Energy storage device
By designing a weak point area and a safety valve structure at the bottom of the battery, the problem of the bottom structure being susceptible to gas influence is solved, achieving safe and effective gas emission and avoiding additional cost increases.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-25
AI Technical Summary
In existing battery designs, the bottom structure is susceptible to gas emissions, which also increases additional costs and material requirements.
A bottom structure was designed, comprising upper and lower plates, wherein the upper plate has a weak area for rupturing during gas release to form a gas release channel, avoiding the use of additional insulation materials, and utilizing safety valves and burst valves for gas release.
It effectively protects the structure beneath the battery from gas, while avoiding increased costs, and achieves a safe gas emission channel design.
Smart Images
Figure 2026085410000001_ABST
Abstract
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. Each cell has a box that houses an electrode assembly. A relief mechanism is provided on the bottom 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 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. 202A 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 located 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, and the bottom wall has a plurality of vulnerable portions, each located opposite each of the safety valves. [Effects of the Invention]
[0007] This disclosure provides an energy storage device that can protect the underside of energy storage cells from gas while avoiding a significant increase in costs. [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] This is a plan view of the vulnerable area. [Figure 5] This is a schematic cross-sectional view showing modified examples of the bottom wall and weak areas. [Figure 6] This is a schematic cross-sectional view showing modified examples of the bottom wall and weak areas. [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.
[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 3, the energy storage device 10 comprises six energy storage stacks 11 to 16, a housing 200, a surrounding member 290, 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 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. 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 3, 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 具有底壁212、周壁214和一对隔壁216。
[0021] The bottom wall 212 is located below each of the power storage stacks 11 to 16. As shown in FIG. 3, the bottom wall 212 is formed in a hollow shape. The bottom wall 212 may be formed by extrusion molding. The bottom wall 212 has an upper plate portion 212A and a lower plate portion 212B.
[0022] The upper plate portion 212A is provided below each energy storage stack 11-16. The upper plate portion 212A may be formed in a flat plate shape. The upper plate portion 212A has a plurality of vulnerable portions 213 provided at positions facing each safety valve SV. In other words, the number of vulnerable portions 213 arranged along the first direction DR1 is the same as the number of energy storage cells 100 included in each energy storage stack 11-16.
[0023] The strength or rigidity of each weak portion 213 is less than the strength or rigidity of the upper plate portion 212A. In this embodiment, the thickness (vertical dimension) of each weak portion 213 is set to be less than the thickness of the upper plate portion 212A. As shown in Figure 3, the weak portion 213 may be provided below the upper plate portion 212A. In this example, the upper surface of the weak portion 213 is located below the upper surface of the upper plate portion 212A, and the lower surface of the weak portion 213 is formed flush with the lower surface of the upper plate portion 212A.
[0024] Figure 4 is a plan view of the weak portion 213. As shown in Figure 4, the weak portion 213 has a thin-walled portion 213a. The thin-walled portion 213a has a thickness smaller than the thickness of the other parts of the weak portion 213. When a load is applied to the weak portion 213 from above, the weak portion 213 ruptures starting from the thin-walled portion 213a.
[0025] 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 a plurality of through holes h provided at positions opposite each weak portion 213. The length of the through holes h in the first direction DR1 may be set to be the same as or slightly larger than the length of the weak portion 213 in the first direction DR1. The length of the through holes h in the second direction DR2 may be the same as or slightly larger than the length of the weak portion 213 in the second direction DR2.
[0026] 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 vulnerable part 213. 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[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] 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 will collide with the vulnerable part 213. As a result, the vulnerable part 213 will rupture, starting from the thin-walled part 213a, and the discharge containing the contents of the energy storage cell 100 (so-called debris) will flow into the exhaust gas path S through the through hole h. Subsequently, the gas contained in the discharge will spread through the exhaust gas path S and be 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.
[0042] Modifications of the above embodiment will be described below.
[0043] <First variation> As shown in Figure 5, the weak portion 213 may be provided on the upper part of the upper plate portion 212A. In this example, the upper surface of the weak portion 213 is formed flush with the upper surface of the upper plate portion 212A, and the lower surface of the weak portion 213 is located above the lower surface of the upper plate portion 212A.
[0044] <Second variation> As shown in Figure 6, the weak portion 213 may be provided in the lower plate portion 212B. In this example, the upper surface of the weak portion 213 is located below the upper surface of the lower plate portion 212B, and the lower surface of the weak portion 213 is formed flush with the lower surface of the lower plate portion 212B. A through hole h is also formed in the upper plate portion 212A.
[0045] Although not shown in the diagram, when the weak portion 213 is provided on the lower plate portion 212B, the upper surface of the weak portion 213 is formed flush with the upper surface of the lower plate portion 212B, and the lower surface of the weak portion 213 may be located above the lower surface of the lower plate portion 212B.
[0046] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.
[0047] [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 bottom wall has a plurality of weak points, each positioned opposite to one of the safety valves, in the energy storage device.
[0048] In this energy storage device, each vulnerable part ruptures upon impact with waste containing the contents of the energy storage cells (so-called debris), but does not rupture from the gas contained in that waste. Therefore, it is possible to protect the underside of the energy storage cells from gas while avoiding increased costs by omitting the need for insulating materials to protect the energy storage cells from gas.
[0049] [Aspect 2] 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 energy storage device according to embodiment 1, wherein each of the plurality of vulnerable parts is provided on the upper plate portion.
[0050] In this embodiment, the distance between the weak point and the safety valve is smaller compared to the case where the weak point is located on the lower plate, thus shortening the time required for the weak point to rupture.
[0051] [Aspect 3] The energy storage device according to embodiment 2, wherein the thickness of the weak portion is smaller than the thickness of the upper plate portion.
[0052] [Aspect 4] The upper surface of the weak portion is located below the upper surface of the upper plate portion. The energy storage device according to embodiment 3, wherein the lower surface of the weak portion is formed flush with the lower surface of the upper plate portion.
[0053] [Aspect 5] The energy storage device according to any one of embodiments 2 to 4, further comprising a surrounding member provided between each of the energy storage cells and the upper plate portion, and surrounding the vulnerable portion.
[0054] In this embodiment, the discharged material from the safety valve effectively strikes the vulnerable area.
[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, 212A Upper plate section, 212B Lower plate section, 213 Weak section, 213a Thin-walled section, 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, EV Explosion-proof valve, h Through hole, S Space (smoke exhaust path), SV Safety valve.
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 bottom wall has a plurality of weak points, each positioned opposite to one of the safety valves, in the energy storage device.
2. 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 energy storage device according to claim 1, wherein each of the plurality of vulnerable parts is provided on the upper plate portion.
3. The energy storage device according to claim 2, wherein the thickness of the weak portion is smaller than the thickness of the upper plate portion.
4. The upper surface of the weak portion is located below the upper surface of the upper plate portion. The lower surface of the fragile portion is formed flush with the lower surface of the upper plate portion, as described in claim 3.
5. The energy storage device according to any one of claims 2 to 4, further comprising a surrounding member provided between each of the energy storage cells and the upper plate portion, and surrounding the vulnerable portion.