Energy storage device

Abstract

To provide an energy storage device that can suppress the adhesion of waste from one energy storage cell to other energy storage cells. [Solution] The energy storage device 10 comprises a plurality of energy storage cells, a bottom wall 212, and a panel member that defines a smoke exhaust path together with the bottom wall. Each energy storage cell includes a cell case 114 that houses an electrode body. A safety valve 115 is provided on the lower surface of the cell case. The bottom wall 212 has a through hole 212h provided at a position opposite the safety valve 115. The safety valve 115 has a rupture portion 115a that ruptures when the internal pressure of the cell case reaches a reference value, and a connecting portion 115b that connects the cell case and the rupture portion. The connecting portion 115b is deformable into a shape that bulges outward from the cell case when the internal pressure of the cell case reaches a reference value.

Description

Technical Field

[0006] , , ,

[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 protective member that protects the bottom portion of the case, and a cover. The protective member is fixed to the bottom portion of the case by a fastener. A relief mechanism is provided on the bottom surface of each cell. The discharge discharged from the relief mechanism flows into a collection cavity formed between the bottom portion of the case and the protective 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 the discharge discharged from the relief mechanism of one cell may adhere to other cells.

[0005] An object of the present disclosure is to provide a power storage device capable of suppressing the adhesion of discharge from one power storage cell to other power storage cells.

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, a bottom wall disposed 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 includes a cell case for housing an electrode body, a safety valve is 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, the safety valve has a rupture portion that ruptures when the internal pressure of the cell case reaches a reference value, and a connecting portion that connects the cell case and the rupture portion, the connecting portion is deformable into a shape that bulges outward from the cell case when the internal pressure of the cell case reaches the reference value. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can suppress the adhesion of waste from one energy storage cell to other energy storage cells. [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 schematic diagram of a safety valve. [Figure 6] This is a cross-sectional view along the line VI-VI in Figure 5. [Figure 7] This is a schematic cross-sectional view showing the state in which the cracked area has been opened. [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.

[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. As shown in FIG. 3, the six power storage stacks 11 to 16 are arranged so as to be aligned along a second direction that is orthogonal to both the first direction and the vertical direction. In the present embodiment, the first direction corresponds to the front-rear direction of the vehicle, and the second direction corresponds to the left-right 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 be aligned along the first direction. 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 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.

[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 115 is provided on the lower surface of the cell case 114. Details of the safety valve 115 will be described later.

[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.

[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. Each cooling plate 150 is formed in a flat plate shape that is long in the second direction. Each cooling plate 150 has a flow path (not shown) through which a refrigerant flows along the second direction.

[0020] The housing 200 houses six power storage stacks 11 to 16. As shown in FIGS. 2 to 4, 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. 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 FIG. 4, a plurality of through holes 212h are formed in the bottom wall 212. Each through hole 212h is provided at a position facing the safety valve 115.

[0023] A plurality of heat insulating members (not shown) may be provided on the bottom wall 212. Each heat insulating member has a shape that covers the through hole 212h. Each heat insulating member has a function of protecting each power storage cell 100 from the gas discharged from the safety valve 115. Each heat insulating member is made of, for example, mica obtained by solidifying a natural inorganic mineral by hot pressing.

[0024] The peripheral wall 214 stands up from the peripheral edge of 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.

[0025] The front wall 214a is formed on one side (the left side in FIG. 3) of each of the power storage stacks 11 to 16 in the first direction. The front wall 214a extends in the second direction. In the present embodiment, one side in the first direction corresponds to the front side in the vehicle front-rear direction.

[0026] The pair of side walls 214b are spaced apart from each other and face each other in the second direction. Each side wall 214b extends in the first direction. One end (front end) of each side wall 214b in the first direction is connected to the front wall 214a.

[0027] 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 a first direction. Each partition wall 216 extends in a second direction. Each partition wall 216 may be formed in a hollow shape. The pair of partition walls 216 have the function of restraining each energy storage stack 11-16 from both sides in the first direction. As shown in Figure 3, the end of the partition wall 216 formed on one side (front side) in the first direction in the second direction 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 in the second direction is connected to each side wall 214b.

[0028] 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.

[0029] 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.

[0030] 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 115 of the energy storage cell 100 to the outside of the housing 200.

[0031] 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 the 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 the 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 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.

[0032] 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 on the other side of the lower case 210 in the first direction, i.e., the other side (rear side) in the first direction. The equipment 300 may include a junction box. The equipment 300 may include relays, control equipment, etc.

[0033] 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.

[0034] 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.

[0035] As shown in Figure 3, the refrigerant piping 400 includes an upstream pipe 410 and a downstream pipe 420.

[0036] 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. 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, and between the energy storage stack 11 and the side wall 214b located on one side in the second direction. The upstream piping 410 is connected to one end of each cooling plate 150 in the second direction.

[0037] The upstream end of the downstream piping 420 is connected to the other end of the equipment cooler 350 in the second direction. The downstream end of the downstream piping 420 is connected to the outlet port 182. The downstream piping 420 is routed to pass between the front wall 214a and the partition wall 216 formed on one side in the first direction, and between the energy storage stack 16 located on the other side in the second direction and the side wall 214b. The downstream piping 420 is connected to the other end of each cooling plate 150 in the second direction.

[0038] Next, the safety valve 115 will be described in detail with reference to Figures 5 to 7. The safety valve 115 has a splitting portion 115a and a connecting portion 115b.

[0039] The rupture portion 115a ruptures when the internal pressure of the cell case 114 reaches a reference value. The rupture portion 115a may be formed in a circular shape when viewed from the bottom. A rupture-inducing portion (thin-walled portion) is formed in the rupture portion 115a.

[0040] The connecting portion 115b connects the cell case 114 to the split portion 115a. The connecting portion 115b surrounds the split portion 115a in an annular manner. The thickness of the split portion 115a gradually decreases from the connecting portion 115b toward the center of the split portion 115a.

[0041] As shown in Figure 6, the connecting portion 115b has a shape that recesses inward toward the inside of the cell case 114 when the internal pressure of the cell case 114 is below a reference value. As shown in Figure 7, the connecting portion 115b can be deformed to bulge outward toward the outside of the cell case 114 (downward in this embodiment) when the internal pressure of the cell case 114 reaches a reference value. The distance H between the lower surface of the cell case 114 and the upper surface of the bottom wall 212 is set to a length such that the lower end of the rupture portion 115a is located inside the through hole 212h when the rupture portion 115a is ruptured.

[0042] In the energy storage device 10 described above, if the internal pressure of the cell case in any of the energy storage cells 100 reaches the aforementioned reference value due to a short circuit or the like, the connecting portion 115b bulges toward the bottom wall 212, reducing the distance between the rupture portion 115a of the safety valve 115 and the bottom wall 212. Furthermore, as shown in Figure 7, when the rupture portion 115a ruptures, the lower end of the rupture portion 115a is located within the through hole 212h. Therefore, when waste from the energy storage cell 100 is discharged from the rupture portion 115a, the waste effectively flows into the exhaust gas path S. Consequently, the waste is prevented from scattering toward the energy storage cell 100 or adhering to other energy storage cells.

[0043] Then, the gas contained in the exhaust that flows into the exhaust path S from the safety valve 115 spreads out through the exhaust path S and is discharged from the housing 200 through the explosion-proof valve 290, as shown in Figure 4. As a result, the contents of the energy storage cell 100 (so-called debris) contained in the exhaust are prevented from adhering to the external terminals 116, etc., of the energy storage cell 100.

[0044] The distance H between the lower surface of the cell case 114 and the upper surface of the bottom wall 212 may be set to a length such that the lower end of the cracked portion 115a is located above the through hole 212h when the cracked portion 115a is cracked.

[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, 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 plurality of energy storage cells includes a cell case that houses an electrode body. A safety valve is provided on the lower surface of the cell case. The bottom wall has a through hole located opposite the safety valve, The aforementioned safety valve A rupture portion that ruptures when the internal pressure of the cell case reaches a reference value, It has a connecting portion that connects the cell case and the opening portion, The aforementioned connecting portion is deformable into a shape that bulges outward from the cell case when the internal pressure of the cell case reaches the aforementioned reference value, in an energy storage device.

[0047] In this energy storage device, when the internal pressure of the cell case in one energy storage cell reaches a standard value, the connecting portion bulges towards the bottom wall, reducing the distance between the opening of the safety valve and the bottom wall. Therefore, when waste is discharged from the energy storage cell through the opening, the waste effectively flows into the exhaust path. Consequently, the scattering of waste from one energy storage cell toward other energy storage cells and adhesion to other energy storage cells are suppressed.

[0048] [Aspect 2] The energy storage device according to embodiment 1, wherein the connecting portion has a shape that recesses inward toward the inside of the cell case when the internal pressure of the cell case is less than the reference value.

[0049] [Aspect 3] The energy storage device according to embodiment 1 or 2, wherein the thickness of the split portion gradually decreases from the connecting portion toward the center of the split portion.

[0050] In this embodiment, the rupture is effectively ruptured.

[0051] [Aspect 4] The energy storage device according to any one of embodiments 1 to 3, wherein the distance between the lower surface of the cell case and the upper surface of the bottom wall is set to a length such that the lower end of the rupture is located inside the through hole when the rupture occurs.

[0052] In this embodiment, when waste from the energy storage cell is discharged from the slit, the waste is more reliably allowed to flow into the exhaust gas path.

[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] 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, 115 Safety valve, 115a Split section, 115b Connecting section, 116 External terminal, 200 Housing, 210 Lower case, 212 Bottom wall, 214 Peripheral wall, 216 Partition wall, 218 Smoke exhaust duct section, 220 Upper cover, 300 Equipment, 350 Equipment cooler, 400 Refrigerant piping, 410 Upstream piping, 420 Downstream piping, 900 Thermal conductive adhesive, S Space (smoke exhaust path).

Claims

1. Multiple energy storage cells, 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 plurality of energy storage cells includes a cell case that houses an electrode body. A safety valve is provided on the lower surface of the cell case. The bottom wall has a through hole located opposite the safety valve, The aforementioned safety valve A rupture portion that ruptures when the internal pressure of the cell case reaches a reference value, It has a connecting portion that connects the cell case and the opening portion, The aforementioned connecting portion is deformable into a shape that bulges outward from the cell case when the internal pressure of the cell case reaches the aforementioned reference value, in an energy storage device.

2. The energy storage device according to claim 1, wherein the connecting portion has a shape that recesses inward toward the inside of the cell case when the internal pressure of the cell case is less than the reference value.

3. The energy storage device according to claim 1, wherein the thickness of the split portion gradually decreases from the connecting portion toward the center of the split portion.

4. The energy storage device according to claim 1, wherein the distance between the lower surface of the cell case and the upper surface of the bottom wall is set to a length such that the lower end of the rupture portion is located inside the through hole when the rupture portion is ruptured.

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