Electric energy storage device

Abstract

To provide a power storage device that allows a simple configuration to be used to fix a power storage stack to an accommodation case appropriately and can suppress a short circuit of the power storage stack when dew condensation occurs in the accommodation case.SOLUTION: A power storage device 100 comprises: a power storage stack 10; an accommodation case that has a bottom wall portion 23 and accommodates the power storage stack 10 therein; and an adhesive layer 40 that has thermal conductivity and fixes the power storage stack 10 to the bottom wall portion 23. The bottom wall portion 23 includes a receiving portion 24 that has a receiving surface 24a on which the power storage stack 10 is received, a lower wall portion 25 located at a position lower in level than the receiving surface 24a, and a connecting portion 26 that interconnects the receiving portion 24 and the lower wall portion 25. The adhesive layer 40 has a portion 41 disposed between the receiving surface 24a and the power storage stack 10, and a protruding portion 42 that protrudes from the receiving surface 24a to the connecting portion 26.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As a conventional power storage device, Japanese Unexamined Patent Application Publication No. 2019-125449 (Patent Document 1) discloses a device in which a cooler, a heat transfer member, and a power storage stack are housed in a housing case, and are arranged in this order from the side of the bottom wall portion of the case. The heat transfer member is sandwiched between the power storage stack and the cooler, and includes rubber particles and a resin with high thermal conductivity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, in a power storage device in which a cooler, a heat transfer member, and a power storage stack as disclosed in Patent Document 1 are housed in a housing case, a fixing structure for fixing the cooler to the housing case and a fixing structure for fixing the power storage stack to the housing case are provided.

[0005] In recent years, higher capacity of the power storage device has been demanded, and the power storage module housed in the case has also been increased in size and become larger. In order to simplify the above fixing structure or effectively utilize the space in the housing case, it is conceivable to arrange the cooler outside the housing case.

[0006] In such a case, when the power storage stack is fixed to the bottom wall portion of the housing case using an adhesive layer having thermal conductivity without any special measures, when the power storage stack is pressed against the housing case through the adhesive layer, the housing case may be deformed, or the housing case may not be pressed sufficiently. Further, when condensation occurs in the housing case, the power storage stack may be short-circuited.

[0007] The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a power storage device that can appropriately fix a power storage stack to a housing case with a simple configuration and can suppress a short circuit of the power storage stack when condensation occurs in the housing case.

Means for Solving the Problems

[0008] A power storage device according to the present disclosure includes a power storage stack, a housing case having a bottom wall portion for housing the power storage stack, and an adhesive layer having thermal conductivity for fixing the power storage stack to the bottom wall portion. The bottom wall portion includes a placement portion having a placement surface on which the power storage stack is placed, a low wall portion located at a position lower in height than the placement surface, and a connection portion connecting the placement portion and the low wall portion. The adhesive layer has a portion disposed between the placement surface and the power storage stack and an overhanging portion protruding from the placement surface to the connection portion.

[0009] According to the above configuration, since the power storage stack is fixed to the bottom wall portion of the housing case by the adhesive layer having thermal conductivity, the power storage stack can be fixed with a simple configuration. Further, by fixing the power storage stack to the bottom wall portion such that the adhesive layer protrudes from the placement surface, it is possible to reduce the loss of pressing load when pressing and fixing the power storage stack to the bottom wall portion. As a result, the power storage stack can be pressed sufficiently against the bottom wall portion. Furthermore, since the bottom wall portion has the placement surface and the low wall portion, the rigidity of the bottom wall portion can be increased, so that deformation of the bottom wall portion can be suppressed when the power storage stack is pressed against the bottom wall portion for fixing.

[0010] In addition, when condensation occurs inside the storage case, the condensed water moves to a low wall portion located at a position lower than the placement surface. Therefore, it is possible to prevent the power storage stack placed on the placement surface from being short-circuited by the condensed water.

[0011] In the power storage device according to the present disclosure, the power storage stack includes a plurality of power storage cells arranged side by side in the arrangement direction. In this case, the placement surface may include a first portion on which one side of the power storage stack in the intersection direction intersecting the arrangement direction is placed, a second portion on which the other side of the power storage stack in the intersection direction is placed, and a concave portion provided between the first portion and the second portion.

[0012] According to the above configuration, when the power storage stack is pressed against the adhesive layer, air can escape from the gap between the concave portion provided between the first portion and the second portion and the power storage stack. Therefore, it is possible to suppress the formation of an air layer between the power storage stack and the adhesive layer. Thereby, it is possible to suppress a decrease in heat transfer efficiency.

[0013] The power storage device according to the present disclosure is disposed outside the storage case and further includes a cooler for cooling the power storage stack. In this case, the cooler may include a cooling portion having a cooling flow path through which a cooling medium flows. Further, in this case, it is preferable that the cooling portion is disposed so as to contact the back surface of the placement portion located on the side opposite to the side where the placement surface is located.

[0014] According to the above configuration, the placement portion can be efficiently cooled by the cooling portion, and thereby, the power storage stack placed on the placement surface can be efficiently cooled.

Advantages of the Invention

[0015] According to the present disclosure, it is possible to provide a power storage device that can appropriately fix a power storage stack to a storage case with a simple configuration and can suppress a short circuit of the power storage stack when condensation occurs inside the storage case.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0018] (Embodiment 1) FIG. 1 is an exploded perspective view of the power storage device according to Embodiment 1. With reference to FIG. 1, the power storage device 100 according to Embodiment 1 will be described.

[0019] The power storage device 100 is mounted on a hybrid vehicle that can travel using the power of at least one of a motor and an engine, or an electric vehicle that travels with a driving force obtained by electric energy.

[0020] The power storage device 100 includes a plurality of power storage stacks 10, a housing case 20, a cooler 30, an adhesive layer 40 (see FIG. 2), and a shared panel 50.

[0021] Each of the plurality of power storage stacks 10 includes a plurality of power storage cells 11 arranged side by side in the array direction DR1. In a mounted state where the power storage device 100 is mounted on a vehicle, the array direction DR1 is substantially parallel to, for example, the left-right direction of the vehicle. The plurality of power storage cells 11 are sandwiched in the array direction DR1 by a pair of end plates 16 (see FIG. 2). A spacer 15 (see FIG. 2) is disposed between adjacent power storage cells 11.

[0022] The plurality of power storage stacks 10 are arranged side by side in an intersection direction DR2 that intersects the array direction DR1 (more specifically, a direction orthogonal to the array direction). In the mounted state, the intersection direction DR2 is substantially parallel to, for example, the front-rear direction of the vehicle.

[0023] Each of the plurality of power storage stacks 10 is fixed to the bottom wall portion 23 of the housing case 20 by an adhesive layer 40 (see FIG. 2).

[0024] The power storage cell 11 is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The single cell has, for example, a rectangular shape. The secondary battery may use a liquid electrolyte or a solid electrolyte. Further, the power storage cell may be a unit capacitor configured to be able to store electricity.

[0025] The housing case 20 houses the plurality of power storage stacks 10 inside. The housing case 20 includes an upper case 21 and a lower case 22. The upper case 21 has a substantially box-shaped shape that opens downward. The lower case 22 includes a bottom wall portion 23 and has a substantially box-shaped shape that opens upward.

[0026] The bottom wall portion 23 includes, for example, a mounting portion 24, a pair of low wall portions 25, and a pair of connecting portions 26. The mounting portion 24 has a mounting surface 24a on which the power storage stack 10 is mounted. The mounting surface 24a is provided to be substantially flat. The mounting surface 24a is partitioned into a plurality in the intersection direction by a partitioning member 27. The power storage stack 10 is disposed in each of the plurality of partition regions R1 partitioned by the partitioning member 27.

[0027] A pair of low wall portions 25 are provided at both ends of the bottom wall portion 23 in the above-described arrangement direction. The low wall portions 25 extend along the direction (crossing direction DR2) in which the plurality of power storage stacks 10 are arranged. The low wall portions 25 are located at positions lower in height than the placement surface 24a. The height direction is a direction parallel to the direction in which the upper case 21 and the lower case 22 are arranged, and corresponds to the vertical direction.

[0028] A pair of connection portions 26 connect the pair of low wall portions 25 and the placement portion 24. The pair of connection portions 26 are curved so that the height position becomes lower as they go toward the outside in the above-described arrangement direction.

[0029] The cooler 30 is a device for cooling the plurality of power storage stacks 10. The cooler 30 is disposed outside the housing case 20. Specifically, the cooler 30 is disposed below the bottom wall portion 23 of the lower case 22.

[0030] The cooler 30 is made of a metal material such as aluminum. The cooler 30 includes a plurality of cooling portions 32 and a holding frame portion 34.

[0031] The plurality of cooling portions 32 are arranged side by side in a direction parallel to the above-described crossing direction DR2. Each of the plurality of cooling portions 32 is disposed at a position facing the power storage stack 10 with the bottom wall portion 23 interposed therebetween. The cooling portion 32 is disposed so as to be in thermal contact with the back surface 24b (see FIG. 2) of the placement portion 24 on the side opposite to the side where the placement surface 24a is located. Thereby, the placement portion 24 can be efficiently cooled by the cooling portion 32, and the power storage stack 10 placed on the placement surface 24a can be efficiently cooled via the adhesive layer 40.

[0032] Note that the cooling portion 32 has a cooling flow path 32a (see FIG. 4) through which a cooling medium (such as water) for cooling the power storage stack 10 flows.

[0033] The holding frame portion 34 holds each cooling portion 32. The holding frame portion 34 is formed in an annular shape surrounding the plurality of cooling portions 32. In the present embodiment, the holding frame portion 34 is formed in a substantially rectangular shape. Each cooling portion 32 is connected to the holding frame portion 34 at both end portions in the above arrangement direction.

[0034] The shared panel 50 is arranged so as to cover the cooler 30 from below. The shared panel 50 protects the cooler 30. The shared panel 50 is made of a metal material.

[0035] FIG. 2 is a partial cross-sectional view of the power storage device showing one end side of the power storage stack in the power storage device according to Embodiment 1. Note that one end side of the power storage stack 10 is one end side in the above arrangement direction DR1. Also, in FIG. 2, for the sake of convenience, the cooler 30 and the shared panel 50 are omitted.

[0036] As shown in FIG. 2, the bottom wall portion 23 is provided such that the placement portion 24 is located at a position higher than the entire low wall portion 25. Thereby, the rigidity of the bottom wall portion 23 can be increased.

[0037] Further, the power storage stack 10 is placed on the placement portion 24 such that the end plate 16 is located above the low wall portion 25. A protection member 28 for protecting the power storage stack 10 is arranged on the low wall portion 25.

[0038] As described above, the power storage stack 10 is fixed to the bottom wall portion 23 by the adhesive layer 40. Thereby, the power storage stack 10 can be fixed with a simple configuration.

[0039] The adhesive layer 40 is composed of a resin member having thermal conductivity. As the adhesive layer 40, for example, an adhesive containing a silicone-based resin, an acrylic-based resin, or an epoxy resin can be employed. Note that the adhesive layer 40 is formed by curing the adhesive.

[0040] The subsequent layer 40 has a portion 41 disposed between the power storage stack 10 and the mounting surface 24a, and an overhanging portion 42 that protrudes from the mounting surface 24a to the connecting portion 26.

[0041] When fixing the power storage stack 10 to the bottom wall portion 23, an adhesive member is applied to the mounting surface 24a, and the power storage stack 10 is pressed toward the bottom wall portion 23. By spreading the adhesive with the power storage stack 10 and forming the adhesive layer 40 so as to protrude from the mounting surface 24a, the pressing load loss can be reduced. Thereby, the power storage stack 10 can be sufficiently pressed against the bottom wall portion 23.

[0042] At the bottom of the power storage stack 10, unevenness may be formed due to the height positions of the bottom surfaces of the plurality of power storage cells 11 being displaced. Even in such a case, as described above, by pressing the power storage stack 10 against the bottom wall portion 23, the adhesive can be deformed so as to follow the unevenness. Thereby, the adhesive layer 40 can be brought into close contact with the bottom of the power storage stack 10, and good thermal conductivity can be ensured.

[0043] Further, since the bottom wall portion 23 has the mounting portion 24 and the low wall portion 25 with different height positions, the rigidity of the bottom wall portion 23 is increased. Therefore, when pressing and fixing the power storage stack 10 to the bottom wall portion 23, deformation of the bottom wall portion 23 can be suppressed.

[0044] In addition, when condensation occurs in the housing case 20, the condensed water moves to the low wall portion 25 located at a position lower than the mounting surface 24a. Therefore, it is possible to prevent the power storage stack 10 mounted on the mounting surface 24a from being short-circuited by the condensed water.

[0045] (Embodiment 2) FIG. 3 is an exploded perspective view of the power storage device according to Embodiment 2. FIG. 4 is a cross-sectional view of the power storage device showing the bottom wall portion side of the housing case in the power storage device according to Embodiment 2. With reference to FIGS. 3 and 4, the power storage device 100A according to Embodiment 2 will be described.

[0046] As shown in FIGS. 3 and 4, when the power storage device 100A according to the second embodiment is compared with the power storage device 100 according to the first embodiment, the shape of the mounting portion 24 and the configuration of the cooler 30 are different. For other configurations, they are substantially the same as those in the first embodiment.

[0047] In each partition region R1, the mounting surface 24a has a first portion 241, a second portion 242, and a recess 243.

[0048] On the first portion 241, one side of the power storage stack 10 in the crossing direction DR2 is mounted. On the second portion 242, the other side of the power storage stack 10 in the crossing direction DR2 is mounted. The recess 243 is provided between the first portion 241 and the second portion 242. The recess 243 is provided so as to be continuous from one end to the other end of the mounting surface 24a in the array direction DR1.

[0049] Also, in the second embodiment, in each partition region R1, a low wall portion 25 is provided so as to surround the mounting surface 24a when viewed from above.

[0050] The cooler 30 has a different number of cooling portions 32 compared with the first embodiment. The plurality of cooling portions 32 are provided so as to correspond to the first portion 241 and the second portion 242 in each partition region R1. The plurality of cooling portions 32 are in thermal contact with the back surface 24b of the portion located on the opposite side of the first portion 241 and the second portion 242 via a heat conduction layer 60. As the heat conduction layer 60, for example, a silicone-based resin, an acrylic-based resin, an epoxy resin, or the like can be employed. Note that the heat conduction layer 60 may be omitted.

[0051] Also in the second embodiment, the adhesive layer 40 has a portion disposed between the first portion 241 and the second portion 242 and the power storage stack 10, and a protruding portion 42 that protrudes from the mounting surface 24a to the connection portion 26. Thereby, substantially the same effect as in the first embodiment can be obtained.

[0052] In addition, when fixing the power storage stack 10, an adhesive member is applied to the first portion 241 and the second portion 242, and when pressing the power storage stack 10 against the bottom wall portion 23, air can escape from the gap S between the concave portion 243 and the power storage stack 10. Therefore, it is possible to suppress the formation of an air layer between the power storage stack 10 and the adhesive layer 40. Thereby, it is possible to suppress a decrease in heat transfer efficiency.

[0053] As described above, the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

Description of Reference Numerals

[0054] 10 Power storage stack, 11 Power storage cell, 15 Spacer, 16 End plate, 20 Housing case, 21 Upper case, 22 Lower case, 23 Bottom wall portion, 24 Mounting portion, 24a Mounting surface, 24b Back surface, 25 Low wall portion, 26 Connection portion, 27 Partition member, 28 Protection member, 30 Cooler, 32 Cooling portion, 32a Cooling flow path, 34 Holding frame portion, 40 Adhesive layer, 42 Overhang portion, 50 Shared panel, 60 Heat conduction layer, 100, 100A Power storage device, 241 First portion, 242 Second portion, 243 Concave portion.

Claims

1. A storage battery cell, a lower case having a bottom wall portion located below the storage battery cell, and a cooler disposed below the lower case, wherein the bottom wall portion includes a placement portion on which the storage battery cell is placed and a low wall portion located below the placement portion, the low wall portion includes a portion arranged overlapping the storage battery cell in the vertical direction, the cooler is arranged in contact with the placement portion directly or via a heat conducting member. A power storage device.

2. The power storage device according to claim 1, further comprising a plurality of the storage battery cells, the plurality of storage battery cells are arranged side by side in a first direction, and the portion and the placement portion arranged overlapping the storage battery cell in the vertical direction extend in the first direction.

3. The placement portion has a first portion and a second portion spaced apart in a second direction orthogonal to the first direction, and the portion arranged overlapping the storage battery cell in the vertical direction is arranged between the first portion and the second portion in the second direction. The power storage device according to claim 2.

4. The power storage device according to claim 3, wherein the portion arranged overlapping the storage battery cell in the vertical direction overlaps with the central portion of the storage battery cell in the second direction in the vertical direction.

5. The storage battery cell is placed on the placement portion with an adhesive layer interposed therebetween, and the adhesive layer has heat conductivity. The power storage device according to claim 4.

6. The power storage device according to claim 5, further comprising a panel member, wherein the panel member is disposed below the cooler.

7. The storage battery cell is placed on the placement portion with an adhesive layer interposed therebetween, the bottom wall portion includes a connecting portion connecting the portion arranged overlapping the storage battery cell in the vertical direction and the placement portion, and the adhesive layer is arranged to protrude from the placement portion toward the connecting portion. The power storage device according to any one of claims 1 to 6.

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