BATTERY MODULE

Abstract

An inner surface of a connecting section that joins end sections of a first wall and a second wall, which are adjacent to each other, of a housing, is a curved surface that is convex in the direction of one side of a space, wherein at least part of the curved surface is a change-of-curvature section whose radius of curvature gradually decreases from one side of the first wall towards one side of the second wall, and wherein a battery cell that is arranged furthest towards the side of the first wall comprises a section that touches the change-of-curvature section.

Description

BACKGROUNDTechnical field

[0001] The present disclosure relates to a battery module. State of the art

[0002] Japanese Patent Application Laid-Open (JP-A) No. 2021-509524 discloses a battery module including a battery cell laminated body configured by laminating a plurality of laminated-type battery cells, and a case in which the battery cell stack laminated body is housed. The case includes an upper wall portion, a lower wall portion, and a peripheral wall portion connecting outer peripheral portions of the upper wall portion and the lower wall portion. Furthermore, the peripheral wall portion includes a pair of first walls and a pair of second walls perpendicular to the pair of first walls and connected to the pair of first walls. Each battery cell is adjacent to each other in a direction in which the two first walls oppose each other.

[0003] The aforementioned housing may include four connecting portions that connect end portions of a first wall and a second wall that are adjacent to each other and that protrude toward a space side within the housing. In such a housing, an end portion in the longitudinal direction of a battery cell that faces the first wall may collide with the connecting portion, and this end portion may be significantly deformed by contact with the connecting portion.

[0004] In view of the above circumstances, an object of the present disclosure is to obtain a battery module capable of reducing a deformation amount of a battery cell in a case in which a laminated battery cell has contacted a connecting portion connecting end portions of a first wall and a second wall of a case. SUMMARY

[0005] A battery module according to a first aspect comprises: a case including a pair of first walls separated in a predetermined first direction, a pair of second walls separated in a second direction perpendicular to the first direction, and four connecting portions each connecting end portions of adjacent ones of the pair of first walls and the pair of second walls; and a plurality of laminated battery cells accommodated in a space enclosed by the pair of first walls, the pair of second walls, and each of the connecting portions in a state of being juxtaposed in the first direction, and extending in the second direction, wherein an inner surface of each connecting portion is a curved surface that, when the case is viewed in a perpendicular direction perpendicular to the first direction and the second direction,is convex in the direction of space, and wherein 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, and wherein a battery cell arranged furthest toward the first wall side includes a portion contacting the curvature changing portion when viewing the case in the vertical direction.

[0006] The inner surface of the connecting portion of the battery module according to the first aspect is a curved surface convex toward the space side when viewed from the casing in the perpendicular direction perpendicular to the first direction and the second direction. Furthermore, at least a part of the curved surface is a curvature-changing portion in which the radius of curvature gradually decreases from the first wall side toward the second wall side. Furthermore, the battery cell located furthest toward the first wall side includes a portion contacting the curvature-changing portion when viewed from the casing in the perpendicular direction. Therefore, the battery module according to the first aspect makes it possible to reduce a deformation amount of the thickness-changing portion in a casing in which the laminated battery cell has contacted a connecting portion of the casing.Therefore, in a case where the laminated battery cell has contacted a connecting portion, the amount of deformation of the battery cell is reduced.

[0007] A battery module according to a second aspect is the battery module according to the first aspect, wherein: the portion of the battery cell located furthest toward the side of the first wall contacting the curvature changing portion is a thickness changing portion having a thickness that decreases toward the side of the second wall when viewing the case in the vertical direction.

[0008] In the battery module according to the second aspect, by being configured such that the portion in contact with the curvature changing portion is a thickness changing portion, the amount of deformation of the battery cell decreases in a case in which the laminated battery cell has contacted a connecting portion.

[0009] A battery module according to a third aspect is the battery module according to the first aspect, wherein: a size of the radius of curvature at a predetermined portion of the curved surface is greater than or equal to a dimension obtained by multiplying a thickness of the portion of the battery cell contacting the predetermined portion by 0.5.

[0010] In the battery module according to the third aspect, the deformation amount of the thickness changing portion is slightly reduced.

[0011] A battery module according to a fourth aspect is the battery module according to any one of the first aspects to the third aspect, wherein: an entirety of the 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 is slightly reduced.

[0013] As explained above, the battery module according to the present disclosure has an advantageous effect that the amount of deformation of a battery cell in a case can be reduced in which the laminated battery cell has contacted a connecting portion connecting the end portions of a first wall and a second wall of the case. SHORT DESCRIPTION OF THE DRAWINGS

[0014] Exemplary embodiments of the present disclosure are described in detail with reference to the following figures, wherein: Fig. 1 is a bottom view of a vehicle having a battery module mounted thereon according to an exemplary embodiment; Fig. is a perspective view of a battery module; Fig. 3 is an exploded perspective view of a battery module housing; Fig. is a plan view of a case main body, a battery cell, a cushioning material, and a flexible circuit board; Fig. is a side view of a battery cell; Fig. 6 is a view in a width direction of a laminate having a positive electrode sheet, a negative electrode sheet, and two separators; and Fig. 7 is a plan view of a case main body, a battery cell arranged at a front side, and a portion of a cushioning material at a front side. DETAILED DESCRIPTION

[0015] Total vehicle configuration 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 exemplary embodiment has been mounted. As shown in Fig. 1, the vehicle 100 is an electric vehicle (battery electric vehicle (BEV)) in which the battery pack 10 is installed under a floor. Note that, in each of the drawings, the arrow UP, the arrow FR, and the arrow LH respectively indicate a top side in a vehicle top-bottom direction, a front side in a vehicle front-rear direction, and a light side in a vehicle width direction. Unless expressly stated otherwise, in a case where front-rear, left-right, and top-bottom directions are described, the front and rear sides are meant in the vehicle front-rear direction, the left and right sides are meant in the vehicle width direction, and the top and bottom sides are meant in a vehicle top-bottom direction.

[0016] For example, in the vehicle 100 of the present exemplary embodiment, a DC / DC converter 102, an electric compressor 104, and a positive temperature coefficient (PTC) heater 106 are arranged farther toward a vehicle front than the battery pack 10. Further, a motor 108, a transmission 110, an inverter 112, and a charger 114 are arranged farther toward a vehicle rear than the battery pack 10.

[0017] The direct current output from the battery pack 10 is voltage-adjusted by the DC / DC converter 102 and then supplied to the electric compressor 104, the PTC heater 106, the inverter 112, and the like. Furthermore, electrical power is supplied to the motor 108 via the inverter 112, thereby rotating the rear wheels and propelling the vehicle 100.

[0018] A charging port 116 is provided at a right side portion of a rear portion of the vehicle 100, and by connecting a charging plug of an external charging device, not shown in the drawings, to the charging port 116, electric energy can be stored in the battery pack 10 via the in-vehicle charger 114.

[0019] It should be noted that an arrangement, structure, and the like of the respective components configuring the vehicle 100 are not limited to the configuration described above. For example, the present disclosure may be applied to a hybrid vehicle (HV) or a plug-in hybrid vehicle (plug-in hybrid electric vehicle (PHEV)) in which a motor is installed. Further, in the present exemplary embodiment, although the vehicle is configured as a rear-wheel drive vehicle in which the motor 108 is installed at a rear portion of the vehicle, the vehicle may not be limited to this, and the vehicle may be configured as a front-wheel drive vehicle in which the motor 108 is installed at a front portion of the vehicle, and a pair of motors 108 may also be installed at the front and rear of the vehicle.Furthermore, the vehicle can also be equipped with internal wheel motors on the respective wheels.

[0020] The battery pack 10 includes a plurality of battery modules 11. In the present exemplary embodiment, ten battery modules 11 are provided by way of example. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle front-rear direction. Furthermore, each of the battery modules 11 is electrically connected to each other.

[0021] A pair of power terminals 12 and a connector 14 are provided at both vehicle-width-direction end portions of the battery module 11. A flexible printed circuit board 70, described below, is connected to the connector 14. Furthermore, bus bars, not shown in the drawings, are welded to both vehicle-width-direction end portions of the battery module 11.

[0022] As in Fig. 1 and Fig. As shown in Figure 2, each battery module 11 is formed in a substantially rectangular parallelepiped shape with a longitudinal direction along the vehicle width direction. A casing 15, which forms the outer shape of the battery module 11, is made of an aluminum alloy. The casing 15 includes a casing main body 20 and a cover body 50.

[0023] The length MW of the battery module 11 in the vehicle width direction 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 top-bottom direction is, for example, 80 mm to 110 mm.

[0024] As in Fig. 3 and Fig. As shown in Fig. 4, the case main body 20 is an integrally molded article including a bottom wall portion 21 having a rectangular planar shape, a peripheral wall portion 23 connected to an outer peripheral edge portion of an upper surface of the bottom wall portion 21, and four connecting portions 30, 35, 40, and 45. Further, the peripheral wall portion 23 includes a front wall portion (first wall) 24, a rear wall portion (first wall) 25, a light-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 (a second direction) and oppose each other in the front-rear direction (a first direction).In the plan view, the light-side wall portion 26 and the right-side wall portion 27 face each other parallel to the front-back direction (the first direction) and in the left-right direction (the second direction).

[0025] The connecting portion 30 is provided between a left end portion of the front wall portion 24 and a front end portion of the light-side wall portion 26, and the connecting portion 35 is provided between a right end portion of the front wall portion 24 and a front end portion of the right-side wall portion 27. Furthermore, the connecting portion 40 is provided between a left end portion of the rear wall portion 25 and a rear end portion of the light-side wall portion 26, and the connecting portion 45 is provided between a right end portion of the rear wall portion 25 and a rear end portion of the right-side wall portion 27. The lower ends of the connecting portions 30, 35, 40, and 45 are connected to the bottom wall portion 21.Furthermore, the top surfaces of the connecting portions 30, 35, 40, and 45 and an upper surface of the peripheral wall portion 23 are planes that are continuous with each other and that extend perpendicular to the up-down direction (a vertical direction). A plurality of laminated battery cells 60 are accommodated in a space 29 enclosed by the bottom wall portion 21 and the peripheral wall portion 23.

[0026] Inner surfaces 31, 36, 41 and 46, which are surfaces facing the space 29 of the connecting portions 30, 35, 40 and 45, are configured by curved surfaces convex toward one side of the space 29 as viewed in the up-down direction (the perpendicular direction).

[0027] As in Fig. As shown in Fig. 7, a radius of curvature RP of the inner surface 31 of the connecting portion 30, centered on a corner portion 20A where the front wall portion 24 and the light-side wall portion 26 intersect, gradually decreases from a front wall portion 24 side toward a light-side wall portion 26 side when viewed along the up-down direction. Similarly, a radius of curvature of the inner surface 36 of the connecting portion 35, centered on a corner portion 20B where the front wall portion 24 and the right-side wall portion 27 intersect, gradually decreases from the front wall portion 24 side toward a right-side wall portion 27 side when viewed along the up-down direction.A radius of curvature of the inner surface 41 of the connecting portion 40, centered on a corner portion 20C where the rear wall portion 25 and the light-side wall portion 26 intersect, gradually decreases from a rear wall portion 25 side toward the left-side wall portion 26 side, as viewed along the top-bottom direction. A radius of curvature of the inner surface 46 of the connecting portion 45, centered on a corner portion 20D where the rear wall portion 25 and the right-side wall portion 27 intersect, gradually decreases from the rear wall portion 25 side toward the right-side wall portion 27 side, as viewed along the top-bottom direction.Namely, a whole of the inner surface 31, a whole of the inner surface 36, a whole of the inner surface 41 and a whole of the inner surface 46 are each configured by a curvature changing portion.

[0028] As in Fig. 2 and Fig. As shown in Figure 3, the lid body 50 is configured by a plate member having a rectangular shape. A through hole 51 is formed at each of the four corner portions of the lid body 50.

[0029] As in Fig. 4, a plurality of battery cells 60 are accommodated in an interior space of the battery case 20 in an arranged state. In the present exemplary embodiment, for example, 24 battery cells 60 are arranged in the vehicle front-rear direction and bonded to each other (in Fig. 4 only some of the battery cells 60 are shown).

[0030] A flexible printed circuit board 70 is arranged on the battery cells 60. The flexible printed circuit board 70 is formed in a belt shape with its longitudinal direction along the vehicle width direction, and thermistors 75 are provided at both end portions of the flexible printed circuit board 70. The thermistors 75 are not bonded to the battery cells 60 and are configured to be pressed to one side of the battery cells 60 by the cover body 50.

[0031] As in Fig. As shown in FIG. 4, a cushioning material 77 facing an inner surface of the front wall portion 24 and a cushioning material 77 facing an inner surface of the rear wall portion 25 are housed on an inner side of the case main body 20. Thickness directions of the two cushioning materials 77 coincide with an arrangement direction (lamination direction) of the battery cells 60. The cushioning material 77 is, for example, a thin, plate-shaped member that is elastically deformable.

[0032] Fig. 5 is a schematic view of a battery cell 60 incorporated in a battery module 11, viewed from a thickness direction of the battery cell 60. As shown in Fig. 4 and Fig. 5, the battery cell 60 is formed in a substantially rectangular plate shape.

[0033] As in Fig. 5 to Fig. 7, 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 body including the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64 is covered with the 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 and 64 are members with elongated band-like flexibility extending in a predetermined direction (the left-right direction in Fig. 6). The positive electrode sheet 61 includes an elongated belt-shaped positive electrode body and a positive electrode active material coated on both surfaces of the positive electrode body. However, the positive electrode active material is not coated at a positive electrode terminal 61A, which is an end portion of the positive electrode body. The negative electrode sheet 62 includes an elongated belt-shaped negative electrode body and a negative electrode active material coated on both surfaces of the negative electrode body. However, the negative electrode active material is not coated at a negative electrode terminal 62A, which is an end portion of the negative electrode body. The positive electrode terminal 61A and the negative electrode terminal 62A protrude from end portions of the separators 63 and 64.Further, an end portion 61B of the positive electrode sheet 61, which is located on the side opposite to the positive electrode terminal 61A, is arranged further toward a positive electrode terminal side than end portions of the separators 63 and 64 on a negative electrode terminal 62A side. An end portion 62B of the negative electrode sheet 62, which is located on the side opposite to the negative electrode terminal 62A, is arranged further toward the negative electrode terminal 62A side than the end portions of the separators 63 and 64 on the positive electrode terminal 61A side.

[0034] As in Fig. 6, a region formed by the positive electrode terminal 61A of the above-described laminate body is defined as a first region AR1, a region formed by a portion of the separators 63 and 64 that is further toward the positive electrode terminal 61A side than the end portion 62B is defined as a second region AR2, a region formed by the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64 is defined as a third region AR3, a region formed by a portion of the separators 63 and 64 that is further toward the negative electrode terminal 62A side than the end portion 61B is defined as a fourth region AR4, and a region formed by the negative electrode terminal 62A is defined as a fifth region AR5. In this case, a thickness T of the above-described laminate body (see Fig. 6 and Fig. 7) a ratio of: the first area AR1, the fifth area AR5 < the second area AR2, the fourth area AR4 < the third area AR3.

[0035] The laminate body, including the positive electrode sheet 61, the negative electrode sheet 62, and the separators 63 and 64, is folded or wound 99 times and sealed from the outer peripheral side by the laminate film 67 covering the laminate body in this state. For example, in the present exemplary embodiment, the embossed sheet-shaped laminate film 67 is folded and bonded together to form a housing portion of a part other than the positive electrode terminal 61A and the negative electrode terminal 62A of the laminate body. Note that although both a single-cup embossed structure in which embossing is performed at one location and a double-cup embossed structure in which embossing is performed at two locations can be adopted, a single-cup embossed structure with a drawing depth of about 8 mm to about 10 mm is adopted in the present exemplary embodiment.

[0036] The upper ends of the two longitudinal end portions of the battery cell 60 are bent, and the corners thereof form an outer shape. Further, the upper end portions of the battery cell 60 are bent, and a fastening band 78 is wound around the upper end portions of the battery cell 60 in the longitudinal direction.

[0037] As in Fig. 5 and Fig. 6, a portion of the positive electrode terminal 61A and a portion of the negative electrode terminal 62A each protrude from both end portions in the longitudinal direction of the laminate film 67. In the present exemplary embodiment, for example, the positive electrode terminal 61A and the negative electrode terminal 62A are provided at positions offset downward from a center of the battery cell 60 in the up-down direction. The positive electrode terminal 61A and the negative electrode terminal 62A are connected to bus bars, not shown in the drawings, by laser welding or the like. Further, a portion of the battery cell 60 protruding from the laminate film 67 at the positive electrode terminal 61A is defined as a first region AR1-X, and a portion of the battery cell 60 protruding from the laminate film 67 at the negative electrode terminal 62A is defined as a fifth region AR5-X.Further, a region of the laminate film 67 located between the first region AR1-X and the third region AR3 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 package, 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 are in the following relationship: first region AR1-X, fifth region AR5-X < second region AR2-X, fourth region AR4-X < third region AR3-X. Further, as shown in FIG. Fig. 5 and Fig. 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 of the battery cell 60 is a thickness change portion 60TG2. The thickness change portion 60TG1 is a portion where the thickness T decreases toward the left side (the positive electrode terminal 61A side), and the thickness change portion 60TG2 is a portion where the thickness T decreases toward the right side (the negative electrode terminal 62A side).

[0038] As in Fig. As shown in FIG. 5, a length CW1 in the vehicle width direction of the battery cell 60 is, for example, 530 mm to 600 mm, a length CW2 of the third region AR3 of the above-described laminate body is, for example, 500 mm to 520 mm, and a height (a width-direction dimension) CH of the battery cell 60 is, for example, 80 mm to 110 mm. Furthermore, a thickness of the battery cell 60 is from 7.0 mm to 9.0 mm, and a height TH of the positive electrode terminal 61A and the negative electrode terminal 62A is from 40 mm to 50 mm.

[0039] As in Fig. 2, the lid body 50 is fitted over the upper surface of the case main body 20, which accommodates the battery cell 60, the flexible circuit board 70, and the fastening band 78. Screws 80 are inserted from above into the four through holes 51 of the lid body 50, and the male screw grooves of each screw 80 are screwed into the corresponding female screw holes 32. Therefore, an outer peripheral portion of a lower surface of the lid body 50 is in close contact with an upper end surface of the case main body 20.

[0040] As in Fig. 4, 24 battery cells 60 are accommodated on the inside of the case main body 20 side by side in the vehicle front-rear direction, and 24 battery cells 60 are enclosed in the front-rear direction by the cushioning material 77 at the front side contacting the inner surface of the front wall portion 24 and by the cushioning material 77 at the back side contacting the inner surface of the rear wall portion 25. Further, a left end portion of each battery cell 60 is disposed between the connecting portion 30 and the connecting portion 40, and a right end portion of each battery cell 60 is disposed between the connecting portion 35 and the connecting portion 45. Further, the thickness changing portion 60TG1 of the battery cell 60 disposed on the frontmost side contacts the inner surface 31, and the thickness changing portion 60TG2 of the battery cell 60 disposed on the frontmost side contacts the inner surface 36.Furthermore, the thickness changing portion 60TG1 of the battery cell 60 located at the rearmost side contacts the inner surface 41, and the thickness changing portion 60TG2 of the battery cell 60 located at the rearmost side contacts the inner surface 46. Therefore, the thickness changing portions 60TG1 and 60TG2 of the plurality of battery cells 60 located at the front and rear sides are bent by the connecting portions 30, 35, 40, and 45. Here, among the 24 battery cells 60, the battery cell 60 located at the front side is referred to as battery cell 60F, and the battery cell 60 located at the rear side is referred to as battery cell 60R. The thickness changing portions 60TG1 and 60TG2 of the battery cell 60F are directly pressed by the connecting portions 30 and 35, and the thickness changing portions 60TG1 and 60TG2 of the battery cell 60R are directly pressed by the connecting 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, a force corresponding to their bending amounts reaches the first region AR1, the second region AR2, the fourth region AR4, and the fifth region AR5 of the laminate body, respectively. Therefore, it is preferable that the deformation amounts (bending amounts) of the thickness change portions 60TG1 and 60TG2 of the battery cell 60 be small.

[0041] As described above, the thickness T of the thickness change portion 60TG1 of the battery cell 60F gradually decreases toward a distal end portion (positive electrode terminal 61A) side in the up-down direction. Furthermore, the thickness change portion 60TG1 of the battery cell 60F contacts the inner surface 31 of the connecting portion 30. As described above, the radius of curvature RP of the inner surface 31, which is centered on the corner portion 20A gradually decreases from the front side of the wall portion 24 toward the left side of the wall portion 26 when viewed along the up-down direction. Therefore, compared with a case in which a radius of curvature RP of the inner surface 31 is constant in the entire area of ​​the inner surface 31, a force reaching the thickness change portion 60TG1 of the battery cell 60F from the connecting portion 30 (the inner surface 31) is smaller.As a result, although a force larger than a force reaching the thickness change portion 60TG1 of the battery cells 60 (except for the battery cell 60R) arranged at the back of the battery cell 60F reaches an inside of the thickness change portion 60TG1 of the battery cell 60F, there is less risk of a short circuit in the battery cell 60F due to the end portion 62B of the negative electrode sheet 62 contacting the positive electrode sheet 61 while penetrating the separator 64 at an inside of the laminate film 67 of the battery cell 60F.

[0042] Similarly, the thickness change portion 60TG2 of the battery cell 60F contacts the inner surface 36 of the connecting portion 35. The radius of curvature of the inner surface 36 centered on the corner portion 20B gradually decreases when viewed along the up-down direction from the front wall portion 24 side toward the right side wall portion 27 side. Therefore, compared to a case in which the radius of curvature of the inner surface 36 is constant throughout the entire area of ​​the inner surface 36, a force reaching the thickness change portion 60TG2 of the battery cell 60F from the connecting portion 35 (the inner surface 36) is smaller.

[0043] The thickness change portion 60TG1 of the battery cell 60R contacts the inner surface 41 of the connecting portion 40. The radius of curvature of the inner surface 41, centered on the corner portion 20C, gradually decreases when viewed along the up-down direction from the rear wall portion 25 side toward the left side wall portion 26 side. Therefore, compared to a case in which a radius of curvature of the inner surface 41 is constant throughout the entire area of ​​the inner surface 41, a force reaching the thickness change portion 60TG1 of the battery cell 60R from the connecting portion 40 (the inner surface 41) is smaller. Similarly, the thickness change portion 60RTG2 of the battery cell 60R contacts the inner surface 46 of the connecting portion 45.The radius of curvature of the inner surface 46 centered on the corner portion 20D gradually decreases when viewed along the up-down direction from the rear wall portion 25 side toward the right side wall portion 27 side. Therefore, compared to a case in which a radius of curvature of the inner surface 46 is constant throughout the entire area of ​​the inner surface 46, a force reaching the thickness change portion 60TG2 of the battery cell 60R from the connecting portion 45 (the inner surface 46) is smaller.

[0044] It should be noted that in order to reduce the force acting from the connecting portions 30, 35, 40, and 45 on the thickness changing portions 60TG1 and 60TG2 of the battery cells 60F and 60R, it is preferable that the size of the radius of curvature of each portion (predetermined portion) of the inner surfaces 31, 36, 41, and 46 is greater than or equal to a dimension obtained by multiplying a thickness of the respective portions of the thickness changing portions 60TG1 and 60TG2 in contact with each portion (predetermined portion) by 0.5. For example, it is preferable that a radius of curvature RP (mm) of a predetermined portion 31P at the Fig. 7 is greater than or equal to a value obtained by multiplying a thickness TP (mm) of the portion at the thickness changing portion 60TG1 of the battery cell 60F that is in contact with the predetermined portion 31P by 0.5.

[0045] Furthermore, 24 battery cells 60 are clamped in the front-to-rear direction by the front cushioning material 77, which is in contact with the inner surface of the front wall portion 24, and the rear cushioning material 77, which is in contact with the inner surface of the rear wall portion 25. In this way, each battery cell 60 is prevented from vibrating within the housing 15 by the front and rear cushioning materials 77. Furthermore, thermal expansion and thermal contraction of the battery cells 60 can be absorbed by the front and rear cushioning materials 77.

[0046] Although the battery module according to exemplary embodiments has been explained above, the battery module according to exemplary embodiments can be structurally modified as appropriate within a scope that does not deviate from the gist of the present disclosure.

[0047] For example, the connecting portion 30 may be configured such that the radius of curvature RP of the inner surface 31 centered on the corner portion 20A, as viewed along the up-down direction, gradually decreases from the front side of the wall portion 24 toward the left side of the wall portion 26 only in a portion of a region between an end portion on the front side of the wall portion 24 of the inner surface 31 and an end portion on the left side of the wall portion 26 of the inner surface 31. That is, the curvature changing portion may be formed only in a portion of the inner surface 31.

[0048] Likewise, a curvature change section may be formed only in a partial area of ​​the inner surface 36, a curvature change section may be formed only in a partial area of ​​the inner surface 41, or a curvature change section may be formed only in a partial area of ​​the inner surface 46.

[0049] The battery module 11 can be installed on the vehicle 100 such that the cover body 50 is perpendicular to the left-right direction. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-509524

[0002]

Claims

[1] Battery module comprising: a housing comprising a pair of first walls separated in a predetermined first direction, a pair of second walls separated in a second direction perpendicular to the first direction, and four connecting portions each connecting end portions of adjacent ones of the pair of first walls and the pair of second walls; and a plurality of laminated battery cells which, in a state in which they are arranged side by side in the first direction, are accommodated in a space enclosed by the pair of first walls, the pair of second walls and each of the connecting portions, and which extend in the second direction, wherein an inner surface of each connecting portion is a curved surface which is convex toward the space when viewing the housing in a perpendicular direction perpendicular to the first direction and the second direction, and wherein 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, and wherein a battery cell disposed furthest toward the first wall side includes a portion contacting the curvature changing portion when viewing the case in the vertical direction. [2] Battery module according to claim 1, wherein: the portion of the battery cell located furthest toward the side of the first wall contacting the curvature changing portion is a thickness changing portion having a thickness that decreases toward the side of the second wall when viewing the case in the vertical direction. [3] Battery module according to claim 1, wherein: a magnitude of the radius of curvature at a predetermined portion of the curved surface is greater than or equal to a dimension obtained by multiplying a thickness of the portion of the battery cell contacting the predetermined portion by 0.

5. [4] Battery module according to one of claims 1 to 3, wherein: an entirety of the curved surface is the curvature change section.

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