Electricity storage device

Abstract

A power storage device includes: a power storage cell having a first surface; a cooler having a second surface facing the first surface and cooling the power storage unit from the first surface side; and a heat conduction material which is applied to the second surface and is in contact with the first surface. The thermally conductive material expands on the second surface in a first direction and a second direction perpendicular to the first direction. The length of the heat conduction material in the first direction and the length of the heat conduction material in the second direction are 80 mm or less.

Description

Technical Field

[0001] This disclosure relates to energy storage devices. Background Technology

[0002] Previously, electric vehicles such as battery electric vehicles and hybrid electric vehicles were known. These electric vehicles operate by using electricity stored in an energy storage device to drive an electric motor. The energy storage device comprises modules with multiple energy storage units stacked on top of each other. Each energy storage unit is cooled by a cooler. A heat-conducting material is placed between each energy storage unit and the cooler. Generally, after applying the heat-conducting material to the cooler, the module is placed on the cooler. This allows the heat-conducting material to spread out. The heat-conducting material then hardens.

[0003] Japanese Patent Application Publication No. 2016-203050 discloses a method for applying a coating liquid containing a curing component to a sheet that is moving relative to each other, wherein the coating liquid hardens to form a coating film. In Japanese Patent Application Publication No. 2016-203050, one or three stripes of coating film are formed along the conveying direction of the sheet. Summary of the Invention

[0004] During the hardening of a heat-conducting material, volume shrinkage (hardening shrinkage) occurs due to changes in the cross-linking density of the material. In particular, when the heat-conducting material is continuously coated over a long distance on a cooler, stress concentration occurs at the interfaces (contact areas) between the two ends of the material along its length and the energy storage unit. As a result, these ends may peel off from the energy storage unit.

[0005] This disclosure provides an energy storage device capable of suppressing the stripping of thermally conductive material from the energy storage unit.

[0006] According to one aspect of this disclosure, the energy storage device includes: an energy storage unit having a first surface; a cooler having a second surface facing the first surface for cooling the energy storage unit from the first surface side; and a heat-conducting material coated onto the second surface and in contact with the first surface. The heat-conducting material extends on the second surface in a first direction and a second direction perpendicular to the first direction. The lengths of the heat-conducting material in the first direction and the second direction are 80 mm or less.

[0007] This structure can prevent heat-conducting materials from peeling off from the cooler.

[0008] Preferably, the first surface is the bottom surface. Multiple energy storage units are stacked in the first direction. The length of each heat-conducting material in the first direction is less than or equal to the length of the bottom surface in the first direction. The length of each heat-conducting material in the second direction is less than or equal to the length of the bottom surface in the second direction.

[0009] With this structure, heat-conducting material is set independently for each energy storage unit, so the effects of hardening shrinkage can be reduced compared to the case where multiple energy storage units share one heat-conducting material.

[0010] Preferably, the heat-conducting material is made of polyurethane.

[0011] Preferably, the length of the heat-conducting material in the second direction is 12 mm.

[0012] According to this disclosure, it is possible to suppress the stripping of heat-conducting materials from the cooler. Attached Figure Description

[0013] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and are attached as follows:

[0014] Figure 1 This is a top view of the energy storage device.

[0015] Figure 2 yes Figure 1 The arrow of line II-II is shown in the time section view.

[0016] Figure 3 yes Figure 2 The arrow of line III-III is a time-lapse section view.

[0017] Figure 4 It is a graph showing the relationship between the length of the thermally conductive material and the stress in the thermally conductive material. Detailed Implementation

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following description, the same reference numerals will be used for the same components. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0019] The energy storage device described later is used in hybrid electric vehicles that can travel using the power of at least one of a motor and an engine, and in electric vehicles that travel using the driving force obtained by utilizing electrical energy.

[0020] Figure 1 This is a top view of the energy storage device according to this embodiment. Figure 2 yes Figure 1 The arrow of line II-II is shown in the time section view. Figure 3 yes Figure 2 The time-lapse section view with arrows along line III-III. (See attached image.) Figures 1 to 3 As shown, the energy storage device 1 includes multiple energy storage modules 100, a cooler 200, and multiple heat-conducting materials 300.

[0021] In this example, three energy storage modules 100 are arranged at equal intervals in the X direction (second direction). Each energy storage module 100 includes multiple energy storage units 110. In this example, one energy storage module 100 is formed by stacking eight energy storage units 110 in the Y direction (first direction). Each energy storage unit 110 has a bottom surface (first surface) 111 and two side surfaces 112 with the X direction as the normal direction. The bottom surface 111 is rectangular. The Y direction is the width direction of the bottom surface 111, and the X direction, which is perpendicular to the Y direction, is the length direction of the bottom surface 111.

[0022] Cooler 200 cools each energy storage module 100. More specifically, cooler 200 cools each energy storage unit 110. More specifically, cooler 200 cools each energy storage unit 110 from the bottom surface 111 side. Cooler 200 cools each energy storage unit 110 from the bottom surface 111 side via heat-conducting materials 300, as will be described later.

[0023] like Figure 2 As shown, the cooler 200 has a top surface (second surface) 211. The top surface 211 faces the bottom surface 111 of the energy storage unit 110. The cooler 200 also has a plurality of flow path forming sections 210 and flow path forming sections 220. In this example, the top surface 211 is the top surface of the flow path forming section 210.

[0024] Each flow path forming section 210 is disposed directly above the flow path forming section 220. Each flow path forming section 210 extends in the Y direction. In this example, the three flow path forming sections 210 are arranged at equal intervals in the X direction. Antifreeze flows through the interior (i.e., the flow path) of each flow path forming section 210. In this example, a long-life coolant (LLC) is used as the antifreeze. Air flows through the interior of the flow path forming section 220. The cooler 200 cools each energy storage unit 110 by means of the long-life coolant and air.

[0025] Multiple heat-conducting materials 300 are disposed between the cooler 200 and each energy storage unit 110. In this example, three heat-conducting materials 300 are disposed between the flow path forming section 210 and the energy storage unit 110. However, the number of heat-conducting materials 300 is not limited to this.

[0026] Each heat-conducting material 300 is applied to the top surface 211 of the cooler 200. Each heat-conducting material 300 is in contact with the bottom surface 111 of the energy storage unit 110. In this example, three heat-conducting materials 300 are in contact with the bottom surface 111 of one energy storage unit 110. Figure 3 In this example, each heat-conducting material 300 is made of polyurethane (specifically, by DUPONT).

[0027] Each heat-conducting material 300 is generated through the following process. After a liquid (e.g., gel) heat-conducting material is applied to the top surface 211 at intervals, the energy storage module 100 is placed on the cooler 200. Due to the weight of the energy storage module 100, the heat-conducting material is spread out in the X and Y directions. The heat-conducting material is then hardened. Thus, solid heat-conducting materials 300 are generated.

[0028] Each heat-conducting material 300 is cylindrical. Each heat-conducting material 300 is thin and extends in the XY plane. The heat-conducting material 300 extends in both the X and Y directions on the top surface 211. The heat-conducting material 300 extends in the Y direction and the X direction perpendicular to the Y direction through the aforementioned contact between the coating portion and the bottom surface 111. In this example, the length of the heat-conducting material 300 in the X direction is the same as its length in the Y direction.

[0029] like Figure 3 As shown, the diameter of the bottom surface of each heat-conducting material 300 is set as... Let the length of the bottom surface 111 of the energy storage unit 110 in the Y direction be D. Similarly, let the length of the bottom surface 111 in the X direction be W (>D). Furthermore, Indicates diameter, so The value is both the length of the heat-conducting material 300 in the X direction and the length in the Y direction.

[0030] like Figure 3 As shown, in this example, when viewed from the bottom surface 111 of the energy storage unit 110, each heat-conducting material 300 is applied to the cooler 200 in such a manner that the heat-conducting material 300 is not exposed from the bottom surface 111. Therefore, The value is below the value of D. That is, the length of the thermally conductive material 300 in the Y direction. It is the length (D) in the Y direction of the bottom surface 111 of the energy storage unit 110. Furthermore, since the value of W is greater than the value of D, the length in the X direction of each heat-conducting material 300 is... It is the length (W) or less in the X direction of the bottom surface 111.

[0031] In detail, in this example, considering a single energy storage unit 110, three thermally conductive materials 300 are arranged in the X direction, so The value of is less than the value of W. As an example, the value of D is 40 mm. As an example, The value is 12mm, but it is not limited to this. Under the conditions described later, it can be appropriately set. The value. For example, by... Setting the value to 40mm increases the contact area between the heat-conducting material 300, the cooler 200, and the energy storage unit 110.

[0032] Furthermore, in this example, the shape of the heat-conducting material 300 is circular when viewed from the bottom surface 111, but it is not limited to this. The shape of the heat-conducting material 300 when viewed from the bottom surface 111 can also be approximately rectangular. The lengths of the heat-conducting material 300 in the X and Y directions can also be different. Additionally, when viewed from the bottom surface 111, each heat-conducting material 300 can be exposed from one bottom surface 111. For example, each heat-conducting material 300 can also be in contact with multiple energy storage units 110.

[0033] Figure 4 It is a graph showing the relationship between the length of the thermally conductive material and the stress in the thermally conductive material. Figure 4 The 10 data points were obtained by setting the width (length) of the thermally conductive material to 12 mm. Figure 4 In this design, the length of the thermally conductive material along its longitudinal direction is defined as L (mm). The thermally conductive material is a polyurethane thermally conductive material from DUPONT Corporation, the same as thermally conductive material 300. The ambient temperature (room temperature) during application is 25°C.

[0034] However, the longer the coating extends along the length of the thermally conductive material, the larger its volume becomes. Therefore, the volume shrinkage (hardening shrinkage) of the thermally conductive material during curing increases. Consequently, the stress caused by hardening shrinkage increases. Therefore, if the coating length along the length of the thermally conductive material is set such that the stress caused by hardening shrinkage becomes less than the adhesive force at the interface (contact area) between the thermally conductive material and the energy storage unit, it is possible to suppress the thermally conductive material from peeling off from the energy storage unit.

[0035] like Figure 4 As shown, when the value of L is 20 mm, 40 mm, 60 mm, and 80 mm, the stress of the heat-conducting material is less than 1.0 MPa, which is the adhesive force at the interface between the heat-conducting material and the energy storage unit. On the other hand, when the value of L is 100 mm, 200 mm, 400 mm, 600 mm, 800 mm, and 1000 mm, the stress of the heat-conducting material is greater than 1.0 MPa.

[0036] When the stress on the thermally conductive material exceeds 1.0 MPa, the thermally conductive material peels off from the energy storage unit. Therefore, if the value of L is set to below 80 mm, the peeling of the thermally conductive material from the energy storage unit can be suppressed.

[0037] Based on the above, in the energy storage device 1 of this example, by setting the lengths of the heat-conducting material 300 in both the X and Y directions to 80 mm or less, it is possible to suppress the heat-conducting material 300 from peeling off from the energy storage unit 110 (bottom surface 111). In the case of the above example, Figure 3 shown The value can be set to below 80mm.

[0038] Not limited to the examples above, the heat-conducting material 300 can also be continuously applied to the cooler 200 by moving the nozzle that dispenses the heat-conducting material 300 onto the cooler 200 relative to the cooler 200. For example, the length of the heat-conducting material 300 in the width direction (X direction) can also be adjusted to... Figure 4 The same applies to nozzles with a diameter of 12mm. Even in this case, the discharge of heat-conducting material from the nozzle can be controlled by making the length of the heat-conducting material 300 in the Y direction less than 80mm.

[0039] summary

[0040] (1) As described above, the energy storage device 1 includes an energy storage unit 110 having a bottom surface 111. The energy storage device 1 includes a cooler 200 having a top surface 211 facing the bottom surface 111 and cooling the energy storage unit 110 from the bottom surface 111 side. The energy storage device 1 includes a heat-conducting material 300 coated on the top surface 211 and in contact with the bottom surface 111. The heat-conducting material 300 extends in the Y direction and the X direction perpendicular to the Y direction. The length of the heat-conducting material 300 in the Y direction and the length in the X direction are 80 mm or less. With this structure, it is possible to suppress the heat-conducting material 300 from peeling off from the energy storage unit 110.

[0041] (2) Multiple energy storage units 110 are stacked in the Y direction. The length of each heat-conducting material 300 in the Y direction is less than or equal to the length of the bottom surface 111 in the Y direction. The length of each heat-conducting material 300 in the X direction is less than or equal to the length of the bottom surface 111 in the X direction. With this structure, the heat-conducting material 300 is provided independently for each energy storage unit 110, so the effects of hardening shrinkage can be reduced compared to the case where multiple energy storage units 110 share one heat-conducting material.

[0042] (3) The heat-conducting material 300 is made of polyurethane.

[0043] (4) The length of the heat-conducting material 300 in the X direction is 12mm.

[0044] (5) The energy storage device 1 has multiple heat-conducting materials 300 that are in contact with the same bottom surface 111. Each heat-conducting material 300 is separated from each other in the X direction. With this structure, the energy storage unit 110 can be cooled more efficiently than when there is only one heat-conducting material 300 in contact with one bottom surface 111.

[0045] Variations

[0046] The lengths of the heat-conducting material 300 in the X and Y directions can also be different. The heat-conducting material 300 can also have its width in the X direction and its length in the Y direction. That is, the heat-conducting material 300 can also extend in the Y direction. In other words, the heat-conducting material 300 can also extend further in the Y direction compared to the X direction. In this case, the length of the heat-conducting material 300 in the Y direction (when viewed from above in XY mode) can be 80 mm or less.

[0047] Conversely, the heat-conducting material 300 can also have the X direction as its length and the Y direction as its width. That is, the heat-conducting material 300 can also extend in the X direction. In other words, the heat-conducting material 300 can also extend further in the X direction than in the Y direction. In this case, the length of the heat-conducting material 300 in the X direction (viewed from above) can be 80 mm or less.

[0048] The heat-conducting material 300 can also be configured in a state that is inclined towards the X and Y axes. Even in this case, the length in the longitudinal direction can be less than 80 mm.

[0049] In the above description, an example was given of a structure in which the heat-conducting material 300 contacts the bottom surface 111 of the energy storage unit 110, and the cooler 200 cools the energy storage unit 110 from the bottom surface 111 side. However, this is not a limitation. For example, the cooler may also cool the side surface 112 of the energy storage unit 110 via the heat-conducting material. Figure 2 The method of cooling constitutes the energy storage device 1.

[0050] It should be understood that the embodiments disclosed herein are merely illustrative and not restrictive at all points. The scope of this disclosure is shown by the claims and is intended to include all modifications within the meaning and scope of the claims.

Claims

1. An energy storage device, comprising: The energy storage unit has a first surface; A cooler having a second surface facing the first surface, cooling the energy storage unit from the first surface side; and A heat-conducting material is applied to the second surface, making contact with the first surface. The heat-conducting material extends on the second surface in a first direction and in a second direction perpendicular to the first direction. The length of the thermally conductive material in the first direction and the length in the second direction are both less than 80 mm.

2. The energy storage device according to claim 1, wherein, The first surface is the bottom surface. Multiple energy storage units are stacked in the first direction. The length of the first direction of each of the heat-conducting materials is less than or equal to the length of the first direction of the bottom surface. The length of the second direction of each of the heat-conducting materials is less than or equal to the length of the second direction of the bottom surface.

3. The energy storage device according to claim 1, wherein, The heat-conducting material is made of polyurethane.

4. The energy storage device according to claim 1, wherein, The length of the second direction of the thermally conductive material is 12 mm.

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