ENERGY STORAGE DEVICE

Abstract

An energy storage device comprises the following: a plurality of energy storage cells arranged along a single direction; a bottom wall arranged beneath the energy storage cells; and a plate element positioned beneath the bottom wall, which, together with the bottom wall, defines a smoke extraction path. A safety valve is provided in a lower surface of each energy storage cell. The bottom wall comprises a plurality of breakable sections positioned opposite each safety valve.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to an energy storage device. 2. Explanation of the state of the art

[0002] Japanese unpublished patent application No. 2023-126584 (JP 2023-126584 A) discloses, for example, a battery comprising multiple cells, a housing that contains the cells, a protective element that protects a base area of ​​the housing, and a cover. Each cell includes a box that contains an electrode assembly. A relief mechanism is provided in a base surface of the box. Exhaust gases exiting the relief mechanism flow into a collection cavity formed between the base section of the housing and the protective element. BRIEF EXPLANATION OF THE INVENTION

[0003] In the battery described in JP 2023-126584 A, a thermal insulation element made of mica or similar material may be arranged on a portion of the base of the casing facing the relief mechanism to protect the underside of the cells from gases contained in the cell exhaust. However, the cost of the thermal insulation element increases with the number of cells.

[0004] The objective of the present disclosure is to provide an energy storage device that can protect the underside of energy storage cells from a gas, while suppressing a significant increase in cost.

[0005] One aspect of the present disclosure provides for an energy storage device comprising: a plurality of energy storage cells arranged along a direction; a bottom wall arranged below the energy storage cells; and a plate element provided below the bottom wall, which together with the bottom wall defines a smoke vent path, wherein: a safety valve is provided in a lower surface of each of the energy storage cells; and the bottom wall comprises several breakable sections, each provided at a position facing the safety valve.

[0006] According to the present disclosure, an energy storage device is provided which is able to protect the underside of energy storage cells from a gas while suppressing a significant increase in costs. BRIEF EXPLANATION OF THE FIGURES

[0007] Features, advantages and the technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying figures, in which the same reference numerals denote the same elements, and in which: Fig. 1 is a perspective view that schematically represents an energy storage device according to an embodiment of the present disclosure; Fig. 2 is a top view schematically showing a state in which a top cover has been removed from the energy storage device; Fig. 3 a sectional view along line III-III in Fig. 2 is; Fig. 4 is a top view of a fragile section; Fig. 5 is a cross-sectional view that schematically represents a modification of a floor wall and fragile sections; and Fig. Figure 6 is a cross-sectional view that schematically represents a modification of a floor wall and fragile sections. DETAILED EXPLANATION OF EXECUTION FORMS

[0008] One embodiment of the present disclosure is described with reference to the figures. In the figures mentioned below, identical or corresponding elements are designated with the same reference numerals.

[0009] Fig. Figure 1 is a perspective view schematically representing an energy storage device according to an embodiment of the present disclosure. Fig. Figure 2 is a top view schematically representing a state in which a top cover has been removed from the energy storage device. Fig. 3 is a sectional view along line III-III in Fig. 2.

[0010] An energy storage device 10 according to the present embodiment is, for example, installed in a lower part of a vehicle. The vehicle is, for example, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a battery electric vehicle.

[0011] As in the Fig. 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 element 290, devices 300, a device cooler 350, and a cooling or refrigerant line 400. The number of energy storage stacks is not limited to six.

[0012] Each of the energy storage stacks 11 to 16 is designed in the form of a rectangular parallelepiped, which is elongated in a first direction DR1. As shown in Fig. As shown in Figure 2, the six energy storage stacks 11 to 16 are arranged side by side along a second direction DR2, which is orthogonal to both the first direction DR1 and the up-down direction. In the present embodiment, the first direction DR1 corresponds to the front-to-rear direction or longitudinal direction of the vehicle, and the second direction DR2 corresponds to the right-to-left direction (lateral direction) of the vehicle. Each of the energy storage stacks 11 to 16 comprises at least one energy storage cell 100. In the present embodiment, each of the energy storage stacks 11 to 16 comprises a plurality of energy storage cells 100 and a plurality of cooling plates 150.

[0013] The 100 energy storage cells are arranged side by side along the first direction DR1. As shown in Fig. As shown in Figure 3, each of the energy storage cells 100 comprises an electrode body 112, a cell housing 114 and a pair of external terminals 116.

[0014] The electrode body 112 can consist of a wound body in which a positive electrode foil and a negative electrode foil are wound over a separator, or of a stacked body in which a positive electrode foil and a negative electrode foil are stacked over a separator. The electrode body 112 is shaped such that it is elongated in the second direction DR2.

[0015] The cell housing 114 accommodates the electrode body 112. The cell housing 114 is designed in a rectangular parallelepiped shape. The cell housing 114 is made of a metal such as aluminum. A safety valve SV is provided in a lower surface of the cell housing 114.

[0016] The external connections 116 are provided on a top surface of the cell housing 114. The external connections 116 are located at spaced-apart positions along the width of the cell housing 114. The width of the cell housing 114 corresponds to the second direction DR2.

[0017] As in Fig. As shown in Figure 3, each of the cooling plates 150 is arranged between a pair of energy storage cells 100, which are positioned side by side in the first direction DR1. Each of the cooling plates 150 is designed in the form of a flat plate that extends in the second direction DR2. Each of the cooling plates 150 has a flow path (not shown) through which a coolant flows along the second direction DR2.

[0018] The housing 200 accommodates the six energy storage stacks 11 to 16. As in the Fig. As shown in Figures 1 to 3, the housing 200 comprises a lower housing 210, an upper cover 220 and a plate element 230.

[0019] The lower housing 210 is open at the top. The lower housing 210 can be made of a metal such as aluminum. The lower housing 210 comprises a bottom wall 212, a perimeter wall 214, and a pair of partition walls 216.

[0020] The base wall 212 is located below the energy storage stacks 11 to 16. As in Fig. As shown in Figure 3, the bottom wall 212 is hollow. The bottom wall 212 can be manufactured by extrusion. The bottom wall 212 comprises an upper plate section 212A and a lower plate section 212B.

[0021] The upper plate section 212A is located below the energy storage stacks 11 to 16. The upper plate section 212A can be in the form of a flat plate. The upper plate section 212A has several breakable sections 213 located opposite each safety valve SV. That is, the number of breakable sections 213 arranged along the first direction DR1 is equal to the number of energy storage cells 100 contained in each of the energy storage stacks 11 to 16.

[0022] The strength or stiffness of each of the fragile sections 213 is less than the strength or stiffness of the upper plate section 212A. In the present embodiment, the thickness (dimension in the up-down direction) of each of the fragile sections 213 is less than the thickness of the upper plate section 212A. As shown in Fig. As shown in Figure 3, the fragile sections 213 can be provided in a lower part of the upper plate section 212A. In this example, the upper surface of the fragile sections 213 is located below the upper surface of the upper plate section 212A, and the lower surface of the fragile sections 213 is flush with the lower surface of the upper plate section 212A.

[0023] Fig. Figure 4 is a top view of the fragile section 213. As in Fig. As shown in Figure 4, the fragile section 213 includes a thin section 213a. The thin section 213a has a thickness that is less than the thickness of a section of the fragile section 213 that is not the thin section 213a. When a load is applied from above to the fragile section 213, the fragile section 213 fractures, beginning with the thin section 213a.

[0024] The lower plate section 212B is located below the upper plate section 212A. The lower plate section 212B can be in a flat plate shape. The lower plate section 212B has a plurality of through holes h located opposite the breakable sections 213. The length of the through hole h in the first direction DR1 can be equal to or slightly greater than the length of the breakable section 213 in the first direction DR1. The length of the through hole h in the second direction DR2 can be equal to or slightly greater than the length of the breakable section 213 in the second direction DR2.

[0025] The surrounding element 290 is positioned between the lower surface of the energy storage cells 100 and the upper surface of the base wall 212. The surrounding element 290 is shaped to enclose the fragile sections 213. The surrounding element 290 is made of a plastic, a metal, or the like. The surrounding element 290 may be in contact with the lower surface of the cooling plates 150.

[0026] The perimeter wall 214 projects from the circumferential edge section of the base wall 212. The perimeter wall 214 is shaped to surround the energy storage stacks 11 to 16. The perimeter wall 214 may be hollow. The perimeter wall 214 comprises a front wall 214a and a pair of side walls 214b.

[0027] The front wall 214a is on one side (in Fig. 2 on the left side) the energy storage stacks 11 to 16 are formed in the first direction DR1. The front wall 214a extends in the second direction DR2. In the present embodiment, one side in the first direction DR1 corresponds to the front in the front-to-rear direction of the vehicle.

[0028] The side walls 214b are positioned opposite each other in the second direction DR2 at a distance. The side walls 214b extend in the first direction DR1. An end section (front end section) of each of the side walls 214b on one side in the first direction DR1 is connected to the front wall 214a.

[0029] The partitions 216 divide a space enclosed by the bottom wall 212 and the perimeter wall 214 into a space in which the energy storage stacks 11 to 16 are arranged, and the other space. The partitions 216 are spaced apart from each other in the first direction DR1. The partitions 216 extend in the second direction DR2. The partitions 216 may be hollow. The function of the partitions 216 is to contain the energy storage stacks 11 to 16 from both sides in the first direction DR1. As shown in Fig. As shown in Figure 2, the end sections of the partition 216, which is formed on one side (front) in the first direction DR1, are spaced apart from the respective side walls 214b in the second direction DR2. The end sections of the partition 216, which are formed on the other side (rear) in the second direction DR2, are connected to the respective side walls 214b in the first direction DR1.

[0030] The upper cover 220 is arranged over the energy storage stacks 11 to 16. The upper cover 220, together with the lower housing 210, accommodates the six energy storage stacks 11 to 16. Specifically, the upper cover 220, together with the lower housing 210, accommodates the six energy storage stacks 11 to 16 in a sealed configuration. The circumferential edge region of the upper cover 220 is connected to the upper end region of the circumferential wall 214 by means of bolts, screws, or the like, via a sealing element.

[0031] The plate element 230 is located below the lower housing 210. The plate element 230 serves to protect the bottom wall 212 of the lower housing 210. The plate element 230 can be designed in the form of a flat plate. The circumferential edge of the plate element 230 is connected to the lower surface of the lower housing 210 via a sealing element.

[0032] As in Fig. As shown in Figure 3, a space S is formed between the plate element 230 and the bottom wall 212. The space S functions as a smoke extraction path (hereinafter referred to as "smoke extraction path S"). The smoke extraction path S is a path for venting gas released from the safety valve SV of the energy storage cell 100 to the outside, out of the housing 200.

[0033] As in the Fig. 2 and Fig. As shown in Figure 3, a smoke extraction duct section 218 is formed on the circumferential wall 214. The smoke extraction duct section 218 extends upwards from the bottom wall 212. The smoke extraction duct section 218 conveys gas from the smoke extraction path S upwards. An explosion-proof valve EV is provided at the downstream end section of the smoke extraction duct section 218. The explosion-proof valve EV relieves the pressure in the housing 200. The explosion-proof valve EV opens when the pressure in the housing 200 becomes equal to or greater than a reference value. The explosion-proof valve EV consists of a check valve. As shown in Fig. As shown in Figure 3, when a gas escapes from one of the energy storage cells 100, it spreads in the first direction DR1 through the smoke extraction path S and is discharged outwards from the housing 200 through the smoke extraction duct section 218 and the explosion-proof valve EV.

[0034] The devices 300 are housed in the casing 200. As in Fig. As shown in Figure 2, the devices 300 are arranged on the other side of the lower housing 210 in the first direction DR1, i.e., in a space formed between the partition 216, which is formed on the other side (rear) in the first direction DR1, and the circumferential wall 214. The devices 300 may include a junction box. The devices 300 may include a relay, a control device, and the like.

[0035] The device cooler 350 cools the devices 300. As in the Fig. 2 and Fig. As shown in Figure 3, the device cooler 350 is provided between the base wall 212 and the devices 300. A thermally conductive adhesive 900 can be provided between the device cooler 350 and the base wall 212.

[0036] The refrigerant line 400 is routed inside the housing 200. The refrigerant line 400 is connected to the cooling plates 150 and the device cooler 350. As shown in the Fig. 1 and Fig. As shown in Figure 2, the front wall 214a of the circumferential wall 214 is provided with an inlet opening 181 and an outlet opening 182. The refrigerant line 400 is connected to the inlet opening 181 and the outlet opening 182. Therefore, the cooling or refrigerant (such as water or oil) supplied by the inlet opening 181 flows through the refrigerant line 400 into the cooling plates 150 and the device cooler 350, cools the energy storage cells 100 and the devices 300, and then flows out of the outlet opening 182 through the refrigerant line 400.

[0037] As in Fig. As shown in Figure 2, the refrigerant line 400 comprises an upstream line 410 and a downstream line 420.

[0038] The upstream end section of the upstream line 410 is connected to the inlet opening 181. The downstream end section of the upstream line 410 is connected to an end section of the device cooler 350 in the second direction DR2. The upstream line 410 is routed between the front wall 214a and the partition wall 216, which are formed on one side in the first direction DR1, and between the energy storage stack 11, which is arranged on one side in the second direction DR2, and the side wall 214b. The upstream line 410 is connected to an end section of each of the cooling plates 150 in the second direction DR2.

[0039] The upstream end section of the downstream pipe 420 is connected to the other end section of the device cooler 350 in the second direction DR2. The downstream end section of the downstream pipe 420 is connected to the outlet opening 182. The downstream pipe 420 is routed between the front wall 214a and the partition wall 216, which are formed on one side in the first direction DR1, and between the energy storage stack 16, which is arranged on the other side in the second direction DR2, and the side wall 214b. The downstream pipe 420 is connected to the other end section of each of the cooling plates 150 in the second direction DR2.

[0040] In the energy storage device 10 described above, when the exhaust gas escapes downwards from the safety valve SV in one of the energy storage cells 100 due to a short circuit or similar event, it collides with the fragile section 213. The fragile section 213 then breaks, starting with the thin section 213a, and consequently the exhaust gas, containing the contents (so-called debris) of the energy storage cell 100, flows through the through-hole h into the flue gas duct S. The gas contained in the exhaust gas then disperses in the flue gas duct S and is discharged from the housing 200 through the explosion-proof valve EV, as shown in Fig. Figure 3 is shown. This prevents the contents of the energy storage cell 100 from adhering to the external connections 116 and the like.

[0041] Modifications to the above embodiment are described below. First modification

[0042] As in Fig. As shown in Figure 5, the fragile sections 213 can be provided in an upper part of the upper plate section 212A. In this example, the top surface of the fragile sections 213 is flush with the top surface of the upper plate section 212A, and the bottom surface of the fragile sections 213 is located above the bottom surface of the upper plate section 212A. Second modification

[0043] As in Fig. As shown in Figure 6, the fragile sections 213 can be provided in the lower plate section 212B. In this example, the upper surface of the fragile sections 213 is located below the upper surface of the lower plate section 212B, and the lower surface of the fragile sections 213 is flush with the lower surface of the lower plate section 212B. Furthermore, through holes h are formed in the upper plate section 212A.

[0044] Although not shown in the figures, the top surface of the fragile sections 213 can be flush with the top surface of the lower plate section 212B and the bottom surface of the fragile sections 213 can be arranged above the bottom surface of the lower plate section 212B when the fragile sections 213 are provided in the lower plate section 212B.

[0045] It will be clear to those skilled in the art that the exemplary embodiment described above is a specific example of the following aspects. First aspect

[0046] An energy storage device comprising the following: a large number of energy storage cells arranged along one direction; a floor wall located below the energy storage cells; and a panel element that is provided below the floor wall and, together with the floor wall, defines a smoke extraction path, wherein: a safety valve is provided in a lower surface of each of the energy storage cells; and The bottom wall comprises several fragile sections, each located in a position opposite the safety valve.

[0047] In this energy storage device, the fragile sections break when struck by exhaust gases containing debris from the energy storage cell, but they do not break due to the gas contained in the exhaust gases. Therefore, it is possible to protect the bottom surface of the energy storage cells from the gas while simultaneously reducing costs by omitting a thermal insulation element to protect the energy storage cells from the gas. Second aspect

[0048] The energy storage device according to the first aspect, wherein: The floor wall includes the following: an upper plate section that is provided below the energy storage cells, and a lower plate section that is provided below the upper plate section; and Each of the fragile sections is provided in the upper plate section.

[0049] In this respect, the distance between the fragile sections and the safety valves is less than if the fragile sections were located in the lower plate section, thus reducing the time it takes for the fragile sections to break. Third aspect

[0050] The energy storage device according to the second aspect, wherein the thickness of the fragile sections is less than the thickness of the upper plate section. Fourth aspect

[0051] The energy storage device according to the third aspect, wherein: a top side of the fragile sections is arranged below a top side of the upper plate section; and The underside of the fragile sections is flush with a lower surface of the upper plate section. Fifth aspect

[0052] The energy storage device according to one of the second to fourth aspects, which further comprises a surrounding element provided between each of the energy storage cells and the upper plate section, surrounding the fragile sections.

[0053] In this respect, the exhaust gas expelled from the safety valve effectively collides with the fragile section.

[0054] The embodiment disclosed herein should in every respect be considered exemplary and not limiting. The scope of this disclosure is defined by the claims and not by the preceding description of the embodiment, and further includes all modifications that fall within the meaning and scope of the claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-126584 A [0002, 0003]

Claims

Energy storage device comprising: a plurality of energy storage cells arranged along one direction; a bottom wall arranged below the energy storage cells; and a plate element provided below the bottom wall which, together with the bottom wall, defines a smoke extraction path, wherein a safety valve is provided in a lower surface of each of the energy storage cells; and the bottom wall has several breakable sections, each provided at a position opposite the safety valve. Energy storage device according to claim 1, wherein the bottom wall comprises: an upper plate section provided below the energy storage cells, and a lower plate section provided below the upper plate section; and each of the breakable sections is provided in the upper plate section. Energy storage device according to claim 2, wherein the thickness of the fragile sections is less than the thickness of the upper plate section. Energy storage device according to claim 3, wherein a top side of the fragile sections is arranged below a top side of the upper plate section; and a bottom side of the fragile sections is flush with a bottom side of the upper plate section. Energy storage device according to one of claims 2 to 4, further comprising a surrounding element that is provided between each of the energy storage cells and the upper plate section and surrounds the fragile sections.

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