Power storage device

Abstract

To provide a power storage device capable of suppressing disturbance of exhaustion of exhaustion smoke by dispersing the exhaustion smoke which is exhausted from a power storage cell.SOLUTION: A power storage device 1 is disposed in a lower part of a vehicle 10. The power storage device 1 comprises a plurality of power storage stacks 101-106 and a storage case 200 in which the power storage stacks are stored. The power storage stack includes a first end face 100a and a second end face 100b which are arrayed in a first direction L1. The power storage stack includes a plurality of power storage cells 110 arrayed in a second direction L2 which crosses the first direction L1. Each of the plurality of power storage cells 110 is formed long in the first direction L1, and each of the plurality of power storage cells 110 includes an exhaustion part 111 from which a gas inside each of the plurality of power storage cells 110 is exhausted. At least one exhaustion part 111 is provided on the first end face 100a, and at least one exhaustion part 111 is provided on the second end face 100b.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2021-048113 discloses a power storage device in which the exhaust gas from a battery cell is discharged to the outside through an exhaust gas path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the structure of the power storage device disclosed in Patent Document 1, since the discharge part for discharging the exhaust gas from the battery cell faces one direction, the exhaust gas is concentrated, and there is a concern that blockage may occur in the exhaust gas path due to debris and electrolytic solution contained in the exhaust gas.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a power storage device that disperses the exhaust gas discharged from a power storage cell and suppresses the prevention of the discharge of the exhaust gas.

Means for Solving the Problems

[0006] The power storage device according to the present disclosure is a power storage device disposed below a vehicle, and the power storage device includes a plurality of power storage stacks and a housing case that houses the power storage stacks. The power storage stack includes a first end face and a second end face arranged in a first direction, and the power storage stack includes a plurality of power storage cells arranged in a second direction intersecting the first direction. Each of the plurality of power storage cells is formed to be long in the first direction, and each of the plurality of power storage cells includes a discharge portion that discharges gas inside each of the plurality of power storage cells. At least one discharge portion is provided on the first end face, and at least one discharge portion is provided on the second end face.

Advantages of the Invention

[0007] According to the power storage device of the present disclosure, it is possible to provide a power storage device that disperses the smoke discharged from the power storage cells and suppresses the prevention of the discharge of the smoke.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

[0010] FIG. 1 is a diagram schematically showing a vehicle 10 equipped with a power storage device 1 according to the present embodiment. The power storage device 1 is mounted, for example, below the vehicle 10. Note that the lower part of the vehicle 10 means below the floor panel when the floor panel is included. Further, when the vehicle 10 does not include a floor panel, it means below the side member extending in the vehicle width direction of the vehicle 10.

[0011] In FIG. 1 and the like, the first direction L1 indicates the front-rear direction of the vehicle 10, and the second direction L2 indicates the vehicle width direction of the vehicle 10.

[0012] FIG. 2 is a perspective view schematically showing a power storage device according to an embodiment of the present disclosure. FIG. 3 is an exploded perspective view of the power storage device 1 shown in FIG. 2.

[0013] As shown in FIG. 3, the power storage device 1 includes a power storage module 100, a module case 120 that houses the power storage module 100, and a plate 400. The module case 120 includes a housing case 200 and an upper cover 300. The power storage module 100 is housed in the module case 120.

[0014] The upper cover 300 includes a top plate 301 and a peripheral wall 302. The upper cover 300 is formed to open downward. The peripheral wall 302 is formed to extend downward from the outer peripheral edge of the top plate 301. The peripheral wall 302 includes end walls 303 and 304 arranged in the first direction L1 and side walls 305 and 306 arranged in the second direction L2. External discharge ports 311 to 316 are formed in the end wall 303. Further, external discharge ports 317 to 322 are formed in the end wall 304. The external discharge ports 311 to 322 are through holes.

[0015] The power storage module 100 includes a plurality of power storage stacks 101 to 106. Each of the power storage stacks 101 to 106 is sequentially connected electrically in series. Therefore, the voltage difference between the power storage stack 101 and the power storage stack 106 is larger than the voltage difference between the power storage stack 101 and the power storage stack 102.

[0016] In addition, each of the power storage stacks 102 to 106 is formed in the same manner as the power storage stack 101. Therefore, the configuration of the power storage stack 101 will be described.

[0017] FIG. 4 shows a schematic perspective view of the power storage stack 101. The power storage stack 101 includes a plurality of power storage cells 110 arranged so as to be aligned in the second direction L2.

[0018] The power storage cell 110 is formed to be long in the first direction L1. The power storage cell 110 is, for example, a lithium ion battery. The power storage cell 110 includes a cell case 112, an electrode body, and an electrolytic solution housed in the cell case 112.

[0019] The cell case 112 is formed of a metal material such as aluminum, for example. The cell case 112 includes a first cell end face 110a and a second cell end face 110b arranged in the first direction L1, and a discharge portion 111. The discharge portion 111 is formed on the first cell end face 110a.

[0020] For example, the discharge portion 111 is formed to be thinner than the portion of the cell case 112 located around the discharge portion 111.

[0021] The power storage stack 101 includes a first end face 100a and a second end face 100b arranged in the first direction L1.

[0022] The first end face 100a is formed by a plurality of first cell end faces 110a and a plurality of second cell end faces 110b. On the first end face 100a, the first cell end face 110a and the second cell end face 110b are arranged so as to be alternately arranged in the second direction L2.

[0023] Similarly, the second end face 100b also includes a plurality of first cell end faces 110a and a plurality of second cell end faces 110b. On the second end face 100b, the first cell end faces 110a and the second cell end faces 110b are arranged alternately in the second direction L2.

[0024] Therefore, at least one discharge portion 111 is provided on the first end face 100a, and at least one discharge portion 111 is provided on the second end face 100b.

[0025] Specifically, the discharge portions 111 provided on the first end face 100a of the power storage stack 101 are provided at intervals in the second direction L2. Further, the discharge portions 111 provided on the second end face 100b of the power storage stack 101 are provided at intervals in the second direction L2.

[0026] In this way, in the present embodiment, the discharge portions 111 are dispersedly arranged on the first cell end faces 110a and the second cell end faces 110b.

[0027] In the present embodiment, the first direction L1 is shown as the longitudinal direction of the vehicle, and the second direction L2 is shown as the vehicle width direction, but the present disclosure is not limited thereto. For example, the first direction L1 may be the vehicle width direction, and the second direction L2 may be the longitudinal direction of the vehicle.

[0028] FIG. 5 is a perspective view schematically showing the housing case 200. The housing case 200 includes a wall portion 210, a bottom plate 220, and a seal member 221. The wall portion 210 and the seal member 221 are provided on the upper surface of the bottom plate 220.

[0029] The outer peripheral edge portion of the bottom plate 220 is spaced in the second direction L2, and includes a pair of side edges extending in the first direction L1 and a pair of end edges spaced in the first direction L1 and extending in the second direction L2.

[0030] The wall portion 210 includes a side wall 211A, a side wall 211B, a partition wall 212, partition walls 213A and 213B, and partition walls 214A and 214B.

[0031] The side wall 211A is formed on one side of the bottom plate 220 and is formed to extend upward from the side of the bottom plate 220. The side wall 211A is formed on the other side of the bottom plate 220 and is formed to extend upward from the other side.

[0032] The partition wall 212 is formed on the upper surface of the bottom plate 220 so as to extend in the second direction L2. The partition wall 212 is arranged so as to pass through the center of the bottom plate 220 in the first direction L1.

[0033] Figure 6 is a cross-sectional view taken along line VI-VI in Figure 3. The seal member 221 is formed along the outer peripheral edge portion extending in the second direction L2 on the upper surface of the bottom plate 220 and the lower surface of the partition wall 212.

[0034] Returning to FIG. 5 again. The partition walls 213A and 214A are formed to extend from one end of the bottom plate 220 toward the partition wall 212. The partition walls 213A and 214A are provided at intervals in the second direction L2.

[0035] The partition walls 213B and 214B are formed to extend from the other end of the bottom plate 220 toward the partition wall 212. The partition walls 213B and 214B are arranged at intervals in the second direction L2.

[0036] Inside the housing case 200, a housing portion 290 is formed by the wall portion 210. The housing portion 290 includes housing portions 291 to 296. In each of the housing portions 291 to 296, power storage stacks 101 to 106 are housed. Specifically, the power storage stack 101 is housed in the housing portion 291, and the power storage stack 102 is housed in the housing portion 292. Similarly, the power storage stack 106 is housed in the housing portion 296.

[0037] The accommodating portions 291, 292, and 293 are formed on one end side of the bottom plate 220 with respect to the partition wall 212, and the accommodating portions 294, 295, and 296 are formed on the other end side of the bottom plate 220 with respect to the partition wall 212.

[0038] Specifically, the accommodating portion 291 is formed by the side wall 211A, the partition wall 212, and the partition wall 213A. The accommodating portion 292 is formed by the partition wall 212, the partition wall 213A, and the partition wall 214A. The accommodating portion 293 is formed by the side wall 211B, the partition wall 212, and the partition wall 213A. The accommodating portion 296 is formed by the side wall 211A, the partition wall 212, and the partition wall 213B. The accommodating portion 295 is formed by the partition wall 212, the partition wall 213B, and the partition wall 214B. The accommodating portion 294 is formed by the side wall 211B, the partition wall 212, and the partition wall 214B.

[0039] The accommodating portions 291 and 292 are arranged in the second direction L2, and the accommodating portions 291 and 296 are arranged in the first direction L1. Further, the side wall 211A is formed to extend from the accommodating portion 291 to the accommodating portion 296.

[0040] In FIG. 5, the details of the side walls 211A and 211B, the partition walls 213A and 213B, and the partition walls 214A and 214B will be described.

[0041] The side wall 211A is formed with an opening 253, an opening 254, a path 263, a path 264, a discharge port 273, and a discharge port 274. Further, the side wall 211A has an end face 211A1 and an end face 211A2. The end face 211A1 and the end face 211A2 are arranged so as to be arranged in the first direction L1 of the side wall 211A. The end face 211A1 is an end face located in the vicinity of the accommodating portion 291. The end face 211A2 is an end face located in the vicinity of the accommodating portion 294.

[0042] The opening 253 is formed to open toward the accommodating portion 291 and is formed near the partition wall 212. The opening 254 is formed to open toward the accommodating portion 296 and is formed near the partition wall 212. Note that the opening 253 is located below the opening 254. The path 263 and the path 264 are formed to extend in the first direction L1.

[0043] The path 263 and the path 264 are formed to extend in the first direction L1 within the side wall 211A. The path 263 communicates the opening 253 and the discharge port 273. The path 264 communicates the opening 254 and the discharge port 274.

[0044] The discharge port 273 is formed on the end face 211A1 and is provided at a position facing the external discharge port 313 shown in FIG. 3. The discharge port 274 is formed on the end face 211A2 and is provided at a position facing the external discharge port 319 shown in FIG. 3. The side wall 211B has the same configuration.

[0045] In FIG. 5, an opening 251, an opening 252, a path 261, a path 262, a discharge port 271, and a discharge port 272 are formed in the partition wall 213A. The partition wall 213A has an end face 213A1. The end face 213A1 is disposed at one end of the partition wall 213A in the first direction L1. The end face 213A1 is an end face located farther from the partition wall 212.

[0046] The opening 251 is formed to open toward the accommodating portion 291 and is formed near the partition wall 212. The opening 252 is formed to open toward the accommodating portion 292 and is formed near the partition wall 212. Note that the opening 251 is located below the opening 252.

[0047] Path 261 and path 262 are formed in partition wall 213A so as to extend in the first direction L1. Path 261 and path 262 are formed in partition wall 213A. Path 261 communicates with opening 251 and discharge port 271. Path 262 communicates with opening 252 and discharge port 272.

[0048] Discharge port 271 is formed on end face 213A1 and is provided at a position facing external discharge port 311. Discharge port 272 is formed on end face 213A1 and is provided at a position facing external discharge port 312. Partition wall 213B has the same configuration.

[0049] In FIG. 5, in partition wall 214A, opening 255, opening 256, path 265, path 266, discharge port 275, and discharge port 276 are formed. Further, partition wall 214A has end face 214A1. End face 214A1 is arranged so as to be arrayed in the first direction L1 of partition wall 214A. End face 214A1 is an end face located farther from partition wall 212.

[0050] Opening 255 is formed so as to open toward accommodating portion 292 and is formed in the vicinity of partition wall 212. Opening 256 is formed so as to open toward accommodating portion 293 and is formed in the vicinity of partition wall 212. Note that opening 255 is located below opening 256.

[0051] Path 265 and path 266 are formed in partition wall 214A so as to extend in the first direction L1. Path 265 and path 266 are formed in partition wall 214A. Path 265 communicates with opening 255 and discharge port 275. Path 266 communicates with opening 256 and discharge port 276.

[0052] Discharge port 275 is formed on end face 214A1 and is provided at a position facing external discharge port 314 shown in FIG. 3. Discharge port 276 is formed on end face 214A1 and is provided at a position facing external discharge port 315 shown in FIG. 3. Partition wall 214B has the same configuration.

[0053] In this embodiment, the discharge portion 111 provided in the power storage cell 110 is formed thinner than the portion of the cell case 112 located around the discharge portion 111. Thereby, the discharge portion 111 has a function of being damaged by the increase in the internal pressure of the power storage cell 110 when gas is generated in the power storage cell 110. Due to the function of this discharge portion 111, an increase in the internal pressure of the power storage cell 110 can be suppressed.

[0054] At least one discharge portion 111 is provided on the first end face 100a, and at least one discharge portion 111 is also provided on the second end face 100b. The discharge portions 111 are not concentrated on one side end face of the power storage module 100. Thereby, it is possible to suppress clogging by the electrolytic solution or debris contained in the gas until the gas discharged from the discharge portion 111 reaches the opening.

[0055] In this embodiment, the opening 252 communicates with a path 262 different from the path with which the opening 251 communicates. Thereby, the gas generated in the accommodating portion 291 and the accommodating portion 292 does not flow into the same path, and clogging of the paths 261 and 262 can be suppressed.

[0056] In this embodiment, the gas generated from the power storage stack 101 is discharged from the discharge port 273 via the path 263. Since the discharge port 273 is provided far from the accommodating portion 296, it is possible to suppress the gas generated from the power storage stack 101 from heating the power storage stack 106. The same applies to the gas generated from the power storage stack 106.

[0057] In this embodiment, the seal member 221 has a function of suppressing debris and electrolytic solution contained in the gas generated in the accommodating portion 291 from spreading on the upper surface of the bottom plate 220 and entering the accommodating portion 296. Thereby, it is possible to suppress a short circuit between the power storage stack 101 and the power storage stack 106 having a large potential difference. The same applies to the gas generated in the accommodating portion 296.

[0058] In this embodiment, an example in which the opening opens into the accommodating portion has been shown, but the present disclosure is not limited thereto. FIG. 7 is a diagram schematically showing the periphery of the opening 253 in another embodiment. For example, as shown in FIG. 7, on the side surface arranged in the second direction L2 of the side wall 211A, a closing member 230 may be provided so as to cover the opening 253. The same applies to other openings. The closing member 230 is, for example, an insulating film formed of polyethylene or the like.

[0059] The closing member 230 can prevent dust or the like flowing in from the external discharge ports 311 to 322 from accumulating in the paths 261 to 266 and prevent the power storage module 100 from being electrically connected to an external electronic device or the like. Note that only a part of the closing member may be formed thinner than the surroundings so that it can be easily broken when the internal pressure of the accommodating portion 290 rises. Further, the closing member 230 may be provided at the discharge port or the external discharge port.

[0060] In this embodiment, an example in which one opening 252 communicating with the path 262 is formed in the accommodating portion 292 has been shown, but the present disclosure is not limited thereto.

[0061] FIG. 8 is a schematic diagram showing a first modification of the accommodating portion. In the example shown in FIG. 8, in the accommodating portion 292A, openings 252A and 252B communicating with the path 262A are formed so as to be arranged in the first direction L1.

[0062] Thus, there may be a plurality of openings communicating with the path 262A. Since the openings 252A and 252B are formed upward from the upper surface of the bottom plate 220, it is possible to prevent the opening areas of the openings 252A and 252B from being reduced by debris or the like accumulated on the upper surface of the bottom plate 220. Further, by providing a plurality of openings, the pressure loss can be reduced by dispersing the discharge paths, and a decrease in air permeability in the gas discharge path can be suppressed.

[0063] FIG. 9 is a schematic diagram showing a second modification of the accommodating portion. In the example shown in FIG. 9, in the accommodating portion 292B, an opening 252C communicating with the path 262B and an opening 252D communicating with the path 261B are formed so as to be arranged in the vertical direction.

[0064] In this way, the pair of openings 252C and 252D may be arranged in the vertical direction. By forming the opening 252D near the upper surface of the bottom plate 220, the discharge of the debris accumulated on the upper surface of the bottom plate 220 can be promoted. Thereby, the heated debris can be discharged to the outside, and the deviation of the temperature distribution and the decrease in air permeability due to the accumulation of debris in the gas discharge path can be suppressed.

[0065] Since the debris is at a high temperature, if the debris accumulates on the upper surface of the bottom plate 220, the temperature around the debris also becomes high, which may increase the temperature of the adjacent cells. On the other hand, in the example shown in FIG. 9, such adverse effects can be suppressed.

[0066] In addition, by making the opening area of the opening 252D formed near the upper surface of the bottom plate 220 larger than that of the opening 252C, the deviation of the temperature distribution and the decrease in air permeability can be further suppressed by reducing the pressure loss in the gas discharge path.

[0067] In this embodiment, an example in which the seal member 221 is formed along the outer peripheral edge portion extending in the second direction L2 of the lower surface of the partition wall 212 is shown, but the present disclosure is not limited thereto. For example, the seal member 221 may be arranged along the outer peripheral edge portion extending in the first direction L1 of the lower surfaces of the partition walls 213A and 214A. Thereby, it is possible to suppress the electrolytic solution or the like from spreading on the upper surface of the bottom plate 220 and entering the accommodating portions adjacent in the second direction L2.

[0068] Further, the seal member 221 may be disposed along the outer peripheral edge of the end face arranged in the second direction L2 of the partition wall 212. Similarly, it may be disposed along the outer peripheral edge of the end face located in the vicinity of the partition wall 212 inside the end faces arranged in the first direction L1 of the partition walls 213A and 214A. Thereby, it is possible to suppress the electrolytic solution or the like from entering the adjacent accommodation portion along the surface of the partition wall 212 formed so as to extend upward from the bottom plate.

[0069] Note that the power storage stack 101 is an example of the "first power storage stack" of the present disclosure. The power storage stack 102 is an example of the "second power storage stack" of the present disclosure. The power storage stack 106 is an example of the "third power storage stack" of the present disclosure. The accommodation portion 291 is an example of the "first accommodation portion" of the present disclosure. The accommodation portion 292 is an example of the "second accommodation portion" of the present disclosure. The accommodation portion 296 is an example of the "third accommodation portion" of the present disclosure. The side wall 211A is an example of the "side wall" of the present disclosure. The partition wall 213A is an example of the "first partition wall" of the present disclosure. The partition wall 212 is an example of the "second partition wall" of the present disclosure. The opening 251 is an example of the "first opening" of the present disclosure. The path 261 is an example of the "first path" of the present disclosure. The path 262 is an example of the "second path" of the present disclosure. The opening 251 is an example of the "first opening" of the present disclosure. The opening 252 is an example of the "second opening" of the present disclosure. The opening 253 is an example of the "first side wall opening" of the present disclosure. The opening 254 is an example of the "third side wall opening" of the present disclosure. The path 263 is an example of the "first side wall path" of the present disclosure. The path 264 is an example of the "third side wall path" of the present disclosure. The discharge port 273 is an example of the "first side wall discharge port" of the present disclosure. The discharge port 274 is an example of the "third side wall discharge port" of the present disclosure.

[0070] It should be noted that the embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the above-described embodiments, and further includes all modifications within the meaning and scope equivalent to the claims.

Explanation of reference numerals

[0071] 1 Power storage device, 10 Vehicle, 100 Power storage module, 100a First end face, 100b Second end face, 101, 102, 106 Power storage stack, 110 Power storage cell, 110a First cell end face, 110b Second cell end face, 111 Discharge part, 112 Cell case, 120 Module case, 200 Accommodation case, 210 Wall part, 211A, 211B, 305, 306 Side wall, 211A1, 211A2, 213A1, 214A1 End face, 212, 213A, 213B, 214A, 214B Partition wall, 220 Bottom plate, 221 Seal member, 250, 251, 252, 252A, 252B, 252C, 252D, 253, 254, 255, 256 Opening, 261, 262, 263, 264, 265, 266 Path, 271, 272, 273, 274, 275, 276 Outlet, 290, 291, 292, 293, 294, 295, 296 Accommodation part, 300 Upper cover, 301 Top plate, 302 Peripheral wall, 303, 304 End wall, 311, 312, 313, 314, 315, 316, 317, 319, 322 External outlet, 400 Plate, 2021 Japanese Unexamined Patent Application, L1 First direction, L2 Second direction.

Claims

1. An electric storage device disposed under a vehicle, The power storage device includes a plurality of power storage stacks, a housing case that houses the power storage stack; Equipped with The power storage stack includes a first end surface and a second end surface aligned in a first direction; The power storage stack includes a plurality of power storage cells arranged in a second direction intersecting the first direction, Each of the plurality of storage cells is formed elongated in the first direction, Each of the plurality of power storage cells includes an exhaust portion that exhausts gas inside the each of the plurality of power storage cells, At least one of the discharge portions is provided on the first end surface, At least one of the discharge portions is provided on the second end surface.

2. The discharge portions are provided at intervals in the second direction on the first end surface, The power storage device according to claim 1 , wherein the discharge portions are provided at the second end surface and spaced apart from each other in the second direction.

3. The power storage device according to claim 1 or 2, wherein the power storage cells are arranged in a width direction of the vehicle.

4. The power storage device according to claim 1 or 2, wherein the power storage cells are arranged in a longitudinal direction of the vehicle.

5. the housing case includes a wall portion defining housing portions that individually house the plurality of power storage stacks, The power storage device according to claim 1 , wherein the wall portion is provided with an opening that opens into the storage portion, and a path that is formed within the wall portion and communicates with the opening.

6. The plurality of power storage stacks include a first power storage stack and a second power storage stack, the housing case is formed with a first housing portion that houses the first power storage stack, and a second housing portion that is adjacent to the first housing portion in the second direction and houses the second power storage stack, the wall portion includes a first partition wall that partitions the first storage portion and the second storage portion, The first partition wall has: A first opening that opens into the first storage portion; a first passage communicating with the first opening; A second opening that opens into the second storage portion; The power storage device according to claim 5 , further comprising a second path formed in communication with the second opening and different from the first path.

7. The plurality of power storage stacks include a first power storage stack and a third power storage stack, the housing case is formed with a first housing portion that houses the first power storage stack, and a third housing portion that is adjacent to the first housing portion in the first direction and houses the third power storage stack, the wall portion includes a side wall extending across the first storage portion and the third storage portion, The side wall has: a first side wall opening that opens into the first storage portion; a first sidewall passage communicating with the first storage portion; a first sidewall outlet port to which the first sidewall passage is connected; a third side wall opening that opens into the third storage portion; a third sidewall passage that opens into the third housing portion; a third side wall outlet to which the third side wall passage is connected; The first side wall outlet is formed at a position away from the third storage portion, The power storage device according to claim 5 or 6, wherein the third side wall outlet is formed at a position away from the first housing portion.

8. the plurality of power storage stacks include a first power storage stack, a second power storage stack, and a third power storage stack; The housing case includes a bottom plate on which the wall portion is provided, The storage case includes: a first housing portion that houses the first power storage stack; a second accommodation portion adjacent to the first accommodation portion in the second direction and configured to accommodate the second power storage stack; a third storage portion is formed adjacent to the first storage portion in the first direction and configured to store the third power storage stack; The wall portion is a first partition wall that partitions the first storage section and the second storage section; a second partition wall that partitions the first storage portion and the third storage portion, a potential difference between the first storage stack and the third storage stack is greater than a potential difference between the first storage stack and the second storage stack; The power storage device according to claim 5 , wherein the storage case includes a seal member that seals a gap between the second partition wall and the bottom plate.

9. The power storage device according to claim 5 , wherein the storage case includes a closing member that closes the opening.

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