Electricity storage device

Abstract

A power storage device is provided with a plurality of power storage stacks, a case, a pressure relief valve, and a breathing film. The shell comprises a bottom wall, a peripheral wall and an upper wall. The pressure relief valve is arranged on the upper wall. The breathing film is provided in the bottom wall and the peripheral wall at a position below the pressure relief valve.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a power storage device. BACKGROUND

[0002] For example, in Japanese Patent Application Publication No. 2023-47012, a battery pack is disclosed that includes a plurality of battery cells, a case that houses the plurality of battery cells, a pressure release valve provided to the case, and a breather membrane provided to the case. The case has a lower case and an upper cover. The pressure release valve is provided to the upper cover, and the breather membrane is provided to a side wall portion of the lower case. SUMMARY

[0003] In the battery pack described in Japanese Patent Application Publication No. 2023-47012, when the pressure in the case reaches a reference value due to gas generation from any of the battery cells, the gas is discharged through the pressure release valve. Thereafter, in order to adjust the internal pressure of the case, air flows into the case through the breather membrane.

[0004] At this time, in a case where a battery cell that is different from the battery cell from which the gas was first generated is generating heat, the air that has flowed into the case through the breather membrane comes into contact with the battery cell, and thus it is possible that the generation of heat is promoted in the case.

[0005] An object of the present disclosure is to provide a power storage device that can suppress the promotion of heat generation in a case.

[0006] An object of the present disclosure is to provide a power storage device that can suppress the promotion of heat generation in a case after gas discharge through a pressure release valve.

[0007] A power storage device according to an aspect of the present disclosure includes a plurality of power storage stacks arranged in a manner of being aligned in one direction; a case that houses the plurality of power storage stacks; a pressure release valve provided to the case; and a breather membrane provided to the case, the plurality of power storage stacks each having a plurality of power storage cells, the case including a bottom wall that supports the plurality of power storage stacks, a peripheral wall that surrounds the plurality of power storage stacks, and an upper wall that covers the plurality of power storage stacks, the pressure release valve being provided to the upper wall, and the breather membrane being provided to a portion of the bottom wall and the peripheral wall that is located lower than the pressure release valve.

[0008] The above and other objects, features, aspects, and advantages of the present utility model will become more apparent from the following detailed description of the present utility model with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a perspective view that schematically shows a power storage device in an embodiment of the present disclosure.

[0010] Figure 2 is a perspective view that schematically shows a power storage device in an embodiment of the present disclosure.Figure 1 The diagram shows the energy storage device with its top cover removed.

[0011] Figure 3 It is a top view that roughly shows the state of the battery with the top cover removed.

[0012] Figure 4 yes Figure 3 A cross-sectional view at line IV-IV.

[0013] Figure 5 yes Figure 3 A cross-sectional view at the VV line.

[0014] Figure 6 This is a top view that roughly shows a modified example of the configuration of the pressure relief valve and the breather membrane.

[0015] Figure 7 This is a top view that roughly shows a modified example of the configuration of the pressure relief valve and the breather membrane.

[0016] Figure 8 yes Figure 7 A cross-sectional view at line VIII-VIII.

[0017] Figure 9 This is a cross-sectional view that roughly represents a modified example of the opposing plate section. Detailed Implementation

[0018] Embodiments of this disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent components are labeled with the same reference numerals.

[0019] Figure 1 This is a perspective view schematically representing an embodiment of the energy storage device of the present disclosure. Figure 2 It is a general representation from Figure 1 The diagram shows the energy storage device with its top cover removed. Figure 3 It is a top view that roughly shows the state of the battery with the top cover removed. Figure 4 yes Figure 3 A cross-sectional view at line IV-IV. Figure 5 yes Figure 3 A cross-sectional view at the VV line. The energy storage device 1 is, for example, mounted on the bottom of the vehicle.

[0020] like Figures 1 to 5 As shown, the energy storage device 1 includes multiple first energy storage stacks 110, multiple second energy storage stacks 120, a first busbar 210, a second busbar 220, a first junction box 310, a second junction box 320, a housing 500, a pressure relief valve 600, and a breathing membrane 700.

[0021] A plurality of first energy storage stacks 110 are arranged in a first direction. In this embodiment, the plurality of first energy storage stacks 110 includes six first energy storage stacks 110. However, the number of first energy storage stacks 110 is not limited to six. Each first energy storage stack 110 is formed into a cuboid shape that is longer in a second direction orthogonal to both the first direction and the vertical direction. The first energy storage stack 110 is an example of an "energy storage stack" in this disclosure. In addition, the first direction is an example of a "direction" in this disclosure, and the orthogonal direction is an example of a "second direction" in this disclosure.

[0022] Each first energy storage stack 110 includes multiple energy storage units 111 (see reference). Figure 4 Multiple energy storage cells 111 are arranged, for example, in a first direction. Alternatively, the multiple energy storage cells 111 may be arranged in a second direction. Each energy storage cell 111 is formed in a flat cuboid shape. Examples of each energy storage cell 111 include lithium-ion batteries. Each energy storage cell 111 may also be constituted as an all-solid-state battery using a solid electrolyte. Figure 4 As shown, each energy storage unit 111 includes a safety valve 111a disposed on the upper surface of the housing of the energy storage unit 111.

[0023] A plurality of second energy storage stacks 120 are configured to face the plurality of first energy storage stacks 110 in a second direction and to be arranged in a first direction. In this embodiment, the plurality of second energy storage stacks 120 includes six second energy storage stacks 120. However, the number of second energy storage stacks 120 is not limited to six. The structure of each second energy storage stack 120 is the same as the structure of the first energy storage stack 110. The second energy storage stack 120 is an example of "other energy storage stacks" in this disclosure.

[0024] The first busbar 210 connects a pair of adjacent first energy storage stacks 110 in a first direction. The second busbar 220 connects a pair of adjacent second energy storage stacks 120 in a first direction. The first busbar 210 and the second busbar 220 are arranged in the space between the plurality of first energy storage stacks 110 and the plurality of second energy storage stacks 120. Additionally, in Figure 3 The illustrations of the first busbar 210 and the second busbar 220 are omitted in the text.

[0025] The first junction box 310 is positioned opposite to a plurality of first energy storage stacks 110 in a first direction. More specifically, the first junction box 310 is positioned opposite the outermost first energy storage stack 110 in the first direction. The first junction box 310 houses relays, fuses, etc. The first junction box 310 has a first connector 312. The first connector 312 protrudes outward in the first direction.

[0026] The second junction box 320 is positioned opposite the plurality of second energy storage stacks 120 in a first direction and spaced apart from the first junction box 310 in a second direction. The second junction box 320 houses relays, fuses, etc. The second junction box 320 has a second connector 322. The second connector 322 protrudes outward in the first direction.

[0027] The housing 500 houses a plurality of first energy storage stacks 110, a plurality of second energy storage stacks 120, a first busbar 210, a second busbar 220, a first junction box 310, and a second junction box 320. The housing 500 includes a side space S1 formed on one side of the plurality of first energy storage stacks 110 and the plurality of second energy storage stacks 120 in a first direction. Each junction box 310, 320 is disposed in this side space S1. The housing 500 has a lower housing 510 and an upper cover 520.

[0028] The lower housing 510 opens upwards. The lower housing 510 has a bottom wall 512, a peripheral wall 514, and a partition 516.

[0029] The bottom wall 512 supports each energy storage stack 110 and 120. For example... Figures 3 to 5 As shown, the bottom wall 512 includes a middle portion 512a located below the inter-box space S2 between the first junction box 310 and the second junction box 320. The inter-box space S2 is part of one side space S1.

[0030] The peripheral wall 514 rises from the periphery of the base wall 512. The peripheral wall 514 surrounds a plurality of first energy storage stacks 110 and a plurality of second energy storage stacks 120. The peripheral wall 514 is formed in a generally square cylindrical shape.

[0031] The peripheral wall 514 includes a side wall 514a facing each of the energy storage stacks 110, 120 in a first direction. The side wall 514a faces each of the energy storage stacks 110, 120 in the first direction across a space S1 on one side. The side wall 514a extends along a second direction. The side wall 514a is inclined in such a way that it gradually moves away from each of the energy storage stacks 110, 120 as it faces upward. However, the side wall 514a may also be orthogonal to the bottom wall 512.

[0032] A separator 516 separates the plurality of first energy storage stacks 110 from the plurality of second energy storage stacks 120. The separator 516 has a shape extending along a first direction. The height of the separator 516 is lower than the height of the peripheral wall 514. Figure 2 As shown, busbars 210 and 220 are arranged on the partition 516.

[0033] The upper cover 520 and the lower housing 510 together house multiple first energy storage stacks 110, multiple second energy storage stacks 120, a first busbar 210, a second busbar 220, a first junction box 310, and a second junction box 320. The periphery of the upper cover 520 is fixed to the upper end of the peripheral wall 514 by bolts or the like.

[0034] The top cover 520 has an upper wall 522. The upper wall 522 faces the bottom wall 512. The upper wall 522 covers a plurality of first energy storage stacks 110, a plurality of second energy storage stacks 120, a first busbar 210, a second busbar 220, a first junction box 310, and a second junction box 320.

[0035] A pressure relief valve 600 is provided in the housing 500. The pressure relief valve 600 releases pressure within the housing 500. The pressure relief valve 600 opens when the pressure within the housing 500 reaches a reference value. The pressure relief valve 600 is constructed from a check valve. The pressure relief valve 600 is provided on the upper wall 522 of the upper cover 520. Preferably, the pressure relief valve 600 is located above one side space S1 in the upper wall 522. In this embodiment, the pressure relief valve 600 is located above the inter-box space S2 in the upper wall 522.

[0036] A breathing membrane 700 is disposed on the housing 500. The breathing membrane 700 adjusts the pressure inside the housing 500 by allowing gas to pass between the inside and outside of the housing 500. The breathing membrane 700 is disposed in the bottom wall 512 and the peripheral wall 514 at a position lower than the pressure relief valve 600. In this embodiment, the breathing membrane 700 is disposed on the bottom wall 512. The breathing membrane is preferably disposed in the bottom wall 512 at a position lower than one side space S1. Specifically, the breathing membrane 700 is disposed in the middle portion 512a of the bottom wall 512. A through hole is provided in the middle portion 512a, and the breathing membrane 700 is mounted on the outer side of the middle portion 512a to cover the through hole. Figures 3 to 5 As shown, at least a portion of the breathing membrane 700 may overlap with the projection plane of the pressure relief valve 600. Alternatively, the entire area of ​​the breathing membrane 700 may overlap with the projection plane of the pressure relief valve 600.

[0037] In the energy storage device 1 described above, for example, when gas is generated from one energy storage cell 111 and the internal pressure of the housing 500 reaches or exceeds a reference value, the gas is discharged from the pressure relief valve 600 to the outside of the housing 500. At this time, the contents of the energy storage cell 111 contained in the gas discharged from the pressure relief valve 600 (so-called fragments) accumulate on the breathing membrane 700, which is located below the pressure relief valve 600, and thus the breathing membrane 700 is blocked. Therefore, the inflow of air through the breathing membrane 700 into the housing 500 after the gas is discharged through the pressure relief valve 600 is suppressed. Therefore, even if a different energy storage cell 111 (e.g., an energy storage cell 111 adjacent to one of the aforementioned energy storage cells 111) heats up, the promotion of heat generation in the housing 500 caused by the inflow of air into the housing 500 can be suppressed.

[0038] Hereinafter, variations of the above-described embodiments will be described.

[0039] <First Variation>

[0040] like Figure 6 As shown, the pressure relief valve 600 can also be located above the space outside each junction box 310, 320 in the second direction of the side space S1 in the upper wall 522. In this case, the breathing membrane 700 is preferably located at a position where at least a portion of the breathing membrane 700 overlaps with the projected surface of the pressure relief valve 600.

[0041] <Second Variation>

[0042] like Figure 7 and Figure 8 As shown, the breathing membrane 700 can also be disposed on the side wall 514a. In this case, the energy storage device 1 preferably also includes an opposing plate portion 800. The opposing plate portion 800 is disposed within the housing 500 and is opposite to each energy storage stack 110, 120 in a first direction. The opposing plate portion 800 forms a stacking space S3 between the opposing plate portion 800 and the side wall 514a (see reference). Figure 8 In this example, the portions of each junction box 310, 320 that face the side wall 514a constitute the opposing plate portion 800.

[0043] In this method, debris accumulates in the accumulation space S3, thereby blocking the breathing membrane 700.

[0044] <Third Variation>

[0045] like Figure 9 As shown, the opposing plate portion 800 can also be constructed from components different from those in each junction box 310, 320. In this example, the opposing plate portion 800 is connected to the portion of the side wall 514a below the through hole formed opposite to the breathing membrane 700 by welding or the like.

[0046] Those skilled in the art will understand that the above exemplary embodiments are specific examples of the following approaches.

[0047] [Method 1]

[0048] An energy storage device, comprising:

[0049] Multiple energy storage stacks are configured to be arranged in one direction;

[0050] A housing that contains the plurality of energy storage stacks;

[0051] A pressure relief valve, disposed in the housing, releases pressure within the housing; and

[0052] A breathing membrane, disposed within the housing, adjusts the pressure within the housing by allowing the passage of gas between the inside and outside of the housing.

[0053] Each of the multiple energy storage stacks has multiple energy storage units.

[0054] The housing includes:

[0055] The bottom wall supports the plurality of energy storage stacks;

[0056] The surrounding walls enclose the plurality of energy storage stacks; and

[0057] The upper wall covers the multiple energy storage stacks.

[0058] The pressure relief valve is located on the upper wall.

[0059] The breathing membrane is disposed in the bottom wall and the peripheral wall at a position lower than the pressure relief valve.

[0060] In this energy storage device, the contents of the energy storage unit (so-called fragments) contained in the gas generated from the energy storage unit and discharged from the pressure relief valve accumulate on the breathing membrane located below the pressure relief valve, thus clogging the breathing membrane. Therefore, the inflow of air through the breathing membrane into the housing after the gas is discharged through the pressure relief valve, and the resulting heating within the housing, are suppressed.

[0061] [Method 2]

[0062] According to the energy storage device of method 1, the breathing membrane is disposed on the bottom wall.

[0063] In this method, debris accumulates more effectively on the respiratory membrane.

[0064] [Method 3]

[0065] The energy storage device according to method 2 further comprises:

[0066] Multiple other energy storage stacks are configured to face the multiple energy storage stacks and be arranged along the one direction in an orthogonal direction orthogonal to both the one direction and the up and down directions;

[0067] A first junction box is configured in a position opposite to the plurality of energy storage stacks in the said one direction; and

[0068] The second junction box is positioned opposite the plurality of other energy storage stacks in one direction and spaced apart from the first junction box in the orthogonal direction.

[0069] The bottom wall includes a central portion located below the space between the first junction box and the second junction box.

[0070] The breathing membrane is disposed in the middle part.

[0071] In this method, debris accumulates between the first and second junction boxes, i.e., in the middle, thus further promoting the blockage of the breathing membrane.

[0072] [Method 4]

[0073] According to the energy storage device of method 1, wherein...

[0074] It also includes an opposing plate portion disposed within the housing and facing the plurality of energy storage stacks in one direction.

[0075] The peripheral wall includes sidewalls that face the plurality of energy storage stacks in one direction and slope toward the plurality of energy storage stacks in a manner that gradually moves away from them as the orientation toward the top.

[0076] The breathing membrane is disposed on the side wall.

[0077] The opposing plate portion forms an accumulation space between the opposing plate portion and the side wall.

[0078] In this method, debris accumulates in the accumulation space, thereby blocking the breathing membrane.

[0079] [Method 5]

[0080] According to the energy storage device described in method 4, wherein...

[0081] It also includes a junction box configured between the plurality of energy storage stacks and the sidewall.

[0082] The junction box includes the opposing plate portion.

[0083] In this method, part of the junction box also serves as the opposing plate, thus reducing the number of components compared to the case where a dedicated opposing plate is provided.

[0084] [Method 6]

[0085] The energy storage device according to any one of methods 1 to 5, wherein...

[0086] At least a portion of the breathing membrane overlaps with the projection surface of the pressure relief valve.

[0087] In this method, as gas is discharged from the pressure relief valve, the debris that falls due to the collision with the pressure relief valve accumulates efficiently on the breathing membrane.

[0088] While embodiments of the present invention have been described, it should be considered that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

Claims

1. An electric power storage device, characterized by comprising: Possessing: a plurality of electricity storage stacks arranged in a manner of being aligned in one direction; a case that houses the plurality of electricity storage stacks; a pressure release valve provided to the case; and a breather membrane provided to the case, the plurality of electricity storage stacks each have a plurality of electricity storage units, the case includes: a bottom wall that supports the plurality of electricity storage stacks; a peripheral wall that surrounds the plurality of electricity storage stacks; and an upper wall that covers the plurality of electricity storage stacks, the pressure release valve is provided to the upper wall, the breather membrane is provided to a portion of the bottom wall and the peripheral wall that is located lower than the pressure release valve.

2. The electricity storage device according to claim 1, wherein the breather membrane is provided to the bottom wall. Further possessing:

3. The power storage device according to claim 2, wherein a plurality of other electricity storage stacks arranged in a manner of being aligned in the one direction in opposition to the plurality of electricity storage stacks in an orthogonal direction that is orthogonal to both the one direction and a vertical direction; a first junction box arranged at a position in opposition to the plurality of electricity storage stacks in the one direction; and a second junction box arranged at a position in opposition to the plurality of other electricity storage stacks in the one direction and in opposition to the first junction box in the orthogonal direction at a position spaced apart by an interval, the bottom wall includes an intermediate portion that is located below a space between the first junction box and the second junction box, the breather membrane is provided to the intermediate portion.

4. The electricity storage device according to claim 1, wherein further possessing an opposing plate portion provided within the case in opposition to the plurality of electricity storage stacks in the one direction, the peripheral wall includes a side wall that is in opposition to the plurality of electricity storage stacks in the one direction and that is inclined in a manner of gradually moving away from the plurality of electricity storage stacks as moving toward the upper direction, the breather membrane is provided to the side wall, the opposing plate portion forms a stacking space between the opposing plate portion and the side wall.

5. The electricity storage device according to claim 4, wherein further possessing a junction box arranged between the plurality of electricity storage stacks and the side wall, the junction box includes the opposing plate portion.

6. The electricity storage device according to any one of claims 1 to 5, wherein at least a portion of the breather membrane overlaps a projection surface of the pressure release valve. ​

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