Power storage device

Abstract

A power storage device (1) comprises a plurality of first power storage stacks (110), a plurality of second power storage stacks (120), a first junction box (310), a second junction box (320), a case, and a breathing film (700). The case (500) has a side wall (514a). The side wall (514a) has an opposing region (R). The opposing region (R) extends from a portion (a1) that is opposite in a first direction from an outside end part of the first junction box (310) in a second direction to a portion (a2) that is opposite in the first direction from an outside end part of the second junction box (320) in the second direction. The breathing film (700) is provided to the opposing region (R).

Description

Power storage device

[0001] The present disclosure relates to an electricity storage device.

[0002] For example, Japanese Patent Publication No. 2022-516519 discloses a power battery pack including a plurality of cells, a battery tray that houses the cells, and a cover plate connected to the battery tray. A battery pack explosion-proof valve is attached to the side wall of the battery tray and is attached to an exhaust hole.

[0003] Special Publication No. 2022-516519

[0004] In a power storage device such as that described in JP-A-2022-516519, in order to adjust the pressure inside the case, it is conceivable to provide the case with a breathing membrane that allows gas to pass between the inside and outside of the case.

[0005] On the other hand, if gas is discharged from any of the power storage stacks, there is a concern that the gas may come into contact with the breathing membrane and damage the breathing membrane.

[0006] An object of the present disclosure is to provide an electricity storage device that can suppress damage to the respiratory membrane.

[0007] According to one aspect of the present disclosure, there is provided an energy storage device comprising: a plurality of first energy storage stacks arranged to be aligned along a first direction; a plurality of second energy storage stacks facing the plurality of first energy storage stacks in a second direction perpendicular to both the first direction and a vertical direction and arranged to be aligned along the first direction; a first junction box arranged in a position facing the first direction to the first energy storage stack that is arranged outermost in the first direction among the plurality of first energy storage stacks; a second junction box arranged in a position facing the second energy storage stack in the first direction and facing the first junction box at an interval in the second direction; and a plurality of first energy storage stacks, the plurality of second energy storage stacks, the first junction box, and the second junction box. and a breathing membrane provided in the case that adjusts the pressure inside the case by allowing gas to pass between the inside and outside of the case, wherein the case has a side wall formed on the opposite side of the first junction box and the second junction box from the side on which the first storage stack and the second storage stack are arranged, the side wall having an opposing area facing the first junction box and the second junction box, the opposing area extending from a portion facing the outer end of the first junction box in the second direction and the first direction to a portion facing the outer end of the second junction box in the second direction and the first direction, and the breathing membrane is provided in the opposing area.

[0008] According to the present disclosure, it is possible to provide an electricity storage device that can suppress damage to the respiratory membrane.

[0009] 10 is a perspective view schematically showing an electricity storage device according to an embodiment of the present disclosure. FIG. 10 is a perspective view schematically showing a state in which an upper cover and a covering plate have been removed from the electricity storage device. FIG. 10 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 10 is a plan view schematically showing a state in which an upper cover and a covering plate have been removed from the electricity storage device. FIG. 4 is a partially enlarged view of FIG. 4. FIG. 4 is a cross-sectional view taken along line VI-VI in FIG. 4. FIG. 4 is a diagram schematically showing a modified example of the electricity storage device. FIG. 4 is a diagram schematically showing a modified example of the electricity storage device. FIG. 4 is a diagram schematically showing a modified example of the upper cover. FIG. 10 is a cross-sectional view taken along line XI-XI in FIG. 10. FIG. 10 is a diagram schematically showing a modified example of the upper cover.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0011] FIG. 1 is a perspective view that schematically shows an electric storage device according to an embodiment of the present disclosure. FIG. 2 is a perspective view that schematically shows a state in which an upper cover and a covering plate are removed from the electric storage device shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a plan view that schematically shows a state in which an upper cover and a covering plate are removed from the electric storage device. FIG. 5 is a partially enlarged view of FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4. This electric storage device 1 is mounted, for example, on the bottom of a vehicle.

[0012] As shown in Figures 1 to 6, the energy storage device 1 includes a plurality of first energy storage stacks 110, a plurality of second energy storage stacks 120, a first bus bar 210, a second bus bar 220, a first junction box 310, a second junction box 320, a covering plate 400, a case 500, a pressure release valve 600, and a breathing membrane 700.

[0013] The plurality of first power storage stacks 110 are arranged to line up in the first direction. In the present embodiment, the plurality of first power storage stacks 110 includes six first power storage stacks 110. However, the number of first power storage stacks 110 is not limited to six. Each first power storage stack 110 is formed in a rectangular parallelepiped shape that is long in a second direction that is perpendicular to both the first direction and the up-down direction.

[0014] Each first power storage stack 110 includes a plurality of power storage cells 111 (see FIG. 3 ). The plurality of power storage cells 111 are arranged, for example, to be aligned in a first direction. Note that the plurality of power storage cells 111 may also be arranged to be aligned in a second direction. Each power storage cell 111 is formed in a flat rectangular parallelepiped shape. An example of each power storage cell 111 is a lithium ion battery. Each power storage cell 111 may be configured as an all-solid-state battery using a solid electrolyte. As shown in FIG. 6 , each power storage cell 111 includes a safety valve 111 a provided at a position facing the upper cover 520, i.e., on the upper surface of the housing of the power storage cell 111.

[0015] The second power storage stacks 120 are arranged to face the first power storage stacks 110 in the second direction and to be aligned in the first direction. In the present embodiment, the second power storage stacks 120 include six second power storage stacks 120. However, the number of second power storage stacks 120 is not limited to six. The configuration of each second power storage stack 120 is the same as the configuration of the first power storage stack 110.

[0016] The first bus bar 210 connects a pair of first power storage stacks 110 adjacent to each other in the first direction. The first bus bar 210 is routed in a routing space S1 (see FIG. 3 ) between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120.

[0017] The second bus bar 220 connects a pair of second power storage stacks 120 adjacent to each other in the first direction. The second bus bar 220 is routed in the routing space S1.

[0018] The first junction box 310 is disposed at a position facing, in the first direction, a first power storage stack 110 that is disposed outermost in the first direction (e.g., on the front side in the longitudinal direction of the vehicle) among the multiple first power storage stacks 110. The first junction box 310 houses a relay, a fuse, and the like. The first junction box 310 has a first connector 312. The first connector 312 protrudes outward in the first direction.

[0019] The second junction box 320 is disposed at a position facing the second power storage stack 120 in the first direction and facing the first junction box 310 at a distance in the second direction. That is, an inter-box space S2 (see FIG. 4 ) is formed between the first junction box 310 and the second junction box 320. The inter-box space S2 is a space through which gas discharged from either of the power storage stacks 110, 120 can pass. The second junction box 320 accommodates relays, fuses, and the like. As shown in FIG. 2 , in this embodiment, the outer shape of the second junction box 320 is larger than the outer shape of the first junction box 310. The second junction box 320 has a second connector 322. The second connector 322 protrudes outward in the first direction.

[0020] The first junction box 310 has a first protrusion 314 that protrudes toward the second junction box 320. The second junction box 320 has a second protrusion 324 that protrudes toward the first junction box 310. Each of the protrusions 314, 324 reduces the flow path area of ​​the inter-box space S2.

[0021] As shown in FIG. 4 , the covering plate 400 covers the first bus bar 210 and the second bus bar 220 from above. The covering plate 400 is disposed between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. The covering plate 400 extends along the first direction. The covering plate 400 is formed in a flat plate shape. The covering plate 400 is made of an insulating material. The covering plate 400 is made of, for example, mica, which is a natural inorganic mineral solidified by heat pressing. The covering plate 400 has a function of blocking gas ejected upward from any of the power storage stacks from contacting each of the bus bars 210, 220. Note that the covering plate 400 is not shown in FIGS. 2 , 4 , and 5 .

[0022] The case 500 accommodates the plurality of first power storage stacks 110, the plurality of second power storage stacks 120, the first bus bar 210, the second bus bar 220, the first junction box 310, the second junction box 320, and the cover plate 400. The case 500 has a lower case 510 and an upper cover 520.

[0023] The lower case 510 is open upward and has a bottom wall 512, a peripheral wall 514, and a partition 516.

[0024] The bottom wall 512 supports each of the power storage stacks 110 and 120 .

[0025] The peripheral wall 514 stands upright from the peripheral edge of the bottom wall 512. The peripheral wall 514 surrounds the periphery of the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. The peripheral wall 514 is formed in a substantially rectangular cylindrical shape.

[0026] The peripheral wall 514 includes a side wall 514a formed on the side opposite (the left side in FIG. 4 ) to the side on which the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120 are arranged, with the first junction box 310 and the second junction box 320 as references. The side wall 514a extends along the second direction.

[0027] The partition 516 separates the plurality of first power storage stacks 110 from the plurality of second power storage stacks 120. The partition 516 has a shape that extends along the first direction. The height of the partition 516 is lower than the height of the peripheral wall 514. As shown in FIG. 3 , a wiring space S1 is formed between the partition 516 and the cover plate 400.

[0028] Upper cover 520, together with lower case 510, accommodates a plurality of first power storage stacks 110, a plurality of second power storage stacks 120, first bus bars 210, second bus bars 220, first junction boxes 310, second junction boxes 320, and cover plate 400. The peripheral edge of upper cover 520 is fixed to the upper end of peripheral wall 514 with bolts or the like.

[0029] 6 , a shielding portion 525 is provided on the inner surface of the upper cover 520. The shielding portion 525 is provided on a path connecting the safety valve 111a and the pressure release valve 600. In the present embodiment, the shielding portion 525 is provided on a portion of the inner surface of the upper cover 520 in front of each of the power storage stacks 110, 120. The shielding portion 525 is provided above the inter-box space S2. The shielding portion 525 has a shape that extends downward from the upper cover 520.

[0030] 6, the shielding portion 525 may have a shielding plate 525a extending downward from the inner surface of the upper cover 520. The lower end of the shielding plate 525a is preferably located lower than the covering plate 400.

[0031] The pressure release valve 600 is provided in the case 500. The pressure release valve 600 releases pressure inside the case 500. The pressure release valve 600 opens when the pressure inside the case 500 reaches or exceeds a reference value. The pressure release valve 600 is configured as a check valve. As shown in FIGS. 4 to 6 , the pressure release valve 600 is provided in a portion of the upper cover 520 between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120 and outside the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120 in the first direction. In this embodiment, the pressure release valve 600 is provided in a portion of the upper cover 520 above the inter-box space S2.

[0032] The breathing membrane 700 is provided on the case 500. The breathing membrane 700 adjusts the pressure inside the case 500 by allowing gas to pass between the inside and outside of the case 500. The breathing membrane 700 is disposed on the opposite side of the pressure release valve 600 from the side on which the power storage stacks 110, 120 are disposed. In this embodiment, the breathing membrane 700 is provided on the side wall 514a. Specifically, a through-hole is provided in the side wall 514a, and the breathing membrane 700 is attached to the outer surface of the side wall 514a so as to cover the through-hole.

[0033] 4 and 5, the breathing membrane 700 is provided on the outer surface of a facing region R of the side wall 514a that faces the first junction box 310 and the second junction box 320. As shown in Fig. 4, the facing region R extends from a portion a1 that faces the outer end of the first junction box 310 in the second direction in the first direction to a portion a2 that faces the outer end of the second junction box 320 in the second direction in the first direction. Note that in Figs. 4 and 5, the facing region R is indicated by dots.

[0034] The facing region R has a first facing portion R1, a second facing portion R2, and an intermediate portion R3. The first facing portion R1 faces the first junction box 310. The first facing portion R1 is an area that overlaps with the first junction box 310 in the first direction. The second facing portion R2 faces the second junction box 320. The second facing portion R2 is an area that overlaps with the second junction box 320 in the first direction. In this embodiment, the area of ​​the second facing portion R2 is larger than the area of ​​the first facing portion R1. The intermediate portion R3 faces the inter-box space S2. The intermediate portion R3 is located between the first facing portion R1 and the second facing portion R2. In this embodiment, the respiratory membrane 700 is provided in the intermediate portion R3.

[0035] 5, the length D2 of the breathing membrane 700 in the second direction is greater than the length D1 between the first junction box 310 and the second junction box 320 in the second direction. In this embodiment, the length D1 is the length between each of the protrusions 314, 324.

[0036] As described above, in the energy storage device 1 of this embodiment, when gas is discharged from either of the energy storage stacks 110, 120, the gas mainly flows toward the inter-box space S2 between the first junction box 310 and the second junction box 320, where it changes direction upward and flows toward the pressure release valve 600, thereby reducing the flow rate of the gas discharged from the case 500.

[0037] Furthermore, in the above embodiment, the breathing membrane 700 is provided in the opposing region R in the side wall 514a of the lower case 510, in other words, downstream of each junction box 310, 320 in the flow direction of gas discharged from either of the power storage stacks 110, 120. Therefore, the gas discharged from either of the power storage stacks 110, 120 collides with each of the junction boxes 310, 320 before reaching the breathing membrane 700. Furthermore, the inter-box space S2 serves as a buffer region, which prevents the exhaust gas from reaching the breathing membrane 700 and thereby prevents damage to the breathing membrane 700.

[0038] Furthermore, if gas is generated from either of the storage stacks 110, 120 and air flows into the case 500 through the breathing membrane 700, the air comes into contact with each of the junction boxes 310, 320, thereby preventing the air that has flowed into the case 500 from reaching the storage stacks 110, 120 and the resulting generation of a blast from the safety valve 111a.

[0039] Modifications of the above embodiment will now be described.

[0040] <First Modification> As shown in FIG. 7, when the outer shape of the second junction box 320 is larger than the outer shape of the first junction box 310, the breathing film 700 may be provided on the second opposing portion R2.

[0041] 8, the breathing membrane 700 may have a first breathing portion 710 provided in the first opposing portion R1 and a second breathing portion 720 provided in the second opposing portion R2. The configuration of each breathing portion 710, 720 is the same as the configuration of the breathing membrane 700 in the above embodiment.

[0042] 9 , the lower case 510 may have an opposite-side space S3 located between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120 and on the opposite side to the side on which the inter-box space S2 is located with respect to the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. In this case, the pressure release valve 600 may be provided in a portion of the upper cover 520 above the opposite-side space S3.

[0043] In this case, the breathing membrane 700 is provided on a side wall 514 b formed on the side of the peripheral wall 514 opposite the side on which the power storage stacks 110 and 120 are arranged, with the pressure release valve 600 as the reference.

[0044] <Fourth Modification> As shown in FIGS. 10 and 11 , an upper cover 520 may have a first base portion 521 , a second base portion 522 , and an intermediate portion 523 .

[0045] The first base portion 521 covers the plurality of first power storage stacks 110. The second base portion 522 covers the plurality of second power storage stacks 120. Each of the base portions 521, 522 extends along the first direction. Each of the base portions 521, 522 may be formed in a flat plate shape.

[0046] The intermediate portion 523 is provided between the first base portion 521 and the second base portion 522. The intermediate portion 523 extends along the first direction. The intermediate portion 523 is located above the inter-box space S2. The intermediate portion 523 protrudes from each of the base portions 521, 522. As a result, a space S4 is formed between the intermediate portion 523 and the covering plate 400.

[0047] In this example, the pressure relief valve 600 is provided in the middle portion 523 .

[0048] 12 , the intermediate portion 523 of the upper cover 520 may have a bending rigidity lower than that of each of the base portions 521, 522. In this example, a rib extending along the second direction is formed on each of the base portions 521, 522. However, the thickness of each of the base portions 521, 522 may be greater than the thickness of the intermediate portion 523. Alternatively, a plurality of grooves (deformation promoting portions) spaced apart from each other in the second direction and each extending along the first direction may be formed in the intermediate portion 523.

[0049] In this embodiment, the intermediate portion 523 deforms so as to bulge upward relative to the base portions 521 and 522 when the internal pressure of the case 500 increases, so that an exhaust flow path is formed between the upper cover 520 and the cover plate 400 .

[0050] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0051] a first junction box arranged in a position facing the first direction from a first power storage stack that is arranged outermost in the first direction among the plurality of first power storage stacks; a second junction box arranged in a position facing the second power storage stack in the first direction and from the first junction box in the second direction; a case that houses the plurality of first power storage stacks, the plurality of second power storage stacks, the first junction box, and the second junction box; and a pressure release valve that is provided in the case and releases pressure inside the case, wherein the case includes an upper cover that covers the plurality of first power storage stacks, the plurality of second power storage stacks, the first junction box, and the second junction box, and an inter-box space is formed between the first junction box and the second junction box, The pressure release valve is provided in a portion of the upper cover above the inter-box space.

[0052] In this energy storage device, when gas is discharged from any of the energy storage stacks, the gas mainly flows toward the inter-box space between the first junction box and the second junction box, where it changes direction upward and flows toward the pressure release valve, thereby reducing the flow rate of the gas discharged from the case.

[0053] [Aspect 2] The energy storage device according to Aspect 1, further comprising a shielding portion provided on an inner surface of the upper cover, wherein the first energy storage stack and the second energy storage stack each include a plurality of energy storage cells, each of the energy storage cells includes a safety valve provided at a position facing the upper cover, and the shielding portion is provided on a path connecting the safety valve and the pressure release valve and has a shape that extends downward from the upper cover.

[0054] In this embodiment, the gas and blast discharged from the safety valve are blocked by the shielding portion before they reach the pressure release valve, thereby further reducing the flow rate of the gas discharged from the pressure release valve and suppressing the blast from reaching the pressure release valve.

[0055] [Aspect 3] The energy storage device according to Aspect 1 or 2, further comprising a breathing membrane provided on the case that adjusts the pressure inside the case by allowing gas to pass between the inside and outside of the case, the case having a side wall formed on the side opposite to the side on which the plurality of first energy storage stacks and the plurality of second energy storage stacks are arranged, with the first junction box and the second junction box as reference, and the breathing membrane provided on the side wall.

[0056] In this embodiment, two junction boxes are arranged between the breathing membrane and each storage stack, thereby preventing air that flows into the case through the breathing membrane from reaching the storage stack and the resulting generation of blast.

[0057] [Aspect 4] The energy storage device according to any one of Aspects 1 to 3, further including: a first bus bar connecting a pair of the first storage stacks adjacent to each other in the first direction and arranged in a routing space between the plurality of first storage stacks and the plurality of second storage stacks; a second bus bar connecting a pair of the second storage stacks adjacent to each other in the first direction and arranged in the routing space; and a cover plate disposed between the plurality of first storage stacks and the plurality of second storage stacks and covering the first bus bar and the second bus bar from above.

[0058] In this embodiment, the space between each storage stack is utilized as routing space for routing each bus bar, and furthermore, the covering plate effectively prevents gas discharged from the storage stack from coming into contact with each bus bar.

[0059] [Aspect 5] The upper cover has a first base portion covering the plurality of first storage stacks, a second base portion covering the plurality of second storage stacks, and an intermediate portion provided between the first base portion and the second base portion and extending along the first direction, the intermediate portion being located above the inter-box space and protruding from the first base portion and the second base portion, in the storage device described in any one of Aspects 1 to 4.

[0060] In this aspect, an exhaust flow path is formed between the intermediate portion and each power storage stack, so that gas exhausted from the power storage stack is effectively guided toward the pressure release valve.

[0061] [Aspect 6] The upper cover has a first base portion that covers the plurality of first storage stacks, a second base portion that covers the plurality of second storage stacks, and an intermediate portion that is provided between the first base portion and the second base portion and extends along the first direction, and the intermediate portion is located above the inter-box space and has a bending rigidity that is lower than the bending rigidity of the first base portion and the second base portion. This is the energy storage device described in any one of Aspects 1 to 4.

[0062] In this embodiment, when the internal pressure of the case rises, the intermediate portion deforms relative to each base portion in a direction away from each storage stack, thereby forming an exhaust flow path between the intermediate portion and each storage stack, and therefore the gas discharged from the storage stack is effectively guided toward the pressure release valve.

[0063] [Aspect 7] A power storage device comprising: a plurality of first power storage stacks arranged to be lined up along a first direction; a plurality of second power storage stacks facing the plurality of first power storage stacks in a second direction orthogonal to both the first direction and the up-down direction and arranged to be lined up along the first direction; a first junction box arranged in a position facing, in the first direction, a first power storage stack that is arranged outermost in the first direction among the plurality of first power storage stacks; a second junction box arranged in a position facing, in the first direction, the second power storage stack and facing, in the second direction, the first junction box at an interval; a case accommodating the plurality of first power storage stacks, the plurality of second power storage stacks, the first junction box, and the second junction box; a pressure release valve provided in the case and releasing pressure inside the case; and a breathing membrane provided in the case and adjusting pressure inside the case by allowing gas to pass between the inside of the case and the outside of the case, the case includes an upper cover that covers the plurality of first storage stacks, the plurality of second storage stacks, the first junction box, and the second junction box; the pressure release valve is provided in a portion of the upper cover between the plurality of first storage stacks and the plurality of second storage stacks and above a space outside the plurality of first storage stacks and the plurality of second storage stacks in the first direction; the case has a side wall formed on the side opposite to the side on which the plurality of first storage stacks and the plurality of second storage stacks are arranged, with the pressure release valve as a reference; and the breathing membrane is provided on the side wall.

[0064] In this energy storage device, when gas is discharged from any of the energy storage stacks, the gas heads toward the space on the opposite side of the junction boxes, where it changes direction upward toward the pressure release valve, thereby preventing the exhaust gas from reaching the junction boxes and reducing the flow rate of the gas discharged from the case.

[0065] a first junction box arranged in a position facing the first direction from a first power storage stack that is arranged outermost in the first direction among the plurality of first power storage stacks; a second junction box arranged in a position facing the second power storage stack in the first direction and opposed to the first junction box at an interval in the second direction; a case accommodating the plurality of first power storage stacks, the plurality of second power storage stacks, the first junction box, and the second junction box; and a breathing membrane provided in the case that adjusts pressure inside the case by allowing gas to pass between the inside of the case and the outside of the case, wherein the case has a sidewall formed on the side opposite to the side on which the first power storage stacks and the second power storage stacks are arranged with respect to the first junction box and the second junction box, the side wall has an opposing region facing the first junction box and the second junction box, the opposing region extending from a portion facing the outer end of the first junction box in the second direction and the first direction to a portion facing the outer end of the second junction box in the second direction and the first direction, and the breathing membrane is provided in the opposing region.

[0066] In this energy storage device, the breathing membranes are provided in opposing regions on the side walls of the case. In other words, the breathing membranes are located downstream of the junction boxes in the flow direction of gas discharged from any of the energy storage stacks. Therefore, the gas discharged from the energy storage stacks collides with the junction boxes before reaching the breathing membrane. Furthermore, the spaces between the junction boxes act as buffer regions, preventing exhaust gas from reaching the breathing membrane and resulting damage to the breathing membrane.

[0067] [Aspect 9] The power storage device according to Aspect 8, wherein the facing region includes an intermediate portion facing an inter-box space between the first junction box and the second junction box, and the breathing membrane is provided in the intermediate portion.

[0068] [Aspect 10] The power storage device according to Aspect 8, wherein the facing region includes a first facing portion facing the first junction box and a second facing portion facing the second junction box, and the breathing membrane is provided on the first facing portion or the second facing portion.

[0069] In this embodiment, the breathing film is located downstream of one of the junction boxes, so that the exhaust gas is more reliably prevented from reaching the breathing film.

[0070] [Aspect 11] The power storage device according to aspect 10, wherein the second junction box has an outer shape larger than an outer shape of the first junction box, and the breathing film is provided on the second opposing portion.

[0071] [Aspect 12] The power storage device according to Aspect 8, wherein the opposing region includes a first opposing portion opposing the first junction box and a second opposing portion opposing the second junction box, and the breathing membrane has a first breathing portion provided in the first opposing portion and a second breathing portion provided in the second opposing portion.

[0072] [Aspect 13] The power storage device according to any one of Aspects 8 to 12, wherein the first junction box has a first protrusion that protrudes toward the second junction box, and the second junction box has a second protrusion that protrudes toward the first junction box.

[0073] In this embodiment, the dimensions between the junction boxes are reduced by the protrusions, so that gas discharged from any of the power storage stacks is more reliably prevented from reaching the breathing membrane.

[0074] [Aspect 14] The power storage device according to any one of Aspects 8 to 13, wherein the length of the breathing membrane in the second direction is greater than the length between the first junction box and the second junction box in the second direction.

[0075] In this embodiment, the air that flows into the case through the breathing membrane comes into contact with the junction box, thereby preventing the air that flows into the case from reaching the storage stack and causing blasting or other problems.

[0076] [Aspect 15] The energy storage device according to any one of Aspects 8 to 14, further comprising a pressure release valve provided in the case to release pressure within the case, wherein the case includes an upper cover that covers the first energy storage stack, the second energy storage stack, the first junction box, and the second junction box, and the pressure release valve is provided in a portion of the upper cover above an inter-box space between the first junction box and the second junction box.

[0077] In this embodiment, gas discharged from either storage stack primarily flows toward the inter-box space between the first junction box and the second junction box, where it changes direction upward toward the pressure release valve, thereby reducing the flow rate of gas discharged from the case.

[0078] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims.

[0079] 1 Energy storage device, 110 First energy storage stack, 111 Energy storage cell, 111a Safety valve, 120 Second energy storage stack, 210 First bus bar, 220 Second bus bar, 310 First junction box, 312 First connector, 314 First protrusion, 320 Second junction box, 322 Second connector, 324 Second protrusion, 400 Covering plate, 500 Case, 510 Lower case, 512 Bottom wall, 514 Peripheral wall, 514a Side wall, 520 Upper cover, 521 First base portion, 522 Second base portion, 523 Middle portion, 525 Shielding portion, 525a Shielding plate, 600 Pressure release valve, 700 Breathing membrane, R Opposing area, R1 First opposing portion, R2 Second opposing portion, R3 Middle portion, S1 Wiring space, S2 Space between boxes, S3 opposite side space.

Claims

1. A power storage device comprising: a plurality of first storage stacks arranged to be lined up along a first direction; a plurality of second storage stacks facing the plurality of first storage stacks in a second direction perpendicular to both the first direction and the up-down direction and arranged to be lined up along the first direction; a first junction box arranged in a position facing the first direction to the first storage stack that is arranged outermost in the first direction among the plurality of first storage stacks; a second junction box arranged in a position facing the second storage stack in the first direction and facing the first junction box at an interval in the second direction; a case accommodating the plurality of first storage stacks, the plurality of second storage stacks, the first junction box, and the second junction box; and a breathing membrane provided in the case that adjusts the pressure inside the case by allowing gas to pass between the inside and the outside of the case, wherein the case has a sidewall formed on the side opposite to the side on which the first storage stacks and the second storage stacks are arranged with respect to the first junction box and the second junction box, the side wall has an opposing region facing the first junction box and the second junction box, the opposing region extending from a portion facing the outer end of the first junction box in the second direction and the first direction to a portion facing the outer end of the second junction box in the second direction and the first direction, and the breathing membrane is provided in the opposing region.

2. The energy storage device according to claim 1, wherein the opposing region includes an intermediate portion facing an inter-box space between the first junction box and the second junction box, and the breathable membrane is provided in the intermediate portion.

3. The storage device according to claim 1, wherein the opposing region includes a first opposing portion opposing the first junction box and a second opposing portion opposing the second junction box, and the breathing membrane is provided on the first opposing portion or the second opposing portion.

4. The energy storage device according to claim 3, wherein the second junction box has an outer shape larger than the outer shape of the first junction box, and the breathing membrane is provided on the second opposing portion.

5. The energy storage device according to claim 1, wherein the opposing region includes a first opposing portion opposing the first junction box and a second opposing portion opposing the second junction box, and the breathing membrane has a first breathing portion provided in the first opposing portion and a second breathing portion provided in the second opposing portion.

6. The energy storage device according to claim 1, wherein the first junction box has a first protrusion that protrudes toward the second junction box, and the second junction box has a second protrusion that protrudes toward the first junction box.

7. The energy storage device according to claim 1, wherein the length of the breathing membrane in the second direction is greater than the length between the first junction box and the second junction box in the second direction.

8. The energy storage device according to claim 1, further comprising a pressure release valve provided in the case for releasing pressure within the case, the case including an upper cover that covers the first energy storage stack, the second energy storage stack, the first junction box, and the second junction box, and the pressure release valve is provided in a portion of the upper cover above the inter-box space between the first junction box and the second junction box.

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