Energy storage device

Abstract

To provide an energy storage device that can suppress the promotion of heat generation within the case. [Solution] The energy storage device 1 comprises a plurality of energy storage modules 101, a case, a pressure relief valve 600, and a breathing membrane 700. Each of the plurality of energy storage modules 101 has an exhaust port h for discharging gas. The distance D1 between the breathing membrane 700 and the pressure relief valve 600 is smaller than the distance D2 between the exhaust port h and the pressure relief valve 600.

Description

Technical Field

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

Background Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2023-47012 discloses a battery pack including a plurality of battery cells, a case that houses 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 Unexamined Patent Application Publication 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. Thereafter, air flows into the case through the breathing film to adjust the internal pressure of the case.

[0005] At this time, if a battery cell different from the battery cell that generated gas first is generating heat, there is a concern that heat generation in the case may be promoted by contact of air with the blast generated from the battery cell.

[0006] An object of the present disclosure is to provide a power storage device capable of suppressing the promotion of heat generation in the case.

Means for Solving the Problems

[0007] A power storage device according to one aspect of the present disclosure comprises a plurality of power storage modules arranged in a line along a first direction; a case housing the plurality of power storage modules; a pressure relief valve provided in the case for releasing pressure inside the case; and a breathing membrane provided in the case for regulating pressure inside the case by allowing the passage of gas between the inside and outside of the case, wherein each of the plurality of power storage modules has an exhaust port for discharging gas, and the distance between the breathing membrane and the pressure relief valve is smaller than the distance between the exhaust port and the pressure relief valve. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an energy storage device that can suppress the promotion of heat generation within the case. [Brief explanation of the drawing]

[0009] [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 and protective plate removed. [Figure 3] This is a schematic plan view showing the energy storage device with the upper cover and protective plate removed. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Figure 5] Figure 3 is a cross-sectional view along the VV line. [Figure 6] This is a schematic cross-sectional view showing a modified example of an energy storage device. [Figure 7] This is a schematic plan view showing a modified example of an energy storage device. [Figure 8] This is a schematic plan view showing a modified example of an energy storage device. [Modes for carrying out the invention]

[0010] 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.

[0011] 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 and protective plate removed. Figure 3 is a schematic plan view showing the energy storage device with the upper cover and protective plate removed. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Figure 5 is a cross-sectional view taken along line VV in Figure 3. This energy storage device 1 is mounted, for example, on the bottom of a vehicle.

[0012] As shown in Figures 1 to 5, the energy storage device 1 comprises a plurality of first energy storage modules 101, a plurality of second energy storage modules 102, a first busbar 210, a second busbar 220, a first junction box 310, a second junction box 320, a covering plate 400, a case 500, a pressure relief valve 600, and a breathing membrane 700.

[0013] Multiple first energy storage modules 101 are arranged in a line in a first direction. In this embodiment, the multiple first energy storage modules 101 include six first energy storage modules 101. However, the number of first energy storage modules 101 is not limited to six. Each first energy storage module 101 is formed in a rectangular parallelepiped shape that is elongated in a second direction perpendicular to both the first direction and the vertical direction. The first energy storage module 101 is an example of an "energy storage module" in this disclosure.

[0014] A plurality of second power storage modules 102 are arranged to face a plurality of first power storage modules 101 in a second direction and to be aligned in a first direction. In the present embodiment, the plurality of second power storage modules 102 includes six second power storage modules 102. However, the number of the second power storage modules 102 is not limited to six. The configuration of each second power storage module 102 is the same as that of the first power storage stack module. The second power storage module 102 is an example of the "other power storage module" in the present disclosure.

[0015] Each of the power storage modules 101 and 102 has a plurality of power storage cells 110, a stack case 120, and a protection plate 130.

[0016] The plurality of power storage cells 110 are arranged, for example, to be aligned in a first direction. Note that the plurality of power storage cells 110 may be arranged to be aligned in a second direction. Each power storage cell 110 has a shape that extends long in a second direction. The plurality of power storage cells 110 constitute a power storage stack. Each power storage cell 110 may be composed of a so-called laminated cell provided with a laminated exterior body, or may be composed of a so-called rectangular cell formed in a flat rectangular parallelepiped shape. As each power storage cell 110, for example, a lithium ion battery can be mentioned. Each power storage cell 110 may be composed of an all-solid-state battery using a solid electrolyte.

[0017] The stack case 120 houses the plurality of power storage cells 110, that is, the power storage stack. The stack case 120 is formed in a rectangular parallelepiped shape. As shown in FIG. 5, the stack case 120 has a lower case 122 and a lid 124. The lower case 122 is open upward. The lid 124 closes the opening of the lower case 122. The lid 124 is fixed to the opening of the lower case 122 by welding or the like. A plurality of through holes 124h are formed in the lid 124.

[0018] The protection plate 130 covers the stack case 120. The protection plate 130 is made of a material having heat resistance and insulation. The protection plate 130 is made of, for example, mica obtained by solidifying natural inorganic minerals by hot pressing. An exhaust port h for discharging the gas generated from the power storage cell 110 is formed in the protection plate 130.

[0019] As shown in FIG. 5, the protection plate 130 has a covering portion 132 and an edge portion 134. The covering portion 132 covers the lid 124 of the stack case 120. The covering portion 132 is formed in a flat plate shape. The exhaust port h is formed in the covering portion 132. The edge portion 134 extends downward from the end of the covering portion 132 in the first direction. The edge portion 134 covers the boundary portion between the lower case 122 and the lid 124.

[0020] The first bus bar 210 (see FIG. 2) connects a pair of first power storage modules 101 adjacent to each other in the first direction. The first bus bar 210 is arranged in a layout space S1 (see FIGS. 3 and 4) between the plurality of first power storage modules 101 and the plurality of second power storage modules 102.

[0021] The second bus bar 220 (see FIG. 2) connects a pair of second power storage modules 102 adjacent to each other in the first direction. The second bus bar 220 is arranged in the layout space S1. In FIG. 3, the illustration of the first bus bar 210 and the second bus bar 220 is omitted.

[0022] The first junction box 310 is arranged at a position facing the first power storage module 101 arranged on the outermost side in the first direction (for example, the front side in the longitudinal direction of the vehicle) among the plurality of first power storage modules 101. 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.

[0023] The second junction box 320 is positioned opposite the second energy storage module 102 in the first direction and opposite the first junction box 310 at a distance in the second direction. The second junction box 320 houses relays, fuses, and the like. As shown in Figures 2 and 3, in this embodiment, the external dimensions of the second junction box 320 are larger than those 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.

[0024] The covering plate 400 (see Figure 4) covers the first busbar 210 and the second busbar 220 from above. The covering plate 400 is positioned between a plurality of first energy storage modules 101 and a plurality of second energy storage modules 102. The covering plate 400 extends along a first direction. The covering plate 400 is formed in a flat plate shape. The covering plate 400 is made of an insulating material. The covering plate 400 is made of, for example, mica, which is made by solidifying natural inorganic minerals by heat pressing. The covering plate 400 has the function of shielding gas ejected upward from any of the energy storage modules from contacting each of the busbars 210 and 220. Note that the covering plate 400 is not shown in Figures 2 and 3.

[0025] The case 500 houses a plurality of first energy storage modules 101, a plurality of second energy storage modules 102, a first bus bar 210, a second bus bar 220, a first junction box 310, a second junction box 320, and a covering plate 400. The case 500 includes a one-sided space S2 formed on one side of the plurality of first energy storage modules 101 and the plurality of second energy storage modules 102 in a first direction. The junction boxes 310 and 320 are arranged in this one-sided space S2. The case 500 has a lower case 510 and an upper cover 520.

[0026] The lower case 510 is open upwards. The lower case 510 has a bottom wall 512, a peripheral wall 514, and a partition 516.

[0027] The bottom wall 512 supports each of the energy storage modules 101 and 102.

[0028] The peripheral wall 514 rises from the periphery of the bottom wall 512. The peripheral wall 514 surrounds the multiple first energy storage modules 101 and the multiple second energy storage modules 102. The peripheral wall 514 is formed in a roughly rectangular cylindrical shape.

[0029] The peripheral wall 514 includes a side wall 514a formed on the side opposite to the side (left side in Figure 3) where the multiple first energy storage modules 101 and multiple second energy storage modules 102 are arranged relative to the first junction box 310 and the second junction box 320. In other words, the side wall 514a faces each energy storage module 101, 102 in the first direction across the one-sided space S2. The side wall 514a extends along the second direction. The side wall 514a may be inclined so as to gradually move outward in the first direction as it moves upward, or it may be perpendicular to the bottom wall 512.

[0030] The partition 516 separates the multiple first energy storage modules 101 from the multiple second energy storage modules 102. The partition 516 has a shape that extends along the first direction. The height of the partition 516 is lower than the height of the peripheral wall 514. As shown in Figure 4, the space S1 is formed between the partition 516 and the covering plate 400.

[0031] The upper cover 520, together with the lower case 510, houses a plurality of first energy storage modules 101, a plurality of second energy storage modules 102, a first bus bar 210, a second bus bar 220, 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.

[0032] The upper 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 modules 101, a plurality of second energy storage modules 102, a first bus bar 210, a second bus bar 220, a first junction box 310, a second junction box 320, and a covering plate 400.

[0033] The pressure relief valve 600 is provided in the case 500. The pressure relief valve 600 releases the pressure inside the case 500. The pressure relief valve 600 opens when the pressure inside the case 500 exceeds a reference value. The pressure relief valve 600 is composed of a check valve. As shown in Figures 3 and 4, the pressure relief valve 600 is provided in the upper part of the upper wall 522 above the one-sided space S2. In this embodiment, the pressure relief valve 600 is provided in the upper part of the upper wall 522 above the inter-box space S3 (see Figures 3 and 4) formed between the first junction box 310 and the second junction box 320. The inter-box space S3 is part of the one-sided space S2.

[0034] As shown in Figures 4 and 5, a shielding portion 525 is provided on the inner surface of the upper cover 520. The shielding portion 525 is provided on the inner surface of the upper cover 520 in front of each energy storage module 101, 102. The shielding portion 525 is provided above the inter-box space S3. The shielding portion 525 has a shape that extends downward from the upper cover 520.

[0035] The breathing membrane 700 is provided in the case 500. The breathing membrane 700 regulates 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 located on the side opposite to the side where the energy storage modules 101 and 102 are arranged, with respect to the pressure relief valve 600. In this embodiment, the breathing membrane 700 is provided in the side wall 514a. Specifically, a through hole is provided in the side wall 514a, and the breathing membrane 700 is attached to the outer surface of the side wall 514a so as to cover the through hole. As shown in Figures 3 to 5, the breathing membrane 700 is provided in the part of the side wall 514a facing the inter-box space S3.

[0036] As shown in Figure 5, the exhaust port h is formed at a position spaced apart from the end of the stack case 120 that is closer to the pressure relief valve 600. The distance D1 between the breathing membrane 700 and the pressure relief valve 600 is smaller than the distance D2 between the exhaust port h and the pressure relief valve 600.

[0037] Distance D1 is the length between the center of the through-hole formed in the part of the side wall 514a facing the breathing membrane 700 and the center of the through-hole formed in the part of the upper wall 522 facing the pressure relief valve 600. Here, if multiple breathing membranes 700 are provided in the side wall 514a, the "breathing membrane 700" used as the reference for distance D1 refers to the breathing membrane 700 located closest to the pressure relief valve 600 among all the breathing membranes 700. Distance D2 is the length between the center of the through-hole formed in the part of the upper wall 522 facing the pressure relief valve 600 and the exhaust port h formed in the protective plate 130 closest to the pressure relief valve 600. Here, if multiple exhaust ports h are formed in the protective plate 130, the "exhaust port h" used as the reference for distance D2 refers to the exhaust port h located closest to the pressure relief valve 600 among all the exhaust ports h.

[0038] As described above, in the energy storage device 1 of this embodiment, the distance D1 between the breathing membrane 700 and the pressure relief valve 600 is smaller than the distance D2 between the exhaust port h and the pressure relief valve 600. Therefore, after gas has been discharged once through the pressure relief valve 600, the air flowing between the breathing membrane 700 and the pressure relief valve 600 is suppressed from moving towards the exhaust port h, and the generation of blast caused by this is suppressed.

[0039] Furthermore, if gas is generated from either of the energy storage modules 101 or 102 and air flows into the case 500 through the breathing membrane 700, that air will come into contact with each of the junction boxes 310 or 320, thereby suppressing the air that has flowed into the case 500 from reaching the energy storage modules 101 or 102 and preventing the generation of blasts that may result from this.

[0040] Modifications of the above embodiment will be described below.

[0041] <First variation> As shown in Figure 6, each energy storage module 101, 102 does not necessarily have a protective plate 130. In this case, the boundary between the lower case 122 and the lid 124 constitutes the exhaust port h. In this example, the distance D2 is the length between the center of the through hole formed in the upper wall 522 in the part facing the pressure relief valve 600 and the part of the boundary between the lower case 122 and the lid 124 closest to the pressure relief valve 600.

[0042] <Second variation> As shown in Figures 7 and 8, each energy storage cell 110 may be composed of a so-called rectangular cell. In the example shown in Figure 7, the multiple energy storage cells 110 are arranged in a line in a first direction, and in the example shown in Figure 8, the multiple energy storage cells 110 are arranged in a line in a second direction. Each energy storage cell 110 has a safety valve 112 and a pair of external terminals 114. The safety valve 112 is located opposite the upper wall 522, that is, on the upper surface of the housing of the energy storage cell 110. The pair of external terminals 114 are located on the upper surface of the housing of the energy storage cell, sandwiching the safety valve 112. A protective plate 130 covers each external terminal 114.

[0043] In this example, distance D2 is the length between the center of the through hole formed in the upper wall 522 in the portion facing the pressure relief valve 600 and the portion of the safety valve 112 of the energy storage cell 110, which is located closest to the pressure relief valve 600.

[0044] <Third variation> Although not shown in the diagram, multiple second energy storage modules 102 may be omitted.

[0045] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0046] [Aspect 1] Multiple energy storage modules arranged in a line along the first direction, A case for housing the aforementioned multiple energy storage modules, A pressure relief valve is provided in the aforementioned case for releasing the pressure inside the case, The case is provided with a breathing membrane that adjusts the pressure inside the case by allowing the passage of gas between the inside and outside of the case, Each of the aforementioned plurality of energy storage modules has an exhaust port for discharging gas, An energy storage device in which the distance between the breathing membrane and the pressure relief valve is smaller than the distance between the exhaust port and the pressure relief valve.

[0047] In this energy storage device, the distance between the breathing membrane and the pressure relief valve is smaller than the distance between the exhaust port and the pressure relief valve. This suppresses the air flowing between the breathing membrane and the pressure relief valve from moving towards the exhaust port and the resulting blast generation.

[0048] [Aspect 2] Each of the aforementioned energy storage modules is Multiple energy storage cells, A stack case for housing the aforementioned multiple energy storage cells, It comprises a protective plate made of a heat-resistant and insulating material that covers the stack case, The protective plate has the exhaust port formed therein. The energy storage device according to embodiment 1, wherein the exhaust port is formed at a position spaced apart from the end of the stack case closest to the pressure relief valve.

[0049] [Aspect 3] Each of the aforementioned energy storage modules is Multiple energy storage cells, It comprises a stack case that houses the plurality of energy storage cells, The aforementioned stack case is A lower case that opens upwards, The lower case has a lid that closes the opening, The energy storage device according to embodiment 1, wherein the boundary between the lower case and the lid constitutes the exhaust port.

[0050] [Aspect 4] The case includes an upper wall that covers the plurality of energy storage modules, Each of the aforementioned energy storage modules includes a plurality of energy storage cells, Each of the plurality of energy storage cells includes a safety valve located opposite the upper wall, The energy storage device according to embodiment 1, wherein the safety valve constitutes the exhaust port.

[0051] [Aspect 5] The case includes a one-sided space formed on one side of the plurality of energy storage modules in the first direction, The aforementioned case is, Aside from the aforementioned one-sided space, a side wall facing the plurality of energy storage modules in the first direction, The upper wall covering the plurality of energy storage modules, The pressure relief valve is provided in the upper part of the upper wall above the space on one side, The energy storage device according to any one of embodiments 1 to 4, wherein the respiratory membrane is provided on the side wall.

[0052] In this embodiment, when gas is discharged from any of the energy storage modules, the gas flows into the space on one side, where it changes direction upward and heads towards the pressure relief valve, thus reducing the flow velocity of the gas discharged from the case.

[0053] [Aspect 6] A plurality of other energy storage modules are arranged facing the plurality of energy storage modules in a second direction perpendicular to both the first direction and the vertical direction, and arranged in a line along the first direction, The first junction box is positioned opposite the energy storage module in the first direction, The system further comprises a second junction box positioned opposite the other energy storage modules in the first direction and at a distance from the first junction box in the second direction, The aforementioned one-sided space is formed on one side of the plurality of energy storage modules and the plurality of other energy storage modules in the first direction, The first junction box and the second junction box are arranged in the one-sided space, The pressure relief valve is provided in the upper part of the upper wall, in the space between the first junction box and the second junction box. The energy storage device according to embodiment 5, wherein the respiratory membrane is provided in the portion of the side wall facing the inter-box space.

[0054] In this embodiment, after gas is discharged from the pressure relief valve, when air flows into the case through the breathing membrane, that air tends to accumulate in one side of the space due to contact with each junction box.

[0055] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0056] 1 Energy storage device, 101 First energy storage module (energy storage module), 102 Second energy storage module (other energy storage module), 110 Energy storage cell, 112 Safety valve, 114 External terminal, 120 Stack case, 122 Lower case, 124 Cover, 130 Protective plate, 132 Covering part, 134 Edge part, 210 First bus bar, 220 Second bus bar, 310 First junction box, 312 First connector, 320 Second junction box, 322 Second connector, 400 Covering plate, 500 Case, 510 Lower case, 512 Bottom wall, 514 Peripheral wall, 514a Side wall, 520 Upper cover, 525 Shielding part, 600 Pressure relief valve, 700 Breathing membrane, h Exhaust port, S1 Wiring space, S2 One-sided space, S3 Space between boxes.

Claims

[Claim 1] Multiple energy storage modules arranged in a line along the first direction, A case for housing the aforementioned multiple energy storage modules, A pressure relief valve is provided in the aforementioned case for releasing the pressure inside the case, The case is provided with a breathing membrane that adjusts the pressure inside the case by allowing the passage of gas between the inside and outside of the case, The pressure relief valve and the breathing membrane are provided in the case at locations that are spaced apart from each other in the first direction. At least one of the plurality of energy storage modules has a plurality of energy storage cells, At least one of the plurality of energy storage cells has a safety valve for discharging gas. The distance between the respiratory membrane and the pressure relief valve is smaller than the distance between the safety valve and the pressure relief valve. An energy storage device in which the pressure relief valve and the breathing membrane are provided on adjacent surfaces of the case.

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