Electric storage cell

Abstract

To provide a power storage cell capable of suppressing inhibition of heat transfer between the power storage cell and a cooler.SOLUTION: A power storage cell 60 includes an electrode body 61, a cell case 70 housing the electrode body 61, and a thermally conductive film T formed on an outer surface 80 of the cell case 70. The outer surface 80 includes a facing surface 82 facing the cooler 19 provided outside. The thermally conductive film T is formed on the facing surface 82 and has an insulating property and elasticity.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2018-37343 discloses an electricity storage device including an electricity storage cell and a cooler. The surface of the electricity storage cell is covered with an insulating film. The electricity storage cell is placed on the cooler with a thermally conductive material sandwiched between the insulating film and the cooler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-037343 Summary of the Invention [Problem to be solved by the invention]

[0004] The energy storage cell of the energy storage device disclosed in JP 2018-037343 A is placed on a cooler with an insulating film and a thermally conductive material sandwiched between them. When the energy storage cell expands or contracts, the insulating film wrinkles or kinks, creating an air layer at the interface between the energy storage cell and the insulating film. As a result, heat transfer between the energy storage cell and the cooler is hindered.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide an energy storage device that can suppress the obstruction of heat transfer between the energy storage cells and the cooler. [Means for solving the problem]

[0006] A storage cell according to a first aspect of the present disclosure comprises an electrode body, a cell case that houses the electrode body, and a heat conductive film formed on the outer surface of the cell case, the outer surface including an opposing surface that faces an externally provided cooler, and the heat conductive film is formed on the opposing surface and has insulating and elastic properties.

[0007] The thermal conductive film of the energy storage cell according to the first aspect of the present disclosure has elasticity of 5 points or more on a Type C durometer and 50 points or less on a Type A durometer, and the breakdown voltage of the thermal conductive film is 5 kV / mm or more and 30 kV / mm or less.

[0008] The elasticity of the heat conductive film of the storage cell according to the first aspect of the present disclosure includes an insulating filer material.

[0009] A storage cell according to a first aspect of the present disclosure is housed in a storage device, the storage device including a housing case and a cooler, the housing case including an upper cover and a lower case, the lower case having a bottom plate and a wall portion formed to rise from the bottom plate in a first direction, the bottom plate supporting the storage cell in the first direction, and the cooler provided on the bottom plate and positioned on the opposite side of the storage cell in the first direction with respect to the bottom plate.

[0010] The energy storage cell according to a first aspect of the present disclosure further includes an exhaust valve and an external terminal, and the outer surface has an end face arranged at a distance from the opposing face in a first direction, and a peripheral face connecting the opposing face and the end face, the peripheral face having a first side face and a second side face arranged at a distance from the first side face in a second direction intersecting the first direction, the exhaust valve is formed on the outer surface, the external terminal is formed on at least one of the first side face and the second side face, and the heat conduction film is formed to avoid the external terminal and the exhaust valve. [Effects of the Invention]

[0011] According to the energy storage cell according to the present disclosure, it is possible to prevent the heat transfer between the energy storage cell and the cooler from being hindered. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a side view showing a vehicle equipped with a power storage device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an exploded perspective view of the power storage device according to the embodiment of the present disclosure. [Figure 3] FIG. 1 is a perspective view of a storage cell according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] FIG. 10 is a perspective view showing a modified example of the storage cell according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0014] FIG. 1 is a side view that schematically shows a vehicle equipped with a power storage device according to this embodiment. Note that the up-down direction H shown in FIG. 1 indicates the up-down direction of the vehicle 1. The width direction W indicates the width direction of the vehicle 1. The front-rear direction D indicates the front-rear direction of the vehicle 1. Note that the up-down direction H and the width direction W are examples of the "first direction" and "second direction" of the present disclosure, respectively.

[0015] The vehicle 1 includes a vehicle body 2 and a power storage device 3. The vehicle 1 includes, for example, a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), or a fuel cell electric vehicle (FCEV). The power storage device 3 is mounted on a lower portion of the vehicle body 2.

[0016] 2 is an exploded perspective view of the power storage device according to the embodiment of the present disclosure. The power storage device 3 includes a housing case 10, a power storage stack 50, and a cooler 19 shown in FIG.

[0017] The housing case 10 includes an upper cover 11 and a lower case 12. The housing case 10 defines a housing space R defined by the upper cover 11 and the lower case 12.

[0018] The upper cover 11 is formed to cover a lower case 12 that is formed to open upward.

[0019] The lower case 12 includes a bottom plate 13 and a wall portion 14. The bottom plate 13 supports the electricity storage stack 50 in the up-down direction H.

[0020] The wall portion 14 is formed to rise upward from the bottom plate 13 in the up-down direction H. The wall portion 14 has a peripheral wall 15 and a reinforcing portion 18. The peripheral wall 15 is formed to extend annularly and is formed to extend upward in the up-down direction H from the outer circumferential edge of the bottom plate 13. The peripheral wall 15 has a first side wall 16 and a second side wall 17. The first side wall 16 and the second side wall 17 are formed to extend in the front-rear direction D and are arranged at an interval in the width direction W.

[0021] The reinforcing portion 18 is formed to extend in the front-rear direction D. The reinforcing portion 18 is disposed to pass through the center between the first side wall 16 and the second side wall 17 in the width direction W.

[0022] The power storage stack 50 is accommodated in the accommodation space R. The power storage stack 50 is formed from a plurality of power storage cells 60. The plurality of power storage cells 60 are arranged in a front-rear direction D. The power storage cells 60 are formed in the shape of a rectangular parallelepiped that is elongated in the width direction W.

[0023] 3 is a perspective view of an energy storage cell 60 according to an embodiment of the present disclosure. The energy storage cell 60 includes a cell case 70, an external terminal 91, and an exhaust valve 92.

[0024] The cell casing 70 is formed in the shape of a rectangular parallelepiped. The cell casing 70 is made of a metal such as aluminum. The cell casing 70 has an outer surface 80. The outer surface 80 has a first end face 81, a second end face 82, and a peripheral surface 83. The first end face 81 and the second end face 82 are arranged with an interval in the up-down direction H. The second end face 82 is positioned closer to the bottom plate 13 than the first end face 81. The second end face 82 is the surface that faces the bottom plate 13.

[0025] The peripheral surface 83 is formed to connect the first end surface 81 and the second end surface 82. The peripheral surface 83 has a first side surface 83a, a second side surface 83b, a first long surface 83c, and a second long surface 83d. The first side surface 83a and the second side surface 83b are arranged at an interval in the width direction W. The first long surface 83c and the second long surface 83d are arranged at an interval in the front-rear direction D. The first long surface 83c is formed to extend in the width direction W and is formed to connect one end of the first side surface 83a to one end of the second side surface 83b. The second long surface 83d is formed to extend in the width direction W and is formed to connect the other end of the first side surface 83a to the other end of the second side surface 83b. In the power storage stack 50, at least one of the first long faces 83c and the second long faces 83d of the plurality of power storage cells 60 faces an adjacent power storage cell 60.

[0026] The external terminal 91 and the exhaust valve 92 are provided on the first end face 81. The exhaust valve 92 opens when the gas pressure inside the cell casing 70 reaches or exceeds a certain level. In other words, the first end face 81 on which the exhaust valve 92 is provided constitutes the pressure release surface of the cell casing 70.

[0027] 4 is a cross-sectional view taken along the line IV-IV in FIG. 1. The cooler 19 is provided on the bottom plate 13 with a heat transfer material 21 sandwiched therebetween. The cooler 19 is disposed on the opposite side of the bottom plate 13 from the energy storage cells 60 in the up-down direction H. The cooler 19 faces the second end surface 82 with the bottom plate 13 sandwiched therebetween. In this embodiment, the cooler 19 cools the energy storage cells 60 of the energy storage stack 50. A cooling medium (oil, etc.) flows inside the cooler 19. The second end surface 82 facing the cooler 19 is an example of the "facing surface" of the present disclosure.

[0028] The storage case 10 further has a shear panel 20. The shear panel 20 is located on the opposite side of the bottom plate 13 from the storage cells 60 in the up-down direction H. The shear panel 20 is provided on the bottom plate 13 with a cooler 19 sandwiched therebetween. The shear panel 20 has a function of protecting the lower case 12. The shear panel 20 may be formed in a flat plate shape.

[0029] The energy storage cell 60 further includes an electrode assembly 61 housed in a cell case 70, and a heat conduction film T formed on an outer surface 80 of the cell case 70. The heat conduction film T is formed on the outer surface 80, avoiding the external terminal 91 and the exhaust valve 92. More preferably, the heat conduction film T is formed so as to cover the entire second end face 82 and the entire circumferential surface 83 of the energy storage cell 60, avoiding the external terminal 91 and the exhaust valve 92. This can promote the dissipation of heat generated from inside the storage case 10 to the outside.

[0030] The thermally conductive film T has elasticity. The thickness of the thermally conductive film T formed on the outer surface 80 is 1 mm or more and 10 mm or less. By using such a thermally conductive film T, it is possible to prevent gaps from being generated between the energy storage cells 60 and the bottom plate 13. As a result, it is possible to prevent the heat transfer between the energy storage cells 60 and the bottom plate 13 from being hindered by gaps. In addition, the thermally conductive film T functions as an elastic body between adjacent energy storage cells 60. This allows the number of parts of the energy storage device 3 to be reduced compared to when elastic bodies are disposed between the multiple energy storage cells 60.

[0031] Here, the thermal conduction film T having elasticity means that the film has a hardness of 5 points or more in a measurement method using a Type C durometer based on JIS K 7312, and 50 points or less in a measurement method using a Type A durometer based on JIS K 6253-3. This makes it possible to prevent the thermal conduction film T from being damaged when the energy storage cell 60 is assembled into the casing 10. In addition, the thermal conduction film T can prevent the energy storage cell 60 from being hindered from adhering to adjacent members of the energy storage cell 60.

[0032] The thermal conductivity of the thermally conductive film T is 1.0 W / mK or more and 30.0 W / mK or less. By using such a thermally conductive film T, it is possible to prevent the heat transfer between the power storage cells 60 and the bottom plate 13 from being hindered without interposing a heat-conductive material between the power storage cells 60 and the bottom plate 13. As a result, the number of parts in the power storage device 3 can be reduced. The thermally conductive film T may contain an insulating filler material. The insulating filler material is made of a material such as an inorganic compound. More specifically, the insulating filler material is made of a material such as a silicon compound such as fused silica, a metal oxide such as alumina or magnesium, or a nitrogen compound such as boron nitride or aluminum nitride. By including the insulating filler material in the thermally conductive film T, the thermal conductivity of the thermally conductive film T can be improved.

[0033] The thermally conductive film T has insulating properties. The breakdown voltage of the thermally conductive film T is 5 kV / mm or more and 30 kV / mm or less. The volume resistivity of the thermally conductive film T is 1.0×10 10 Ω·cm or more, 1.0×10 17 The electrical resistivity is Ω·cm or less. By using such a thermally conductive film T, it is possible to prevent the power storage cell 60 from being electrically connected to the adjacent power storage cell 60 or the like.

[0034] The thermally conductive film T covers the cell case 70 after hardening. For example, the thermally conductive film T is fixed to the cell case 70 during the hardening process. The thermally conductive film T does not have adhesive properties after hardening. In other words, the energy storage cells 60 housed in the housing space R are not bonded to the bottom plate 13. By using such a thermally conductive film T, the energy storage cells 60 can be easily removed from the energy storage device 3. Furthermore, the thermally conductive film T does not have to be fixed to the cell case 70. This allows the thermally conductive film T to be easily peeled off from the cell case 70.

[0035] The material forming the thermally conductive film T is paste-like when uncured. Preferably, the material forming the thermally conductive film T has thixotropy when uncured. The material forming the thermally conductive film T is a curable liquid material. The curable liquid material is, for example, a one-component or two-component potting material or a gap filler. The material forming the thermally conductive film T is a material that hardens by heat curing, room temperature curing, moisture curing, or ultraviolet curing. The material forming the thermally conductive film T has a base resin of silicone resin, epoxy resin, or urethane resin. By forming the thermally conductive film T using such a material, defects or damage to the thermally conductive film T can be repaired by touch-up. As a result, the increase in labor required for repairs can be suppressed compared to replacing the entire thermally conductive film T covering the energy storage cell 60. Here, the viscosity of the material forming the thermally conductive film T when uncured is 0.1 Pa·s or more and 500 Pa·s or less. This allows the thermally conductive film T to be formed on the cell casing 70 by coating or dipping. In addition, it is possible to prevent the thermal conductive film T from becoming thin due to sagging or the like during the curing process.

[0036] In the above embodiment, the thermally conductive film T is formed on the entire surface of the outer surface 80, but the present disclosure is not limited thereto. For example, the thermally conductive film T may not be formed on the first end surface 81. Alternatively, the thermally conductive film T may be formed only on the surface of the outer surface 80 that contacts the adjacent energy storage cell 60 and the surface that contacts the bottom plate 13. More specifically, the thermally conductive film T may be formed only on the second end surface 82 and at least one of the first long surface 83c and the second long surface 83d. Furthermore, the thermally conductive film T may be formed only on a portion of the surface of the outer surface 80 that faces the adjacent energy storage cell 60. By forming the thermally conductive film T on a portion, a gap is formed between the adjacent energy storage cells. This ensures spatial insulation and makes it possible to prevent short circuits between the adjacent energy storage cells 60.

[0037] In the above embodiment, the thermally conductive film T is formed on the outer surface 80, avoiding the external terminal 91 and the exhaust valve 92. This makes it possible to prevent the thermally conductive film T applied to the cell casing 70 from impairing the functions of the external terminal 91 and the exhaust valve 92.

[0038] In the above embodiment, an example was shown in which the exhaust valve 92 was provided on the first end surface 81, but the present disclosure is not limited to this. For example, as shown in FIG. 5, the exhaust valve 92 may be provided on the second end surface 82.

[0039] In the above embodiment, an example has been shown in which the external terminals 91 are provided on the first end surface 81, but the present disclosure is not limited to this. For example, as shown in Fig. 5, the external terminals 91 may be provided on both the first side surface 83a and the second side surface 83b. Alternatively, the external terminals 91 may be provided on only one of the first side surface 83a or the second side surface 83b. <Method for forming the thermal conductive film T> Next, an example of a method for forming the thermally conductive film T of the energy storage cell 60 will be described. The method for forming the thermally conductive film T includes, in order of steps, a preparation step, a curing step, a coating step, and a drying step. Each step will be described in detail below.

[0040] In the preparation process, the energy storage cell 60 is prepared before the thermal conduction film T is formed. In the curing process, the external terminals 91 and exhaust valves 92 of the energy storage cell 60 prepared in the preparation process are masked. Also in the preparation process, an insulating filler is added to the uncured material of the thermal conduction film T and mixed well. In the painting process, the material of the thermal conduction film T is applied to the energy storage cell 60. The application is performed by dipping or coating. In the drying process, the applied material of the thermal conduction film T is dried and the thermal conduction film T is cured. Through the above processes, the thermal conduction film T is formed on the outer surface 80 of the energy storage cell 60.

[0041] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0042] 1 vehicle, 2 vehicle body, 3 energy storage device, 10 storage case, 11 upper cover, 12 lower case, 13 bottom plate, 14 wall portion, 15 peripheral wall, 16 first side wall, 17 second side wall, 18 reinforcement portion, 19 cooler, 20 share panel, 21 heat transfer material, 50 energy storage stack, 60 energy storage cell, 61 electrode body, 70 cell case, 80 outer surface, 81 first end face, 82 second end face, 83 peripheral surface, 83a first side face, 83b second side face, 83c first long face, 83d second long face, 91 external terminal, 92 exhaust valve, R storage space, T heat conduction film.

Claims

1. an electrode assembly, a cell case that houses the electrode assembly, and a heat conductive film formed on the outer surface of the cell case; the outer surface includes an opposing surface facing an externally provided cooler, The heat conductive film is formed on the opposing surface and has elasticity and insulation properties.

2. 2. The energy storage cell according to claim 1, wherein the thermal conduction film has an elasticity of 5 points or more on a Type C durometer and 50 points or less on a Type A durometer, and the thermal conduction film has a breakdown voltage of 5 kV / mm or more and 30 kV / mm or less.

3. The energy storage cell according to claim 1 , wherein the thermally conductive film contains an insulating filer material.

4. The storage cell is housed in a storage device, The power storage device includes a housing case and the cooler, The housing case includes an upper cover and a lower case, the lower case has a bottom plate and a wall portion formed to rise from the bottom plate in a first direction, the bottom plate supports the energy storage cells in the first direction; The energy storage cell according to claim 1 , wherein the cooler is provided on the bottom plate and is disposed on an opposite side of the bottom plate from the energy storage cell in the first direction.

5. The storage cell further includes an exhaust valve and an external terminal, the outer surface has an end surface arranged at an interval from the opposing surface in the first direction, and a circumferential surface connecting the opposing surface and the end surface, the peripheral surface has a first side surface and a second side surface arranged at an interval from the first side surface in a second direction intersecting the first direction, The exhaust valve is formed on the outer surface, the external terminal is formed on at least one of the first side surface and the second side surface, The energy storage cell according to claim 1 , wherein the thermally conductive film is formed so as to avoid the external terminal and the exhaust valve.

Images