Manufacturing method for energy storage devices

Abstract

The present invention provides a method for manufacturing an energy storage device that can suppress variations in the thickness of the thermal conductive material located in the gap between the lower case and the energy storage module. [Solution] The method for manufacturing the energy storage device comprises the steps of applying a thermal conductive agent 60 to the upper surface 22a of the bottom wall 22 of the lower case 21, and pressing the energy storage module 10 against the thermal conductive agent 60 applied to the upper surface 22a. The overlapping region R1 of the bottom wall 22 that overlaps with the energy storage module 10 includes a deformable portion 25 that protrudes upward and deforms downward when pressed downward. In the step of pressing the energy storage module 10, the deformable portion 25 deforms downward, thereby making the thermal conductive agent 60 located between the energy storage module 10 and the upper surface a predetermined thickness.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing a power storage device.

Background Art

[0002] As a conventional power storage device, Japanese Unexamined Patent Application Publication No. 2024-092300 (Patent Document 1) discloses a structure in which a plurality of power storage modules are fixed to a lower case of a housing case that houses the plurality of power storage modules using an adhesive.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When fixing a plurality of power storage modules to the bottom wall of the lower case using a heat conductive agent, the plurality of power storage modules are pressed against the heat conductive agent applied to the upper surface of the bottom wall from above. At this time, if the bottom wall of the lower case is configured to be flat, the bottom of the lower case may sink downward due to the pressing force from the plurality of power storage modules. In such a case, the distance between the lower surface of the power storage module and the bottom wall increases, and the thickness of the heat conductive agent becomes larger than the design target. In addition, due to the design variations of the lower case and the power storage module, there is a concern that the thickness of the heat conductive agent spreading into the gap between the lower case and the power storage module may vary.

[0005] This disclosure has been made in view of the above problems, and an object of this disclosure is to provide a method for manufacturing a power storage device capable of suppressing variations in the thickness of the heat conductive agent located in the gap between the lower case and the power storage module.

Means for Solving the Problems

[0006] A method for manufacturing an energy storage device according to this disclosure comprises the steps of applying a thermal conductive agent to the upper surface of the bottom wall of a lower case, and pressing an energy storage module onto the thermal conductive agent applied to the upper surface. The overlapping region of the bottom wall that overlaps with the energy storage module includes a deformable portion that protrudes upward and deforms downward when pressed downward. In the step of pressing the energy storage module, the deformable portion deforms downward, thereby making the thermal conductive agent located between the energy storage module and the upper surface a predetermined thickness.

[0007] Generally, as the thermal conductive material is compressed by the energy storage module and its thickness decreases, the load on the bottom wall of the lower case increases, and the deformation of the bottom wall increases. When the deformation of the bottom wall increases, it becomes difficult to further reduce the thickness of the thermal conductive material.

[0008] As described above, the overlapping region that overlaps with the energy storage module has a deformed portion that protrudes upward. Therefore, during the process of pressing the energy storage module, when this deformed portion is deformed downward, the amount of deformation of the bottom wall is large. For this reason, when the deformed portion is deformed, the thickness of the thermal conductive material does not easily become any thinner and remains at a predetermined thickness. As a result, variations in the thickness of the thermal conductive material located in the gap between the lower case and the energy storage module can be suppressed.

[0009] In the method for manufacturing an energy storage device according to the above disclosure, the energy storage module may include a plurality of energy storage cells arranged in the arrangement direction. The bottom wall may include both end portions located at both ends in a direction parallel to the arrangement direction, and a central portion located between the two end portions. The deformed portion may have a shape that extends upward from the end portions towards the central portion in the state before the step of pressing the energy storage module is performed.

[0010] With the above configuration, the thermal conductive material can be spread outwards from the central part, making it possible to more effectively suppress variations in the thickness of the thermal conductive material located in the gap between the lower case and the energy storage module.

[0011] In the method for manufacturing an energy storage device based on the above disclosure, the deformed portion may become substantially flat in the step of pressing the energy storage module.

[0012] According to the above configuration, the deformation state of the deformed part becomes approximately flat, which more effectively suppresses variations in the thickness of the thermal conductive material located in the gap between the lower case and the energy storage module. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide a method for manufacturing an energy storage device that can suppress variations in the thickness of the thermal conductive material located in the gap between the lower case and the energy storage module. [Brief explanation of the drawing]

[0014] [Figure 1] This is an exploded perspective view of the energy storage device according to the embodiment. [Figure 2] This is a cross-sectional view of an energy storage device according to an embodiment. [Figure 3] This is a flowchart showing the manufacturing process of the energy storage device according to the embodiment. [Figure 4] This figure shows the process of pressing the energy storage module in the manufacturing process shown in Figure 3. [Figure 5] This figure shows the state after the step of pressing the energy storage module in the manufacturing process shown in Figure 3. [Modes for carrying out the invention]

[0015] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.

[0016] FIG. 1 is an exploded perspective view of a power storage device according to an embodiment. FIG. 2 is a cross-sectional view of the power storage device according to the embodiment, and is a cross-sectional view taken along line II-II shown in FIG. 1. In FIG. 2, for convenience, a protection panel 50 described later is omitted from the illustration. The power storage device 1 according to the embodiment will be described with reference to FIGS. 1 and 2.

[0017] The power storage device 1 according to the embodiment 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.

[0018] As shown in FIGS. 1 and 2, the power storage device 1 according to the embodiment includes a plurality of power storage modules 10, a housing case 20, a cooler 30, an outer heat conduction layer 40, a protection panel 50, a heat conduction agent 60, and a pressing member 80 (see FIG. 2).

[0019] Each of the plurality of power storage modules 10 includes a plurality of power storage cells 12 arranged side by side in an arrangement direction (DR1 direction). In a mounted state where the power storage device 1 is mounted on a vehicle, the DR1 direction is substantially parallel to, for example, the left-right direction of the vehicle. The plurality of power storage cells 12 are sandwiched in the DR1 direction by a pair of end plates 16 (see FIG. 2). The pair of end plates 16 is made of, for example, a metal material such as aluminum. A spacer (not shown) is disposed between adjacent power storage cells 12.

[0020] The plurality of power storage modules 10 are arranged side by side in an intersecting direction DR2 (more specifically, a direction orthogonal to the above-described arrangement direction) that intersects the DR1 direction. In the above-described mounted state, the DR2 direction is substantially parallel to, for example, the front-rear direction of the vehicle.

[0021] Each of the plurality of power storage modules 10 is fixed to the bottom wall 22 of the housing case 20 by a heat conduction agent 60.

[0022] The housing case 20 houses multiple energy storage modules 10 inside. The housing case 20 includes a lower case 21 and an upper case 26.

[0023] The lower case 21 has a substantially box-like shape that opens upward. The lower case 21 is thermally conductive and is made of, for example, metal. The lower case 21 has a bottom wall 22, a peripheral wall portion 23, a flange portion 24, and a partition wall 211.

[0024] The bottom wall 22 is located below the multiple energy storage modules 10. The bottom wall 22 has an upper surface 22a facing the energy storage modules 10 and a lower surface 22b facing the opposite side from where the energy storage modules 10 are located.

[0025] The peripheral wall portion 23 is provided to rise from the periphery of the bottom wall 22. The flange portion 24 is provided to protrude outward from the upper end of the peripheral wall portion 23.

[0026] Multiple partition walls 211 are provided. The partition walls 211 are arranged in a line in the DR2 direction at predetermined intervals. The partition walls 211 divide the area in which the energy storage modules 10 are arranged at predetermined intervals. In this embodiment, the partition walls 211 divide the area in which two energy storage modules 10 are arranged, but are not limited to this, and the position of the partition walls 211 can be set as appropriate. Both ends of the partition walls 211 in the DR1 direction may be connected to the peripheral wall portion 23. The partition walls 211 may reinforce the peripheral wall portion 23.

[0027] The upper case 26 has a roughly box-like shape that opens downwards. The upper case 26 is made of, for example, metal.

[0028] The upper case 26 has a ceiling portion 27, a peripheral wall portion 28, and a flange portion 29. The ceiling portion 27 forms the upper wall of the housing case 20. The peripheral wall portion 28 extends downward from the periphery of the ceiling portion 27. The flange portion 29 is provided so as to protrude outward from the lower end of the peripheral wall portion 28.

[0029] The flange portion 24 and the flange portion 29 are fastened together by a plurality of fastening members (not shown) while overlapping each other in the vertical direction, thereby allowing the upper case 26 and the lower case 21 to house a plurality of energy storage modules 10 inside.

[0030] The cooler 30 is a device for cooling multiple energy storage modules 10. The cooler 30 is located on the outside of the housing case 20. Specifically, the cooler 30 is located below the bottom wall 22 of the lower case 21. An outer heat conduction layer 40 is placed between the cooler 30 and the bottom surface 22b. The cooler 30 is located on the outside of the lower case 21 so as to be in thermal contact with the bottom surface 22b.

[0031] The cooler 30 is made of a metal material such as aluminum. The cooler 30 includes a plurality of main cooling sections 31 and a holding section 32. Inside the plurality of main cooling sections 31 and the holding section 32, a refrigerant flow path 31a (see Figure 2) is arranged through which a refrigerant for cooling the energy storage module 10 flows. In the main cooling section 31, the refrigerant flows in a direction parallel to the arrangement direction, as indicated by the arrows in Figure 2.

[0032] The cooler 30 has a refrigerant inlet 33 and a refrigerant outlet 34. Refrigerant is introduced into the refrigerant flow path from the outside via the refrigerant inlet 33. Refrigerant is discharged from the refrigerant flow path via the refrigerant outlet 34.

[0033] The multiple main cooling units 31 are arranged in a direction parallel to the DR2 direction. The multiple main cooling units 31 extend along the DR1 direction. Each of the multiple main cooling units 31 is positioned opposite the energy storage module 10, with the bottom wall 22 in between.

[0034] The holding portion 32 holds a plurality of main cooling units 31. The holding portion 32 is provided to hold at least both ends of the main cooling units 31 in the DR1 direction. The holding portion 32 includes, for example, a pair of extending portions that extend along the DR2 direction at both ends of the main cooling units 31. The holding portion 32 may also be provided in a frame shape to surround the plurality of main cooling units 31.

[0035] The outer heat conduction layer 40 is made of a heat conductive material and is placed between the bottom wall 22 of the lower case 21 and the cooler 30. The outer heat conduction layer 40 has a plurality of central heat conduction sections 41 and an annular heat conduction section 42.

[0036] Multiple central heat conduction sections 41 are positioned between each main cooling section 31 and the bottom wall 22 of the lower case 21. The central heat conduction sections 41 have a shape that extends in the DR1 direction.

[0037] The annular heat conduction section 42 has a shape that surrounds each central heat conduction section 41. The annular heat conduction section 42 is positioned between the holding section 32 and the housing case 20. This prevents water from entering the space inside the annular heat conduction section 42.

[0038] The outer heat conductive layer 40 also functions as an adhesive layer, bonding and fixing the cooler 30 to the bottom wall 22. The outer heat conductive layer 40 is composed of an adhesive containing a silicone resin, acrylic resin, urethane resin, or epoxy resin, etc.

[0039] The protective panel 50 is positioned to cover the cooler 30 from below. The protective panel 50 protects the cooler 30 and prevents water from getting onto the cooler 30. The protective panel 50 is made of a metal material.

[0040] The thermal conductive material 60 is placed between each energy storage module 10 and the bottom wall 22 (more specifically, the top surface 22a). The thermal conductive material 60 also functions as an adhesive layer, bonding and fixing each energy storage module 10 to the bottom wall 22.

[0041] The thermal conductive agent 60 can be, for example, an adhesive containing a silicone resin, acrylic resin, urethane resin, or epoxy resin.

[0042] The pressing member 80 is a member that presses the energy storage module 10 toward the bottom wall 22. The pressing member 80 attaches the energy storage module 10 to the housing case 20 while pressing the energy storage module 10 toward the bottom wall 22 so that the heat conductive material 60 spreads out. The pressing member 80 has a first pressing portion 81 and a second pressing portion 82.

[0043] The first pressing portion 81 presses one end of the energy storage module 10 toward the bottom wall 22 in the DR1 direction. The first pressing portion 81 includes a bracket 811 and a fastening member 812.

[0044] One end of the bracket 811 is fixed to the flange portion 24, and the other end of the bracket 811 is fixed to the energy storage module 10. The bracket 811 has a roughly L-shape.

[0045] The bracket 811 has a first portion extending along the DR1 direction and a second portion extending along the DR2 direction. The tip of the first portion is fixed to the flange portion 24. The second portion extends upward from the base end of the first portion located on the energy storage module 10 side. The second portion is fixed by a fastening member 812 to the end plate 16 located on one side in the DR1 direction. The bracket 811 is made of metal.

[0046] The second pressing portion 82 presses the other end of the energy storage module 10 in the DR1 direction toward the bottom wall 22. The second pressing portion 82 includes a bracket 821 and a fastening member 822.

[0047] One end of the bracket 821 is fixed to the flange portion 24, and the other end of the bracket 821 is fixed to the energy storage module 10. The bracket 821 has a roughly L-shape.

[0048] The bracket 821 has a first portion extending along the DR1 direction and a second portion extending along the DR2 direction. The tip of the first portion is fixed to the flange portion 24. The second portion extends upward from the base end of the first portion located on the energy storage module 10 side. The second portion is fixed by a fastening member 822 to the end plate 16 located on the other side in the DR1 direction. The bracket 821 is made of metal.

[0049] The first pressing portion 81 and the second pressing portion 82 press the energy storage module 10 toward the bottom wall 22, thereby spreading out the heat conductive material 60 placed between the energy storage module 10 and the bottom wall 22.

[0050] Figure 3 is a flowchart showing the manufacturing process of the energy storage device according to the embodiment. Figure 4 is a diagram showing the process of pressing the energy storage module in the manufacturing process shown in Figure 3. Figure 5 is a diagram showing the state after the process of pressing the energy storage module in the manufacturing process shown in Figure 3. The manufacturing method of the energy storage device 1 according to the embodiment will be described with reference to Figures 3 to 5.

[0051] As shown in Figure 3, the manufacturing method of the energy storage device 1 includes the steps of applying a thermal conductive agent (S10) and pressing the energy storage module (S20).

[0052] When carrying out process (S10), a power storage module 10 is prepared in which at least the overlapping region R1 (see Figure 4) has a deformable portion 25 (see Figure 4) that protrudes upward and deforms downward when pressed downward. The overlapping region R1 is the region of the bottom wall 22 that overlaps with each power storage module 10.

[0053] The bottom wall 22 of the energy storage module 10 includes both end portions located on both sides in a direction parallel to the DR1 direction, and a central portion located between the two end portions. The deformed portion 25, in the state before the step (B)S20) of pressing the energy storage module is performed, for example, has a shape that extends upward from the end portions of the bottom wall 22 towards the central portion of the bottom wall 22. The deformed portion 25 may have a shape in a cross section perpendicular to the DR1 direction that is composed of the sides of a triangle excluding the base, a shape composed of the sides of a trapezoid excluding the base, or a dome shape.

[0054] In step (S10), a thermal conductive agent 60 is applied to the upper surface 22a of the bottom wall 22. The thermal conductive agent 60 is applied in a strip-like manner to each overlapping region R1. The thermal conductive agent 60 is applied, for example, along the DR2 direction.

[0055] Next, as shown in Figure 4, the energy storage module 10 is pressed against the heat conductive agent 60 applied to the upper surface 22a of the bottom wall 22. Specifically, with the brackets 811 and 821 fixed to both ends of the energy storage module 10, the energy storage module 10 is moved from above to below the heat conductive agent 60, as indicated by arrow AR1 in Figure 4. The tips of the brackets 811 and 821 overlap the flange portion 24 of the lower case 21 in the vertical direction.

[0056] As the energy storage module 10 is pressed against the thermal conductive material 60, the pressing force is transmitted to the bottom wall 22 of the lower case 21 via the thermal conductive material 60. As a result, the deformed portion 25 deforms downward, as shown by the dashed line in Figure 4. In this case, it is preferable that the deformed portion 25 becomes substantially flat. That is, it is preferable that the deformed portion 25 is parallel to the DR1 direction.

[0057] As shown in Figure 5, in the state after process (S10), the deformation of the deformed portion 25 as described above results in the thickness of the thermal conductive material 60 located between the energy storage module 10 and the upper surface 22a of the bottom wall 22 being a predetermined thickness. The predetermined thickness is approximately equal to the target value in the design.

[0058] Furthermore, in the aforementioned post-installation state, the tip of the bracket 811 and the flange portion 24 face each other, and by fixing the tip and flange portion together, the state in which the heat conductive material 60 has reached a predetermined thickness can be maintained.

[0059] Generally, the heat conductive material is compressed by the energy storage module, reducing its thickness. As the thickness of the heat conductive material decreases, the load on the bottom wall of the lower case increases, and the deformation of the bottom wall increases. When the deformation of the bottom wall increases, it becomes difficult to further reduce the thickness of the heat conductive material.

[0060] In this embodiment, as described above, the overlapping region R1 that overlaps with the energy storage module 10 has a deformable portion 25 that protrudes upward. Therefore, in the step of pressing the energy storage module 10 (S20), when the deformable portion 25 is deformed downward, the amount of deformation of the bottom wall 22 is large. As a result, when the deformable portion 25 is deformed, the thickness of the thermal conductive material 60 does not easily become any thinner and remains at a predetermined thickness. As a result, variations in the thickness of the thermal conductive material 60 located in the gap between the lower case 21 and the energy storage module 10 can be suppressed.

[0061] Furthermore, as described above, the deformed portion 25 has a shape that, in its pre-deformation state, increases in direction from both ends of the bottom wall 22 in the DR1 direction towards the center. Therefore, in step (S20), the thermal conductive material 60 can be spread outwards from the center. This makes it possible to more effectively suppress variations in the thickness of the thermal conductive material 60 located in the gap between the lower case 21 and the energy storage module 10.

[0062] In addition, since the deformed portion 25 becomes substantially flat in the deformed state, variations in the thickness of the thermal conductive material 60 located in the gap between the lower case 21 and the energy storage module 10 can be more effectively suppressed.

[0063] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and all modifications are made in the sense and scope equivalent to the claims. [Explanation of symbols]

[0064] 1 Energy storage device, 10 Energy storage module, 12 Energy storage cell, 16 End plate, 20 Housing case, 21 Lower case, 22 Bottom wall, 22a Top surface, 22b Bottom surface, 23 Peripheral wall section, 24 Flange section, 25 Deformed section, 26 Upper case, 27 Ceiling section, 28 Peripheral wall section, 29 Flange section, 30 Cooler, 31 Main cooling section, 31a Refrigerant flow path, 32 Holding section, 33 Refrigerant introduction section, 34 Refrigerant discharge section, 40 Outer heat conduction layer, 41 Central heat conduction section, 42 Annular heat conduction section, 50 Protective panel, 60 Heat conductive material, 80 Pressing member, 81 First pressing section, 82 Second pressing section, 211 Partition wall, 811, 821 Bracket, 812, 822 Fastening member, DR1 Arrangement direction, DR2 Intersecting direction, R1 Overlapping regions.

Claims

1. A step of applying a heat conductive agent to the upper surface of the bottom wall of the lower case, The process includes pressing the energy storage module against the heat conductive agent applied to the upper surface, The overlapping region of the bottom wall that overlaps with the energy storage module includes a deformable portion that protrudes upward and deforms downward when pressed downward. A method for manufacturing an energy storage device, wherein, in the step of pressing the energy storage module, the deformed portion deforms downward so that the heat conductive material located between the energy storage module and the upper surface becomes a predetermined thickness.

2. The aforementioned energy storage module includes a plurality of energy storage cells arranged in the direction of the arrangement, The bottom wall includes both end portions located on both sides in a direction parallel to the arrangement direction, and a central portion located between the two end portions. The method for manufacturing an energy storage device according to claim 1, wherein the deformed portion has a shape that is directed upward from both ends towards the central part when the step of pressing the energy storage module is performed.

3. A method for manufacturing an energy storage device according to claim 1 or 2, wherein the deformed portion becomes substantially flat in the step of pressing the energy storage module.

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