Power storage device

Abstract

To provide a power storage device capable of suppressing heat generation within a case after gas is discharged through a pressure relief valve.SOLUTION: A power storage device 1 includes a plurality of power storage stacks 110, a case 500, a pressure relief valve 600, and a breathing membrane 700. The case 500 includes a bottom wall 512, a peripheral wall 514, and a top wall 522. The pressure relief valve 600 is provided in the top wall. The breathing membrane 700 is provided in a portion of the bottom wall and the peripheral wall that is located below the pressure relief valve.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an electricity storage device. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2023-47012 discloses a battery pack including a plurality of battery cells, a case for accommodating the plurality of battery cells, a pressure release valve provided in the case, and a breather membrane provided in the case. The case has a lower case and an upper cover. The pressure release valve is provided in the upper cover, and the breather membrane is provided in a side wall portion of the lower case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-47012 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack described in JP 2023-47012 A, when gas is generated from one of the battery cells and the pressure inside the case reaches a reference value, the gas is released through the pressure release valve, and then air flows into the case through the breathing membrane to adjust the internal pressure of the case.

[0005] At this time, if a battery cell other than the battery cell from which gas was previously generated is generating heat, there is a concern that the air flowing into the case through the breathing membrane will come into contact with that battery cell, thereby promoting heat generation within the case.

[0006] An object of the present disclosure is to provide an electricity storage device that can suppress the promotion of heat generation inside the case.

[0007] An object of the present disclosure is to provide an electricity storage device that can suppress the promotion of heat generation inside the case after gas is discharged through a pressure release valve. [Means for solving the problem]

[0008] An energy storage device according to one aspect of the present disclosure comprises a plurality of energy storage stacks arranged in a line in one direction, a case accommodating the plurality of energy storage stacks, a pressure release valve provided in the case, and a breather membrane provided in the case, wherein each of the plurality of energy storage stacks has a plurality of energy storage cells, the case including a bottom wall supporting the plurality of energy storage stacks, a peripheral wall surrounding the plurality of energy storage stacks, and a top wall covering the plurality of energy storage stacks, the pressure release valve being provided in the top wall, and the breather membrane being provided in portions of the bottom wall and the peripheral wall that are located below the pressure release valve. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide an electricity storage device that can suppress the promotion of heat generation inside the case after gas is discharged through the pressure release valve. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view schematically illustrating a power storage device according to an embodiment of the present disclosure. [Figure 2] 2 is a perspective view schematically illustrating a state in which an upper cover is removed from the electricity storage device illustrated in FIG. 1. FIG. [Figure 3] FIG. 2 is a plan view schematically showing a state in which an upper cover is removed from the power storage device. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 10 is a plan view schematically showing a modified example of the arrangement of the pressure release valve and the breathing membrane. [Figure 7]FIG. 10 is a plan view schematically showing a modified example of the arrangement of the pressure release valve and the breathing membrane. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. [Figure 9] FIG. 10 is a cross-sectional view schematically showing a modified example of the opposing plate portion. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0012] Fig. 1 is a perspective view that schematically shows an electricity storage device according to an embodiment of the present disclosure. Fig. 2 is a perspective view that schematically shows a state in which an upper cover is removed from the electricity storage device shown in Fig. 1. Fig. 3 is a plan view that schematically shows a state in which the upper cover is removed from the electricity storage device. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. This electricity storage device 1 is mounted, for example, on the bottom of a vehicle.

[0013] As shown in Figures 1 to 5, the energy storage device 1 includes a plurality of first energy storage stacks 110, a plurality of second energy storage stacks 120, a first bus bar 210, a second bus bar 220, a first junction box 310, a second junction box 320, a case 500, a pressure release valve 600, and a breathing membrane 700.

[0014] The multiple first power storage stacks 110 are arranged side by side in a first direction. In this embodiment, the multiple first power storage stacks 110 include six first power storage stacks 110. However, the number of first power storage stacks 110 is not limited to six. Each first power storage stack 110 is formed in a rectangular parallelepiped shape that is long in a second direction that is perpendicular to both the first direction and the up-down direction. The first power storage stack 110 is an example of a "power storage stack" in the present disclosure. Furthermore, the first direction is an example of a "one direction" in the present disclosure, and the perpendicular direction is an example of a "second direction" in the present disclosure.

[0015] Each first power storage stack 110 includes a plurality of power storage cells 111 (see FIG. 4). The plurality of power storage cells 111 are arranged, for example, to be aligned in a first direction. The plurality of power storage cells 111 may also be arranged to be aligned in a second direction. Each power storage cell 111 is formed in a flat rectangular parallelepiped shape. An example of each power storage cell 111 is a lithium ion battery. Each power storage cell 111 may be formed as an all-solid-state battery using a solid electrolyte. As shown in FIG. 4, each power storage cell 111 includes a safety valve 111a provided on an upper surface of a housing of the power storage cell 111.

[0016] The multiple second power storage stacks 120 are arranged to face the multiple first power storage stacks 110 in the second direction and to be aligned in the first direction. In this embodiment, the multiple second power storage stacks 120 include six second power storage stacks 120. However, the number of second power storage stacks 120 is not limited to six. The configuration of each second power storage stack 120 is the same as the configuration of the first power storage stack 110. The second power storage stack 120 is an example of "another power storage stack" in the present disclosure.

[0017] The first bus bar 210 connects a pair of first power storage stacks 110 adjacent to each other in the first direction. The second bus bar 220 connects a pair of second power storage stacks 120 adjacent to each other in the first direction. The first bus bar 210 and the second bus bar 220 are arranged in a space between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. Note that the first bus bar 210 and the second bus bar 220 are not shown in FIG. 3 .

[0018] The first junction box 310 is disposed at a position facing the multiple first power storage stacks 110 in the first direction. More specifically, the first junction box 310 is disposed at a position facing the first direction of the first power storage stack 110 that is disposed outermost in the first direction among the multiple first power storage stacks 110. The first junction box 310 houses a relay, a fuse, and the like. The first junction box 310 has a first connector 312. The first connector 312 protrudes outward in the first direction.

[0019] The second junction box 320 is disposed at a position facing the plurality of second power storage stacks 120 in the first direction and facing the first junction box 310 at an interval in the second direction. The second junction box 320 houses a relay, a fuse, etc. The second junction box 320 has a second connector 322. The second connector 322 protrudes outward in the first direction.

[0020] The case 500 accommodates a plurality of first power storage stacks 110, a plurality of second power storage stacks 120, a first bus bar 210, a second bus bar 220, a first junction box 310, and a second junction box 320. The case 500 includes a one-side space S1 formed on one side of the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120 in the first direction. The junction boxes 310, 320 are arranged in this one-side space S1. The case 500 has a lower case 510 and an upper cover 520.

[0021] The lower case 510 is open upward and has a bottom wall 512, a peripheral wall 514, and a partition 516.

[0022] The bottom wall 512 supports each of the power storage stacks 110, 120. As shown in FIGS. 3 to 5, 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 the one-side space S1.

[0023] The peripheral wall 514 stands upright from the peripheral edge of the bottom wall 512. The peripheral wall 514 surrounds the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. The peripheral wall 514 is formed in a substantially rectangular cylindrical shape.

[0024] The peripheral wall 514 includes a side wall 514a that faces each of the power storage stacks 110, 120 in the first direction. The side wall 514a faces each of the power storage stacks 110, 120 in the first direction, with one side space S1 between them. The side wall 514a extends along the second direction. The side wall 514a is inclined so as to gradually move away from each of the power storage stacks 110, 120 as it extends upward. However, the side wall 514a may be perpendicular to the bottom wall 512.

[0025] The partition portion 516 separates the plurality of first power storage stacks 110 from the plurality of second power storage stacks 120. The partition portion 516 has a shape that extends along the first direction. The height of the partition portion 516 is lower than the height of the peripheral wall 514. As shown in FIG. 2 , the bus bars 210, 220 are arranged on the partition portion 516.

[0026] Upper cover 520, together with lower case 510, accommodates a plurality of first power storage stacks 110, a plurality of second power storage stacks 120, first bus bars 210, second bus bars 220, first junction box 310, and second junction box 320. A peripheral edge portion of upper cover 520 is fixed to an upper end portion of peripheral wall 514 with bolts or the like.

[0027] The upper cover 520 has an upper wall 522. The upper wall 522 faces the bottom wall 512. The upper wall 522 covers the plurality of first power storage stacks 110, the plurality of second power storage stacks 120, the first bus bar 210, the second bus bar 220, the first junction box 310, and the second junction box 320.

[0028] The pressure release valve 600 is provided in the case 500. The pressure release valve 600 releases the pressure inside the case 500. The pressure release valve 600 opens when the pressure inside the case 500 reaches or exceeds a reference value. The pressure release valve 600 is configured as a check valve. The pressure release valve 600 is provided in the top wall 522 of the upper cover 520. The pressure release valve 600 is preferably provided in a portion of the top wall 522 above the one-side space S1. In this embodiment, the pressure release valve 600 is provided in a portion of the top wall 522 above the inter-box space S2.

[0029] The breathing membrane 700 is provided on the case 500. The breathing membrane 700 adjusts the pressure inside the case 500 by allowing gas to pass between the inside and outside of the case 500. The breathing membrane 700 is provided on the bottom wall 512 and the peripheral wall 514 at a location below the pressure release valve 600. In this embodiment, the breathing membrane 700 is provided on the bottom wall 512. The breathing membrane is preferably provided on a location of the bottom wall 512 below the one-side space S1. Specifically, the breathing membrane 700 is provided on 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 attached to the outer surface of the middle portion 512a so as to cover the through-hole. As shown in FIGS. 3 to 5, at least a portion of the breathing membrane 700 may overlap the projection plane of the pressure release valve 600. The entire area of ​​the breathing membrane 700 may overlap the projection surface of the pressure relief valve 600 .

[0030] In the energy storage device 1 described above, for example, when gas is generated from one of the energy storage cells 111 and the internal pressure of the case 500 becomes equal to or greater than a reference value, the gas is discharged to the outside of the case 500 through the pressure release valve 600. At this time, contents of the energy storage cell 111 (so-called debris) contained in the gas discharged from the pressure release valve 600 are deposited on the breathing membrane 700 provided below the pressure release valve 600, causing the breathing membrane 700 to close. This prevents air from flowing into the case 500 through the breathing membrane 700 after the gas is discharged through the pressure release valve 600. Therefore, even if a storage cell 111 other than the one energy storage cell 111 (for example, a storage cell 111 adjacent to the one energy storage cell 111) generates heat, the promotion of heat generation in the case 500 due to the flow of air into the case 500 is suppressed.

[0031] Modifications of the above embodiment will now be described.

[0032] <First Modification> 6, the pressure release valve 600 may be provided in a portion of the upper wall 522 that is located above the space outside the junction boxes 310, 320 in the second direction in the one-side space S1. In this case, it is preferable that the breathing membrane 700 is provided at a position where at least a part of the breathing membrane 700 overlaps with the projection plane of the pressure release valve 600.

[0033] <Second Modification> 7 and 8, the breathing membrane 700 may be provided on the side wall 514a. In this case, it is preferable that the energy storage device 1 further includes an opposing plate portion 800. The opposing plate portion 800 is provided inside the case 500 and faces each of the energy storage stacks 110, 120 in the first direction. The opposing plate portion 800 forms a deposition space S3 (see FIG. 8) between the opposing plate portion 800 and the side wall 514a. In this example, the portion of each of the junction boxes 310, 320 that faces the side wall 514a constitutes the opposing plate portion 800.

[0034] In this embodiment, the respiratory membrane 700 is blocked by debris deposited in the deposition space S3.

[0035] <Third Modification> 9, the opposing plate portion 800 may be made of a material different from that of each of the junction boxes 310 and 320. In this example, the opposing plate portion 800 is connected by welding or the like to a portion below a through-hole formed in the side wall 514a at a position facing the breathing membrane 700.

[0036] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0037] [Aspect 1] a plurality of power storage stacks arranged in a line along one direction; a case that houses the plurality of power storage stacks; a pressure relief valve provided in the case for releasing pressure inside the case; a breathing membrane provided in the case, which adjusts the pressure inside the case by allowing gas to pass between the inside of the case and the outside of the case; Each of the plurality of power storage stacks includes a plurality of power storage cells, The case is a bottom wall supporting the plurality of power storage stacks; a peripheral wall surrounding the plurality of power storage stacks; a top wall covering the plurality of power storage stacks; The pressure relief valve is provided on the upper wall, The breathing membrane is provided at a portion of the bottom wall and the peripheral wall that is located below the pressure release valve.

[0038] In this energy storage device, the gas generated from one of the energy storage cells and discharged through the pressure release valve contains material (so-called debris) that accumulates on the breathing membrane located below the pressure release valve, thereby blocking the breathing membrane, thereby preventing air from flowing into the case through the breathing membrane after the gas is discharged through the pressure release valve and the resulting promotion of heat generation inside the case.

[0039] [Aspect 2] 2. The power storage device according to aspect 1, wherein the breathing membrane is provided on the bottom wall.

[0040] In this manner, debris is more efficiently deposited on the breathing membrane.

[0041] [Aspect 3] a plurality of other power storage stacks that are arranged to face the plurality of power storage stacks in an orthogonal direction that is orthogonal to both the one direction and the up-down direction and to be aligned along the one direction; a first junction box disposed at a position facing the plurality of power storage stacks in the one direction; a second junction box arranged at a position facing the plurality of other power storage stacks in the one direction and facing the first junction box at an interval in the orthogonal direction, the bottom wall includes an intermediate portion located below a space between the first junction box and the second junction box, 3. The power storage device according to aspect 2, wherein the breathing membrane is provided in the middle portion.

[0042] In this embodiment, debris accumulates between the first junction box and the second junction box, i.e., on the intermediate portion, further promoting blockage of the breathing membrane.

[0043] [Aspect 4] a facing plate portion provided in the case and facing the plurality of power storage stacks in the one direction; the peripheral wall includes a side wall that faces the plurality of power storage stacks in the one direction and is inclined so as to gradually become farther away from the plurality of power storage stacks as it extends upward, The breathing membrane is provided on the side wall, 2. The power storage device according to aspect 1, wherein the opposing plate portion forms a deposition space between the opposing plate portion and the side wall.

[0044] In this embodiment, debris accumulates in the accumulation space, causing the breathing membrane to become blocked.

[0045] [Aspect 5] a junction box disposed between the plurality of power storage stacks and the side wall; 5. The power storage device according to aspect 4, wherein the junction box includes the opposing plate portion.

[0046] In this embodiment, a part of the junction box also serves as the opposing plate portion, so the number of parts is reduced compared to when a dedicated opposing plate portion is provided.

[0047] [Aspect 6] Aspect 6. The power storage device of any one of aspects 1 to 5, wherein at least a portion of the breathing membrane overlaps with a projection surface of the pressure release valve.

[0048] In this embodiment, when gas is discharged from the pressure relief valve, debris that falls by colliding with the pressure relief valve is efficiently deposited on the breathing membrane.

[0049] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0050] 1 energy storage device, 110 first energy storage stack (energy storage stack), 111 energy storage cell, 111a safety valve, 120 second energy storage stack (other energy storage stack), 210 first bus bar, 220 second bus bar, 310 first junction box, 312 first connector, 320 second junction box, 322 second connector, 500 case, 510 lower case, 512 bottom wall, 514 surrounding wall, 514a side wall, 520 upper cover, 522 top wall, 600 pressure release valve, 700 breathing membrane, S1 one side space, S2 inter-box space, S3 deposition space.

Claims

1. a plurality of power storage stacks arranged in a line along one direction; a case that houses the plurality of power storage stacks; a pressure release valve provided in the case; a breathing membrane provided on the case; Each of the plurality of power storage stacks includes a plurality of power storage cells, The case is a bottom wall supporting the plurality of power storage stacks; a peripheral wall surrounding the plurality of power storage stacks; a top wall covering the plurality of power storage stacks; The pressure relief valve is provided on the upper wall, The breathing membrane is provided at a portion of the bottom wall and the peripheral wall that is located below the pressure release valve.

2. The power storage device according to claim 1 , wherein the breathing membrane is provided on the bottom wall.

3. a plurality of other power storage stacks that are arranged to face the plurality of power storage stacks in an orthogonal direction that is orthogonal to both the one direction and the up-down direction and to be aligned along the one direction; a first junction box disposed at a position facing the plurality of power storage stacks in the one direction; a second junction box arranged at a position facing the plurality of other power storage stacks in the one direction and facing the first junction box at an interval in the orthogonal direction, the bottom wall includes an intermediate portion located below a space between the first junction box and the second junction box, The power storage device according to claim 2 , wherein the breathing membrane is provided in the intermediate portion.

4. a facing plate portion provided in the case and facing the plurality of power storage stacks in the one direction; the peripheral wall includes a side wall that faces the plurality of power storage stacks in the one direction and is inclined so as to gradually become farther away from the plurality of power storage stacks as it extends upward, The breathing membrane is provided on the side wall, The power storage device according to claim 1 , wherein the opposing plate portion forms a stacking space between the opposing plate portion and the side wall.

5. a junction box disposed between the plurality of power storage stacks and the side wall; The power storage device according to claim 4 , wherein the junction box includes the opposing plate portion.

6. The power storage device according to claim 1 , wherein at least a portion of the breathing membrane overlaps with a projection surface of the pressure release valve.

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