Energy storage device

Abstract

To provide an energy storage device capable of suppressing rapid combustion inside the case after gas has been discharged through a pressure relief valve. [Solution] The energy storage device 1 comprises a plurality of first energy storage stacks 110, a plurality of second energy storage stacks 120, a case, a first pressure relief valve 610, a second pressure relief valve 620, a first breathing membrane 710, and a second breathing membrane 720. The case has a first housing chamber S10, a second housing chamber S20, and a blocking wall 516. The first pressure relief valve 610 and the first breathing membrane 710 are provided in the first housing chamber S10. The second pressure relief valve 620 and the second breathing membrane 720 are provided in the second housing chamber S20.

Description

Technical Field

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

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2023-47012 discloses a battery pack including a plurality of battery cells, a case housing the plurality of battery cells, a pressure release valve provided in the case, and a breathing film 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 breathing film is provided in a side wall portion of the lower case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery pack described in Japanese Patent Application Laid-Open No. 2023-47012, when gas is generated from any one of the battery cells and the pressure in the case reaches a reference value, the gas is discharged through the pressure release valve. At this time, since the gas spreads in the case, the gas also contacts the battery cells that do not generate gas among the plurality of battery cells.

[0005] An object of the present disclosure is to provide a power storage device capable of reducing the number of power storage cells that come into contact with gas.

Means for Solving the Problems

[0006] A power storage device according to one aspect of the present disclosure comprises: a plurality of first power storage stacks arranged in a line along a first direction; a plurality of second power storage stacks arranged opposite to the plurality of first power storage stacks in a second direction orthogonal to both the first direction and the vertical direction, and arranged in a line along the first direction; a case housing the plurality of first power storage stacks and the plurality of second power storage stacks; a first pressure relief valve provided in the case; a second pressure relief valve provided in the case; a first breathing membrane provided in the case; and a second breathing membrane provided in the case, wherein the case has a first housing chamber housing the plurality of first power storage stacks; a second housing chamber housing the plurality of second power storage stacks; and a barrier wall separating the first housing chamber from the second housing chamber, wherein the first pressure relief valve and the first breathing membrane are provided in the first housing chamber, and the second pressure relief valve and the second breathing membrane are provided in the second housing chamber. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can reduce the number of energy storage cells that come into contact with the gas. [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] Figure 1 is a schematic perspective view showing the energy storage device with the upper cover removed. [Figure 3] This is a schematic plan view showing the power storage device with the upper cover removed. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Figure 5] This diagram schematically shows a modified example of an energy storage device. [Figure 6] This diagram schematically shows a modified example of an energy storage device. [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 perspective view showing the energy storage device shown in Figure 1 with the upper cover removed. Figure 3 is a schematic plan view showing the energy storage device with the upper cover removed. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. This energy storage device 1 is mounted, for example, on the bottom of a vehicle.

[0011] As shown in Figures 1 to 4, the energy storage device 1 comprises 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 third busbar 230, a first junction box 310, a second junction box 320, a covering plate 400, a case 500, a first pressure relief valve 610, a second pressure relief valve 620, a first breathing membrane 710, and a second breathing membrane 720.

[0012] Multiple first energy storage stacks 110 are arranged in a line in a first direction. In this embodiment, the multiple first energy storage stacks 110 include 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 in a rectangular parallelepiped shape that is elongated in a second direction perpendicular to both the first direction and the vertical direction.

[0013] Each first energy storage stack 110 includes a plurality of energy storage cells 111 (see Figures 3 and 4). The plurality of energy storage cells 111 are arranged, for example, in a first direction. Alternatively, the plurality of energy storage cells 111 may be arranged in a second direction. Each energy storage cell 111 is formed in a flattened rectangular parallelepiped shape. Examples of each energy storage cell 111 include lithium-ion batteries. Each energy storage cell 111 may be composed of an all-solid-state battery using a solid electrolyte. Each energy storage cell 111 may include a safety valve located opposite the upper cover 520, i.e., on the upper surface of the housing of the energy storage cell 111.

[0014] The multiple second energy storage stacks 120 are arranged so as to face the multiple first energy storage stacks 110 in the second direction and be aligned in the first direction. In this embodiment, the multiple second energy storage stacks 120 include six second energy storage stacks 120. However, the number of second energy storage stacks 120 is not limited to six. The configuration of each second energy storage stack 120 is the same as the configuration of the first energy storage stack 110.

[0015] The first busbar 210 connects a pair of first energy storage stacks 110 that are adjacent to each other in the first direction. The first busbar 210 is routed between multiple first energy storage stacks 110 and multiple second energy storage stacks 120.

[0016] The second busbar 220 connects a pair of adjacent second energy storage stacks 120 in the first direction. The second busbar 220 is routed between multiple first energy storage stacks 110 and multiple second energy storage stacks 120.

[0017] The third bus bar 230 is located between the first energy storage stack (hereinafter referred to as "first energy storage stack 110A") which is the outermost of the multiple first energy storage stacks 110 in the first direction (for example, the front side in the longitudinal direction of the vehicle) and the first of the multiple second energy storage stacks 120 It is connected to a second power storage stack (hereinafter referred to as "second power storage stack 120A") disposed on the outermost side in the direction (for example, the front side in the longitudinal direction of the vehicle).

[0018] The first junction box 310 is disposed at a position facing the first power storage stack 110 disposed on the outermost side in the first direction (for example, the rear side in the longitudinal direction of the vehicle) among the plurality of first power storage stacks 110. More specifically, the first junction box 310 faces the first power storage stack 110 disposed at the end on the opposite side to the side where the first power storage stack 110A connected to the third bus bar 230 among the plurality of first power storage stacks 110 is disposed. The first junction box 310 houses relays, fuses, 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 second power storage stack 120 in the first direction and spaced apart from the first junction box 310 in the second direction. The second junction box 320 houses relays, fuses, and the like. As shown in FIG. 3, in this embodiment, the outer shape of the second junction box 320 is larger than the outer shape of the first junction box 310. The second junction box 320 has a second connector 322. The second connector 322 protrudes outward in the first direction.

[0020] The covering plate 400 (see FIG. 4) covers the first bus bar 210 and the second bus bar 220 from above. The covering plate 400 is disposed between the plurality of first power storage stacks 110 and the plurality of second power storage stacks 120. The covering plate 400 extends along the first direction. The covering plate 400 is formed in a flat plate shape. The covering plate 400 is made of an insulating member. The covering plate 400 is made of, for example, mica obtained by solidifying natural inorganic minerals by hot pressing. The covering plate 400 has a function of shielding the gas ejected upward from any of the power storage stacks from contacting the bus bars 210, 220, and 230. In FIGS. 2 and 3, the illustration of the covering plate 400 is omitted.

[0021] The case 500 houses 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 third bus bar 230, the first junction box 310, the second junction box 320, and the covering plate 400. The case 500 has a lower case 510 and an upper cover 520.

[0022] The lower case 510 is open upward. The lower case 510 has a bottom wall 512, a peripheral wall 514, a partition wall 516, and a partition portion 518.

[0023] The bottom wall 512 supports the power storage stacks 110 and 120. The bottom wall 512 may be formed in a flat plate shape.

[0024] The peripheral wall 514 stands up 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 tubular shape. The peripheral wall 514 includes a first side wall 514a and a second side wall 514b.

[0025] The first side wall 514a is formed on the side opposite to the side (the lower side in Figure 3) where the multiple first energy storage stacks 110 and the multiple second energy storage stacks 120 are arranged relative to the first junction box 310 and the second junction box 320. The first side wall 514a extends along the second direction. The first side wall 514a gradually widens as it extends upward. It may be inclined outward in the first direction, or it may be perpendicular to the bottom wall 512.

[0026] The second side wall 514b faces the first side wall 514a in the first direction. The second side wall 514b faces the first energy storage stack 110A and the second energy storage stack 120A. The second side wall 514b extends along the second direction.

[0027] The barrier wall 516 separates the multiple first energy storage stacks 110 and the multiple second energy storage stacks 120. The barrier wall 516 has a shape that extends along the first direction. As shown in Figures 3 and 4, the barrier wall 516 has a reinforcing portion 516a and a barrier portion 516b. Note that the barrier portion 516b is not shown in Figure 2.

[0028] The reinforcing section 516a is connected to the bottom wall 512. The reinforcing section 516a extends in a first direction. Each end of the reinforcing section 516a in the first direction is connected to the perimeter wall 514.

[0029] The blocking section 516b is positioned on the reinforcing section 516a. Each end of the blocking section 516b in the first direction is connected to the peripheral wall 514. The dimensions of the blocking section 516b in the second direction may be smaller than the dimensions of the reinforcing section 516a in the second direction. As shown in Figure 4, the upper end of the blocking section 516b is in contact with the upper cover 520. For example, the first bus bar 210 is positioned on one side of the blocking section 516b in the second direction, and the second bus bar 220 is positioned on the other side of the blocking section 516b in the second direction.

[0030] As shown in Figure 3, the third busbar 230 penetrates the blocking portion 516b in the second direction. The blocking portion 516b is provided with a through hole through which the third busbar 230 is inserted. The gap between the third busbar 230 and the through hole in the blocking portion 516b is filled with a component made of a heat-resistant material (such as heat-resistant silicone).

[0031] The partition 518 separates the first energy storage stack 110 from the first junction box 310, and the second energy storage stack 120 from the second junction box 320. Each end of the partition 518 in the second direction is connected to the peripheral wall 514.

[0032] The upper cover 520 covers 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 third bus bar 230, a first junction box 310, a second junction box 320, and a covering plate 400. The upper cover 520, together with the lower case 510, houses the 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 third bus bar 230, a first junction box 310, a second junction box 320, and a covering plate 400. The peripheral edge of the upper cover 520 is fixed to the upper end of the peripheral wall 514 by bolts or the like.

[0033] Case 500 has a first containment chamber S10 and a second containment chamber S20.

[0034] The first storage chamber S10 houses multiple first energy storage stacks 110. The first storage chamber S10 is composed of one side of the bottom wall 512 of the barrier wall 516 in the second direction (the left side in Figure 3), one side of the peripheral wall 514 of the barrier wall 516 in the second direction, and one side of the upper cover 520 of the barrier wall 516 in the second direction.

[0035] The second storage chamber S20 houses multiple second energy storage stacks 120. The second storage chamber S20 is located on the other side (right side in Figure 3) of the bottom wall 512 of the barrier wall 516 in the second direction. It is composed of a part, the other side of the barrier wall 516 in the second direction of the peripheral wall 514, and the other side of the barrier wall 516 in the second direction of the upper cover 520.

[0036] The barrier wall 516 separates the first containment chamber S10 from the second containment chamber S20.

[0037] The first junction box 310 is located in the first housing chamber S10. More specifically, the first housing chamber S10 includes a first space S11, and the first junction box 310 is located in the first space S11. The first space S11 is defined by a first defining section 501d. The first defining section 501d is part of the first housing chamber S10. The first defining section 501d defines the first space S11 on one side of a plurality of first energy storage stacks 110 in a first direction. In this embodiment, the first defining portion 501d is composed of one side portion 512d of the bottom wall 512 of the partition portion 518 in the first direction (see Figure 3), one side portion of the peripheral wall 514 of the partition portion 518 in the first direction, one side portion of the barrier wall 516 of the partition portion 518 in the first direction, and one side portion 520d of the upper cover 520 of the partition portion 518 in the first direction (see Figure 1).

[0038] The second junction box 320 is located in the second storage chamber S20. More specifically, the second storage chamber S20 includes a second space S21, and the second junction box 320 is located in the second space S21. The second space S21 is defined by a second defining section 502d. The second defining section 502d is part of the second storage chamber S20. The second defining section 502d defines the second space S21 on one side of the plurality of second energy storage stacks 120 in the first direction, and in a position opposite the first space S11 in the second direction, separated by a barrier wall 516. In this embodiment, the second defining portion 502d is composed of one side portion 512d of the bottom wall 512 of the partition portion 518 in the first direction (see Figure 3), one side portion of the peripheral wall 514 of the partition portion 518 in the first direction, one side portion of the barrier wall 516 of the partition portion 518 in the first direction, and one side portion 520d of the upper cover 520 of the partition portion 518 in the first direction (see Figure 1).

[0039] The first pressure relief valve 610 is located in the first housing chamber S10 of the case 500. The first pressure relief valve 610 releases the pressure inside the first housing chamber S11. The first pressure relief valve 610 opens when the pressure inside the first housing chamber S11 exceeds a reference value. The first pressure relief valve 610 is composed of a check valve.

[0040] In this embodiment, the first pressure relief valve 610 is provided in the first regulating section 501d. More specifically, as shown in Figures 1 and 3, the first pressure relief valve 610 is provided in the upper part of the upper cover 520 above the first space S11. In Figure 3, the first pressure relief valve 610 is indicated by a dashed line.

[0041] The second pressure relief valve 620 is located in the second housing chamber S20 of the case 500. The configuration of the second pressure relief valve 620 is the same as that of the first pressure relief valve 610.

[0042] In this embodiment, the second pressure relief valve 620 is provided in the second restricting portion 502d. More specifically, as shown in Figures 1 and 3, the second pressure relief valve 620 is provided in the upper part of the upper cover 520 above the second space S21. In Figure 3, the second pressure relief valve 620 is indicated by a dashed line.

[0043] The first breathing membrane 710 is provided in the first containment chamber S11 of the case 500. The first breathing membrane 710 regulates the pressure inside the first containment chamber S11 by allowing gas to pass between the inside of the first containment chamber S11 and the outside of the case 500.

[0044] In this embodiment, the first breathing membrane 710 is provided in the first defining portion 501d. Preferably, the first breathing membrane 710 is positioned on the side opposite to the side where the first energy storage stack 110 is located, with reference to the first pressure relief valve 610. In this embodiment, the first breathing membrane 710 is provided in the first side wall 514a. Specifically, a through hole is provided in the first side wall 514a, and the first breathing membrane 710 is attached to the outer surface of the first side wall 514a so as to cover the through hole.

[0045] The second respiratory membrane 720 is located in the second containment chamber S21 of case 500. The configuration of the second respiratory membrane 720 is the same as that of the first respiratory membrane 710.

[0046] In this embodiment, the second respiratory membrane 720 is provided in the second regulating portion 502d. It is preferable that the second respiratory membrane 720 is located on the side opposite to the side where the second energy storage stack 120 is positioned, with reference to the second pressure relief valve 620. In this embodiment, the second respiratory membrane 720 is provided in the first side wall 514a.

[0047] As described above, in the energy storage device 1 of this embodiment, each storage chamber S10, S20, which is separated from each other by a barrier wall 516, is provided with pressure relief valves 610, 620 and breathing membranes 710, 720. For example, if gas is discharged from the first energy storage stack 110 located in the first storage chamber S10, the gas is discharged outside the case 500 through the first pressure relief valve 610. Therefore, contact between the gas discharged from the first energy storage stack 110 and the second energy storage stack 120 located in the second storage chamber S20 is suppressed.

[0048] Modifications of the above embodiment will be described below.

[0049] <First variation> As shown in Figure 5, the first pressure relief valve 610 and the first breathing membrane 710 may be provided in the first housing chamber S10 on the side opposite to the side where the first junction box 310 is located in the first direction (the upper side in Figure 5). Similarly, the second pressure relief valve 620 and the second breathing membrane 720 may be provided in the second housing chamber S20 on the side opposite to the side where the second junction box 320 is located in the first direction.

[0050] The "opposite side" of the first containment chamber S10 includes the portion of the bottom wall 512 that overlaps vertically with the first energy storage stack 110A, which is located on the outermost side in the first direction; the portion of the peripheral wall 514 that surrounds the first energy storage stack 110A; and the portion of the upper cover 520 that overlaps vertically with the first energy storage stack 110A.

[0051] The "opposite side" of the second containment chamber S20 includes the portion of the bottom wall 512 that overlaps vertically with the second energy storage stack 120A, which is located on the outermost side in the first direction; the portion of the peripheral wall 514 that surrounds the second energy storage stack 120A; and the portion of the upper cover 520 that overlaps vertically with the second energy storage stack 120A.

[0052] In the example shown in Figure 5, the first pressure relief valve 610 and the second pressure relief valve 620 are provided on the upper cover 520. The first respiratory membrane 710 and the second respiratory membrane 720 are provided on the second side wall 514b of the peripheral wall 514.

[0053] In this embodiment, since each junction box 310, 320 is positioned away from each pressure relief valve 610, 620 and each breathing membrane 710, 720, the thermal effects of the gas discharged from the energy storage stack on each junction box 310, 320 are suppressed.

[0054] <Second variation> As shown in Figure 6, each respiratory membrane 710, 720 may be provided on the peripheral wall 514 at a portion facing each other in the second direction. The same applies to each pressure relief valve 610, 620. However, in the example shown in Figure 6, each pressure relief valve 610, 620 is provided on the upper cover 520.

[0055] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0056] [Aspect 1] Multiple first energy storage stacks arranged in a line along the first direction, A plurality of second energy storage stacks are arranged facing the plurality of first energy storage stacks in a second direction perpendicular to both the first direction and the vertical direction, and are arranged in line along the first direction, A case housing the plurality of first energy storage stacks and the plurality of second energy storage stacks, The case is provided with a first pressure relief valve, A second pressure relief valve is provided in the aforementioned case, The first respiratory membrane provided in the aforementioned case, The case comprises a second respiratory membrane provided in the aforementioned case, The aforementioned case is, A first housing chamber housing the plurality of first energy storage stacks, A second housing chamber housing the plurality of second energy storage stacks, The first containment chamber has a barrier wall that separates it from the second containment chamber, The first pressure relief valve and the first breathing membrane are provided in the first containment chamber. The second pressure relief valve and the second breathing membrane are energy storage devices provided in the second containment chamber.

[0057] In this energy storage device, each containment chamber, which is separated from each other by a barrier wall, is equipped with a pressure relief valve and a breathing membrane. Therefore, even if gas is discharged from the energy storage stack in one of the containment chambers, contact of the gas with the energy storage stacks contained in the other containment chambers is suppressed.

[0058] [Aspect 2] A first junction box located in the first containment chamber, The system further comprises a second junction box located in the second containment chamber, The first containment chamber has a first defining portion that defines a first space on one side of the plurality of first energy storage stacks in the first direction, The second storage chamber has a second defining portion that defines a second space on one side of the plurality of second energy storage stacks in the first direction, and at a position facing the first space in the second direction across the barrier wall, The first junction box is located in the first space, The aforementioned second junction box is located in the aforementioned second space, The first pressure relief valve and the first breathing membrane are provided in the first specified section. The energy storage device according to embodiment 1, wherein the second pressure relief valve and the second breathing membrane are provided in the second regulated portion.

[0059] In this configuration, the space around the junction box in each space is effectively utilized, thus avoiding the need to enlarge the case due to the installation of each pressure relief valve and each breathing membrane.

[0060] [Aspect 3] A first junction box is positioned within the first containment chamber, facing the plurality of first energy storage stacks in the first direction, The second containment chamber further comprises a second junction box positioned in the second direction, facing the plurality of second energy storage stacks and the first junction box across the barrier wall, The first pressure relief valve and the first breathing membrane are provided in the first containment chamber on the side opposite to the side where the first junction box is located in the first direction. The energy storage device according to embodiment 1, wherein the second pressure relief valve and the second breathing membrane are provided in the second containment chamber on the side opposite to the side where the second junction box is located in the first direction.

[0061] In this embodiment, each junction box is positioned away from each pressure relief valve and each breathing membrane, thereby suppressing the thermal effects of the gas discharged from the energy storage stack on each junction box.

[0062] 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]

[0063] 1 Energy storage device, 110 First energy storage stack, 111 Energy storage cell, 120 Second energy storage stack, 210 First busbar, 220 Second busbar, 230 Third busbar, 310 First junction box, 312 First connector, 320 Second junction box, 322 Second connector, 400 Covering plate, 500 Case, 501d First restricting section, 502d Second restricting section, 510 Lower case, 512 Bottom wall, 514 Peripheral wall, 514a First side wall, 514b Second side wall, 516 Barrier wall, 520 Upper cover, 522 Top wall, 610 First pressure relief valve, 620 Second pressure relief valve, 710 First respiratory membrane, 720 Second respiratory membrane, S10 first containment chamber, S11 first space, S20 second containment chamber, S21 second space.

Claims

1. A first energy storage stack including multiple energy storage cells, A second energy storage stack, which is opposite the first energy storage stack and includes a plurality of energy storage cells, A peripheral wall surrounding the first energy storage stack and the second energy storage stack, A barrier wall is placed between the first energy storage stack and the second energy storage stack, A first pressure relief valve and a first breathing membrane are provided in the peripheral wall, specifically in the portion surrounding the first energy storage stack. A power storage device comprising a second pressure relief valve and a second breathing membrane provided in the peripheral wall surrounding the second power storage stack.

2. The energy storage device according to claim 1, further comprising a busbar disposed between the first energy storage stack and the second energy storage stack.

3. The first respiratory membrane is provided on the peripheral wall on the side opposite to the side where the second energy storage stack is located, with reference to the first energy storage stack. The energy storage device according to claim 1, wherein the second respiratory membrane is provided on the peripheral wall on the side opposite to the side on which the first energy storage stack is arranged, with reference to the second energy storage stack.

4. The first energy storage stack is one of a plurality of first energy storage stacks arranged in a line along a first direction, The second energy storage stack is one of a plurality of second energy storage stacks arranged to face the plurality of first energy storage stacks in a second direction perpendicular to both the first direction and the vertical direction, and to be aligned along the first direction. The peripheral wall surrounds the plurality of first energy storage stacks and the plurality of second energy storage stacks. The first pressure relief valve and the first breathing membrane are provided only in the portion of the peripheral wall surrounding the first energy storage stack located at one end in the first direction among the plurality of first energy storage stacks, and not in the portions surrounding the other first energy storage stacks. The energy storage device according to claim 1, wherein the second pressure relief valve and the second breathing membrane are provided only in the portion of the peripheral wall surrounding the second energy storage stack located at one end of the plurality of second energy storage stacks in the first direction, and not in the portion surrounding the other second energy storage stacks.