Power storage device

Abstract

A power storage device (1) comprises: a plurality of storage cells (110) arranged so as to line up in one direction; a smoke extraction duct (124A) defining a discharge route for gas released from the storage cells; and a cover member (200) covering the smoke extraction duct. Each of the storage cells (110) comprises a valve installation surface (112a) to which a safety valve (SV) is provided. The smoke extraction duct (124A) has a plurality of duct elements (124) that respectively cover the safety valves and are connected to one another. The cover member (200) has a contact section (215) that is in contact with the valve installation surfaces.

Description

Power storage device

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

[0002] For example, Japanese Patent Application Laid-Open No. 2022-76127 discloses a power storage module including a plurality of secondary batteries and a plurality of resin frames. Each resin frame has a partition portion that partitions between a pair of adjacent secondary batteries and a duct element connected to the upper portion of the partition portion. The duct element covers a safety valve formed on the upper surface of each secondary battery. The plurality of duct elements are connected to each other to form a smoke exhaust duct. The smoke exhaust duct forms a smoke exhaust path for discharging gas generated from the secondary battery.

[0003] Japanese Patent Application Laid-Open No. 2022-76127

[0004] In the power storage module described in Japanese Patent Application Laid-Open No. 2022-76127, there is a concern that gas may leak out of the smoke exhaust path between adjacent duct elements.

[0005] An object of the present disclosure is to provide a battery module capable of suppressing gas leaked outside the smoke exhaust duct from contacting the power storage cell.

[0006] A battery module according to an aspect of the present disclosure includes a plurality of power storage cells arranged side by side in one direction, a smoke exhaust duct defining a discharge path for gas released from the power storage cells, and a cover member covering the smoke exhaust duct. Each of the plurality of power storage cells has a valve installation surface provided with a safety valve. The smoke exhaust duct has a plurality of duct elements each covering the safety valve and connected to each other. The cover member has a contact portion that contacts the valve installation surface.

[0007] According to the present disclosure, it is possible to provide a battery module capable of suppressing gas leaked outside the smoke exhaust duct from contacting the power storage cell.

[0008] It is a perspective view schematically showing a power storage device including a battery module in an embodiment of the present disclosure. It is a plan view schematically showing a part of the battery module. It is a cross-sectional view taken along line III-III in FIG. 2. It is a cross-sectional view taken along line IV-IV in FIG. 2. It is a perspective view schematically showing a cover body.

[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 including a battery module in one embodiment of the present disclosure. Figure 2 is a schematic plan view showing a part of the battery module. Figure 3 is a cross-sectional view taken along line III-III in Figure 2. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2. This energy storage device 1 is mounted, for example, in a vehicle.

[0011] As shown in Figures 1 to 4, the energy storage device 1 comprises at least one energy storage module 10 and a housing 20. In this embodiment, the at least one energy storage module 10 includes two energy storage modules 10.

[0012] The housing 20 houses each energy storage module 10. The housing 20 has a lower case 22 and an upper cover 24 (see Figures 3 and 4). The lower case 22 is open upwards. The upper cover 24, together with the lower case 22, houses each energy storage module 10 in a sealed state. Note that the upper cover 24 is not shown in Figure 1.

[0013] Each energy storage module 10 comprises an energy storage stack 100, a cover member 200, a thermistor 300, and a busbar module 400. Note that the busbar module 400 is not shown in Figure 1.

[0014] The energy storage stack 100 includes a plurality of energy storage cells 110, a plurality of resin frames 120, a first end plate 131, and a second end plate 132.

[0015] Multiple energy storage cells 110 are arranged in a line in one direction (hereinafter referred to as "first direction DR1"). Examples of energy storage cells 110 include lithium-ion batteries. Each energy storage cell 110 has a cell case 112 and a pair of external terminals 114.

[0016] The cell case 112 houses the electrode body and electrolyte. The cell case 112 is formed in a rectangular shape. As shown in Figures 3 and 4, the cell case 112 has a valve mounting surface 112a. A safety valve SV is provided on the valve mounting surface 112a. In this embodiment, the valve mounting surface 112a is the upper surface of the cell case 112. However, the valve mounting surface 112a may be the side surface of the cell case 112 in the second direction DR2, or the bottom surface of the cell case 112. The second direction DR2 is a direction perpendicular to both the first direction DR1 and the vertical direction.

[0017] A pair of external terminals 114 are provided on the valve mounting surface 112a of the cell case 112. In this embodiment, each external terminal 114 protrudes upward from the valve mounting surface 112a. One of the pair of external terminals 114 is the positive terminal, and the other is the negative terminal. The positive terminal is provided on one side of the safety valve SV in the second direction DR2. The negative terminal is provided on the other side of the safety valve SV in the second direction DR2.

[0018] Each resin frame 120 is positioned adjacent to a storage cell 110 in the first direction DR1. Each resin frame 120 is positioned between a pair of storage cells 110 that are adjacent to each other in the first direction DR1. Each resin frame 120 has a partition portion 122 and a duct element 124.

[0019] The partition 122 is made of an insulating material (resin). The partition 122 separates the energy storage cells 110 that are adjacent to each other in the first direction DR1.

[0020] The duct element 124 is connected to the partition 122. Specifically, the duct element 124 protrudes from the partition 122 toward the valve mounting surface 112a of the cell case 112. In this embodiment, the duct element 124 is connected to the upper part of the partition 122. As shown in Figures 3 and 4, the duct element 124 has a shape that covers the safety valve SV of each energy storage cell 110.

[0021] Each duct element 124 is connected to an adjacent duct element 124 in the first direction DR1. Multiple duct elements 124 are connected to each other to form a smoke exhaust duct 124A. In other words, the smoke exhaust duct 124A consists of multiple duct elements 124 that are connected to each other. The smoke exhaust duct 124A is installed on multiple energy storage cells 110 and defines the exhaust path C (see Figures 3 and 4) for the gas released from the safety valve SV of the energy storage cells 110.

[0022] The first end plate 131 and the second end plate 132 are positioned outside the plurality of energy storage cells 110 in the first direction DR1. The first end plate 131 is in contact with one end of the exhaust duct 124A in the first direction DR1. The first end plate 131 closes the opening on one end side of the duct element 124. The second end plate 132 is spaced apart from the other end of the duct element 124 in the first direction DR1. An exhaust pipe (not shown) is provided in the gap between the second end plate 132 and the exhaust duct 124A.

[0023] The thermistor 300 can detect the temperature of the energy storage cell 110. The thermistor 300 is located outside the discharge path C. The thermistor 300 is located in a part of the cell case 112 that is separated from the exhaust duct 124A. As shown in Figures 2 and 4, the thermistor 300 is located in contact with the valve mounting surface 112a of the cell case 112.

[0024] The cover member 200 covers the exhaust duct 124A. Note that in Figure 1, one of the cover members 200 is not shown. As shown in Figures 3 and 4, the cover member 200 has a cover body 210 and a sealing member 220.

[0025] Figure 5 is a schematic perspective view of the cover body 210. The cover body 210 is made of, for example, non-combustible paper. The non-combustible paper is formed by compressing ceramic fibers into a sheet. The cover body 210 has a covering portion 212 and a flange portion 214.

[0026] The covering portion 212 covers the exhaust duct 124A. The covering portion 212 extends from one end to the other end of the exhaust duct 124A in the first direction DR1. The covering portion 212 has a pair of upright portions 212a and a connecting portion 212b.

[0027] The pair of upright portions 212a are positioned to sandwich the exhaust duct 124A in the second direction DR2. As shown in Figure 4, a notch 212s is provided in the portion of the upright portion 212a facing the thermistor 300. The notch 212s creates a gap S between the valve mounting surface 112a and the upright portion 212a.

[0028] The connecting portion 212b connects the upper ends of the pair of upright portions 212a.

[0029] The flange portion 214 is connected to the covering portion 212. The flange portion 214 protrudes outward in the second direction DR2 from the end of each upright portion 212a on the valve mounting surface 112a side.

[0030] As shown in Figures 2 and 5, the flange portion 214 is provided with slits 214s. The slits 214s are provided in the portion of the flange portion 214 facing the thermistor 300. As shown in Figure 2, the flange portion 214 is provided with three slits 214s. The first slit 214s is provided at one end of one flange portion 214 in the first direction DR1. The second slit 214s is provided at the other end of the other flange portion 214 in the first direction DR1. The third slit 214s is provided in the middle portion of one flange portion 214 in the first direction DR1.

[0031] The sealing member 220 is provided between the flange portion 214 and the valve mounting surface 112a. The sealing member 220 is made of sponge or the like. A slit is also formed in the portion of the sealing member 220 that overlaps with the slit 214s.

[0032] To prevent gas leaking from between adjacent duct elements 124 from diffusing into the housing 20 or coming into contact with the external terminals 114, the cover member 200 has a contact portion 215 that comes into contact with the valve mounting surface 112a. In this embodiment, the flange portion 214 and the sealing member 220 constitute the contact portion 215. As shown in Figure 2, the thermistor 300 is positioned such that at least a portion of the thermistor 300 faces the contact portion 215 in the first direction DR1.

[0033] The busbar module 400 is attached to the energy storage stack 100. In this embodiment, the busbar module 400 is fixed to the upper part of the energy storage stack 100. Note that the busbar module 400 is not shown in Figure 1. The busbar module 400 has a plurality of busbars 410 (see Figure 2) and a busbar case 420.

[0034] Each busbar 410 electrically connects a pair of adjacent energy storage cells 110 from among the multiple energy storage cells 110. As shown in Figure 2, each busbar 410 connects the positive external terminal 114 of one energy storage cell 110 to the negative external terminal 114 of an adjacent energy storage cell 110. Therefore, each energy storage cell 110 included in the energy storage stack 100 is connected in series by each busbar 410. Note that only some of the busbars 410 are shown in Figure 2.

[0035] The busbar case 420 holds a plurality of busbars 410. The busbar case 420 is made of, for example, synthetic resin. The busbar case 420 may be fixed to the resin frame 120. The busbar case 420 has a wall portion 422 and a pressing portion 424.

[0036] The wall portion 422 is provided in a position that sandwiches the cover member 200 together with the valve mounting surface 112a. In this embodiment, the wall portion 422 is positioned above the cover member 200. As shown in Figures 3 and 4, the wall portion 422 is located above the covering portion 212. As shown in Figure 3, the wall portion 422 may include a projection 423 that contacts the upper surface of the covering portion 212.

[0037] The pressing portion 424 presses the contact portion 215 against the valve mounting surface 112a. In this embodiment, the busbar case 420 has a pair of pressing portions 424. Each pressing portion 424 extends from the wall portion 422 toward the contact portion 215. The lower end of each pressing portion 424 is in contact with the flange portion 214. Each pressing portion 424 is located outside the upright portion 212a in the second direction DR2. Each pressing portion 424 faces the upright portion 212a. A small clearance is provided between the pressing portion 424 and the upright portion 212a.

[0038] In the energy storage device 1 described above, when gas is released from the safety valve SV of any of the energy storage cells 110, the gas flows through the discharge path C in the smoke exhaust duct 124A towards the smoke exhaust pipe. At this time, some of the gas may leak out of the smoke exhaust duct 124A from between adjacent duct elements 124. In this embodiment, since the cover member 200 covers the smoke exhaust duct 124A, the gas that leaks out of the smoke exhaust duct 124A is prevented from diffusing into the housing 20 or coming into contact with the external terminals 114.

[0039] Furthermore, since the cover member 200 is provided with a notch 212s, the gas that flows out of the cover member 200 through the gap S formed by this notch 212s comes into contact with the thermistor 300. Therefore, the thermistor 300 can detect the generation of gas.

[0040] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0041] [Aspect 1] An energy storage device comprising: a plurality of energy storage cells arranged in a line in one direction; a smoke exhaust duct that defines a discharge path for gas released from the energy storage cells; and a cover member that covers the smoke exhaust duct, wherein each of the plurality of energy storage cells has a valve mounting surface on which a safety valve is provided; the smoke exhaust duct has a plurality of duct elements, each covering the safety valve and connected to one another; and the cover member has a contact portion that contacts the valve mounting surface.

[0042] In this power storage device, since the cover member covers the smoke exhaust duct and the cover member has a contact portion, even when gas leaks outside the smoke exhaust duct from between adjacent duct elements, it is possible to prevent the gas from contacting, for example, an external terminal of the power storage cell.

[0043] [Aspect 2] The power storage device further includes a bus bar module including a bus bar that electrically connects a pair of adjacent power storage cells among the plurality of power storage cells. Each of the power storage cells includes a pair of external terminals provided on the valve installation surface. The bus bar module includes a pressing portion that presses the contact portion against the valve installation surface, as described in Aspect 1.

[0044] In this aspect, since the pressing portion presses the contact portion against the valve installation surface by connecting the bus bar module to the plurality of power storage cells, leakage of gas outside the cover member is more reliably suppressed.

[0045] [Aspect 3] The bus bar module further includes a wall portion provided at a position sandwiching the cover member together with the valve installation surface. The pressing portion extends from the wall portion toward the contact portion, as described in Aspect 2.

[0046] In this aspect, the wall portion restricts the cover member from separating from the valve installation surface due to the pressure of the gas released from the safety valve.

[0047] [Aspect 4] The power storage device further includes a thermistor provided outside the discharge path. The cover member has a notch provided at a portion facing the thermistor, as described in any one of Aspects 1 to 3.

[0048] In this aspect, since the gas flowing out of the cover member through the notch of the cover member contacts the thermistor, it is possible to detect the generation of gas by the thermistor.

[0049] [Aspect 5] The cover member further includes a covering portion that covers the smoke exhaust duct. The thermistor is separated from the covering portion, as described in Aspect 4.

[0050] [Aspect 6] The energy storage device according to aspect 5, wherein the contact portion is connected to the covering portion, and the thermistor is provided in a position where at least a part of the thermistor faces the contact portion in one direction.

[0051] In this embodiment, the gas effectively contacts the thermistor while avoiding interference between the thermistor and the covering.

[0052] [Aspect 7] The energy storage device according to aspect 1, wherein the cover member further includes a covering portion that covers the exhaust duct, and the contact portion includes a flange portion connected to the covering portion and a sealing member provided between the flange portion and the valve mounting surface.

[0053] [Aspect 8] The energy storage device according to aspects 1 to 7, wherein the cover member is made of non-combustible paper.

[0054] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure 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.

[0055] 1 Energy storage device, 10 Energy storage module, 20 Housing, 100 Energy storage stack, 110 Energy storage cell, 112 Cell case, 112a Valve mounting surface, 114 External terminal, 120 Resin frame, 122 Partition, 124 Duct element, 124A Smoke exhaust duct, 200 Cover member, 210 Cover body, 212 Covering part, 212a Upright part, 212b Connecting part, 212s Notch, 214 Flange part, 214s Slit, 215 Contact part, 220 Seal member, 300 Thermistor, 400 Busbar module, 410 Busbar, 420 Busbar case, 422 Wall part, 424 Pressing part, C Discharge path, S Gap, SV Safety valve.

Claims

1. An energy storage device comprising: a plurality of energy storage cells arranged in a line in one direction; a smoke exhaust duct defining a discharge path for gas released from the energy storage cells; and a cover member covering the smoke exhaust duct, wherein each of the plurality of energy storage cells has a valve mounting surface on which a safety valve is provided; the smoke exhaust duct has a plurality of duct elements, each covering the safety valve and connected to one another; and the cover member has a contact portion that contacts the valve mounting surface.

2. The energy storage device according to claim 1, further comprising a busbar module including a busbar that electrically connects a pair of adjacent energy storage cells from among the plurality of energy storage cells, each energy storage cell including a pair of external terminals provided on the valve mounting surface, and the busbar module including a pressing portion that presses the contact portion against the valve mounting surface.

3. The energy storage device according to claim 2, wherein the busbar module further includes a wall portion provided at a position that sandwiches the cover member together with the valve mounting surface, and the pressing portion extends from the wall portion toward the contact portion.

4. The energy storage device according to claim 1, further comprising a thermistor provided outside the discharge path, wherein the cover member has a notch provided in a portion facing the thermistor.

5. The energy storage device according to claim 4, wherein the cover member further includes a covering portion that covers the exhaust duct, and the thermistor is separated from the covering portion.

6. The energy storage device according to claim 5, wherein the contact portion is connected to the covering portion, and the thermistor is provided in a position where at least a portion of the thermistor faces the contact portion in one direction.

7. The energy storage device according to claim 1, wherein the cover member further includes a covering portion that covers the exhaust duct, and the contact portion includes a flange portion connected to the covering portion and a sealing member provided between the flange portion and the valve mounting surface.

8. The energy storage device according to claim 1, wherein the cover member is made of non-combustible paper.

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