Energy storage device

Abstract

To provide an energy storage device capable of lowering the temperature of gases discharged into the atmosphere. [Solution] The energy storage device 10 comprises at least one energy storage cell 100, a cooling plate 150, a lower case 210 including a bottom wall 212, a panel member 230 that defines a smoke exhaust path together with the bottom wall, and a refrigerant pipe 400 through which a cooling medium supplied to the cooling plate flows. A safety valve SV is provided on the lower surface of each energy storage cell 100. The lower case 210 has a contact portion 215 that is in contact with the smoke exhaust path S. The refrigerant pipe 400 is in thermal contact with the contact portion 215.

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. The discharged material 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] [[ID= thirty-five ]] In the battery described in Japanese Unexamined Patent Application Publication No. 2023-126584, the gas that has flowed into the collection cavity may be discharged into the atmosphere through an explosion-proof valve or the like. In this case, there is a concern that high-temperature gas is discharged into the atmosphere.

[0005] An object of the present disclosure is to provide a power storage device capable of reducing the temperature of the gas discharged into the atmosphere.

Means for Solving the Problems

[0006] A power storage device according to one aspect of the present disclosure comprises at least one power storage cell, a cooling plate for cooling the at least one power storage cell, a lower case including a bottom wall positioned below the at least one power storage cell and the cooling plate, a panel member provided below the bottom wall and together with the bottom wall defining a smoke exhaust path, and refrigerant piping through which a cooling medium supplied to the cooling plate flows, wherein a safety valve is provided on the lower surface of each of the plurality of power storage cells, the lower case has a contact wall in contact with the smoke exhaust path, and the refrigerant piping is in thermal contact with the contact wall. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can lower the temperature of gases emitted into the atmosphere. [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. [Figure 5] This is a cross-sectional view illustrating a modified example of the lower case. [Figure 6] This is a cross-sectional view illustrating a modified example of the lower case. [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, protective members 280, equipment 300, 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 formed of a wound body in which a positive electrode sheet and a negative electrode sheet are wound via a separator, or may be formed of a stacked body in which a positive electrode sheet and a negative electrode sheet are stacked via a separator. The electrode body 112 is formed in a shape that is long 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. Note that 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 a 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 includes 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 210 has a bottom wall 212, a peripheral wall 214, and a pair of partition walls 216.

[0021] The bottom wall 212 is located below each of the power storage stacks 11 to 16. The bottom wall 212 may be formed in a solid and flat plate shape. The bottom wall 212 may be formed in a hollow shape by extrusion molding. As shown in FIG. 3, a plurality of through holes h1 are formed in the bottom wall 212. Each through hole h1 is provided at a position facing the safety valve SV. The length of each through hole h1 in the first direction DR1 is larger than the length of the safety valve SV in the first direction DR1. The length of each through hole h1 in the second direction DR2 is larger than the length of the safety valve SV in the second direction DR2.

[0022] 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.

[0023] Each heat insulating member 282 is provided in the through hole h1. Each heat insulating member 282 has a shape that closes the through hole h1. 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 28 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.

[0024] The holding sheet 284 holds the plurality of heat insulating members This article is protected by copyright. 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.

[0025] The peripheral wall 214 is connected to the bottom wall 212. The peripheral wall 214 has a shape that surrounds each of the power 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 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 28 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 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] As shown in Figure 4, in this embodiment, the lower case 210 includes a corner wall 213 that is in contact with both the upper surface of the bottom wall 212 and the inner surface of the peripheral wall 214. The corner wall 213 has an internal space C. The corner wall 213 includes a contact portion 215 that is in contact with the smoke exhaust path S. The bottom wall 212 has a communication opening h2 that connects the smoke exhaust path S and the internal space C. In this embodiment, the contact portion 215 is located at the top of the corner wall 213.

[0034] The surrounding member 290 is provided between the lower surface of the energy storage cell 100 and the upper surface of the bottom wall 212. The surrounding member 290 has a shape that surrounds the through hole h1. In this embodiment, the surrounding member 290 is provided between the bottom surface of the cell case 114 and the retaining sheet 284. The lower surface of the surrounding member 290 is in contact with the retaining sheet 284 located on the upper surface of the bottom wall 212. The upper surface of the surrounding member 290 may be in contact with the bottom surface of the cell case 114. The surrounding member 290 is made of resin, metal, or the like. The surrounding member 290 may also be in contact with the underside of the cooling plate 150.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] As shown in Figure 2, the refrigerant piping 400 includes an upstream pipe 410 and a downstream pipe 420.

[0039] 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.

[0040] 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.

[0041] The refrigerant piping 400 is in thermal contact with the contact portion 215. Thermal contact includes both direct contact between the refrigerant piping 400 and indirect contact between the refrigerant piping 400 and the contact portion 215 via a thermally conductive material (such as an adhesive or buffer). As shown in Figure 4, the energy storage device 10 in this embodiment further includes a buffer member 910 provided between the upstream piping 410 and the contact portion 215. The buffer member 910 is made of a thermally conductive material. Although not shown, another buffer member 910 is also provided between the downstream piping 420 and the contact portion 215.

[0042] In the energy storage device 10 described above, if a short circuit or the like causes discharge from the safety valve SV downward in any of the energy storage cells 100, the discharge collides with the retaining sheet 284 and the heat insulating member 282. As a result, the retaining sheet 284 melts and the heat insulating member 282 ruptures, and the discharge containing the contents of the energy storage cell 100 (so-called debris) flows into the exhaust gas path S through the through hole h1. Subsequently, the gas contained in the discharge spreads through the exhaust gas path S and is discharged from the housing 200 through the explosion-proof valve EV as shown in Figure 3. Therefore, the adhesion of the contents of the energy storage cell 100 to the external terminals 116, etc., is suppressed.

[0043] In this embodiment, as the gas spreads through the exhaust path S, a portion of the gas in the exhaust path S is cooled by the refrigerant flowing through the refrigerant piping 400 via the contact portion 215, thereby lowering the temperature of the gas discharged from the exhaust path S into the atmosphere through the explosion-proof valve EV.

[0044] Modifications of the above embodiment will be described below.

[0045] <First variation> As shown in Figure 5, the corner wall 213 may be omitted from the lower case 210, and the edge 212a of the bottom wall 212 may constitute the contact portion 215. In this case, as shown in Figure 5, an upwardly recessed recess h3 may be provided on the lower surface of the edge 212a of the bottom wall 212.

[0046] <Second variation> As shown in Figure 6, the corner wall 213 may be omitted from the lower case 210, and the edge 212a of the bottom wall 212 and the lower part 214c of the inner surface of the peripheral wall 214 may constitute the contact portion 215. In this example, the peripheral wall 214 has an internal space C, and a communication opening h4 is formed in the inner wall of the peripheral wall 214 to connect the smoke exhaust path S and the internal space C.

[0047] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0048] [Aspect 1] At least one energy storage cell, A cooling plate for cooling at least one of the energy storage cells, A lower case including at least one energy storage cell and a bottom wall positioned below the cooling plate, A panel member provided below the bottom wall, which together with the bottom wall defines the smoke exhaust path, The system includes a refrigerant pipe through which a cooling medium supplied to the cooling plate flows, A safety valve is provided on the lower surface of at least one of the energy storage cells. The lower case has a contact portion that is in contact with the exhaust path, The refrigerant piping is in thermal contact with the contact portion of the energy storage device.

[0049] In this embodiment, the gas in the exhaust path is cooled by the refrigerant flowing through the refrigerant piping via the contact portion, so that the temperature of the gas discharged into the atmosphere from the exhaust path decreases.

[0050] [Aspect 2] The aforementioned lower case is A peripheral wall connected to the bottom wall, surrounding the at least one energy storage cell and the cooling plate, The present invention further comprises a corner wall that is in contact with both the upper surface of the bottom wall and the inner surface of the peripheral wall, and has an internal space, The aforementioned corner wall includes the contact portion, The energy storage device according to embodiment 1, wherein a communication opening is formed in the bottom wall to connect the smoke exhaust path and the internal space.

[0051] In this embodiment, the surrounding walls are reinforced by corner walls, and the gas that flows into the internal space through the communication opening is effectively cooled within that internal space.

[0052] [Aspect 3] The system further includes a buffer member provided between the refrigerant piping and the contact portion, The energy storage device according to embodiment 2, wherein the buffer member is made of a material having thermal conductivity.

[0053] In this embodiment, both protection of the refrigerant piping and ensuring good thermal contact between the refrigerant piping and the contact area are achieved.

[0054] [Aspect 4] The lower case is connected to the bottom wall and further has a peripheral wall that surrounds the at least one energy storage cell and the cooling plate. The aforementioned peripheral wall has an internal space, The energy storage device according to embodiment 1, wherein a communication opening is formed in the peripheral wall for connecting the smoke exhaust path and the internal space.

[0055] 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]

[0056] 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, 213 Corner wall, 214 Peripheral wall, 215 Contact part, 216 Partition wall, 218 Smoke exhaust duct part, 220 Upper cover, 280 Protective member, 282 Insulation member, 284 Retaining sheet, 290 Enclosing member, 300 Equipment, 350 Equipment cooler, 400 Refrigerant piping, 410 Upstream piping, 420 Downstream piping, 900 Thermal conductive adhesive, 910 Cushioning member, EV Explosion-proof valve, h1 Through hole, h2 Communication port, h3 Recess, h4 Communication port, S Space (smoke exhaust path), SV Safety valve.

Claims

1. At least one energy storage cell, A cooling plate for cooling at least one of the energy storage cells, A lower case including at least one energy storage cell and a bottom wall positioned below the cooling plate, A panel member provided below the bottom wall, which together with the bottom wall defines the smoke exhaust path, The system includes a refrigerant pipe through which a cooling medium supplied to the cooling plate flows, A safety valve is provided on the lower surface of at least one of the energy storage cells. The lower case has a contact portion that is in contact with the exhaust path, The refrigerant piping is in thermal contact with the contact portion of the energy storage device.

2. The aforementioned lower case is A peripheral wall connected to the bottom wall, surrounding the at least one energy storage cell and the cooling plate, The present invention further comprises a corner wall that is in contact with both the upper surface of the bottom wall and the inner surface of the peripheral wall, and has an internal space, The aforementioned corner wall includes the contact portion, The energy storage device according to claim 1, wherein a communication opening is formed in the bottom wall for connecting the smoke exhaust path and the internal space.

3. The system further includes a buffer member provided between the refrigerant piping and the contact portion, The energy storage device according to claim 2, wherein the buffer member is made of a material having thermal conductivity.

4. The lower case is connected to the bottom wall and further has a peripheral wall that surrounds the at least one energy storage cell and the cooling plate. The aforementioned peripheral wall has an internal space, The energy storage device according to claim 1, wherein a communication opening is formed in the peripheral wall for connecting the smoke exhaust path and the internal space.

Images