Energy storage device

Abstract

To provide an energy storage device that can suppress the diffusion of waste discharged from the energy storage cell between the cell case and the bottom wall. [Solution] The energy storage device 10 comprises a plurality of energy storage cells 100, a bottom wall 212, and a panel member 230 that defines a smoke exhaust path together with the bottom wall. Each energy storage cell 100 has a cell case 114 that houses an electrode body and a safety valve SV provided on the lower surface of the cell case. The bottom wall 212 has a through hole h provided at a position opposite the safety valve. The length W2 of the upper end of the through hole h in the second direction DR2 is greater than the length W1 of the safety valve SV in the second direction DR2.

Description

Technical Field

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

Background Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2023-126584 discloses a battery including a plurality of cells, a case that houses the plurality of cells, a protection member that protects the bottom portion of the case, and a cover. Each cell has a box that houses an electrode assembly. A relief mechanism is provided on the bottom surface of the box, and an external terminal is provided on the upper surface of the box. The discharge discharged from the relief mechanism flows into a collection cavity formed between the bottom portion of the case and the protection member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery described in Japanese Unexamined Patent Application Publication No. 2023-126584, when discharge is discharged from the relief mechanism of the cell, there is a concern that a part of the discharge diffuses into the case without flowing into the collection cavity.

[0005] An object of the present disclosure is to provide a power storage device capable of suppressing the diffusion of discharge discharged from a power storage cell between a cell case and a bottom wall.

Means for Solving the Problems

[0006] A power storage device according to one aspect of the present disclosure comprises a plurality of power storage cells arranged along a first direction, a bottom wall positioned below the plurality of power storage cells, and a panel member provided below the bottom wall and together with the bottom wall defining a smoke exhaust path, wherein each of the plurality of power storage cells has a cell case for housing an electrode body and a safety valve provided on the lower surface of the cell case, the bottom wall has a through hole provided at a position opposite to the safety valve, and the length of the upper end of the through hole in a second direction perpendicular to both the first direction and the vertical direction is greater than the length of the safety valve in the second direction. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can suppress the diffusion of waste discharged from the energy storage cell between the cell case and the bottom wall. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of an energy storage device in one embodiment of the present disclosure. [Figure 2] This is a schematic plan view showing the power storage device with the upper cover removed. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] Figure 2 shows a cross-sectional view along line IV-IV. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a schematic perspective view showing an energy storage device in one embodiment of the present disclosure. Figure 2 is a schematic plan view showing the energy storage device with the upper cover removed. Figure 3 is a cross-sectional view taken along line III-III in Figure 2. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2.

[0011] In this embodiment, the energy storage device 10 is mounted, for example, on the underside of a vehicle. Examples of vehicles include hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles.

[0012] As shown in Figures 1 to 4, the energy storage device 10 comprises six energy storage stacks 11 to 16, a housing 200, a protective member 280, a surrounding member 290, equipment 300, an equipment cooler 350, and refrigerant piping 400. Note that the number of energy storage stacks is not limited to six.

[0013] Each energy storage stack 11-16 is formed in a rectangular parallelepiped shape that is elongated in the first direction DR1. As shown in Figure 2, the six energy storage stacks 11-16 are arranged to line up along a second direction DR2 that is perpendicular to both the first direction DR1 and the vertical direction. In this embodiment, the first direction DR1 corresponds to the longitudinal direction of the vehicle, and the second direction DR2 corresponds to the left-right direction (width direction) of the vehicle. Each energy storage stack 11-16 contains at least one energy storage cell 100. In this embodiment, each energy storage stack 11-16 contains a plurality of energy storage cells 100 and a plurality of cooling plates 150.

[0014] Multiple energy storage cells 100 are arranged in a line along a first direction DR1. As shown in Figure 3, each energy storage cell 100 has an electrode body 112, a cell case 114, and a pair of external terminals 116.

[0015] The electrode body 112 may be composed of a wound body in which a positive electrode sheet and a negative electrode sheet are wound with a separator in between, or it may be composed of a laminate in which a positive electrode sheet and a negative electrode sheet are stacked with a separator in between. The electrode body 112 is formed in a shape that is elongated in the second direction DR2.

[0016] The cell case 114 houses the electrode body 112. The cell case 114 is formed in a rectangular parallelepiped shape. The cell case 114 is made of a metal such as aluminum. A safety valve SV is provided on the lower surface of the cell case 114.

[0017] A pair of external terminals 116 are provided on the upper surface of the cell case 114. The pair of external terminals 116 are provided at positions spaced apart from each other in the width direction of the cell case 114. Incidentally, the width direction of the cell case 114 corresponds to the second direction DR2.

[0018] As shown in FIG. 3, each cooling plate 150 is disposed between a pair of power storage cells 100 adjacent to each other in the first direction DR1. Each cooling plate 150 is formed in a flat plate shape that is long in the second direction DR2. Each cooling plate 150 has a flow path (not shown) through which the refrigerant flows along the second direction DR2.

[0019] The housing 200 houses six power storage stacks 11 to 16. As shown in FIGS. 1 to 4, the housing 200 has a lower case 210, an upper cover 220, and a panel member 230.

[0020] The lower case 210 is open upward. The lower case 210 may be formed of a metal such as aluminum. The lower case 具有底壁212、周壁214以及一対の仕切壁216。

[0021] The bottom wall 212 is located below each of the power storage stacks 11 to 16. In the present embodiment, the bottom wall 212 is formed in a hollow shape. The bottom wall 212 may be formed by extrusion molding. However, the bottom wall 212 may be formed in a solid and flat plate shape. As shown in FIGS. 3 and 4, a plurality of through holes h are formed in the bottom wall 212. Each through hole h is provided at a position facing the safety valve SV.

[0022] As shown in FIG. 3, the length L2 of the upper end portion of the through hole h in the first direction DR1 is greater than the length L1 of the safety valve SV in the first direction DR1. As shown in FIG. 4, the length W2 of the upper end portion of the through hole h in the second direction DR2 is greater than the length W1 of the safety valve SV in the second direction DR2.

[0023] In addition, in the present embodiment, the length L2 of the upper end portion of the through hole h in the first direction DR1 is the same as the length of the lower end portion of the through hole h in the first direction DR1. Similarly, the length W2 of the upper end portion of the through hole h in the second direction DR2 is the same as the length of the lower end portion of the through hole h in the second direction DR2. However, the length of the through hole h in the first direction DR1 may gradually increase or gradually decrease as it goes downward. Similarly, the length of the through hole h in the second direction DR2 may gradually increase or gradually decrease as it goes downward.

[0024] The protection member 280 is provided on the bottom wall 212. As shown in FIGS. 3 and 4, the protection member 280 has a plurality of heat insulating members 282 and a holding sheet 284.

[0025] Each heat insulating member 282 is provided in the through hole h. Each heat insulating member 282 has a shape that closes the through hole h. In the present embodiment, the upper surface of each heat insulating member 282 is set flush with the upper surface of the bottom wall 212. Each heat insulating member 282 has a function of protecting each power storage cell 100 from the gas discharged from the safety valve SV. Each heat insulating member 282 is made of, for example, mica obtained by solidifying natural inorganic minerals by hot pressing.

[0026] The holding sheet 284 holds the plurality of heat insulating members 282. Each heat insulating member 282 may be adhered to the back surface of the holding sheet 284. The holding sheet 284 is made of, for example, polypropylene.

[0027] The surrounding member 290 is provided between the lower surface of the cell case 114 and the bottom wall 212. The surrounding member 290 has a shape that surrounds the through hole h. As shown in Figures 3 and 4, at least a portion of the surrounding member 290 is in contact with the bottom surface of the cell case 114 and the retaining sheet 284. The lower surface of the end 292 of the surrounding member 290 in the second direction DR2 is in contact with the bottom wall 212. The upper surface of the surrounding member 290 is in contact with the bottom surface of the cell case 114 over its entire length. The surrounding member 290 is made of resin, metal, or the like. A portion of the upper surface of the surrounding member 290 may be in contact with the lower surface of the cooling plate 150.

[0028] The peripheral wall 214 rises from the periphery of the bottom wall 212. The peripheral wall 214 has a shape that surrounds each of the energy storage stacks 11 to 16. The peripheral wall 214 may be formed in a hollow shape. The peripheral wall 214 has a front wall 214a and a pair of side walls 214b.

[0029] The front wall 214a is formed on one side (the left side in Figure 2) of each energy storage stack 11-16 in the first direction DR1. The front wall 214a extends in the second direction DR2. In this embodiment, one side in the first direction DR1 corresponds to the front side in the longitudinal direction of the vehicle.

[0030] A pair of side walls 214b are spaced apart from each other and face each other in the second direction DR2. Each side wall 214b extends in the first direction DR1. One end (front end) of each side wall 214b in the first direction DR1 is connected to the front wall 214a.

[0031] A pair of partition walls 216 divide the space enclosed by the bottom wall 212 and the perimeter wall 214 into a space in which each energy storage stack 11-16 is arranged and other spaces. The pair of partition walls 216 are spaced apart from each other in the first direction DR1. Each partition wall 216 extends in the second direction DR2. Each partition wall 216 may be formed in a hollow shape. The pair of partition walls 216 have the function of constraining each energy storage stack 11-16 from both sides in the first direction DR1. As shown in Figure 2, the end of the partition wall 216 formed on one side (front side) in the first direction DR1 in the second direction DR2 is spaced apart from each side wall 214b. The end of the partition wall 216 formed on the other side (rear side) in the first direction DR1 in the second direction DR2 is connected to each side wall 214b.

[0032] The upper cover 220 is positioned above each of the energy storage stacks 11-16. The upper cover 220, together with the lower case 210, houses the six energy storage stacks 11-16. Specifically, the upper cover 220, together with the lower case 210, houses the six energy storage stacks 11-16 in a sealed state. The peripheral edge of the upper cover 220 is connected to the upper end of the peripheral wall 214 by bolts or the like via a sealing member.

[0033] The panel member 230 is located below the lower case 210. The panel member 230 has the function of protecting the bottom wall 212 of the lower case 210. The panel member 230 may be formed in a flat plate shape. The peripheral edge of the panel member 230 is connected to the lower surface of the lower case 210 via a sealing member.

[0034] As shown in Figure 3, a space S is formed between the panel member 230 and the bottom wall 212. Each space S functions as a smoke exhaust path (hereinafter referred to as "smoke exhaust path S"). The smoke exhaust path S is a path for discharging the gas discharged from the safety valve SV of the energy storage cell 100 to the outside of the housing 200.

[0035] As shown in Figures 2 and 3, a smoke exhaust duct section 218 is formed in the peripheral wall 214. The smoke exhaust duct section 218 extends upward from the bottom wall 212. The smoke exhaust duct section 218 guides the gas upward from the smoke exhaust path S. An explosion-proof valve EV is provided at the downstream end of the smoke exhaust duct section 218. The explosion-proof valve EV releases the pressure inside the housing 200. The explosion-proof valve EV opens when the pressure inside the housing 200 exceeds a reference value. The explosion-proof valve EV is composed of a check valve. As shown in Figure 3, when gas is discharged from any of the energy storage cells 100, the gas spreads in the first direction DR1 through the smoke exhaust path S and is discharged outside the housing 200 through the smoke exhaust duct section 218 and the explosion-proof valve EV.

[0036] The equipment 300 is housed in the enclosure 200. As shown in Figure 2, the equipment 300 is located in the space formed between the partition wall 216 and the peripheral wall 214, which are located on the other side of the lower case 210 in the first direction DR1, i.e., on the other side (rear side) in the first direction DR1. The equipment 300 may include a junction box. The equipment 300 may include relays, control equipment, etc.

[0037] The equipment cooler 350 cools the equipment 300. As shown in Figures 2 and 3, the equipment cooler 350 is provided between the bottom wall 212 and the equipment 300. A thermally conductive adhesive 900 may be provided between the equipment cooler 350 and the bottom wall 212.

[0038] The refrigerant piping 400 is routed within the housing 200. The refrigerant piping 400 is connected to each cooling plate 150 and the equipment cooler 350. As shown in Figures 1 and 2, the front wall 214a of the peripheral wall 214 is provided with an inlet port 181 and an outlet port 182. The refrigerant piping 400 is connected to the inlet port 181 and the outlet port 182. Therefore, the refrigerant (water, oil, etc.) supplied from the inlet port 181 flows through the refrigerant piping 400 to each cooling plate 150 and the equipment cooler 350, cools each energy storage cell 100 and equipment 300, and then flows out through the refrigerant piping 400 from the outlet port 182.

[0039] As shown in Figure 2, the refrigerant piping 400 includes an upstream pipe 410 and a downstream pipe 420.

[0040] The upstream end of the upstream piping 410 is connected to the inlet port 181. The downstream end of the upstream piping 410 is connected to one end of the equipment cooler 350 in the second direction DR2. The upstream piping 410 is routed to pass between the front wall 214a and the partition wall 216 formed on one side in the first direction DR1, and between the energy storage stack 11 located on one side in the second direction DR2 and the side wall 214b. The upstream piping 410 is connected to one end of each cooling plate 150 in the second direction DR2.

[0041] The upstream end of the downstream pipe 420 is connected to the other end of the equipment cooler 350 in the second direction DR2. The downstream end of the downstream pipe 420 is connected to the outflow port 182. The downstream pipe 420 is routed to pass between the front wall 214a and the partition wall 216 formed on one side in the first direction DR1, and between the energy storage stack 16 located on the other side in the second direction DR2 and the side wall 214b. The downstream pipe 420 is connected to the other end of each cooling plate 150 in the second direction DR2.

[0042] In the energy storage device 10 described above, if a discharge is made downward from the safety valve SV due to a short circuit or the like in any of the energy storage cells 100, the discharge will collide with the retaining sheet 284 and the heat insulating member 282. As a result, the retaining sheet 284 will melt and the heat insulating member 282 will rupture.

[0043] In this embodiment, the length L2 of the upper end of the through-hole h in the first direction DR1 is greater than the length L1 of the safety valve SV in the first direction DR1, and the length W2 of the upper end of the through-hole h in the second direction DR2 is greater than the length W1 of the safety valve SV in the second direction DR2. Therefore, the discharged material from the safety valve SV flows effectively into the exhaust path S through the through-hole h. Thus, the diffusion of discharged material, including the contents of the energy storage cell 100 (so-called debris), between the cell case 114 and the bottom wall 212 is suppressed.

[0044] Subsequently, the gas contained in the exhaust spreads through the exhaust path S and is discharged from the housing 200 through the explosion-proof valve EV, as shown in Figure 3. Therefore, the adhesion of contents from the energy storage cell 100 to the external terminals 116, etc., is suppressed.

[0045] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0046] [Aspect 1] Multiple energy storage cells arranged along the first direction, A bottom wall positioned below the plurality of energy storage cells, It comprises a panel member provided below the bottom wall, which together with the bottom wall defines a smoke exhaust path, Each of the aforementioned plurality of energy storage cells is A cell case for housing the electrode body, The cell case has a safety valve provided on the lower surface, The bottom wall has a through hole located opposite the safety valve, An energy storage device wherein the length of the upper end of the through hole in a second direction perpendicular to both the first direction and the vertical direction is greater than the length of the safety valve in the second direction.

[0047] In this energy storage device, the length of the upper end of the through-hole in the second direction is greater than the length of the safety valve in the second direction, so that the waste discharged from the safety valve effectively flows into the exhaust path through the through-hole. Therefore, diffusion of waste between the cell case and the bottom wall is suppressed.

[0048] [Aspect 2] The energy storage device according to embodiment 1, wherein the length of the upper end of the through hole in the first direction is greater than the length of the safety valve in the first direction.

[0049] In this embodiment, the diffusion of waste between the cell case and the bottom wall is more reliably suppressed.

[0050] [Aspect 3] The energy storage device according to embodiment 1 or 2, further comprising a surrounding member provided between the cell case and the bottom wall, and having a shape that surrounds the through hole.

[0051] In this embodiment, the surrounding member blocks the diffusion of the discharged material, thus more reliably suppressing the diffusion of the discharged material between the cell case and the bottom wall.

[0052] [Aspect 4] The bottom wall is further provided with a protective member, The protective member is Multiple heat insulating members that close each of the aforementioned through holes, It has a retaining sheet that holds the plurality of heat insulating members, The energy storage device according to embodiment 3, wherein at least a portion of the surrounding member is in contact with the bottom surface of the cell case and the retaining sheet.

[0053] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims rather than the description of the embodiments above, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0054] 10 Energy storage device, 11-16 Energy storage stack, 100 Energy storage cell, 112 Electrode body, 114 Cell case, 116 External terminal, 200 Housing, 210 Lower case, 212 Bottom wall, 214 Surrounding wall, 216 Partition wall, 218 Smoke exhaust duct section, 220 Upper cover, 280 Protective member, 282 Insulation member, 284 Retaining sheet, 290 Enclosing member, 292 End section, 300 Equipment, 350 Equipment cooler, 400 Refrigerant piping, 410 Upstream piping, 420 Downstream piping, 900 Thermal conductive adhesive, EV Explosion-proof valve, h Through hole, S Space (smoke exhaust path), SV Safety valve.

Claims

1. Multiple energy storage cells arranged along the first direction, A bottom wall positioned below the plurality of energy storage cells, It comprises a panel member provided below the bottom wall, which together with the bottom wall defines a smoke exhaust path, Each of the aforementioned plurality of energy storage cells is A cell case for housing the electrode body, The cell case has a safety valve provided on the lower surface, The bottom wall has a through hole located opposite the safety valve, An energy storage device wherein the length of the upper end of the through hole in a second direction perpendicular to both the first direction and the vertical direction is greater than the length of the safety valve in the second direction.

2. The energy storage device according to claim 1, wherein the length of the upper end of the through hole in the first direction is greater than the length of the safety valve in the first direction.

3. The energy storage device according to claim 1 or 2, further comprising a surrounding member provided between the cell case and the bottom wall, and having a shape that surrounds the through hole.

4. The bottom wall is further provided with a protective member, The protective member is Multiple heat insulating members that close each of the aforementioned through holes, It has a retaining sheet that holds the plurality of heat insulating members, The energy storage device according to claim 3, wherein at least a portion of the surrounding member is in contact with the bottom surface of the cell case and the retaining sheet.

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