Power storage device

Abstract

To provide a power storage device capable of suppressing transfer of heat to the other power storage stacks which are adjacent to each other in a lateral direction in a case where heat is generated in any power storage stack in three power storage stacks which are disposed in parallel.SOLUTION: A power storage device 10 comprises: a storage case 120 including a first side wall part, a second side wall part, a first inner side wall part, and a second inner side wall part in each of which an exhaustion path is provided; and a first power storage stack 101, a second power storage stack 102, and a third power storage stack 103 which are disposed between the first side wall part and the first inner side wall part, between the first inner side wall part and the second inner side wall part, and between the second inner side wall part and the second side wall part, respectively. The first inner side wall part and the second inner side wall part include first inner side faces 21a and first outer side faces 22b, and the first side wall part and the second side wall part include second inner side faces 22a. On the first inner side faces 21a and the second inner side faces 22a, more openings communicating to the exhaustion paths are provided than on the first outer side faces 21b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an electric storage device mounted on a vehicle. [Background technology]

[0002] As a conventional electricity storage device, International Publication No. 2020 / 134054 (Patent Document 1) discloses a structure in which a portion of a housing case for housing multiple electricity storage stacks is formed from a hollow member, and the hollow portion of the hollow member is used as an exhaust path. The hollow member has multiple through holes for introducing gas exhausted from the electricity storage device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 134054 Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple power storage stacks are placed in a storage case, one possible approach is to place three power storage stacks side by side and partition the areas where each stack is placed with a wall having an exhaust path inside. In this case, if no other measures are taken, there is a concern that when one of the three power storage stacks generates heat, the heat will be transferred to the other power storage stacks lined up side by side, causing a chain reaction of heat generation.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an energy storage device that can suppress the transfer of heat to other horizontally adjacent energy storage stacks when one of three energy storage stacks arranged horizontally generates heat. [Means for solving the problem]

[0006] An energy storage device according to the present disclosure includes a first energy storage stack, a second energy storage stack, and a third energy storage stack arranged in a first direction, and a housing case that houses the first energy storage stack, the second energy storage stack, and the third energy storage stack. The housing case includes a pair of side wall portions located on both end sides in the first direction and a pair of inner wall portions located between the pair of side wall portions. An exhaust path is provided inside each of the pair of side wall portions and the pair of inner wall portions. The pair of side wall portions include a first side wall portion located on one side in the first direction and a second side wall portion located on the other side in the first direction. The pair of inner wall portions include a first inner wall portion located on the one side in the first direction and a second inner wall portion located on the other side in the first direction. The first energy storage stack is disposed between the first side wall portion and the first inner wall portion. The second energy storage stack is disposed between the pair of inner wall portions. The third power storage stack is disposed between the second inner wall portion and the second side wall portion. The first inner wall portion and the second inner wall portion each have a first inner side surface facing in the first direction and a first outer side surface located on the opposite side in the first direction from the side on which the first inner side surface is located. The first side wall portion and the second side wall portion each have a second inner side surface facing the pair of side wall portions in the first direction. The first inner side surface of each of the first inner wall portion and the second inner wall portion and the second inner side surface of each of the first side wall portion and the second side wall portion are provided with more openings communicating with the exhaust path than the first outer side surfaces.

[0007] According to the above configuration, when gas is discharged from the first or third power storage stack, a greater proportion of the gas is discharged from the pair of side wall portions than from the pair of inner wall portions, making it difficult for heat to be transferred to the pair of inner wall portions. This makes it possible to suppress heat transfer to the second power storage stack disposed between the pair of inner wall portions. When gas is discharged from the second power storage stack, the gas passes through the interior of each of the pair of inner wall portions in a dispersed manner, thereby suppressing heat transfer to the first and third power storage stacks.

[0008] In the power storage device according to the present disclosure, a heat insulating member may be provided on the first outer side surface of each of the first inner wall portion and the second inner wall portion.

[0009] According to the above configuration, when gas is discharged from the second power storage stack, the heat insulating member can effectively suppress heat transfer to the first power storage stack and the third power storage stack. Similarly, when gas is discharged from the first power storage stack or the third power storage stack, the heat insulating member can effectively suppress heat transfer to the second power storage stack.

[0010] In the power storage device according to the present disclosure, each of the first inner wall portion and the second inner wall portion has an inner end portion located on the first inner side surface side in the first direction and an outer end portion located on the first outer side surface side. In the first inner wall portion and the second inner wall portion, the exhaust path is located between the inner end portion and the outer end portion. In this case, the thickness of the outer end portion in the first direction may be greater than the thickness of the inner end portion in the first direction.

[0011] According to the above configuration, the thick outer end portion is located as described above, which further reduces heat transfer to the first and third power storage stacks when gas is discharged from the second power storage stack. Similarly, the thick outer end portion is located as described above, which further reduces heat transfer to the second power storage stack when gas is discharged from the first or third power storage stack. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide an energy storage device including three energy storage stacks arranged side by side, which is capable of suppressing the transfer of heat to other energy storage stacks adjacent to it in the horizontal direction when one of the energy storage stacks generates heat. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a vehicle according to an embodiment. [Figure 2] 1 is a schematic cross-sectional view showing a state in which an electricity storage device according to an embodiment is mounted on a vehicle body. [Figure 3] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0015] Fig. 1 is a schematic diagram showing a vehicle according to an embodiment. Fig. 2 is a schematic cross-sectional view showing a state in which an electricity storage device according to an embodiment is mounted on a vehicle body. Vehicle 1 according to an embodiment will be described with reference to Figs. 1 and 2.

[0016] The vehicle 1 is a hybrid vehicle that can run using at least one of the power of a motor and an engine, or an electric vehicle that runs using driving force obtained from electrical energy.

[0017] As shown in FIG. 1, a vehicle 1 includes a vehicle body 2, front wheels 3, rear wheels 4, and a power storage device 10. The vehicle body 2 includes a frame member 5. The power storage device 10 is disposed on the lower side of the vehicle body 2. The power storage device 10 is disposed, for example, between the front wheels 3 and the rear wheels 4. Note that a portion of the power storage device 10 may be disposed overlapping at least one of the front wheels 3 and the rear wheels 4 when viewed from the width direction of the vehicle 1. The power storage device 10 has an upper surface 10a. The upper surface 10a may function as a floor member that defines the interior of the vehicle cabin.

[0018] The framework member 5 includes a pair of side members 6 and a pair of side sills 7. The pair of side sills 7 are arranged on both ends of the vehicle 1 in the width direction. The pair of side members 6 are arranged at a distance inside the pair of side sills 7. The pair of side members 6 and the pair of side sills 7 extend along the front-rear direction of the vehicle 1.

[0019] The pair of side members 6 are spaced apart in the width direction of the vehicle 1. A main body 35 of the electricity storage device 10 is disposed in the gap between the pair of side members 6. A gap is provided between the main body 35 and the pair of side members 6. This makes it possible to suppress input of an impact to the electricity storage device 10 even in the event of a side collision of the vehicle 1.

[0020] Fixed portions 36 are provided on both side surfaces of the main body portion 35 in the width direction of the vehicle 1. The fixed portions 36 are fixed to the pair of side members 6 by fastening members 8.

[0021] The framework member 5 also includes a cross framework member 9. The cross framework member 9 straddles from one side sill 7 to the other side sill 7 above the electricity storage device 10. To the cross framework member 9, an upper surface 10a of the electricity storage device 10 is fixed.

[0022] In the above description, the framework member 5 includes a pair of side members 6 and a pair of side sills 7, but is not limited to this. The pair of side sills 7 may also function as the pair of side members 6. In this case, the pair of side members 6 can be omitted, and the above-mentioned fixed portion 36 may be fixed to the pair of side sills 7.

[0023] Fig. 3 is a schematic exploded perspective view of the electricity storage device according to Embodiment 1. The detailed structure of the electricity storage device 10 will be described with reference to Figs.

[0024] 2 and 3, the power storage device 10 includes a plurality of heat insulating members 41, a power storage module 100, and a housing case 120. The power storage module 100 is housed in the housing case 120.

[0025] The power storage module 100 includes a plurality of power storage stacks 101 to 106. The plurality of power storage stacks 101 to 106 are arranged in a matrix in a casing 120. When the first direction (DR1) is the row direction and the second direction (DR2) is the column direction, the plurality of power storage stacks 101 to 106 are arranged in 3 rows and 2 columns.

[0026] The first direction is, for example, parallel to the width direction of the vehicle 1 in a state in which the power storage device 10 is mounted on the vehicle body 2. The second direction is perpendicular to the first direction, and in the mounted state is parallel to the front-rear direction of the vehicle 1. The multiple power storage stacks 101 to 106 are electrically connected in series.

[0027] Each of the power storage stacks 101 to 106 includes a plurality of unit cells 110. In each of the power storage stacks 101 to 106, the plurality of unit cells 110 are arranged in a first direction. The plurality of unit cells 110 are electrically connected in series.

[0028] The unit cell 110 has a longitudinal shape with the second direction as the longitudinal direction, and has a flat rectangular parallelepiped shape with a thickness in the first direction.

[0029] The unit cell 110 includes a housing 112, within which one or more electrode assemblies are housed.

[0030] When a single electrode body is housed in the housing 112, the electrode body has a shape extending in the longitudinal direction. The electrode body may be a laminated electrode body in which a negative electrode sheet, a separator, and a positive electrode sheet are laminated, or may be a wound electrode body in which a negative electrode sheet, a separator, and a positive electrode sheet are wound.

[0031] When multiple electrode bodies are housed in the housing 112, the multiple electrode bodies are arranged side by side in the longitudinal direction and connected in series. In this case, too, the electrode body may be a stacked electrode body or a wound electrode body.

[0032] The unit cell 110 is a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The unit cell 110 may use a liquid electrolyte or a solid electrolyte. The unit cell 110 may also be a chargeable and dischargeable capacitor.

[0033] Housing 112 is formed of a metal material such as aluminum. Housing 112 includes first end face 110a and second end face 110b arranged in a second direction, and exhaust valve 111. Exhaust valve 111 is formed on first end face 110a. Exhaust valve 111 opens when the internal pressure of housing 112 exceeds a predetermined value, and exhausts gas inside housing 112 to the outside.

[0034] In each of the energy storage stacks 101 to 106, the exhaust valves 111 are alternately located on one side in the second direction and the other side in the second direction in the plurality of unit cells 110 arranged in the first direction. That is, the plurality of unit cells 110 are arranged in the first direction with the first end faces 110a and the second end faces 110b alternately arranged in the first direction on each of the one side and the other side in the second direction.

[0035] The housing case 120 includes an upper member 300 and a lower case 200. The upper member 300 has, for example, a generally box-like shape that opens downward. The upper member 300 includes a top plate 301 and a peripheral wall 302. The peripheral wall 302 extends downward from the outer periphery of the top plate 301. The peripheral wall 302 includes end walls 303 and 304 that are aligned in the second direction, and side walls 305 and 306 that are aligned in the first direction.

[0036] The end wall 303 is formed with external discharge ports 311, 312, 315, and 316 penetrating the end wall 303. The end wall 304 is formed with external discharge ports 321, 322, 325, and 326 penetrating the end wall 304.

[0037] The lower case 200 includes a plurality of wall portions 210 and a bottom plate 220. The plurality of wall portions 210 are provided on the upper surface of the bottom plate 220. The lower case 200 includes a main body portion 35 and a fixed portion 36. The main body portion 35 is composed of the plurality of wall portions 210 and the bottom plate 220. The fixed portion 36 is provided on both side surfaces of the main body portion 35 in the second direction.

[0038] The multiple walls 210 include a pair of side walls 211A, 211B, a partition wall 212, a pair of inner walls 213A, 213B, and a pair of inner walls 214A, 214B. The pair of side walls 211A, 211B, the partition wall 212, the pair of inner walls 213A, 213B, and the pair of inner walls 214A, 214B stand upright from the bottom plate 220.

[0039] The pair of side walls 211A, 211B, the pair of inner wall portions 213A, 213B, and the pair of inner wall portions 214A, 214B extend in the second direction. Exhaust paths through which gas discharged from the power storage stack can flow are provided inside the pair of side walls 211A, 211B, the pair of inner wall portions 213A, 213B, and the pair of inner wall portions 214A, 214B, as will be described later.

[0040] The pair of side walls 211A, 211B are arranged at an interval in the first direction. The pair of side walls 211A, 211B are arranged on both sides of the bottom plate in the first direction. The side wall 211A corresponds to the first side wall and is arranged on one side in the first direction. The side wall 211B corresponds to the second side wall and is arranged on the other side in the first direction.

[0041] Each of the side walls 211A, 211B has a second inner side surface 22a facing the pair of inner wall portions 213A, 213B in the first direction, and a second outer side surface 22b facing the opposite side to the side on which the second inner side surface 22a is located in the first direction.

[0042] Partition wall portion 212 extends in a first direction on the upper surface of bottom plate 220. Partition wall portion 212 is disposed in approximately the center of bottom plate 220 in the second direction. Partition wall portion 212 divides the space inside accommodation case 120 in the second direction.

[0043] The pair of inner wall portions 213A, 213B are arranged in a space on one side in the second direction within the accommodating case 120, which is partitioned by the partition wall portion 212. The pair of inner wall portions 213A, 213B are arranged between the pair of side wall portions 211A, 211B on one side in the second direction. The pair of inner wall portions 213A, 213B are arranged apart from the pair of side wall portions 211A, 211B and are arranged with a gap in between in the first direction. The inner wall portion 213A corresponds to a first inner wall portion and is located on one side in the first direction. The inner wall portion 213B corresponds to a second inner wall portion and is located on the other side in the first direction.

[0044] The pair of inner wall portions 213A, 213B divide the space inside the storage case 120 located on one side in the second direction of the partition wall portion 212 into three regions (first region 291, second region 292, third region 293) in the first direction.

[0045] In a space within the storage case located on one side in the second direction, a power storage stack 101 (first power storage stack) is arranged between the side wall 211A and the inner wall 213A. A power storage stack 102 (second power storage stack) is arranged between the inner wall 213A and the inner wall 213B. A power storage stack 103 (third power storage stack) is arranged between the inner wall 213B and the side wall 211B.

[0046] Each of the pair of inner wall portions 213A, 213B has a first inner side surface 21a facing each other in the first direction, and a first outer side surface 21b located on the opposite side in the first direction to the side on which the first inner side surface 21a is located.

[0047] Each of the pair of inner wall portions 213A, 213B has an inner end portion 213c located on the first inner side surface 21a side in the first direction and an outer end portion 213d located on the first outer side surface 21b side. Exhaust paths 271, 272, which will be described later, are located between the inner end portion 213c and the outer end portion 213d of each of the inner wall portions 213A, 213B.

[0048] The thickness of the outer end 213d in the first direction is greater than the thickness of the inner end 213c in the first direction. Note that the relationship in thickness between the outer end 213d and the inner end 213c is not limited to the above, and the thickness of the outer end 213d and the thickness of the inner end 213c may be approximately equal.

[0049] The pair of inner wall portions 214A, 214B (third inner wall portion, fourth inner wall portion) are arranged in a space on the other side in the first direction within the accommodating case 120, which is partitioned by the partition wall portion 212. The pair of inner wall portions 214A, 214B are arranged between the pair of side wall portions 211A, 211B. The pair of inner wall portions 214A, 214B are arranged apart from the pair of side wall portions 211A, 211B and are arranged with a gap between them in the first direction. The inner wall portion 214A is located on one side in the first direction, and the inner wall portion 214B is located on the other side in the first direction.

[0050] The pair of inner wall portions 214A, 214B divide the space within the storage case 120 located on the other side in the second direction from the partition wall portion 212 into three regions (fourth region 294, fifth region 295, sixth region 296) in the first direction.

[0051] In the space within the storage case located on the other side in the second direction, a power storage stack 104 (fourth power storage stack) is arranged between the side wall 211A and the inner wall 214A. A power storage stack 105 (fifth power storage stack) is arranged between the inner wall 214A and the inner wall 214B. A power storage stack 106 (sixth power storage stack) is arranged between the inner wall 214B and the side wall 211B.

[0052] Each of the pair of inner wall portions 214A, 214B has a third inner side surface 23a facing each other in the first direction and a third outer side surface 23b located on the opposite side in the first direction to the side on which the third inner side surface 23a is located. In the pair of inner wall portions 214A, 214B, the thickness of the outer end portion located on the third outer side surface 23b side in the first direction is also thicker than the thickness of the inner end portion located on the third inner side surface 23a side in the first direction. Note that the relationship in thickness between the outer end portion and the inner end portion is not limited to the above, and the thickness of the outer end portion and the thickness of the inner end portion may be approximately equal.

[0053] The side wall portion 211A is provided with a plurality of openings 255, 265 and exhaust paths 275, 285. The plurality of openings 255, 265 are provided in the second inner side surface 22a of the side wall portion 211A.

[0054] The plurality of openings 255 are open toward a first region 291 located between the side wall portion 211A and the inner wall portion 213A. The plurality of openings 255 are in communication with an exhaust path 275 provided inside the side wall portion 211A. The exhaust path 275 extends from the partition wall portion 212 side toward one side in the second direction. The exhaust path 275 is in communication with the external exhaust port 315.

[0055] The plurality of openings 265 are open toward a fourth region 294 located between the side wall portion 211A and the inner wall portion 214A. The plurality of openings 265 are in communication with an exhaust path 285 provided inside the side wall portion 211A. The exhaust path 285 extends from the partition wall portion 212 side toward the other side in the second direction. The exhaust path 285 is in communication with the external exhaust port 325.

[0056] A plurality of openings 251, 252 and exhaust paths 271, 272 are provided in the pair of inner wall portions 213A, 213B.

[0057] The plurality of openings 251 are provided in the first inner side surface 21a of the inner wall portion 213A. The plurality of openings 252 are provided in the first inner side surface 21a of the inner wall portion 213B. The plurality of openings 251, 252 open toward the second region 292 located between the pair of inner wall portions 213A, 213B.

[0058] The openings 251 communicate with an exhaust path 271 provided in the inner wall portion 213A. The exhaust path 271 extends from the partition wall portion 212 side toward one side in the second direction. The exhaust path 271 communicates with the external exhaust port 311.

[0059] The openings 252 communicate with an exhaust path 272 provided in the inner wall portion 213B. The exhaust path 272 extends from the partition wall portion 212 side toward one side in the second direction. The exhaust path 272 communicates with the external exhaust port 312.

[0060] The side wall portion 211B is provided with a plurality of openings 256, 266 and exhaust paths 276, 286. The plurality of openings 256, 266 are provided in the second inner side surface 22a of the side wall portion 211B.

[0061] The plurality of openings 256 are open toward a third region 293 located between the side wall portion 211B and the inner wall portion 213B. The plurality of openings 256 are connected to an exhaust path 276 provided inside the side wall portion 211B. The exhaust path 276 extends from the partition wall portion 212 side toward one side in the second direction. The exhaust path 276 is connected to the external exhaust port 316.

[0062] The plurality of openings 266 are open toward a sixth region 296 located between the side wall portion 211B and the inner wall portion 214B. The plurality of openings 266 are connected to an exhaust path 286 provided inside the side wall portion 211B. The exhaust path 286 extends from the partition wall portion 212 side toward the other side in the second direction. The exhaust path 286 is connected to the external exhaust port 326.

[0063] A plurality of openings 261, 262 and exhaust paths 281, 282 are provided in the pair of inner wall portions 214A, 214B.

[0064] The plurality of openings 261 are provided in the third inner side surface 23a of the inner wall portion 214A. The plurality of openings 262 are provided in the third inner side surface 23a of the inner wall portion 214B. The plurality of openings 261, 262 open toward the second region 292 located between the pair of inner wall portions 214A, 214B.

[0065] The openings 261 communicate with an exhaust path 281 provided in the inner wall portion 214A. The exhaust path 281 extends from the partition wall portion 212 side toward the other side in the second direction. The exhaust path 281 communicates with the external exhaust port 321.

[0066] The openings 262 communicate with an exhaust path 282 provided in the inner wall portion 214B. The exhaust path 282 extends from the partition wall portion 212 side toward the other side in the second direction. The exhaust path 282 communicates with the external exhaust port 322.

[0067] Each of the plurality of openings 251, 252, 255, and 256 is provided on one side in the second direction within the storage case 120 partitioned by the partition wall portion 212, closer to the partition wall portion 212. Each of the plurality of openings 261, 262, 265, and 266 is provided on the other side in the second direction within the storage case 120 partitioned by the partition wall portion 212, closer to the partition wall portion 212.

[0068] Each of the plurality of openings 251, 252, 255, 256, 261, 262, 265, and 266 includes, for example, three openings, and is arranged at intervals in the vertical direction. The vertical direction is a direction perpendicular to the first direction and the second direction. Note that the plurality of openings 251, 252, 255, 256, 261, 262, 265, and 266 may be arranged at intervals in the second direction, not limited to the vertical direction.

[0069] A plurality of heat insulating members 41 are provided on the first outer side surface 21b of each of the pair of inner wall portions 213A, 213B and on the third outer side surface 23b of each of the pair of inner wall portions 214A, 214B. Each heat insulating member 41 covers the entire outer side surface.

[0070] Here, in this embodiment, within the storage case, on one side of the second direction separated by the partition wall portion 212, the first inner side surface 21a of each of the inner wall portions 213A, 213B and the second inner side surface 22a of each of the side wall portions 211A, 211B have more openings communicating with the exhaust path than the first outer side surface 21b of the inner wall portions 213A, 213B.

[0071] When gas is discharged from the power storage stack 101, the number of openings 255 provided in the second inner side surface 22a of the side wall portion 211A is greater than the number of openings provided in the first outer side surface 21b of the inner wall portion 213A, and therefore a higher proportion of gas is discharged from the side wall portion 211A side to the outside through the exhaust path 275. This makes it difficult for heat to be transferred to the inner wall portion 213A, and ultimately makes it possible to suppress the transfer of heat to the power storage stack 102 located on the pair of inner wall portions 213A, 213B.

[0072] Similarly, when gas is discharged from the power storage stack 103, a higher proportion of the gas is discharged to the outside from the side wall portion 211B side through the exhaust path 276. This makes it difficult for heat to be transferred to the inner wall portion 213B, and ultimately makes it possible to suppress the transfer of heat to the power storage stack 102 located on the pair of inner wall portions 213A, 213B.

[0073] When gas is discharged from the power storage stack 102, the gas passes through the exhaust paths 271, 272 inside each of the pair of inner wall portions 213A, 213B in a dispersed manner, thereby suppressing heat transfer to the power storage stacks 101 and 103.

[0074] The gas flow when gas is discharged from any of the power storage stacks 104, 105, and 106 differs from the gas flow when gas is discharged from any of the above-described power storage stacks 101, 102, and 103 only in terms of exhaust paths 285, 281, 282, and 286. Therefore, similarly to the above, when gas is discharged from the power storage stack 104 or the power storage stack 106, heat transfer to the power storage stack 105 can be suppressed, and when gas is discharged from the power storage stack 105, heat transfer to the power storage stacks 104 and 106 can be suppressed.

[0075] Thus, in this embodiment, in a storage device 10 including three storage stacks arranged side by side, when any of the storage stacks generates heat, the transfer of heat to other storage stacks adjacent to it in the horizontal direction can be suppressed.

[0076] Although the present embodiment illustrates a case in which no openings are provided in the first outer side surface 21b and the third outer side surface 23b, as described above, one or more openings may be provided in the first outer side surface 21b as long as the number of each of the plurality of openings 251, 252, 255, and 256 is greater than the number of openings provided in the first outer side surface 21b. Similarly, one or more openings may be provided in the third outer side surface 23b as long as the number of each of the plurality of openings 261, 262, 265, and 266 is greater than the number of openings provided in the third outer side surface 23b. When openings are provided in the first outer side surface 21b and the third outer side surface 23b, it is preferable that the heat insulating member 41 be provided so as not to cover the portions where the openings are located.

[0077] Furthermore, by providing the heat insulating member 41 as described above, when gas is discharged from the power storage stack 102 or the power storage stack 105, it is possible to effectively suppress the transfer of heat to the power storage stacks 101 and 103 or the power storage stacks 104 and 106. Similarly, when gas is discharged from the power storage stacks 101 and 103 or the power storage stacks 104 and 106, it is possible to effectively suppress the transfer of heat to the power storage stack 102 or the power storage stack 105.

[0078] In addition, as described above, in the pair of inner wall portions 213A, 213B and the pair of inner wall portions 214A, 214B, the thickness of the outer ends is greater than the thickness of the inner ends, which makes it possible to further suppress heat transfer to the power storage stacks 101, 103 or the power storage stacks 104, 106 when gas is discharged from the power storage stack 102 or the power storage stack 105. Similarly, it is possible to further suppress heat transfer to the power storage stack 102 or the power storage stack 105 when gas is discharged from the power storage stacks 101, 103 or the power storage stacks 104, 106.

[0079] (Other variations) In the present embodiment, the case where the multiple unit cells 110 are arranged in the first direction with the exhaust valves 111 alternately positioned on one side of the second direction and the other side of the second direction has been described as an example, but the present invention is not limited to this. The multiple unit cells 110 may also be arranged in the first direction with all the exhaust valves 111 facing the partition wall portion 212. In this case, the distance between all the exhaust valves 111 and the opening is shortened. Therefore, it is possible to suppress the diffusion of gas discharged from the exhaust valves 111 in each region (first region 291 to sixth region 296).

[0080] Furthermore, although the case where the unit cells 110 are arranged in the first direction has been described as an example, the present invention is not limited thereto and the unit cells 110 may be arranged in the second direction. In this case, the unit cells 110 have an elongated shape with the first direction as the longitudinal direction.

[0081] In the above-described embodiment, the case has been exemplified in which the number of openings 255, 256 provided in the second inner side surface 22a is the same as the number of openings 251, 252 provided in the first inner side surface 21a on one side in the second direction partitioned by the partition wall portion 212, but this is not limiting. The number of openings 255, 256 provided in the second inner side surface 22a may be more or less than the number of openings 251, 252 provided in the first inner side surface 21a.

[0082] When the number of openings 255, 256 is greater than the number of openings 251, 252, gas discharged from the power storage stacks 101, 103 can be discharged to the outside more quickly, thereby further reducing heat transfer to the power storage stack 102.

[0083] On the other hand, if the number of openings 255, 256 is smaller than the number of openings 251, 252, the rigidity of the sidewalls 211A, 211B can be increased.

[0084] Similarly, on the other side of the second direction partitioned by the partition wall portion 212, the number of openings 265, 266 provided in the second inner side surface 22a may be greater or less than the number of openings 261, 262 provided in the third inner side surface 23a.

[0085] In the above-described embodiment, the case has been exemplified in which no openings are provided on the second outer side surface 22b of the side wall portions 211A, 211B and the number of openings provided on the second inner side surface 22a is greater than the number of openings provided on the second outer side surface 22b, but openings may be provided on the second outer side surface 22b. Even in this case, the number of openings provided on the second inner side surface 22a may be greater than the number of openings provided on the second outer side surface 22b, or the number of openings provided on the second inner side surface 22a may be less than the number of openings provided on the second outer side surface 22b.

[0086] If the number of openings provided on the second inner side surface 22a is smaller than the number of openings provided on the second outer side surface 22b, gas discharged from the power storage stacks 101, 103, 104, 106 can be discharged outside the housing case 120 more quickly.

[0087] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0088] REFERENCE SIGNS LIST 1 vehicle, 2 vehicle body, 3 front wheel, 4 rear wheel, 5 frame member, 6 side member, 7 side sill, 8 fastening member, 9 cross frame member, 10 electricity storage device, 10a upper surface, 21a first inner side surface, 21b first outer side surface, 22a second inner side surface, 22b second outer side surface, 23a third inner side surface, 23b third outer side surface, 35 main body portion, 36 fixed portion, 41 heat insulating member, 100 electricity storage module, 101, 102, 103, 104, 105, 106 electricity storage stack, 110 unit cell, 110a first end surface, 110b second end surface, 111 exhaust valve, 112 housing, 120 storage case, 200 lower case, 210 wall portion, 211A, 211B side wall portion, 212 Partition wall portion, 213A, 213B, 214A, 214B inner wall portion, 213c inner end portion, 213d outer end portion, 220 bottom plate, 251, 252, 255, 256, 261, 262, 265, 266 openings, 271, 272, 275, 276, 281, 282, 285, 286 exhaust path, 291 first region, 292 second region, 293 third region, 294 fourth region, 295 fifth region, 296 sixth region, 300 upper member, 301 top plate, 302 peripheral wall, 303, 304 end wall, 305, 306 side wall, 311, 312, 315, 316, 321, 322, 325, 326 external exhaust port.

Claims

1. a first storage stack, a second storage stack, and a third storage stack arranged in a first direction; a housing case that houses the first power storage stack, the second power storage stack, and the third power storage stack, the storage case includes a pair of side wall portions located on both end sides in the first direction, and a pair of inner wall portions disposed between the pair of side wall portions, an exhaust path is provided inside each of the pair of side wall portions and the pair of inner wall portions, the pair of side wall portions include a first side wall portion located on one side in the first direction and a second side wall portion located on the other side in the first direction, the pair of inner wall portions include a first inner wall portion located on the one side in the first direction and a second inner wall portion located on the other side in the first direction, the first power storage stack is disposed between the first side wall portion and the first inner wall portion, the second power storage stack is disposed between the pair of inner wall portions, the third power storage stack is disposed between the second inner wall portion and the second side wall portion, each of the first inner wall portion and the second inner wall portion has a first inner side surface facing each other in the first direction and a first outer side surface located on the opposite side to the side on which the first inner side surface is located in the first direction; each of the first side wall portion and the second side wall portion has a second inner side surface facing the pair of side wall portions in the first direction; a first inner side surface of each of the first inner wall portion and the second inner wall portion, and a second inner side surface of each of the first side wall portion and the second side wall portion, each having more openings communicating with the exhaust path than each of the first outer side surfaces.

2. The power storage device according to claim 1 , wherein a heat insulating member is provided on the first outer side surface of each of the first inner wall portion and the second inner wall portion.

3. each of the first inner wall portion and the second inner wall portion has an inner end portion located on the first inner side surface side in the first direction and an outer end portion located on the first outer side surface side; In the first inner wall portion and the second inner wall portion, the exhaust path is located between the inner end portion and the outer end portion, The power storage device according to claim 1 , wherein a thickness of the outer end portion in the first direction is greater than a thickness of the inner end portion in the first direction.

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