Battery module

Abstract

The invention relates to a battery module. An inner surface of a connection portion connecting end portions of a first wall and a second wall adjacent to each other of the case is a curved surface protruding toward the space side, at least a portion of the curved surface is a curvature change portion having a curvature radius gradually decreasing from the first wall side to the second wall side, and the battery cell closest to the first wall side includes a portion in contact with the curvature change portion.

Description

Technical Field

[0001] The present disclosure relates to a battery module. Background Art

[0002] Japanese Patent Application No. 2021-509524 discloses a battery module having a battery cell stack formed by stacking a plurality of laminated battery cells and a housing for accommodating the battery cell stack. The housing 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 to each other. Moreover, the peripheral wall portion has a pair of first walls and a pair of second walls that are orthogonal to the first wall and connected to the first wall. Each battery cell is arranged along the opposite direction of the pair of first walls.

[0003] The housing may have four connecting portions that connect the ends of the adjacent first wall and second wall and protrude toward the space inside the housing. In this case, the end of the battery cell in the longitudinal direction opposite to the first wall interferes with the connecting portion, and the end may be greatly deformed due to contact with the connecting portion.

[0004] The present disclosure takes the above-mentioned facts into consideration and aims to obtain a battery module capable of reducing the deformation amount of a laminated battery cell when the laminated battery cell contacts a connection portion connecting the ends of a first wall and a second wall of a case. Summary of the invention

[0005] The battery module of the first scheme comprises: a shell having a pair of first walls separated in a predetermined first direction, a pair of second walls separated in a second direction orthogonal to the first direction, and four connecting parts connecting the ends of adjacent first walls and second walls to each other; and a plurality of laminated battery cells, which are accommodated in a space surrounded by a pair of the first walls, a pair of the second walls, and the connecting parts in a state of being arranged along the first direction, and extend along the second direction, the inner surface of the connecting part is a curved surface convex to the space side when the shell is observed 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 change part whose curvature radius gradually decreases as it goes from the first wall side to the second wall side, and the battery cell closest to the first wall side has a part that contacts the curvature change part when the shell is observed along the orthogonal direction.

[0006] The inner surface of the connection portion of the battery module of the first embodiment is a curved surface that bulges toward the space side when the outer shell is observed along an orthogonal direction that is orthogonal to the first direction and the second direction. Moreover, at least a portion of the curved surface is a curvature change portion whose curvature radius gradually decreases as it goes from the first wall side to the second wall side. Moreover, the battery cell closest to the first wall side has a portion that contacts the curvature change portion when the outer shell is observed along the orthogonal direction. Therefore, the battery module of the first embodiment can reduce the deformation of the thickness change portion when the laminated battery cell contacts the connection portion of the outer shell. Therefore, when the laminated battery cell contacts the connection portion, the deformation of the battery cell becomes smaller.

[0007] In the battery module according to the second aspect, the portion of the battery cell closest to the first wall that contacts the curvature changing portion is a thickness changing portion whose thickness decreases toward the second wall when the outer casing is viewed in the orthogonal direction.

[0008] In the battery module of the second aspect, since the portion in contact with the curvature changing portion is the thickness changing portion, when the laminated battery cell contacts the connection portion, the amount of deformation of the battery cell is further reduced.

[0009] In the battery module according to claim 3 , according to claim 1 , the radius of curvature of the predetermined portion of the curved surface is equal to or larger than a size obtained by multiplying the thickness of a portion of the battery cell in contact with the predetermined portion by 0.5.

[0010] According to the battery module of the third aspect, the deformation amount of the thickness change portion can be easily reduced.

[0011] A battery module according to a fourth aspect is according to any one of the first to third aspects, wherein the entire curved surface is the curvature changing portion.

[0012] In the battery module according to the fourth aspect, the deformation amount of the thickness change portion can be easily reduced.

[0013] As described above, the battery module according to the present disclosure has an excellent effect of reducing the amount of deformation of the battery cell when the 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

[0014] Typical embodiments of the present disclosure will be described in detail based on the following drawings.

[0015] Figure 1 It is a bottom view of a vehicle to which the battery module according to the embodiment is applied.

[0016] Figure 2 It is a three-dimensional diagram of a battery module.

[0017] Figure 3 It is an exploded perspective view of the outer casing of the battery module.

[0018] Figure 4 It is a top view of the housing body, battery unit, buffer and flexible printed circuit board.

[0019] Figure 5 is a side view of a battery cell.

[0020] Figure 6 This is a diagram of a stacked product including a positive electrode sheet, a negative electrode sheet, and two separators when viewed along the width direction.

[0021] Figure 7 It is a top view of the housing body, the battery cell located on the frontmost side, and a portion of the buffer member on the front side. DETAILED DESCRIPTION

[0022] (Overall Structure of Vehicle 100)

[0023] Figure 1 FIG. 1 is a schematic plan view showing the main parts of a vehicle 100 to which the battery pack 10 according to the embodiment is applied. Figure 1 As shown, the vehicle 100 is an electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrows UP, FR, and LH in each figure respectively indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-back direction, and the left side in the vehicle width direction. When the front-back, left-right, up-down and down directions are used for explanation, unless otherwise specified, they indicate the front-back in the vehicle front-back direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction.

[0024] The vehicle 100 of the present embodiment is provided with a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 as an example on the vehicle front side relative to the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are provided on the vehicle rear side relative to the battery pack 10.

[0025] The DC current output from battery pack 10 is regulated in voltage by DC / DC converter 102 and then supplied to electric compressor 104, PTC heater 106, inverter 112, etc. In addition, by supplying electric power to motor 108 via inverter 112, the rear wheels rotate and vehicle 100 travels.

[0026] A charging port 116 is provided on the right side of the rear portion of the vehicle 100 . By connecting a charging plug of an external charging device (not shown) to the charging port 116 , electric power can be stored in the battery pack 10 via the on-vehicle charger 114 .

[0027] In addition, the configuration and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, it can also be applied to a hybrid vehicle (HV: Hybrid Vehicle) or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle) equipped with an engine. In addition, in the present embodiment, the motor 108 is mounted on the rear of the vehicle and is a rear-wheel drive vehicle, but it is not limited to this. It can also be a front-wheel drive vehicle with the motor 108 mounted on the front of the vehicle, and a pair of motors 108 can be mounted on the front and rear of the vehicle. Moreover, it can also be a vehicle with a hub motor on each wheel.

[0028] 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, five battery modules 11 are arranged in the vehicle front-rear direction on the right side of the vehicle 100, and five battery modules 11 are arranged in the vehicle front-rear direction on the left side of the vehicle 100. In addition, each battery module 11 is electrically connected.

[0029] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 70 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0030] like Figure 1 and Figure 2 As shown, each battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer casing 15 constituting the outer shape of the battery module 11 is formed of an aluminum alloy. The outer casing 15 includes an outer casing body 20 and a cover 50 .

[0031] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle vertical direction of, for example, 80 mm to 110 mm.

[0032] like Figure 3 and Figure 4As shown, the housing body 20 is an integrally formed 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. In addition, 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 a 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-back direction (first direction). In a plan view, the left side wall portion 26 and the right side wall portion 27 are parallel to the front-back direction (first direction) and face each other in the left-right direction (second direction).

[0033] A connection portion 30 is provided between the left end of the front wall portion 24 and the front end of the left side wall portion 26, and a connection portion 35 is provided between the right end of the front wall portion 24 and the front end of the right side wall portion 27. Furthermore, a connection portion 40 is provided between the left end of the rear wall portion 25 and the rear end of the left side wall portion 26, and a connection portion 45 is provided between the right end of the rear wall portion 25 and the rear end of the right side wall portion 27. The lower ends of the connection portions 30, 35, 40, 45 are connected to the bottom wall portion 21. Moreover, the upper surfaces of the connection 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 up-down direction (orthogonal direction). A plurality of laminated battery cells 60 are accommodated in the space 29 surrounded by the bottom wall portion 21 and the peripheral wall portion 23.

[0034] The inner surfaces 31 , 36 , 41 , 46 of the connection portions 30 , 35 , 40 , 45 that face the space 29 are formed of curved surfaces that are convex toward the space 29 when viewed in the up-down direction (orthogonal direction).

[0035] like Figure 7 As shown, the radius of curvature RP of the inner surface 31 of the connection portion 30, which is centered at the corner 20A where the front wall portion 24 and the left side wall portion 26 intersect when viewed in the vertical direction, gradually decreases as it goes from the front wall portion 24 side to the left side wall portion 26 side. Similarly, the radius of curvature of the inner surface 36 of the connection portion 35, which is centered at the corner 20B where the front wall portion 24 and the right side wall portion 27 intersect when viewed in the vertical direction, gradually decreases as it goes from the front wall portion 24 side to the right side wall portion 27 side. The radius of curvature of the inner surface 41 of the connection portion 40, which is centered at the corner 20C where the rear wall portion 25 and the left side wall portion 26 intersect when viewed in the vertical direction, gradually decreases as it goes from the rear wall portion 25 side to the left side wall portion 26 side. The radius of curvature of the inner surface 46 of the connection portion 45, which is centered at the corner 20D where the rear wall portion 25 and the right side wall portion 27 intersect when viewed in the vertical direction, gradually decreases as it goes from the rear wall portion 25 side to 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 portion.

[0036] like Figure 2 and Figure 3 As shown in FIG. 1 , the cover 50 is formed of a rectangular plate. Through holes 51 are formed at four corners of the cover 50 .

[0037] like Figure 4 As shown in FIG. 1 , a plurality of battery cells 60 are housed in an arranged state inside the housing body 20. In the present embodiment, as an example, 24 battery cells 60 are arranged in the front-rear direction of the vehicle and bonded to each other (in Figure 4 , only a portion of the battery cell 60 is shown).

[0038] 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. The thermistor 75 is not bonded to the battery cell 60, but is pressed toward the battery cell 60 by the cover 50.

[0039] In addition, if Figure 4 As shown, a buffer member 77 facing the inner surface of the front wall portion 24 and a buffer member 77 facing the inner surface of the rear wall portion 25 are accommodated inside the housing body 20. The thickness direction of the two buffer members 77 is consistent with the arrangement direction (stacking direction) of the battery cells 60. For example, the buffer member 77 is a thin plate-shaped member that can be elastically deformed.

[0040] Figure 5 1 is a schematic diagram of a battery cell 60 housed in a battery module 11 when viewed from the thickness direction of the battery cell 60. Figure 4 and Figure 5 As is apparent, the battery unit 60 is formed in a substantially rectangular plate shape.

[0041] like Figure 5 to Figure 7 As shown in FIG. 6 , the battery cell 60 includes a positive electrode sheet 61, a negative electrode sheet 62, separators 63 and 64, and a laminate film 67. The battery cell 60 has a structure in which a laminate having the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64 is covered with the laminate film 67. Figure 6 As shown, the positive electrode sheet 61 is sandwiched by a separator 63 and a separator 64, and the separator 64 is sandwiched by 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 and 64 are arranged along a predetermined direction ( Figure 6A flexible member in the shape of a long strip extending in the left and right directions of the positive electrode sheet 61. The positive electrode sheet 61 includes a positive electrode body in the shape of a long strip and a positive electrode active material applied to both sides of the positive electrode body. However, the positive electrode active material is not applied to the end of one side of the positive electrode body, that is, the positive terminal 61A. The negative electrode sheet 62 includes a negative electrode body in the shape of a long strip and a negative electrode active material applied to both sides of the negative electrode body. However, the negative electrode active material is not applied to the end of one side of the negative electrode body, that is, the negative terminal 62A. The positive terminal 61A and the negative terminal 62A protrude from the ends of the separators 63 and 64. In addition, the end 61B of the positive electrode sheet 61 on the opposite side to the positive terminal 61A is located closer to the positive terminal 61A side than the end of the separators 63 and 64 on the negative terminal 62A side. An end portion 62B of the negative electrode sheet 62 on the opposite side to the negative electrode terminal 62A is located closer to the negative electrode terminal 62A than ends of the separators 63 and 64 on the positive electrode terminal 61A side.

[0042] Here, if Figure 6 As shown, the region of the stacked body formed by the positive terminal 61A is defined as the first region AR1, the region formed by the portion of the separators 63 and 64 closer to the positive terminal 61A than the end 62B is defined as the second region AR2, the region formed by the positive electrode sheet 61, the negative electrode sheet 62, the separators 63 and 64 is defined as the third region AR3, the region formed by the portion of the separators 63 and 64 closer to the negative terminal 62A than the end 61B is defined as the fourth region AR4, and the region formed by the negative terminal 62A is defined as the fifth region AR5. In this case, the thickness T (refer to Figure 6 , Figure 7 ) becomes the relationship of the first area AR1, the fifth area AR5<the second area AR2, and the fourth area AR4<the third area AR3.

[0043] The stacked body having the positive electrode sheet 61, the negative electrode sheet 62, the separators 63 and 64 is zigzag or wound, and is sealed by a laminate film 67 covering the stacked body in this state from the outer peripheral side. In the present embodiment, as an example, the accommodating portion of the stacked body except for a part of the positive terminal 61A and a part of the negative terminal 62A is formed by folding and sticking together the sheet-like laminate film 67 after embossing (embossing). In addition, both a single cup embossing structure with embossing at one place and a double cup embossing structure with embossing at two places can be adopted, but in the present embodiment, a single cup embossing structure with a drawing depth of about 8 mm to 10 mm is adopted.

[0044] The upper end of the battery cell 60 is bent at both ends in the longitudinal direction, and the corners become the outer shape. In addition, the upper end of the battery cell 60 is bent, and a fixing band 78 is wound around the upper end of the battery cell 60 along the longitudinal direction.

[0045] like Figure 5 and Figure 6 As shown, a portion of the positive terminal 61A and the negative terminal 62A protrude from both ends of the laminate film 67 in the longitudinal direction. In the present embodiment, as an example, the positive terminal 61A and the negative terminal 62A are provided at a position offset downward from the center of the vertical direction of the battery cell 60. The positive terminal 61A and the negative terminal 62A are joined to a bus bar (not shown) by laser welding or the like. Furthermore, the area of ​​the positive terminal 61A in the battery cell 60 protruding from the laminate film 67 is defined as the first area AR1-X, and the area of ​​the negative terminal 62A protruding from the laminate film 67 is defined as the fifth area AR5-X. Furthermore, the area of ​​the laminate film 67 between the first area AR1-X and the third area AR3 is defined as the second area AR2-X, the area corresponding to the third area AR3 is defined as the third area AR3-X, and the area between the fifth area AR5-X and the third area AR3-X is defined as the fourth area AR4-X. In this case, the thickness 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 is in 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. Figure 5 and Figure 6 As shown, the portion of the battery cell 60 corresponding to the second region AR2-X is the thickness variation portion 60TG1, and the portion corresponding to the fourth region AR4-X is the thickness variation portion 60TG2. The thickness variation portion 60TG1 is a portion where the thickness T decreases as it goes to the left side (positive electrode terminal 61A), and the thickness variation portion 60TG2 is a portion where the thickness T decreases as it goes to the right side (negative electrode terminal 62A).

[0046] like Figure 5 As shown, the length CW1 of the battery cell 60 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the third region AR3 of the stack is, for example, 500 mm to 520 mm, and the height (width dimension) CH of the battery cell 60 is, for example, 80 mm to 110 mm. In addition, the thickness of the battery cell 60 is 7.0 mm to 9.0 mm, and the height TH of the positive terminal 61A and the negative terminal 62A is 40 mm to 50 mm.

[0047] like Figure 2As shown, the cover 50 is placed on the upper surface of the housing body 20 housing the battery cell 60, the flexible printed circuit board 70 and the fixing belt 78, and screws 80 are inserted from above into the four through holes 51 of the cover 50, and the male thread groove of each screw 80 is screwed into the corresponding female thread hole 32. Thus, the outer peripheral portion of the lower surface of the cover 50 is in close contact with the upper end surface of the housing body 20.

[0048] like Figure 4 As shown, inside the housing body 20, 24 battery cells 60 are arranged and stored in the front-to-back direction of the vehicle, and the 24 battery cells 60 are sandwiched in the front-to-back direction by the front buffer 77 in contact with the inner surface of the front wall 24 and the rear buffer 77 in contact with the inner surface of the rear wall 25. In addition, the left end of each battery cell 60 is located between the connection part 30 and the connection part 40, and the right end of each battery cell 60 is located between the connection part 35 and the connection part 45. In addition, the thickness change part 60TG1 of the battery cell 60 located at the frontmost side is in contact with the inner surface 31, and the thickness change part 60TG2 is in contact with the inner surface 36. In addition, the thickness change part 60TG1 of the battery cell 60 located at the rearmost side is in contact with the inner surface 41, and the thickness change part 60TG2 is in contact with the inner surface 46. Therefore, the thickness change parts 60TG1 and 60TG2 of the battery cells 60 located at the front and rear sides are bent by the connection parts 30, 35, 40, and 45. Here, among the 24 battery cells 60, the battery cell 60 located at the front is called the battery cell 60F, and the battery cell 60 located at the rear is called the battery cell 60R. The thickness change parts 60TG1 and 60TG2 of the battery cell 60F are directly pressed by the connecting parts 30 and 35, and the thickness change parts 60TG1 and 60TG2 of the battery cell 60R are directly pressed by the connecting parts 40 and 45. Therefore, the bending amount of the thickness change parts 60TG1 and 60TG2 of the battery cells 60F and 60R is greater than that of other battery cells 60. If the thickness change parts 60TG1 and 60TG2 of the battery cells 60 are bent, the force corresponding to the bending amount will act on the first area AR1, the second area AR2, the fourth area AR4, and the fifth area AR5 of the above-mentioned stacked body, respectively. Therefore, the deformation amount (bending amount) of the thickness change parts 60TG1 and 60TG2 of the battery cells 60 is preferably small.

[0049] As described above, the thickness T of the thickness change portion 60TG1 of the battery cell 60F when viewed in the up-down direction gradually decreases as it goes to the top end (positive terminal 61A) side. Moreover, 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 of the inner surface 31 centered on the corner 20A when viewed in the up-down direction gradually decreases as it goes from the front wall portion 24 side to 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 in the entire area of ​​the inner surface 31, the force acting from the connection portion 30 (inner surface 31) to the thickness change portion 60TG1 of the battery cell 60F is small. Therefore, although a force greater than that of the thickness change portion 60TG1 of the battery cell 60 (except the battery cell 60R) located to the rear of the battery cell 60F is applied inside the thickness change portion 60TG1 of the battery cell 60F, the possibility of a short circuit occurring in the battery cell 60F due to the end portion 62B of the negative electrode sheet 62 penetrating the separator 64 and contacting the positive electrode sheet 61 inside the laminate film 67 of the battery cell 60F is small.

[0050] 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 of the inner surface 36 centered at the corner 20B when viewed in the up-down direction gradually decreases as it goes from the front wall portion 24 side to the right side wall portion 27 side. Therefore, compared with the case where the radius of curvature of the inner surface 36 is constant in the entire area of ​​the inner surface 36, the force acting from the connection portion 35 (inner surface 36) on the thickness change portion 60TG2 of the battery cell 60F is small.

[0051] In addition, the thickness change portion 60TG1 of the battery cell 60R contacts the inner surface 41 of the connection portion 40. The radius of curvature of the inner surface 41, which is centered at the corner 20C when viewed in the up-down direction, gradually decreases as it goes from the rear wall portion 25 side to the left side wall portion 26 side. Therefore, compared with the case where the radius of curvature of the inner surface 41 is constant in the entire area of ​​the inner surface 41, the force acting from the connection portion 40 (inner surface 41) to the thickness change portion 60TG1 of the battery cell 60R is small. 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 of the inner surface 46, which is centered at the corner 20D when viewed in the up-down direction, gradually decreases as it goes from the rear wall portion 25 side to the right side wall portion 27 side. Therefore, compared with the case where the radius of curvature of the inner surface 46 is constant in the entire area of ​​the inner surface 46, the force acting from the connection portion 45 (inner surface 46) to the thickness change portion 60TG2 of the battery cell 60R is small.

[0052] In order to reduce the force acting from the connection parts 30, 35, 40, 45 on the thickness change parts 60TG1, 60TG2 of the battery cells 60F, 60R, it is preferable to make the radius of curvature of each part (predetermined part) of the inner surface 31, 36, 41, 46 to be greater than the size obtained by multiplying the thickness of the part that contacts each part (predetermined part) of the thickness change parts 60TG1, 60TG2 by 0.5. For example, Figure 7 The curvature radius RP (mm) of the predetermined portion 31P of the inner surface shown is preferably equal to or larger than the value obtained by multiplying the thickness TP (mm) of the portion of the thickness variation portion 60TG1 of the battery cell 60F that contacts the predetermined portion 31P by 0.5.

[0053] In addition, the 24 battery cells 60 are sandwiched in the front-to-back direction by the front buffer 77 in contact with the inner surface of the front wall portion 24 and the rear buffer 77 in contact with the inner surface of the rear wall portion 25. Therefore, the front and rear buffers 77 can suppress the vibration of each battery cell 60 in the housing 15. In addition, the front and rear buffers 77 can absorb the thermal expansion and thermal contraction of the battery cell 60.

[0054] As mentioned above, although the battery module concerning embodiment was demonstrated, it can design and change suitably within the range which does not deviate from the summary of this disclosure.

[0055] For example, the connection portion 30 may be configured such that the curvature radius RP of the inner surface 31 centered at the corner 20A when viewed in the vertical direction gradually decreases from the front wall 24 side to the left wall 26 side only in a portion of the region between the end portion on the front wall 24 side and the end portion on the left wall 26 side of the inner surface 31. That is, the curvature changing portion may be formed only in a portion of the region of the inner surface 31.

[0056] Likewise, the curvature changing portion may be formed only in a portion of the inner surface 36 , the curvature changing portion may be formed only in a portion of the inner surface 41 , or the curvature changing portion may be formed only in a portion of the inner surface 46 .

[0057] Alternatively, the battery module 11 may be mounted on the vehicle 100 in a manner such that the cover 50 is perpendicular to the left-right direction.

Claims

1. A battery module comprising: A housing having a pair of first walls separated in a predetermined first direction, a pair of second walls separated in a second direction orthogonal to the first direction, and four connecting portions connecting ends of adjacent first walls and second walls to each other; and A plurality of laminated battery cells are accommodated in a space surrounded by a pair of the first walls, a pair of the second walls and the connecting portions in a state of being arranged along the first direction, and extend along the second direction. The inner surface of the connecting portion is a curved surface that is convex toward the space side when the housing is viewed along an orthogonal direction that is orthogonal to the first direction and the second direction, and at least a portion of the curved surface is a curvature changing portion whose curvature radius gradually decreases as it goes from the first wall side to the second wall side. The battery cell closest to the first wall includes a portion that contacts the curvature changing portion when the outer casing is viewed along the orthogonal direction.

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

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

5.

4. The battery module according to any one of claims 1 to 3, The entire curved surface is the curvature changing portion.

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