Energy storage device

Abstract

To provide an energy storage device that can prevent gases contained in emissions discharged from one energy storage cell from coming into contact with an adjacent energy storage cell. [Solution] The energy storage device 10 comprises a plurality of energy storage cells 100, a bottom wall 212, and a panel member 230. A safety valve SV is provided on the lower surface of each energy storage cell 100. The bottom wall 212 includes an upper plate portion 212A and a lower plate portion 212B. The upper plate portion 212A has at least two upper through holes h1 located opposite each safety valve. The lower plate portion 212B has at least one lower through hole h2 located opposite the at least two upper through holes. The length L2 of the lower through hole h2 in one direction is greater than the length L1 of each upper through hole h1 in one direction.

Description

Technical Field

[0001] This 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, and a protection member that protects the bottom portion of the case. A relief mechanism is provided on the bottom surface of each cell. A relief structure is provided on the bottom portion of the case. The discharge of the cell discharged from the relief mechanism passes through the relief structure and 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, there is a concern that a part of the gas contained in the discharge discharged from one cell may go toward a cell adjacent to the one cell without passing through the relief structure.

[0005] An object of this disclosure is to provide a power storage device capable of suppressing the gas contained in the discharge discharged from one power storage cell from coming into contact with the power storage cell adjacent to the one power storage cell.

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 in one 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 a safety valve is provided on the lower surface of each of the plurality of power storage cells, the bottom wall includes an upper plate portion provided below the plurality of power storage cells and a lower plate portion provided below the upper plate portion, the upper plate portion having at least two upper through holes provided at positions opposite to each of the safety valves, and the lower plate portion having at least one lower through hole provided at positions opposite to the at least two upper through holes, the length of the lower through holes in one direction being greater than the length of each of the upper through holes in one direction. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can suppress the contact of gases contained in emissions discharged from one energy storage cell with an adjacent energy storage cell. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows a vehicle equipped with an energy storage device according to one embodiment of the present disclosure. [Figure 2] This is a schematic perspective view of an energy storage device. [Figure 3] This is a schematic plan view showing the power storage device with the upper cover removed. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Figure 5] This is a perspective view that provides a general overview of the lower case. [Figure 6] This is a schematic cross-sectional view showing a modified example of the bottom wall. [Figure 7] This is a schematic cross-sectional view showing a modified example of the protective member. [Figure 8] This is a perspective view illustrating a schematic variation of the bottom wall. [Figure 9] This is a schematic cross-sectional view showing a modified example of the bottom wall. [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 diagram showing a vehicle equipped with a power storage device according to one embodiment of the present disclosure. Figure 2 is a schematic perspective view showing the power storage device. Figure 3 is a schematic plan view showing the power storage device with the upper cover removed. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Figure 5 is a schematic perspective view showing the lower case.

[0011] As shown in Figure 1, vehicle 1 comprises a vehicle body 2 and an energy storage device 10. Examples of vehicle 1 include a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a battery electric vehicle.

[0012] As shown in Figures 1 and 2, the vehicle body 2 includes a frame member 20. The frame member 20 is located at the bottom of the vehicle body 2. The frame member 20 is formed in a roughly rectangular cylindrical shape that surrounds the energy storage device 10.

[0013] The energy storage device 10 is mounted on the frame member 20. As shown in Figures 1 to 4, the energy storage device 10 comprises six energy storage stacks 11 to 16, a housing 200, equipment 300, equipment cooler 350, and refrigerant piping 400. Note that the number of energy storage stacks is not limited to six.

[0014] Each of the power storage stacks 11 to 16 is formed in a rectangular parallelepiped shape that is long in the first direction DR1. As shown in FIG. 3, the six power storage stacks 11 to 16 are arranged so as to line up along the second direction DR2 that is orthogonal to both the first direction DR1 and the vertical direction. In the present embodiment, the first direction DR1 corresponds to the longitudinal direction of the vehicle, and the second direction DR2 corresponds to the lateral direction (width direction) of the vehicle. Each of the power storage stacks 11 to 16 includes at least one power storage cell 100. In the present embodiment, each of the power storage stacks 11 to 16 includes a plurality of power storage cells 100 and a plurality of cooling plates 150.

[0015] The plurality of power storage cells 100 are arranged so as to line up along the first direction DR1. As shown in FIG. 4, each power storage cell 100 has an electrode body 112, a cell case 114, and a pair of external terminals 116.

[0016] The electrode body 112 may be configured by a wound body in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween, or may be configured by a stacked body in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween. The electrode body 112 is formed in a shape that is long in the second direction DR2.

[0017] 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.

[0018] The 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. Note that the width direction of the cell case 114 corresponds to the second direction DR2.

[0019] As shown in FIG. 4, 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 a refrigerant flows along the second direction DR2.

[0020] The housing 200 houses six power storage stacks 11 to 16. As shown in FIGS. 2 to 5, the housing 200 has a lower case 210, an upper cover 220, and a panel member 230.

[0021] The lower case 210 is open upward. The lower case 210 may be formed of a metal such as aluminum. The lower case 210 has a bottom wall 212, a peripheral wall 214, and a pair of partition walls 216.

[0022] The bottom wall 212 is located below each of the power storage stacks 11 to 16. As shown in FIG. 4, the bottom wall 212 is formed in a hollow shape. The bottom wall 212 may be formed by extrusion molding. As shown in FIGS. 4 and 5, the bottom wall 212 has an upper plate portion 212A and a lower plate portion 212B.

[0023] The upper plate portion 212A is provided below each of the power storage stacks 11 to 16. The upper plate portion 212A may be formed in a flat plate shape. The upper plate portion 212A has at least two upper through holes h1 provided at positions facing each safety valve SV. At least two upper through holes h1 are arranged at intervals in the first direction DR1. In the present embodiment, at least two upper through holes h1 include a plurality of upper through holes h1. Each upper through hole h1 is provided at a position facing the safety valve SV. That is, the number of upper through holes h1 arranged along the first direction DR1 is the same as the number of power storage cells 100 included in each of the power storage stacks 11 to 16.

[0024] The lower plate portion 212B is provided below the upper plate portion 212A. The lower plate portion 212B may be formed in a flat plate shape. The lower plate portion 212B has at least one lower through hole h2 provided opposite to at least two upper through holes h1. The at least one lower through hole h2 is provided in a position that overlaps vertically with at least a portion of each of a pair of upper through holes h1 adjacent to each other in the first direction DR1. In this embodiment, the at least one lower through hole h2 includes a plurality of lower through holes h2. As shown in Figure 4, each lower through hole h2 overlaps vertically with a pair of upper through holes h1 adjacent to each other in the first direction DR1.

[0025] The length L2 of the lower through-hole h2 in the first direction DR1 is greater than the length L1 of each upper through-hole h1 in the first direction DR1. In this embodiment, the length from one end to the other of a pair of upper through-holes h1 adjacent to each other in the first direction DR1 is equal to the length L2 of a single lower through-hole h2 in the first direction DR1.

[0026] As shown in Figure 4, a protective member 280 may be provided on the upper plate portion 212A. The protective member 280 has a plurality of heat insulating members 282 and a retaining member 284.

[0027] Each insulating member 282 has a shape that closes the upper through-hole h1. Each insulating member 282 has the function of protecting each energy storage cell 100 from gas discharged from the safety valve SV. Each insulating member 282 is made of, for example, mica, which is made by solidifying natural inorganic minerals by heat pressing.

[0028] The retaining member 284 holds a plurality of heat insulating members 282 aligned in the first direction DR1. Each heat insulating member 282 may be bonded to the lower surface of the retaining member 284. The retaining member 284 is made of, for example, polypropylene.

[0029] 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.

[0030] The front wall 214a is formed on one side (the left side in Figure 3) 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.

[0031] 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.

[0032] 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 3, 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.

[0033] 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.

[0034] 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.

[0035] As shown in Figure 4, 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.

[0036] As shown in Figures 3 and 4, 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 gas upward from the smoke exhaust path S. An explosion-proof valve 290 is provided at the downstream end of the smoke exhaust duct section 218. The explosion-proof valve 290 releases pressure inside the housing 200. The explosion-proof valve 290 opens when the pressure inside the housing 200 exceeds a reference value. The explosion-proof valve 290 is a check valve. As shown in Figure 4, 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 290.

[0037] The equipment 300 is housed in the enclosure 200. As shown in Figure 3, 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.

[0038] The equipment cooler 350 cools the equipment 300. As shown in Figures 3 and 4, 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.

[0039] 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 2 and 3, 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.

[0040] As shown in Figure 3, the refrigerant piping 400 includes an upstream pipe 410 and a downstream pipe 420.

[0041] 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.

[0042] 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.

[0043] In the energy storage device 10 described above, as shown in Figure 4, 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 protective member 280. As a result, the holding member 284 will melt and the heat insulating member 282 will rupture, causing the discharge to flow into the exhaust path S.

[0044] In this embodiment, since the length L2 of the lower through-hole h2 in the first direction DR1 is greater than the length L1 of each upper through-hole h1 in the first direction DR1, the pressure loss that occurs when the gas contained in the exhaust passes through the lower through-hole h2 is reduced. Therefore, the gas flows effectively into the exhaust gas path S.

[0045] Subsequently, the gas contained in the exhaust material spreads through the exhaust path S and is discharged from the housing 200 through the explosion-proof valve 290. This prevents the contents of the energy storage cell 100 (so-called debris) contained in the exhaust material discharged from the energy storage cell 100 from adhering to the external terminals 116, etc., of the energy storage cell 100.

[0046] Modifications of the above embodiment will be described below.

[0047] <First variation> As shown in Figure 6, the lower through-hole h2 may overlap vertically with only one upper through-hole h1. In this example as well, the length L2 of the lower through-hole h2 in the first direction DR1 is greater than the length L1 of each upper through-hole h1 in the first direction DR1.

[0048] <Second variation> As shown in Figure 7, the energy storage device 10 may further include a protective member 280 provided on the bottom wall 212. The protective member 280 includes a plurality of cylindrical portions 286. Each cylindrical portion 286 protrudes from the upper through hole h1 toward the panel member 230. The lower end of each cylindrical portion 286 is separated upward from the panel member 230. The protective member 280 is made of, for example, synthetic resin.

[0049] In this embodiment, as the gas that flows into the exhaust path S through the cylindrical portion 286 spreads within the exhaust path S, as shown in Figure 7, the gas forms a swirling flow within the cylindrical portion 286 located below the energy storage cell 100 adjacent to the energy storage cell 100 that discharged the exhaust. As a result, the gas rising within the cylindrical portion 286 prevents it from contacting the safety valve SV of the adjacent energy storage cell 100.

[0050] <Third variation> As shown in Figures 8 and 9, the upper plate portion 212A is provided with two upper through holes h1, and the lower plate portion 212B may be provided with a single lower through hole h2. The lower through hole h2 is a single through hole that extends from a position that overlaps vertically with the safety valve SV of the energy storage cell 101 located at one end in the first direction DR1 to a position that overlaps vertically with the safety valve SV of the energy storage cell 102 located at the other end in the first direction DR1.

[0051] In this embodiment, the pressure loss that occurs when the gas contained in the waste discharged from one energy storage cell 100 passes through the lower through-hole h2 is further reduced. In addition, the bottom wall 212 is made lighter.

[0052] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0053] [Aspect 1] Multiple energy storage cells arranged in one 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, A safety valve is provided on the lower surface of each of the aforementioned plurality of energy storage cells. The aforementioned bottom wall is An upper plate portion provided below the plurality of energy storage cells, It includes a lower plate portion provided below the upper plate portion, The upper plate portion has at least two upper through holes provided at positions facing each of the safety valves, The lower plate portion has at least one lower through hole located opposite the at least two upper through holes, A power storage device wherein the length of the lower through-hole in one direction is greater than the length of each of the upper through-holes in one direction.

[0054] In this energy storage device, the pressure loss that occurs when gas contained in the exhaust from the energy storage cell passes through the lower through-hole is reduced, allowing the gas to flow effectively into the exhaust path. Therefore, contact between gas contained in the exhaust from one energy storage cell and an adjacent energy storage cell is suppressed.

[0055] [Aspect 2] The energy storage device according to embodiment 1, wherein the at least one lower through-hole is provided in a position that overlaps in the vertical direction with at least a portion of each of the pair of upper through-holes that are adjacent to each other in one direction.

[0056] [Aspect 3] The energy storage device according to embodiment 1, wherein the at least one lower through-hole is a single through-hole extending from a position overlapping the safety valve of the energy storage cell located at one end in the one direction to a position overlapping the safety valve of the energy storage cell located at the other end in the one direction.

[0057] In this embodiment, gas flows more effectively into the exhaust gas path, and the bottom wall is made lighter.

[0058] [Aspect 4] The bottom wall is further provided with a protective member, The energy storage device according to embodiment 1 or 2, wherein the protective member includes a plurality of heat insulating members that close each of the at least two upper through holes.

[0059] In this embodiment, contact between gases contained in the waste discharged from one energy storage cell and the safety valve of an adjacent energy storage cell is suppressed.

[0060] [Aspect 5] The bottom wall is further provided with a protective member, The energy storage device according to embodiment 1 or 2, wherein the protective member includes a plurality of cylindrical portions, each protruding toward the panel member from each of the at least two upper through holes.

[0061] In this embodiment, contact between gases contained in the waste discharged from one energy storage cell and the safety valve of an adjacent energy storage cell is suppressed.

[0062] 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]

[0063] 1 Vehicle, 2 Vehicle body, 10 Energy storage device, 11-16 Energy storage stack, 20 Frame member, 100 Energy storage cell, 112 Electrode body, 114 Cell case, 116 External terminal, 200 Housing, 210 Lower case, 212 Bottom wall, 212A Upper plate section, 212B Lower plate section, 214 Peripheral wall, 216 Partition wall, 218 Smoke exhaust duct section, 220 Upper cover, 280 Protective member, 282 Insulation member, 284 Holding member, 286 Cylindrical section, 300 Equipment, 350 Equipment cooler, 400 Refrigerant piping, 410 Upstream piping, 420 Downstream piping, 900 Thermal conductive adhesive, h1 Upper through hole, h2 Lower through hole, S Space (smoke exhaust path).

Claims

1. Multiple energy storage cells arranged in one 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, A safety valve is provided on the lower surface of each of the aforementioned plurality of energy storage cells. The aforementioned bottom wall is An upper plate portion provided below the plurality of energy storage cells, It includes a lower plate portion provided below the upper plate portion, The upper plate portion has at least two upper through holes provided at positions facing each of the safety valves, The lower plate portion has at least one lower through hole located opposite the at least two upper through holes, A power storage device wherein the length of the lower through-hole in one direction is greater than the length of each of the upper through-holes in one direction.

2. The energy storage device according to claim 1, wherein the at least one lower through-hole is provided in a position that overlaps in the vertical direction with at least a portion of each of the pair of upper through-holes that are adjacent to each other in one direction.

3. The energy storage device according to claim 1, wherein the at least one lower through-hole is a single through-hole extending from a position overlapping the safety valve of the energy storage cell located at one end in the same direction to a position overlapping the safety valve of the energy storage cell located at the other end in the same direction.

4. The bottom wall is further provided with a protective member, The energy storage device according to claim 1, wherein the protective member includes a plurality of heat insulating members that close each of the at least two upper through holes.

5. The bottom wall is further provided with a protective member, The energy storage device according to claim 1, wherein the protective member includes a plurality of cylindrical portions, each protruding toward the panel member from each of the at least two upper through holes.

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