Electricity storage device

Abstract

A power storage device includes: a housing case including a first side wall portion, a second side wall portion, a first inner side wall portion, and a second inner side wall portion; and a first power storage stack, a second power storage stack, and a third power storage stack disposed between the first side wall portion and the first inner side wall portion, between the first inner side wall portion and the second inner side wall portion, and between the second inner side wall portion and the second side wall portion, respectively, the first inner side wall portion and the second inner side wall portion having a first inner side surface and a first outer side surface. The first side wall portion and the second side wall portion have a second inner side surface, and the first inner side surface and the second inner side surface are provided with more openings communicating with the exhaust path than the first outer side surfaces.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electrical storage device mounted on a vehicle. BACKGROUND

[0002] As a conventional electrical storage device, a configuration is disclosed in International Publication No. 2020 / 134054 in which a portion of a housing case that houses a plurality of electrical storage stack bodies is constituted by a hollow member, and a hollow portion of the hollow member is utilized as an exhaust path. A plurality of through holes for introducing gas discharged from the electrical storage device are provided in the hollow member. SUMMARY

[0003] In a case where a plurality of electrical storage stack bodies are arranged in the housing case, it is conceivable to arrange three electrical storage stack bodies in a lateral arrangement, and to divide regions in which the electrical storage stack bodies are arranged by wall portions in which exhaust paths are provided inside. In this case, when the electrical storage stack body of any one of the three electrical storage stack bodies heats up without any measures being taken, it is possible for heat to be transmitted to the other electrical storage stack bodies arranged in the lateral arrangement, and for the electrical storage stack bodies to heat up in a chain reaction.

[0004] The present disclosure is made in view of the above-described problem. An object of the present disclosure is to provide an electrical storage device that can suppress transmission of heat to an other electrical storage stack body adjacent in the lateral direction in a case where the electrical storage stack body of any one of three electrical storage stack bodies arranged in a lateral arrangement heats up.

[0005] The electrical storage device according to the present disclosure includes:

[0006] a first electrical storage stack body, a second electrical storage stack body, and a third electrical storage stack body arranged in a first direction; and

[0007] a housing case that houses the first electrical storage stack body, the second electrical storage stack body, and the third electrical storage stack body.

[0008] The housing case includes a pair of side wall portions on both end portions in the first direction, and a pair of inner side wall portions arranged between the pair of side wall portions.

[0009] An exhaust path is provided inside each of the pair of side wall portions and the pair of inner side wall portions.

[0010] The pair of side wall portions includes a first side wall portion on one side in the first direction, and a second side wall portion on the other side in the first direction.

[0011] The pair of inner side wall portions includes a first inner side wall portion on the one side in the first direction, and a second inner side wall portion on the other side in the first direction.

[0012] The first power storage stack is disposed between the first side wall portion and the first inner side wall portion.

[0013] The second power storage stack is disposed between the pair of inner side wall portions.

[0014] The third power storage stack is disposed between the second inner side wall portion and the second side wall portion.

[0015] The first inner side wall portion and the second inner side 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 of the first inner side surface in the first direction.

[0016] 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.

[0017] More openings communicating with the exhaust path are provided in the first inner side surface of each of the first inner side wall portion and the second inner side wall portion, and in the second inner side surface of each of the first side wall portion and the second side wall portion, than in the first outer side surface of each.

[0018] According to the above configuration, in a case where gas is exhausted from the first power storage stack or the third power storage stack, the proportion of gas exhausted from the pair of side wall portions is greater than the proportion of gas exhausted from the pair of inner side wall portions, and thus heat is less likely to be transmitted to the pair of inner side wall portions. Thus, heat transmission to the second power storage stack disposed between the pair of inner side wall portions can be suppressed. In a case where gas is exhausted from the second power storage stack, the gas dispersively passes through the inside of each of the pair of inner side wall portions, and thus heat transmission to the first power storage stack and the third power storage stack can be suppressed.

[0019] In the power storage device based on the above disclosure,

[0020] A heat insulating member can be provided in the first outer side surface of each of the first inner side wall portion and the second inner side wall portion.

[0021] According to the above configuration, heat transmission to the first power storage stack and the third power storage stack in a case where gas is exhausted from the second power storage stack can be effectively suppressed by the heat insulating member. Similarly, heat transmission to the second power storage stack in a case where gas is exhausted from the first power storage stack or the third power storage stack can be effectively suppressed by the heat insulating member.

[0022] In the power storage device based on the above disclosure,

[0023] The first inner side wall portion and the second inner side wall portion each have an inner side end portion on the first inner side surface side in the first direction and an outer side end portion on the first outer side surface side.

[0024] In the first inner side wall portion and the second inner side wall portion, the exhaust passage is located between the inner side end portion and the outer side end portion.

[0025] In this case, the thickness of the outer side end portion in the first direction can be thicker than the thickness of the inner side end portion in the first direction.

[0026] According to the above configuration, by configuring the thick outer side end portion as described above, in a case where gas is exhausted from the second power storage stack, heat transfer to the first power storage stack and the third power storage stack can be further suppressed. Similarly, in a case where gas is exhausted from the first power storage stack or the third power storage stack, heat transfer to the second power storage stack can be further suppressed.

[0027] According to the present disclosure, it is possible to provide a power storage device that can suppress heat transfer to an adjacent power storage stack in a case where heat is generated in any one of the three power storage stacks arranged in a lateral direction. BRIEF DESCRIPTION OF DRAWINGS

[0028] Features, advantages, and technical and industrial significance of exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein like numerals denote like elements, and wherein:

[0029] Figure 1 is a schematic view of a vehicle of an embodiment;

[0030] Figure 2 is a schematic cross-sectional view showing a case where the power storage device of the embodiment is mounted on a vehicle body; and

[0031] Figure 3 is an exploded perspective view of the power storage device of the embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, with reference to the drawings, an embodiment of the present disclosure will be described in detail. Furthermore, in the embodiment shown below, for the same or common parts, the same reference numerals are marked in the drawings, and the description thereof will not be repeated.

[0033] Figure 1 is a schematic view of a vehicle of an embodiment. Figure 2 is a schematic cross-sectional view showing a case where the power storage device of the embodiment is mounted on a vehicle body. With reference to Figure 1 and Figure 2A vehicle 1 according to an embodiment will be described.

[0034] The vehicle 1 is a hybrid electric vehicle capable of traveling using power of at least one of a motor and an engine, or an electrified vehicle that travels using driving force obtained by electric energy.

[0035] As shown in Figure 1 The vehicle 1 is provided with a vehicle body 2, front wheels 3, rear wheels 4, and an electrical storage device 10. The vehicle body 2 includes a skeletal member 5. The electrical storage device 10 is disposed on a lower side of the vehicle body 2. The electrical storage device 10 is disposed, for example, between the front wheels 3 and the rear wheels 4. Further, in a case where the vehicle 1 is viewed in a width direction thereof, a part of the electrical storage device 10 can be disposed in overlap with at least one of the front wheels 3 and the rear wheels 4. The electrical storage device 10 has an upper surface 10a. The upper surface 10a can function as a floor member that defines an interior of the vehicle.

[0036] The skeletal member 5 includes a pair of side members 6 and a pair of side sills 7. The pair of side sills 7 is disposed on both end sides in the width direction of the vehicle 1. The pair of side members 6 is disposed at a distance from the inside of the pair of side sills 7. The pair of side members 6 and the pair of side sills 7 extend in the front-rear direction of the vehicle 1.

[0037] The pair of side members 6 is separated in the width direction of the vehicle 1. A main body portion 35 of the electrical storage device 10 is disposed in a gap between the pair of side members 6. A gap is provided between the main body portion 35 and the pair of side members 6. Thus, even in a case where the vehicle 1 has undergone a side collision, it is possible to suppress input of an impact to the electrical storage device 10.

[0038] Fixed portions 36 are provided on both sides 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 a connecting member 8.

[0039] The skeletal member 5 further includes a cross skeletal member 9. The cross skeletal member 9 spans from one side sill 7 to the other side sill 7 above the electrical storage device 10. The upper surface 10a of the electrical storage device 10 is fixed to the cross skeletal member 9.

[0040] Further, in the above description, a case where the skeletal member 5 includes the pair of side members 6 and the pair of side sills 7 is exemplified and described, but the present embodiment is not limited thereto. The pair of side sills 7 can also function as the pair of side members 6. In this case, the pair of side members 6 can be omitted, and the fixed portions 36 described above can be fixed to the pair of side sills 7.

[0041] Figure 3is a schematic exploded perspective view of the power storage device of Embodiment 1. Reference is made to the above-described Figure 2 and Figure 3 The detailed configuration of the power storage device 10 will be described.

[0042] As shown in Figs. 1 and 2, 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. Figure 2 Figure 3 As shown in Figs. 1 and 2, 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.

[0043] 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 the housing case 120. In a case where a first direction (DR1) is set as a row direction and a second direction (DR2) is set as a column direction, the plurality of power storage stacks 101 to 106 are arranged in a manner of 3 rows and 2 columns.

[0044] In a mounted state in which the power storage device 10 is mounted on the vehicle main body 2, the first direction is parallel to a width direction of the vehicle 1, for example. The second direction is orthogonal to the first direction and is parallel to a front-rear direction of the vehicle 1 in the above-described mounted state. The plurality of power storage stacks 101 to 106 are electrically connected in series.

[0045] 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 the first direction. The plurality of unit cells 110 are electrically connected in series.

[0046] The unit cell 110 has a long dimension (elongated, vertical) shape having the second direction as a length direction. The unit cell 110 has a flat cuboid shape having a thickness in the first direction.

[0047] The unit cell 110 includes a case 112 in which a single or a plurality of electrode bodies are housed.

[0048] In a case where a single electrode body is housed in the case 112, the electrode body has a shape extending in the above-described length direction. The electrode body can be a laminated electrode body in which a negative electrode sheet, a separator, and a positive electrode sheet are laminated, or can be a wound electrode body in which a negative electrode sheet, a separator, and a positive electrode sheet are wound.

[0049] In a case where a plurality of electrode bodies are housed in the case 112, the plurality of electrode bodies are arranged in the length direction and are connected in series. In this case as well, the electrode body can be a laminated electrode body or can be a wound electrode body.

[0050] ​The unit cell 110 is a secondary battery such as a nickel-hydrogen battery or a lithium-ion battery. The unit cell 110 can use a liquid electrolyte or a solid electrolyte. The unit cell 110 can also be a capacitor that can be charged and discharged.

[0051] The case 112 is formed of a metal material such as aluminum. The case 112 includes a first end surface 110a and a second end surface 110b arranged in the second direction, and an exhaust valve 111. The exhaust valve 111 is formed in the first end surface 110a. The exhaust valve 111 opens to discharge gas in the case 112 to the outside of the case 112 when the internal pressure of the case 112 exceeds a predetermined value.

[0052] In each of the power storage stacks 101 to 106, the exhaust valves 111 are alternately positioned on one side in the second direction and on the other side in the second direction among 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 in a state in which the first end surface 110a and the second end surface 110b are alternately arranged in the first direction at one side and the other side in the second direction, respectively.

[0053] The housing 120 includes an upper member 300 and a lower case 200. The upper member 300 has, for example, a substantially box shape that is open downward. The upper member 300 includes a top plate 301 and a peripheral wall 302. The peripheral wall 302 extends downward from an outer peripheral edge portion of the top plate 301. The peripheral wall 302 includes an end wall 303 and an end wall 304 arranged in the second direction, and a side wall 305 and a side wall 306 arranged in the first direction.

[0054] An external discharge port 311, 312, 315, 316 that penetrates the end wall 303 is formed in the end wall 303. In addition, an external discharge port 321, 322, 325, 326 that penetrates the end wall 304 is formed in the end wall 304.

[0055] 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 an 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 constituted by 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.

[0056] The plurality of wall portions 210 include a pair of side wall portions 211A, 211B, a partition wall portion 212, a pair of inner side wall portions 213A, 213B, and a pair of inner side wall portions 214A, 214B. The pair of side wall portions 211A, 211B, the partition wall portion 212, the pair of inner side wall portions 213A, 213B, and the pair of inner side wall portions 214A, 214B rise from the bottom plate 220.

[0057] The pair of side wall portions 211A, 211B, the pair of inner side wall portions 213A, 213B, and the pair of inner side wall portions 214A, 214B extend in the second direction. Inside the pair of side wall portions 211A, 211B, the pair of inner side wall portions 213A, 213B, and the pair of inner side wall portions 214A, 214B, an exhaust path through which gas discharged from the power storage stack can flow is provided, as described later.

[0058] The pair of side wall portions 211A, 211B are disposed apart from each other in the first direction. The pair of side wall portions 211A, 211B are disposed on both sides of the floor in the first direction. The side wall portion 211A corresponds to a first side wall portion and is disposed on one side in the first direction. The side wall portion 211B corresponds to a second side wall portion and is disposed on the other side in the first direction.

[0059] The side wall portions 211A, 211B each have a second inner side surface 22a facing the pair of inner side wall portions 213A, 213B in the first direction, and a second outer side surface 22b facing the opposite side of the second inner side surface 22a in the first direction.

[0060] The partition wall portion 212 extends in the first direction at the upper surface of the floor 220. The partition wall portion 212 is disposed at substantially the center of the floor 220 in the second direction. The partition wall portion 212 divides the space inside the housing case 120 in the second direction.

[0061] The pair of inner side wall portions 213A, 213B are disposed in the space on one side in the second direction inside the housing case 120 divided by the partition wall portion 212. The pair of inner side wall portions 213A, 213B are disposed on one side in the second direction between the pair of side wall portions 211A, 211B. The pair of inner side wall portions 213A, 213B are disposed separately from the pair of side wall portions 211A, 211B and are disposed apart from each other in the first direction. The inner side wall portion 213A corresponds to a first inner side wall portion and is located on one side in the first direction. The inner side wall portion 213B corresponds to a second inner side wall portion and is located on the other side in the first direction.

[0062] The pair of inner side wall portions 213A, 213B divide the space inside the housing case 120 on one side in the second direction from the partition wall portion 212 into three regions (a first region 291, a second region 292, and a third region 293) in the first direction.

[0063] The space in the space in the housing on the one side in the second direction is provided with the electricity storage stack 101 (first electricity storage stack) between the side wall portion 211A and the inner side wall portion 213A. The electricity storage stack 102 (second electricity storage stack) is provided between the inner side wall portion 213A and the inner side wall portion 213B. The electricity storage stack 103 (third electricity storage stack) is provided between the inner side wall portion 213B and the side wall portion 211B.

[0064] The pair of inner side wall portions 213A, 213B each has a first inner side surface 21a facing in the first direction, and a first outer side surface 21b on the opposite side of the first inner side surface 21a in the first direction.

[0065] The pair of inner side wall portions 213A, 213B each has an inner side end portion 213c on the side of the first inner side surface 21a in the first direction, and an outer side end portion 213d on the side of the first outer side surface 21b. The exhaust passages 271, 272 described later are located between the inner side end portion 213c and the outer side end portion 213d of each of the inner side wall portions 213A, 213B.

[0066] The thickness of the outer side end portion 213d in the first direction is thicker than the thickness of the inner side end portion 213c in the first direction. Further, the relationship between the thickness of the outer side end portion 213d and the thickness of the inner side end portion 213c is not limited to the above, and the thickness of the outer side end portion 213d and the thickness of the inner side end portion 213c can be substantially equal.

[0067] The pair of inner side wall portions 214A, 214B (third inner side wall portion, fourth inner side wall portion) is provided in the space on the other side in the first direction in the housing 120 divided by the partition wall portion 212. The pair of inner side wall portions 214A, 214B is provided between the pair of side wall portions 211A, 211B. The pair of inner side wall portions 214A, 214B is provided separately from the pair of side wall portions 211A, 211B, and is provided at intervals in the first direction. The inner side wall portion 214A is on the one side in the first direction, and the inner side wall portion 214B is on the other side in the first direction.

[0068] The pair of inner side wall portions 214A, 214B divides the space in the housing 120 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.

[0069] In the space within the housing located on the other side in the second direction, a battery storage stack 104 (fourth battery storage stack) is disposed between the side wall portion 211A and the inner side wall portion 214A. A battery storage stack 105 (fifth battery storage stack) is disposed between the inner side wall portion 214A and the inner side wall portion 214B. A battery storage stack 106 (sixth battery storage stack) is disposed between the inner side wall portion 214B and the side wall portion 211B.

[0070] Each of the pair of inner wall portions 214A and 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 of the third inner side surface 23a in the first direction. Also in the pair of inner wall portions 214A and 214B, the thickness of the outer end portion located on the third outer side surface 23b side in the first direction is greater than the thickness of the inner end portion located on the third inner side surface 23a side in the first direction. Furthermore, the relationship between the thickness of the outer end portion and the inner end portion is not limited to the above description; the thickness of the outer end portion and the thickness of the inner end portion may also be approximately equal.

[0071] 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 on the second inner side surface 22a of the side wall portion 211A.

[0072] Multiple openings 255 open toward a first region 291 located between sidewall portion 211A and inner sidewall portion 213A. The multiple openings 255 communicate with an exhaust path 275 disposed inside the sidewall portion 211A. The exhaust path 275 extends from the partition wall portion 212 side toward a second direction. The exhaust path 275 communicates with the aforementioned external exhaust port 315.

[0073] Multiple openings 265 open toward the fourth region 294 located between the sidewall portion 211A and the inner sidewall portion 214A. The multiple openings 265 communicate with an exhaust path 285 disposed inside the sidewall 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 communicates with the aforementioned external exhaust port 325.

[0074] Multiple openings 251 and 252, and exhaust paths 271 and 272 are provided on a pair of inner sidewall portions 213A and 213B.

[0075] Multiple openings 251 are provided on the first inner side surface 21a of the inner side wall portion 213A. Multiple openings 252 are provided on the first inner side surface 21a of the inner side wall portion 213B. The multiple openings 251 and 252 open toward the second region 292 located between the pair of inner side wall portions 213A and 213B.

[0076] Multiple openings 251 communicate with an exhaust path 271 provided on the inner sidewall 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 aforementioned external exhaust port 311.

[0077] Multiple openings 252 communicate with an exhaust path 272 provided on the inner sidewall 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 aforementioned external exhaust port 312.

[0078] 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 on the second inner side surface 22a of the side wall portion 211B.

[0079] Multiple openings 256 open toward the third region 293 located between the side wall portion 211B and the inner side wall portion 213B. The multiple openings 256 communicate with an exhaust path 276 disposed 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 communicates with the aforementioned external exhaust port 316.

[0080] Multiple openings 266 open toward the sixth region 296 located between the side wall portion 211B and the inner side wall portion 214B. The multiple openings 266 communicate with an exhaust path 286 disposed 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 communicates with the aforementioned external exhaust port 326.

[0081] Multiple openings 261 and 262, and exhaust paths 281 and 282 are provided on a pair of inner sidewall portions 214A and 214B.

[0082] Multiple openings 261 are provided on the third inner side surface 23a of the inner side wall portion 214A. Multiple openings 262 are provided on the third inner side surface 23a of the inner side wall portion 214B. The multiple openings 261, 262 open toward the second region 292 located between the pair of inner side wall portions 214A, 214B.

[0083] Multiple openings 261 communicate with an exhaust path 281 provided on the inner sidewall 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 aforementioned external exhaust port 321.

[0084] Multiple openings 262 communicate with an exhaust path 282 provided on the inner sidewall 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 aforementioned external exhaust port 322.

[0085] Multiple openings 251, 252, 255, and 256 are each provided on one side of the receiving shell 120, which is separated by the partition wall 212, in a second direction, near the partition wall 212. Multiple openings 261, 262, 265, and 266 are each provided on the other side of the receiving shell 120, which is separated by the partition wall 212, in a second direction, near the partition wall 212.

[0086] 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 orthogonal to the first direction and the second direction. Furthermore, each of the plurality of openings 251, 252, 255, 256, 261, 262, 265, and 266 is not limited to the vertical direction, and may also be arranged at intervals in the second direction.

[0087] Multiple heat insulation members 41 are disposed on the first outer side surface 21b of each of a pair of inner sidewall portions 213A and 213B, and on the third outer side surface 23b of each of a pair of inner sidewall portions 214A and 214B. Each heat insulation member 41 covers the entirety of each outer side surface.

[0088] In this embodiment, within the housing, on one side in the second direction separated by the partition wall 212, each of the first inner side surface 21a and each of the second inner side surface 22a has more openings than the first outer side surface 21b. Here, each of the first inner side surface 21a refers to the first inner side surface 21a of each of the inner side wall portions 213A and 213B. Each of the second inner side surface 22a refers to the second inner side surface 22a of each of the side wall portions 211A and 211B. The first outer side surface 21b refers to the first outer side surface 21b of the inner side wall portions 213A and 213B. The openings are openings that communicate with the exhaust path.

[0089] When gas is discharged from the energy storage stack 101, the number of openings 255 on the second inner side surface 22a of the side wall portion 211A is greater than the number of openings on the first outer side surface 21b of the inner side wall portion 213A. Therefore, the proportion of gas discharged to the outside from the side wall portion 211A through the exhaust path 275 is higher. Consequently, heat transfer to the inner side wall portion 213A is difficult, and heat transfer to the energy storage stack 102 located at the pair of inner side wall portions 213A and 213B can be suppressed.

[0090] Similarly, when gas is discharged from the energy storage stack 103, the proportion of gas discharged to the outside through the exhaust path 276 from the side wall 211B becomes higher. As a result, it is difficult to transfer heat to the inner side wall 213B, and thus, it is possible to suppress the transfer of heat to the energy storage stack 102 located at the pair of inner side walls 213A, 213B.

[0091] When gas is discharged from the energy storage stack 102, the gas disperses through the exhaust paths 271 and 272 inside the respective inner sidewall portions 213A and 213B, thereby suppressing the transfer of heat to the energy storage stack 101 and the energy storage stack 103.

[0092] Furthermore, there is a possibility that gas may be discharged from any of the energy storage stacks 104, 105, and 106. In this case, the gas flow differs from the case where gas is discharged from any of the aforementioned energy storage stacks 101, 102, and 103, except that the exhaust paths 285, 281, 282, and 286 are different. Similarly, there is a possibility that gas may be discharged from either energy storage stack 104 or energy storage stack 106. Therefore, in this case, heat transfer to energy storage stack 105 can be suppressed, and when gas is discharged from energy storage stack 105, heat transfer to energy storage stacks 104 and 106 can be suppressed.

[0093] Thus, in this embodiment, in the energy storage device 10 which includes three energy storage stacks arranged in a horizontal manner, it is possible to suppress the transfer of heat to the other energy storage stacks that are horizontally adjacent when one of the energy storage stacks heats up.

[0094] Furthermore, in this embodiment, an example is shown where no openings are provided on the first outer side surface 21b and the third outer side surface 23b. As described above, if the number of each of the plurality of openings 251, 252, 255, and 256 is greater than the number of openings provided on the first outer side surface 21b, then more than one opening may be provided on the first outer side surface 21b. Similarly, if the number of each of the plurality of openings 261, 262, 265, and 266 is greater than the number of openings provided on the third outer side surface 23b, then more than one opening may be provided on the third outer side surface 23b. Preferably, when openings are provided on the first outer side surface 21b and the third outer side surface 23b, the heat insulation member 41 is configured not to cover the portion where the opening is located.

[0095] Furthermore, by providing the heat insulation member 41 as described above, heat transfer to the energy storage stacks 101, 103, 104, and 106 can be effectively suppressed when gas is discharged from the energy storage stacks 102 and 105. Similarly, heat transfer to the energy storage stacks 102 and 105 can be effectively suppressed when gas is discharged from the energy storage stacks 101, 103, 104, and 106.

[0096] Furthermore, as described above, in the pair of inner sidewall portions 213A, 213B and the pair of inner sidewall portions 214A, 214B, the thickness of the outer end portion is greater than the thickness of the inner end portion. Therefore, when gas is discharged from the energy storage stack 102 or the energy storage stack 105, heat transfer to the energy storage stacks 101, 103 or 104, 106 can be further suppressed. Similarly, when gas is discharged from the energy storage stacks 101, 103 or 104, 106, heat transfer to the energy storage stack 102 or the energy storage stack 105 can be further suppressed.

[0097] Other variations

[0098] In this embodiment, a plurality of unit cells 110 are illustrated by being arranged in the first direction with the exhaust valves 111 alternately located on one side of the second direction and the other side of the second direction, but this is not a limitation. The plurality of unit cells 110 may also be arranged in the first direction with all exhaust valves 111 facing the partition wall 212. In this case, the distance of all exhaust valves 111 from the opening is shortened. Therefore, in each region (first region 291 to sixth region 296), the diffusion of gas discharged from the exhaust valves 111 can be suppressed.

[0099] Furthermore, the illustration shows a case where multiple unit cells 110 are arranged in the first direction, but this is not a limitation; they can also be arranged in the second direction. In this case, the unit cell 110 has an elongated shape with the first direction as its length direction.

[0100] In the above embodiment, an example is shown where the number of openings 255, 256 on one side in the second direction separated by the partition wall 212 is the same as the number of openings 251, 252 provided on the first inner side surface 21a, but this is not a limitation. Here, each opening 255, 256 is provided on the second inner side surface 22a. The number of openings 255, 256 provided on the second inner side surface 22a may be more or less than the number of openings 251, 252 provided on the first inner side surface 21a.

[0101] When the number of openings 255 and 256 is greater than the number of openings 251 and 252, the gas discharged from the energy storage stack 101 and 103 can be discharged to the outside more quickly, thus further reducing the heat transfer to the energy storage stack 102.

[0102] On the other hand, when the number of openings 255 and 256 is less than the number of openings 251 and 252, the rigidity of the sidewalls 211A and 211B can be improved.

[0103] Similarly, on the other side of the second direction separated by the partition wall 212, the number of openings 265 and 266 provided on the second inner side surface 22a can be more or less than the number of openings 261 and 262 provided on the third inner side surface 23a.

[0104] In the above embodiment, an example is shown where no opening is provided on the second outer side surface 22b of the sidewall portions 211A and 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. However, an opening may also be provided on the second outer side surface 22b. In this case, the number of openings provided on the second inner side surface 22a may also be greater than the number of openings provided on the second outer side surface 22b. However, the number of openings provided on the second inner side surface 22a may also be less than the number of openings provided on the second outer side surface 22b.

[0105] When the number of openings provided on the second inner side 22a is less than the number of openings provided on the second outer side 22b, the gas discharged from the energy storage stacks 101, 103, 104, and 106 can be discharged to the outside of the housing 120 more quickly.

[0106] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the invention is defined by the claims, which include all modifications within the scope and equivalent meaning of the claims.

Claims

1. An energy storage device, comprising: The first, second, and third energy storage stacks are arranged in the first direction; and A housing housing the first energy storage stack, the second energy storage stack, and the third energy storage stack. The housing includes: a pair of sidewall portions located at both ends in the first direction; and a pair of inner sidewall portions disposed between the pair of sidewall portions. An exhaust path is provided inside each of the pair of sidewall portions and the pair of inner sidewall portions. The pair of sidewall portions includes: a first sidewall portion located on one side in the first direction; and a second sidewall portion located on the other side in the first direction. The pair of inner sidewall portions include: a first inner sidewall portion located on one side in the first direction; and a second inner sidewall portion located on the other side in the first direction. The first energy storage stack is disposed between the first sidewall portion and the first inner sidewall portion. The second energy storage stack is disposed between the pair of inner sidewall portions. The third energy storage stack is disposed between the second inner sidewall portion and the second sidewall portion. The first inner sidewall portion and the second inner sidewall portion each have: a first inner sidewall facing each other in the first direction; and a first outer sidewall located on the opposite side of the first inner sidewall in the first direction. The first sidewall portion and the second sidewall portion each have a second inner side surface portion facing the pair of sidewall portions in the first direction. Compared to each of the first outer side surfaces, the first inner side wall portion and the second inner side wall portion each have more openings communicating with the exhaust path on their respective first inner side surfaces.

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

3. The energy storage device according to claim 1 or 2, The first inner sidewall portion and the second inner sidewall portion each have an inner end portion located on the first inner sidewall side and an outer end portion located on the first outer sidewall side in the first direction. In the first inner sidewall portion and the second inner sidewall portion, the exhaust path is located between the inner end and the outer end. The thickness of the outer end in the first direction is greater than the thickness of the inner end in the first direction.

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