Power storage device

Abstract

To provide a power storage device capable of preventing a local load from being applied to cells of a power storage module.SOLUTION: A power storage device 1 includes a power storage module 10 and a case 110. The power storage module 10 includes a plurality of cells 50. The case 110 includes a first wall 111, a pair of second walls 112, and a first reinforcing member 120. The first reinforcing member 120 is provided on the first wall 111. The first reinforcing member 120 extends along a first direction D1. The first reinforcing member 120 is more rigid than the first wall 111 and the pair of second walls 112. The first reinforcing member 120 includes a first region 121 and a second region 122. The first region 121 extends in the first direction D1. The second region 122 is aligned with the first region 121 in the first direction D1. The second region 122 extends in the first direction D1. The second region 122 is less rigid than the first region 121.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2018-144700) discloses a battery pack that houses a drive battery. A reinforcing frame is provided at the trailing edge of the battery pack and extends in the vehicle width direction along at least the rear end face.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional power storage device, when a load is applied to a reinforcing member, it can be deformed in an arch shape with both ends of the reinforcing member as fulcrums. There is a risk that the arch-shaped deformed reinforcing member and a part of the adjacent pack apply a local load to the cells of the power storage module housed in the pack.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a power storage device capable of suppressing a local load from being applied to the cells of a power storage module.

Means for Solving the Problems

[0006] A power storage device according to an aspect of the present disclosure includes a power storage module and a case. The power storage module includes a plurality of cells. The plurality of cells are stacked on top of each other in a first direction. The case houses the power storage module. The case includes a first wall portion, a pair of second wall portions, and a first reinforcing member. The first wall portion is located on one side of the power storage module at least in a second direction intersecting the first direction. The first wall portion extends along the first direction. The pair of second wall portions are respectively located on both sides of the power storage module in the first direction. The pair of second wall portions extend along the second direction. The pair of second wall portions are respectively connected to both ends of the first wall portion. The first reinforcing member is provided on the first wall portion. The first reinforcing member extends along the first direction. The first reinforcing member has a higher rigidity than the first wall portion and the pair of second wall portions. The first reinforcing member includes a first region and a second region. The first region extends in the first direction. The second region is arranged beside the first region in the first direction. The second region extends in the first direction. The second region has a lower rigidity than the first region.

[0007] According to the above configuration, when a load is applied to the second region of the first reinforcing member from one side in the second direction, the entire second region is displaced along the second direction toward the power storage module. The displaced second region contacts the plurality of cells stacked in the first direction together with the first wall portion. Therefore, the load applied to the second region of the first reinforcing member can be dispersed to the plurality of cells. That is, according to the above configuration, it is possible to suppress the first reinforcing member from deforming in an arc shape with the pair of second wall portions as fulcrums. It is possible to suppress the arcuately deformed first reinforcing member and the first wall portion from applying a local load to the cells of the power storage module.

[0008] In the above power storage device, the second region may be located on the outer surface of the center of the first wall portion in the first direction of the first reinforcing member.

[0009] According to the above configuration, since the second region is disposed at a position relatively far from the pair of second wall portions, when a load is applied to the second region, the entire second region is more likely to be displaced. As a result, it is possible to further suppress the arcuate deformation of the first reinforcing member and the first wall portion. The load applied to the second region of the first reinforcing member can be dispersed by a plurality of cells.

[0010] Furthermore, the length of the second region in the first direction may be equal to or more than half of the length of the first reinforcing member.

[0011] According to the above configuration, even if the maximum load position on the first reinforcing member is unevenly distributed in the first direction, the possibility that the entire second region can be displaced by the load on the first reinforcing member is increased. Therefore, the load on the first reinforcing member can be effectively dispersed to a plurality of cells.

[0012] In the above-described power storage device, the case may further include a pair of second reinforcing members. The pair of second reinforcing members may be respectively provided on the pair of second wall portions. The pair of second reinforcing members may have a higher rigidity than the first wall portion and the pair of second wall portions. The second region may have a lower rigidity than the pair of second reinforcing members.

[0013] According to the above configuration, the strength of the second wall portion can be improved by the second reinforcing member, and the strength of the case can be improved. Since the first reinforcing member includes a second region having a lower rigidity than the second reinforcing member, arcuate deformation of the first reinforcing member with the second reinforcing member as a fulcrum can be suppressed.

[0014] Furthermore, the pair of second reinforcing members may be separated from the first reinforcing member. According to this configuration, arcuate deformation of the first reinforcing member with the connection portion with the second reinforcing member as a fulcrum can be further suppressed.

[0015] In the above-described power storage device, the case may further include a third wall portion. The third wall portion may be located on the other side of the power storage module in the second direction. The third wall portion may extend along the first direction. The pair of second wall portions may be connected to both ends of the third wall portion, respectively. The case may further include a third reinforcing member. The third reinforcing member may be provided on the third wall portion. The third reinforcing member may extend along the first direction. The third reinforcing member may have a higher rigidity than the third wall portion and the pair of second wall portions. The second region may have a lower rigidity than the third reinforcing member.

[0016] According to the above-described configuration, the rigidity of the entire case in the first direction can be improved. When a load is applied from the side of the third reinforcing member in the second direction, the second region of the first reinforcing member deforms, thereby suppressing the bow-shaped deformation of the third reinforcing member and the third wall portion.

[0017] In the above-described power storage device, each of the plurality of cells may include an electrode body and a cell case. The electrode body may include a positive electrode layer, a negative electrode layer, and a separator. The cell case may accommodate the electrode body. The positive electrode layer and the negative electrode layer may be laminated in the first direction with the separator interposed therebetween.

[0018] When the cell having the above-described configuration is compressed and deformed in the second direction, an internal short circuit is likely to occur. However, since the load applied to one cell is reduced by the above-described second region, the compression deformation in the second direction is suppressed. Therefore, an internal short circuit of the cell can be suppressed.

[0019] In the above-described power storage device, each of the plurality of cells may include an electrode body and a cell case. The electrode body may include a positive electrode layer, a negative electrode layer, and a separator. The separator may be interposed between the positive electrode layer and the negative electrode layer. The cell case may accommodate the electrode body. The electrode body may be wound around an axis in a direction orthogonal to the first direction.

[0020] Cells configured as described above are likely to experience internal short - circuit when compressed and deformed in a direction orthogonal to the first direction. However, since the load applied to one cell is reduced by the above - mentioned second region, compression deformation in the direction orthogonal to the first direction is suppressed. Therefore, internal short - circuit of the cell can be suppressed.

Advantages of the Invention

[0021] According to the present disclosure, it is possible to suppress local loads from being applied to the cells of the power storage module.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0023] Hereinafter, a power storage device according to an embodiment of the present disclosure will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

[0024] FIG. 1 is a schematic diagram showing a state in which a power storage device according to an embodiment of the present disclosure is mounted on a vehicle. The power storage device 1 can be mounted on the vehicle 5. The vehicle 5 is, for example, a battery electric vehicle (BEV). The vehicle 5 may be another type of electric vehicle such as a plug-in hybrid electric vehicle (PHEV).

[0025] When the power storage device 1 is mounted on the vehicle 5, the first direction D1 of the power storage device 1 is typically the left-right direction of the vehicle 5. The second direction D2 of the power storage device 1 is typically the front-rear direction of the vehicle 5. The third direction D3 of the power storage device 1 is typically the up-down direction.

[0026] The second direction D2 intersects the first direction D1. Specifically, the second direction D2 is orthogonal to the first direction D1. The third direction D3 intersects both the first direction D1 and the second direction D2. Specifically, the third direction D3 is orthogonal to both the first direction D1 and the second direction D2.

[0027] FIG. 2 is a perspective view showing a power storage device according to an embodiment of the present disclosure. FIG. 3 is a partial perspective view showing the region III in FIG. 2 from a different angle. FIG. 4 is a schematic plan view of a power storage device in which the internal structure is partially illustrated.

[0028] As shown in FIGS. 2 to 4, the power storage device 1 includes a plurality of power storage modules 10 and a case 110.

[0029] As shown in FIG. 4, the plurality of power storage modules 10 are arranged side by side in the second direction D2. In the present embodiment, the plurality of power storage modules 10 are arranged so as to be arranged only in the second direction D2.

[0030] Each of the plurality of power storage modules 10 includes a plurality of cells 50, a pair of end plates 60, and a restraining member 70.

[0031] The plurality of cells 50 are stacked on top of each other in the first direction D 1. Preferably, the plurality of cells 50 are directly stacked on top of each other. Thereby, the energy density of the power storage module 10 can be improved. Note that the plurality of cells 50 may be stacked on top of each other with a spacer interposed between adjacent cells 50. The pair of end plates 60 are disposed on both sides of the entire plurality of cells 50 in the first direction D 1. The restraining member 70 applies a predetermined restraining load in the first direction D 1 to the plurality of cells 50 stacked on top of each other and the pair of end plates 60.

[0032] FIG. 5 is an exploded perspective view of a cell. As shown in FIG. 5, each of the plurality of cells 50 includes an electrode body 51 and a cell case 52. The cell 50 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, for example.

[0033] FIG. 6 is a partial cross-sectional view of the electrode body of FIG. 5 as viewed in the direction of the arrow of line VI-VI. As shown in FIGS. 5 and 6, the electrode body 51 includes a positive electrode layer 51a, a negative electrode layer 51b, and a separator 51c. The positive electrode layer 51a and the negative electrode layer 51b are stacked in the first direction D 1 with the separator 51c interposed therebetween.

[0034] In the present embodiment, the positive electrode layer 51a includes a positive electrode current collector foil 511a and a positive electrode active material layer 512a. The positive electrode active material layer 512a is provided on both sides of the positive electrode current collector foil 511a.

[0035] The negative electrode layer 51b includes a negative electrode current collector foil 511b and a negative electrode active material layer 512b. The negative electrode active material layer 512b is provided on both sides of the negative electrode current collector foil 511b.

[0036] The separator 51c insulates between the positive electrode layer 51a and the negative electrode layer 51b. The separator 51c is made of an insulating material and has minute voids that allow the permeation of ions.

[0037] Note that the electrode body 51 is not limited to the above configuration. FIG. 7 is an exploded perspective view showing a cell according to a modification. As shown in FIG. 7, the electrode body 51X may be wound with the second direction D2 as the axial direction. In the wound electrode body 51X, the separator 51c is interposed between the positive electrode layer 51a and the negative electrode layer 51b.

[0038] The cell case 52 houses the electrode body 51. The cell case 52 may further house an electrolytic solution (not shown).

[0039] The cell case 52 has a substantially rectangular parallelepiped outer shape. The cell 50 in the present embodiment is a so-called square battery. The dimension of the cell case 52 in the first direction D1 is shorter than the dimensions in the second direction D2 and the third direction D3. The dimension of the cell case 52 in the second direction D2 is longer than the dimensions in the first direction D1 and the third direction D3.

[0040] The cell case 52 includes a cell case body 53 and a lid 54. The cell case body 53 has an opening facing one side in the third direction D3. The lid 54 closes the opening. Note that the cell case body 53 may have one or more openings facing one side or both sides in the second direction D2.

[0041] As shown in FIGS. 2 to 4, the case 110 houses a plurality of power storage modules 10. The case 110 includes a first wall portion 111, a pair of second wall portions 112, a third wall portion 113, a bottom portion 114, a cover 115, a first reinforcing member 120, a pair of second reinforcing members 130, and a third reinforcing member 140.

[0042] The first wall portion 111 is located on one side of the power storage module 10 at least in the second direction D2. Specifically, the first wall portion 111 is located on one side of the entire plurality of power storage modules 10 in the second direction D2. The first wall portion 111 extends along the first direction D1. The first wall portion 111 has a longer length in the first direction D1 than each of the plurality of power storage modules 10.

[0043] A pair of second wall portions 112 are respectively located on both sides of the power storage module 10 in the first direction D1. A pair of second wall portions 112 are respectively located on both sides of the entire plurality of power storage modules 10 in the first direction D1. A pair of second wall portions 112 extend along the second direction D2. A pair of second wall portions 112 have a longer length in the second direction D2 than the entire plurality of power storage modules 10. A pair of second wall portions 112 are respectively connected to both ends of the first wall portion 111 in the first direction D1. A pair of second wall portions 112 are integrally formed with the first wall portion 111.

[0044] The third wall portion 113 is located on the other side of the power storage module 10 in the second direction D2. Specifically, the third wall portion 113 is located on the other side of the entire plurality of power storage modules 10 in the second direction D2. The third wall portion 113 extends along the first direction D1. The third wall portion 113 has a longer length in the first direction D1 than each of the plurality of power storage modules 10. A pair of second wall portions 112 are respectively connected to both ends of the third wall portion 113 in the first direction D1. The third wall portion 113 is integrally formed with both of the pair of second wall portions 112.

[0045] The bottom portion 114 covers one side of the plurality of power storage modules 10 in the third direction D3. The bottom portion 114 covers the lower part of the plurality of power storage modules 10. The bottom portion 114 is connected to the first wall portion 111. The bottom portion 114 is integrally formed with the first wall portion 111. The bottom portion 114 is connected to a pair of second wall portions 112. The bottom portion 114 is integrally formed with a pair of second wall portions 112. The bottom portion 114 is connected to the third wall portion 113. The bottom portion 114 is integrally formed with the third wall portion 113.

[0046] Cover 115 covers the other side of the plurality of power storage modules 10 in the third direction D3. Cover 115 is connected to the first wall portions 111, a pair of second wall portions 112, and the third wall portion 113. Cover 115 is fastened to the first wall portions 111, a pair of second wall portions 112, and the third wall portion 113 by a fastening tool (not shown) such as a screw.

[0047] The case 110 (the first wall portions 111, a pair of second wall portions 112, the third wall portion 113, the bottom portion 114, and the cover 115) is made of, for example, metal. Specifically, the case 110 is formed of a steel plate. The first wall portions 111, a pair of second wall portions 112, the third wall portion 113, and the bottom portion 114 may be formed from a single steel plate by press working or the like. For this reason, the respective thicknesses of the first wall portions 111, a pair of second wall portions 112, the third wall portion 113, and the bottom portion 114 may be substantially equal to each other.

[0048] The first reinforcing member 120 is provided on the first wall portion 111. The first reinforcing member 120 extends along the first direction D1.

[0049] The first reinforcing member 120 has a higher rigidity than the first wall portion 111 and a pair of second wall portions 112. For example, the first reinforcing member 120 may be made of a material having a higher Young's modulus than the material constituting the first wall portion 111 and a pair of second wall portions 112. The first reinforcing member 120 may be made of a material having a lower yield strength than the first wall portion 111 and a pair of second wall portions 112. The first reinforcing member 120 may have a lower second moment of area than the first wall portion 111 and a pair of second wall portions 112. The first reinforcing member 120 may have a lower flexural rigidity than the first wall portion 111 and a pair of second wall portions 112. The first reinforcing member 120 may be made of a material having a lower tensile strength than the first wall portion 111 and a pair of second wall portions 112.

[0050] The first reinforcing member 120 includes a pair of first regions 121 and a second region 122. The pair of first regions 121 each extend in the first direction D1. The pair of first regions 121 each include both ends of the first reinforcing member 120 in the first direction D1.

[0051] The second region 122 is arranged side by side with the first region 121 in the first direction D1. Specifically, the second region 122 is disposed between the pair of first regions 121. The second region 122 extends in the first direction D1. The second region 122 is located on the outer surface at the center of the first wall portion 111 of the first reinforcing member 120 in the first direction D1. The length of the second region 122 in the first direction D1 is equal to or greater than half of the length of the first reinforcing member 120.

[0052] The second region 122 has less rigidity than the first region 121. The method of making the rigidity of the second region 122 less than that of the first region 121 is not particularly limited. In the present embodiment, the second region 122 may be formed of a material having a lower Young's modulus than the first region 121. The second region 122 may be formed of a material having a lower yield strength than the first region 121. The second region 122 may have a lower second moment of area than the first region 121. The second region 122 may have a lower flexural rigidity than the first region 121.

[0053] The second region 122 may be formed of a material having a lower tensile strength than the first region 121. Specifically, the pair of first regions 121 and the second region 122 may be formed of a steel plate with a plating treatment on the surface. The pair of first regions 121 and the second region 122 may be hot-dip galvanized steel plates. The tensile strength of the hot-dip galvanized steel plate constituting the pair of first regions 121 is preferably, for example, 440 MPa or more. The tensile strength of the hot-dip galvanized steel plate constituting the second region 122 is preferably, for example, less than 440 MPa and 270 MPa or more. The tensile strength of the material constituting the first region 121 may be 1.1 times or more, 1.2 times or more, or 1.5 times or more the tensile strength of the material constituting the second region 122.

[0054] A pair of second reinforcing members 130 are respectively provided on a pair of second wall portions 112. The pair of second reinforcing members 130 are spaced apart from the first reinforcing member 120.

[0055] The pair of second reinforcing members 130 are more rigid than the first wall portion 111 and the pair of second wall portions 112. For example, the second reinforcing member 130 may be made of a material with a higher Young's modulus than the materials constituting the first wall portion 111 and the pair of second wall portions 112. The second reinforcing member 130 may be made of a material with a higher yield strength than the first wall portion 111 and the pair of second wall portions 112. The second reinforcing member 130 may have a higher second moment of area than the first wall portion 111 and the pair of second wall portions 112. The second reinforcing member 130 may have a higher flexural rigidity than the first wall portion 111 and the pair of second wall portions 112. The second reinforcing member 130 may be made of a material with a higher tensile strength than the first wall portion 111 and the pair of second wall portions 112.

[0056] The second region 122 is less rigid than the pair of second reinforcing members 130. The method of making the rigidity of the second region 122 less than that of the pair of second reinforcing members 130 is not particularly limited. In the present embodiment, the second region 122 may be made of a material with a lower Young's modulus than the pair of second reinforcing members 130. The second region 122 may be made of a material with a lower yield strength than the pair of second reinforcing members 130. The second region 122 may have a lower second moment of area than the pair of second reinforcing members 130. The second region 122 may have a lower flexural rigidity than the pair of second reinforcing members 130.

[0057] The second region 122 may be made of a material with a lower tensile strength than the pair of second reinforcing members 130. Specifically, the pair of second reinforcing members 130 may be hot-dip galvanized steel sheets. The tensile strength of the hot-dip galvanized steel sheets constituting the pair of first regions 121 is preferably, for example, 440 MPa or more.

[0058] The third reinforcing member 140 is provided on the third wall portion 113. The third reinforcing member 140 extends along the first direction D1. The third reinforcing member 140 is spaced apart from the pair of second reinforcing members 130.

[0059] The third reinforcing member 140 has a higher rigidity than the third wall portion 113 and the pair of second wall portions 112. For example, the third reinforcing member 140 may be made of a material having a higher Young's modulus than the third wall portion 113 and the pair of second wall portions 112. The third reinforcing member 140 may be made of a material having a higher yield strength than the third wall portion 113 and the pair of second wall portions 112. The third reinforcing member 140 may have a higher second moment of area than the third wall portion 113 and the pair of second wall portions 112. The third reinforcing member 140 may have a higher flexural rigidity than the third wall portion 113 and the pair of second wall portions 112. The third reinforcing member 140 may be made of a material having a higher tensile strength than the third wall portion 113 and the pair of second wall portions 112.

[0060] The second region 122 has a lower rigidity than the third reinforcing member 140. The method of making the rigidity of the second region 122 lower than that of the third reinforcing member 140 is not particularly limited. In the present embodiment, the second region 122 may be made of a material having a lower Young's modulus than the third reinforcing member 140. The second region 122 may be made of a material having a lower yield strength than the third reinforcing member 140. The second region 122 may have a lower second moment of area than the third reinforcing member 140. The second region 122 may have a lower flexural rigidity than the third reinforcing member 140.

[0061] The second region 122 may be made of a material having a lower tensile strength than the third reinforcing member 140. Specifically, the third reinforcing member 140 may be a hot-dip galvanized steel sheet. The tensile strength of the hot-dip galvanized steel sheet constituting the third reinforcing member 140 is preferably, for example, 440 MPa or more.

[0062] FIG. 8 is a schematic perspective view partially showing the configuration of the power storage device. As shown in FIGS. 4 and 8, the case 110 further includes a pair of internal side frames 150 and a plurality of internal cross frames 160.

[0063] The pair of internal side frames 150 are housed inside the case 110. That is, the pair of internal side frames 150 are located inside each of the pair of second wall portions 112. The pair of internal side frames 150 are located on both sides of the entire plurality of power storage modules 10 in the second direction D2.

[0064] The plurality of internal cross frames 160 extend along the first direction D1. The plurality of internal cross frames 160 are arranged side by side at intervals in the second direction D2. Both ends of the plurality of internal cross frames 160 are connected to each of the pair of internal side frames 150. Examples of the method of connecting the internal cross frame 160 and the internal side frame 150 include fastening using a fastening member such as a bolt, welding, or caulking. The plurality of power storage modules 10 are arranged side by side in the second direction D2 via the internal cross frames 160.

[0065] Here, the deformation of the power storage device 1 when a load is applied to the power storage device 1 from one side (the first reinforcing member 120 side) in the second direction D2 will be described. FIG. 9 is a schematic plan view showing the power storage device to which a load is applied. Also in FIG. 9, as in FIG. 4, the internal structure of the power storage device 1 is partially shown.

[0066] FIG. 9 shows the power storage device 1 in a state where the other side of the power storage device 1 in the second direction D2 is supported by the support member 200 and one side of the power storage device 1 in the second direction D2 is pressed by the pressing member 300.

[0067] As described above, in the present embodiment, the second region 122 has a lower rigidity than the first region 121. Thus, as shown in FIG. 9, when a load is applied to the second region 122 of the first reinforcing member 120 from one side in the second direction D2, the entire second region 122 is displaced along the second direction D2 toward the power storage module 10. The displaced second region 122 contacts the plurality of cells 50 laminated in the first direction D1 together with the first wall portion 111. Therefore, the load applied to the second region 122 of the first reinforcing member 120 can be dispersed to the plurality of cells 50. More specifically, the load can be dispersed to the plurality of cell cases 52.

[0068] That is, according to the above configuration, it is possible to suppress the first reinforcing member 120 from deforming in an arcuate shape with the pair of second wall portions 112 as fulcrums. It is possible to suppress the arcuately deformed first reinforcing member 120 and the first wall portion 111 from applying a local load to the cells 50 of the power storage module 10.

[0069] Furthermore, the second region 122 is located on the outer surface of the center of the first wall portion 111 in the first direction D1 of the first reinforcing member 120.

[0070] According to the above configuration, since the second region 122 is disposed at a position relatively far from the pair of second wall portions 112, the entire second region 122 is more likely to be displaced when a load is applied to the second region 122. As a result, it is possible to further suppress the first reinforcing member 120 and the first wall portion 111 from deforming in an arcuate shape. The load applied to the second region 122 of the first reinforcing member 120 can be dispersed by the plurality of cells.

[0071] Furthermore, the length of the second region 122 in the first direction D1 is equal to or greater than half of the length of the first reinforcing member 120.

[0072] According to the above configuration, even if the maximum load position on the first reinforcing member 120 is unevenly distributed in the first direction D1, the possibility that the entire second region 122 can be displaced by the load on the first reinforcing member 120 is increased. Therefore, the load on the first reinforcing member 120 can be effectively dispersed to a plurality of cells.

[0073] Furthermore, the pair of second reinforcing members 130 is more rigid than the first wall portion 111 and the pair of second wall portions 112. The second region 122 is less rigid than the pair of second reinforcing members 130.

[0074] According to the above configuration, the strength of the second wall portion 112 can be improved by the second reinforcing member 130, and the strength of the case 110 can be improved. Since the first reinforcing member 120 includes a second region having a lower rigidity than the second reinforcing member 130, the bow-shaped deformation of the first reinforcing member 120 with the second reinforcing member 130 as a fulcrum can be suppressed.

[0075] Furthermore, the pair of second reinforcing members 130 is separated from the first reinforcing member 120. According to this configuration, the bow-shaped deformation of the first reinforcing member 120 with the connection portion with the second reinforcing member 130 as a fulcrum can be further suppressed.

[0076] Furthermore, the third reinforcing member 140 is more rigid than the third wall portion 113 and the pair of second wall portions 112. The second region 122 is less rigid than the third reinforcing member 140.

[0077] According to the above configuration, the rigidity of the entire case 110 in the first direction D1 can be improved. When a load is applied from the side of the third reinforcing member 140 in the second direction D2, the bow-shaped deformation of the third reinforcing member 140 and the third wall portion 113 can be suppressed by the deformation of the second region 122 of the first reinforcing member 120.

[0078] Furthermore, in each of the plurality of cells 50, the positive electrode layer 51a and the negative electrode layer 51b may be laminated in the first direction D1 via the separator 51c.

[0079] The cell 50 configured as described above is likely to experience an internal short circuit when compressed and deformed in the second direction D2. However, since the load applied to one cell 50 by the second region 122 described above is reduced, compression deformation in the second direction D2 is suppressed. Therefore, an internal short circuit of the cell 50 can be suppressed.

[0080] Furthermore, in each of the plurality of cells 50, the electrode body 51X may be wound with the direction orthogonal to the first direction D1 as the axial direction. More specifically, the electrode body 51X may be wound with the second direction D2 as the axial direction.

[0081] The cell 50X configured as described above is likely to experience an internal short circuit when compressed and deformed in the direction orthogonal to the first direction D1 (second direction D2). However, since the load applied to one cell 50X by the second region 122 described above is reduced, compression deformation in the direction orthogonal to the first direction D1 (second direction D2) is suppressed. Therefore, an internal short circuit of the cell 50X can be suppressed.

[0082] Note that the rigidity of the second region 122 can be made smaller than that of the first region 121, the second reinforcing member 130, and the third reinforcing member 140 by various methods.

[0083] FIG. 10 is a perspective view partially showing the configuration of a power storage device according to a modified example. As shown in FIG. 10, a plurality of through holes 123A may be formed in the second region 122A of the first reinforcing member 120A. Thereby, the rigidity of the second region 122A can be made smaller than that of the first region 121A, the second reinforcing member 130, and the third reinforcing member 140. In this case, the Young's modulus and the like of the material constituting the second region 122A do not have to be smaller than the Young's modulus and the like of the respective materials constituting the first region 121A, the second reinforcing member 130, and the third reinforcing member 140.

[0084] In this modified example, the plurality of through-holes 123A are formed so as to penetrate the first reinforcing member 120A in the second direction D2. The plurality of through-holes 123A may be formed so as to penetrate the first reinforcing member 120A in the third direction D3. Although through-holes may also be formed in the first region 121A, it is preferable that the through-holes formed in the first region 121A have a smaller hole diameter than the through-holes 123A. It is preferable that the interval in the first direction D1 of the plurality of through-holes formed in the first region 121A is larger than the interval of the plurality of through-holes 123A.

[0085] FIG. 11 is a perspective view partially showing the configuration of a power storage device according to another modified example. FIG. 12 is a schematic cross-sectional view of the first reinforcing member in FIG. 11 as seen in the direction of the arrow XII-XII. As shown in FIGS. 11 and 12, a notch 124B extending along the first direction D1 may be formed in the second region 122B of the first reinforcing member 120B. Thereby, the rigidity of the second region 122B can be made smaller than that of the first region 121B and the second reinforcing member 130. As shown by the broken line in FIG. 12, this is because the second region 122B buckles around the notch 124B due to the load from one side in the second direction D2. In this case, the Young's modulus of the material constituting the second region 122B etc. may not be smaller than the Young's modulus etc. of the materials respectively constituting the first region 121B, the second reinforcing member 130, and the third reinforcing member 140.

[0086] In this modified example, the notch 124B does not penetrate the first reinforcing member 120B, but may penetrate the first reinforcing member 120B. The notch 124B is provided on the case 110 side of the first reinforcing member 120B, but may be provided on the side opposite to the case 110 side of the first reinforcing member 120B.

[0087] In the description of the above-described embodiments, combinable configurations may be combined with each other.

[0088] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims rather than the foregoing description, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Explanation of Reference Numerals

[0089] 1 Power storage device, 5 Vehicle, 10 Power storage module, 50, 50X Cells, 51, 51X Electrode body, 51a Positive electrode layer, 511a Positive electrode current collector foil, 512a Positive electrode active material layer, 51b Negative electrode layer, 511b Negative electrode current collector foil, 512b Negative electrode active material layer, 51c Separator, 52 Cell case, 53 Cell case body, 54 Lid, 60 End plate, 70 Restraining member, 110 Case, 111 First wall portion, 112 Second wall portion, 113 Third wall portion, 114 Bottom portion, 115 Cover, 120, 120A, 120B First reinforcing member, 121, 121A, 121B First region, 122, 122A, 122B Second region, 123A Through hole, 124B Notch, 130 Second reinforcing member, 140 Third reinforcing member, 150 Inner side frame, 160 Inner cross frame, 200 Support member, 300 Pressing member.

Claims

1. A power storage module including a plurality of cells laminated on one another in a first direction, and a case housing the power storage module, wherein the case includes a first wall portion located on one side of the power storage module at least in a second direction intersecting the first direction and extending along the first direction; a pair of second wall portions respectively located on both sides of the power storage module in the first direction, extending along the second direction, and respectively connected to both ends of the first wall portion; a first reinforcing member provided on the first wall portion, extending along the first direction, and having higher rigidity than the first wall portion and the pair of second wall portions, wherein the first reinforcing member includes a first region extending in the first direction and a second region arranged side by side with the first region in the first direction and extending in the first direction, and the second region has lower rigidity than the first region. A power storage device.

2. The power storage device according to claim 1, wherein the second region is located on an outer surface at the center of the first wall portion in the first direction of the first reinforcing member.

3. The power storage device according to claim 2, wherein a length of the second region in the first direction is equal to or more than half of a length of the first reinforcing member.

4. The case further includes a pair of second reinforcing members, wherein the pair of second reinforcing members are respectively provided on the pair of second wall portions, extend along the second direction, and have higher rigidity than the first wall portion and the pair of second wall portions, and the second region has lower rigidity than the pair of second reinforcing members. The power storage device according to any one of claims 1 to 3.

5. The power storage device according to claim 4, wherein the pair of second reinforcing members are spaced apart from the first reinforcing member.

6. The case further includes a third wall portion, wherein the third wall portion is located on the other side of the power storage module in the second direction and extends along the first direction, and the pair of second wall portions are respectively connected to both ends of the third wall portion, the case further includes a third reinforcing member, wherein the third reinforcing member is provided on the third wall portion, extends along the first direction, and has higher rigidity than the third wall portion and the pair of second wall portions, and the second region has lower rigidity than the third reinforcing member. The power storage device according to any one of claims 1 to 3.

7. Each of the plurality of cells includes an electrode body including a positive electrode layer, a negative electrode layer, and a separator, and a cell case housing the electrode body. The power storage device according to any one of claims 1 to 3, wherein the positive electrode layer and the negative electrode layer are laminated in the first direction with the separator interposed therebetween.

8. Each of the plurality of cells includes an electrode body including a positive electrode layer, a negative electrode layer, and a separator interposed between the positive electrode layer and the negative electrode layer, a cell case that houses the electrode body, The power storage device according to any one of claims 1 to 3, wherein the electrode body is wound with the direction orthogonal to the first direction as the axial direction.

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