical direction of the inner surface 31 gradually becomes smaller from the front wall portion 24 side toward the left side wall portion 26 side. Therefore, compared with the case where the radius of curvature RP of the inner surface 31 is constant over the entire region of the inner surface 31, the force exerted from the connection portion 30 (inner surface 31) to the thickness change portion 60TG1 of the battery cell 60F is small. Therefore, although a larger force acts on the thickness change portion 60TG1 of the battery cell 60F than on the thickness change portion 60TG1 of the battery cells 60 (excluding the battery cell 60R) located behind the battery cell 60F inside the battery cell 60F, the end portion 62B of the negative electrode sheet 62 contacts the positive electrode sheet 61 while penetrating the separator 64 inside the laminate film 67 of the battery cell 60F, so the risk of a short circuit occurring in the battery cell 60F is small.

[0043] Similarly, the thickness change portion 60TG2 of the battery cell 60F contacts the inner surface 36 of the connection portion 35. The radius of curvature centered on the corner portion 20B when viewed along the vertical direction of the inner surface 36 gradually becomes smaller from the front wall portion 24 side toward the right side wall portion 27 side. Therefore, compared with the case where the radius of curvature of the inner surface 36 is constant over the entire region of the inner surface 36, the force exerted from the connection portion 35 (inner surface 36) to the thickness change portion 60TG2 of the battery cell 60F is small.

[0044] Also, the thickness change portion 60TG1 of the battery cell 60R contacts the inner surface 41 of the connection portion 40. The radius of curvature centered on the corner portion 20C when viewed along the vertical direction of the inner surface 41 gradually decreases from the rear wall portion 25 side toward the left side wall portion 26 side. Therefore, the force exerted from the connection portion 40 (inner surface 41) to the thickness change portion 60TG1 of the battery cell 60R is smaller than the case where the radius of curvature of the inner surface 41 is constant over the entire region of the inner surface 41. Similarly, the thickness change portion 60TG2 of the battery cell 60R contacts the inner surface 46 of the connection portion 45. The radius of curvature centered on the corner portion 20D when viewed along the vertical direction of the inner surface 46 gradually decreases from the rear wall portion 25 side toward the right side wall portion 27 side. Therefore, the force exerted from the connection portion 45 (inner surface 46) to the thickness change portion 60TG2 of the battery cell 60R is smaller than the case where the radius of curvature of the inner surface 46 is constant over the entire region of the inner surface 46.

[0045] In addition, in order to reduce the force exerted from the connection portions 30, 35, 40, 45 to the thickness change portions 60TG1, 60TG2 of the battery cells 60F, 60R, it is preferable that the radius of curvature of each part (predetermined part) of the inner surfaces 31, 36, 41, 46 is larger than the dimension obtained by multiplying the thickness of the part (predetermined part) where each of the thickness change portions 60TG1, 60TG2 contacts by 0.5. For example, it is preferable that the radius of curvature RP (mm) of the predetermined part 31P of the inner surface shown in FIG. 7 is equal to or greater than the value obtained by multiplying the thickness TP (mm) of the part that contacts the predetermined part 31P in the thickness change portion 60TG1 of the battery cell 60F by 0.5.

[0046] Also, the 24 battery cells 60 are sandwiched in the front-rear direction by the front buffer material 77 that contacts the inner surface of the front wall portion 24 and the rear buffer material 77 that contacts the inner surface of the rear wall portion 25. Therefore, the front and rear buffer materials 77 can suppress the vibration of each battery cell 60 within the case 15. Furthermore, the front and rear buffer materials 77 can absorb the thermal expansion and contraction of the battery cells 60.

[0047] As described above, the battery module according to the embodiment has been described, but these can be appropriately designed and changed within a range not departing from the gist of the present invention.

[0048] For example, the connecting portion 30 may be configured such that the radius of curvature RP centered on the corner portion 20A when viewed along the vertical direction of the inner surface 31 gradually decreases from the front wall portion 24 side toward the left side wall portion 26 side only in a partial region between the end portion on the front wall portion 24 side and the end portion on the left side wall portion 26 side of the inner surface 31. That is, a curvature change portion may be formed only in a partial region of the inner surface 31.

[0049] Similarly, a curvature change portion may be formed only in a partial region of the inner surface 36, only in a partial region of the inner surface 41, or only in a partial region of the inner surface 46.

[0050] Further, the battery module 11 may be mounted on the vehicle 100 in a manner orthogonal to the left - right direction of the lid body 50.

Explanation of Reference Numerals

[0051] 11 Battery module 15 Case 24 Front wall portion (first wall) 25 Rear wall portion (first wall) 26 Left side wall portion (second wall) 27 Right side wall portion (second wall) 29 Space 30 Connecting portion 35 Connecting portion 36 Inner surface 40 Connecting portion 41 Inner surface 45 Connecting portion 46 Inner surface 60 Battery cell 60TG1 60TG2 Thickness change portion

Claims

1. a case including a pair of first walls spaced apart in a predetermined first direction, a pair of second walls spaced apart in a second direction perpendicular to the first direction, and four connection portions connecting ends of the first walls and the second walls adjacent to each other; a plurality of laminated battery cells that are housed in a space surrounded by the pair of first walls, the pair of second walls, and the connection portions and that extend along the second direction; Equipped with an inner surface of the connection portion is a curved surface that is convex toward the space when the case is viewed along a direction perpendicular to the first direction and the second direction, and at least a part of the curved surface is a curvature changing portion whose radius of curvature gradually decreases from the first wall side toward the second wall side, The battery module includes a portion in which the battery cell located closest to the first wall contacts the curvature change portion when the case is viewed along the orthogonal direction.

2. 2. The battery module according to claim 1, wherein a portion of the battery cell located closest to the first wall that contacts the curvature change portion is a thickness change portion whose thickness decreases toward the second wall when viewed along the orthogonal direction.

3. 2 . The battery module according to claim 1 , wherein the radius of curvature of the predetermined portion of the curved surface is equal to or greater than a dimension obtained by multiplying the thickness of the portion of the battery cell that contacts the predetermined portion by 0.

5.

4. 4. The battery module according to claim 1, wherein the entire curved surface is the curvature changing portion.

Images