Battery manufacturing method

Abstract

To obtain a battery manufacturing method that can suppress the uneven stretching of the heat-conducting resin sheet. [Solution] The method for manufacturing the battery 10 includes the steps of: housing a thermal conductive resin sheet 24, which has a plurality of slits 24C extending in one direction on at least one surface, at the bottom of the outer casing 12; and compressing the thermal conductive resin sheet 24 between itself and the outer casing 12 while inserting the electrode body into the outer casing 12.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a battery.

Background Art

[0002] Patent Document 1 discloses a structure in which a sheet-like heat conductive material (heat conductive resin) is disposed between an electrode laminate (electrode body) and the bottom surface of an exterior member in a all-solid-state battery cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the electrode body is housed in the exterior body, the heat conductive resin sheet is compressed and stretched. At this time, if the heat conductive resin sheet does not stretch uniformly, there is a possibility that the heat conductive resin sheet may not spread to the corner portion of the exterior body.

[0005] In consideration of the above fact, an object of the present invention is to obtain a method for manufacturing a battery that can suppress non-uniform stretching of the heat conductive resin sheet.

Means for Solving the Problems

[0006] The method for manufacturing a battery according to claim 1 includes a step of housing a heat conductive resin sheet having a plurality of slits extending in one direction on at least one surface in the bottom of an exterior body, and a step of compressing the heat conductive resin sheet between the heat conductive resin sheet and the exterior body while inserting an electrode body into the exterior body.

[0007] The method for manufacturing a battery according to claim 1 includes the steps of housing a thermal conductive resin sheet at the bottom of an outer casing and compressing the thermal conductive resin sheet between the outer casing and the electrode body while inserting the electrode body into the outer casing. Here, at least one surface of the thermal conductive resin sheet has a plurality of slits extending in one direction. As a result, when the thermal conductive resin sheet is compressed, the crushed portion deforms so as to enter the slits, allowing the thermal conductive resin sheet to be stretched more uniformly compared to a structure without slits.

[0008] The method for manufacturing a battery according to claim 2 is as follows: In claim 1, the slit is formed on only one side of the thermal conductive resin sheet, and the sheet is housed in the outer casing such that the side opposite to the side on which the slit is formed faces the bottom of the outer casing.

[0009] In the battery manufacturing method according to claim 2, since the side of the thermal conductive resin sheet without slits is in contact with the bottom of the outer casing, the contact area with the bottom is larger than when the side with slits is placed on the bottom side, making it easier to position the thermal conductive resin sheet.

[0010] The method for manufacturing a battery according to claim 3 is as follows: In claim 1, the thermal conductive resin sheet is formed in a rectangular shape with the short side being one direction, and a plurality of slits are formed at predetermined intervals in a direction perpendicular to the one direction.

[0011] In the battery manufacturing method according to claim 3, more slits can be formed by forming multiple slits along the longitudinal direction of the thermal conductive resin sheet. Furthermore, since the length of each slit is shortened, it is easier to stretch in the desired direction when compressed.

[0012] The method for manufacturing a battery according to claim 4 is as follows: In claim 1, the thermal conductive resin sheet is formed in such a shape that the thickness is thinner in the central part than at the peripheral edges.

[0013] In the battery manufacturing method according to claim 4, because the thickness of the central part of the thermal conductive resin sheet is thin, the peripheral edges are compressed to the electrode body first, and the thermal conductive resin sheet can be stably stretched all the way to the corners of the outer casing. [Effects of the Invention]

[0014] As described above, the battery manufacturing method according to the present invention can suppress the uneven stretching of the thermal conductive resin sheet. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic cross-sectional view showing the battery cells constituting the battery according to the embodiment. [Figure 2] This is a cross-sectional view showing the state after cutting along line 2-2 in Figure 1. [Figure 3] This is an enlarged cross-sectional view of the main part, showing the state after cutting along line 3-3 in Figure 2. [Figure 4] This is a cross-sectional view showing the state after compressing the thermal conductive resin sheet from the state shown in Figure 2. [Figure 5] This is a cross-sectional view corresponding to Figure 3, showing a battery cell in a modified example. [Figure 6] This is a schematic diagram showing the state of the thermal conductive resin sheet before and after compression in the comparative example. [Modes for carrying out the invention]

[0016] A battery according to this embodiment will be described with reference to the drawings.

[0017] Figure 1 is a schematic cross-sectional view showing a battery cell 10 as a battery according to the embodiment. For the purposes of the following explanation, the direction indicated by the arrow UP will be referred to as the upward and downward side of the battery cell 10. The direction indicated by the arrow FR will be referred to as the front side in the front-rear direction of the battery cell 10. Furthermore, the direction indicated by the arrow OUT will be referred to as the outward side in the width direction of the battery cell 10. However, the directions indicated by the arrows UP, FR, and OUT do not necessarily have to coincide with the vertical, front-rear, and width directions of the vehicle on which the battery cell 10 is mounted.

[0018] As shown in FIG. 1, the battery cell 10 includes a can body 12 and a lid 14 that constitute an exterior body.

[0019] The can body 12 is formed in a substantially box shape from metal and has an opening 12A at its upper end. The opening 12A of the can body 12 is closed by the lid 14, and the inside of the can body 12 is sealed. Note that the can body 12 and the lid 14 may be joined by welding or the like, or may be mechanically joined.

[0020] Inside the can body 12, an electrode body 16 and a heat-conductive resin sheet 24 are accommodated. The electrode body 16 of the present embodiment is, as an example, an electrode body of an all-solid-state battery, and includes a laminate in which a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector are laminated. Note that the present invention is not limited thereto, and it may be applied to a liquid-based battery cell containing an electrolytic solution.

[0021] At the upper end of the electrode body 16, a current collection tab 18 where electrode foils are collected is provided, and the current collection tab 18 is connected to a current collection terminal 20 inside the battery cell 10. Further, the current collection terminal 20 is electrically connected to an external terminal 22 that penetrates the lid 14, and is configured to be able to output the electricity generated in the electrode body 16 via the external terminal 22.

[0022] Here, a heat-conductive resin sheet 24 is accommodated in the bottom 12B of the can body 12. The heat-conductive resin sheet 24 has a lower surface 24A in contact with the bottom 12B and an upper surface 24B in contact with the electrode body 16, and is compressed and stretched between the electrode body 16 and the bottom 12B. In each figure, for convenience of explanation, the thickness of the heat-conductive resin sheet 24 is exaggerated. The thickness of the heat-conductive resin sheet 24 is preferably about 0.5 mm to 5 mm from the viewpoint of ensuring heat conductivity while maintaining a wide internal volume of the battery cell 10.

[0023] Figure 2 is a cross-sectional view showing the state when cut along the line 2-2 in Figure 1. As shown in Figure 2, the heat-conductive resin sheet 24 is formed to a size smaller than the bottom 12B of the can body 12 before compression, and in this embodiment, as an example, it is formed in the shape of a roughly rectangular sheet.

[0024] Furthermore, multiple slits 24C are formed on the upper surface 24B (one side) of the thermal conductive resin sheet 24. The slits 24C are formed at predetermined intervals along the width direction of the battery cell 10. In addition, the slits 24C are formed continuously from the front end to the rear end of the thermal conductive resin sheet 24 with the same width.

[0025] Thus, the thermal conductive resin sheet 24 is formed in a rectangular shape with the front-to-back direction being the shorter side, and a plurality of slits 24C are formed at predetermined intervals in the width direction, which is perpendicular to the front-to-back direction.

[0026] Figure 3 is an enlarged cross-sectional view of the main part, showing the state when cut along the line 3-3 in Figure 2. As shown in Figure 3, the slit 24C is formed only on the upper surface 24B of the heat conductive resin sheet 24, and the lower surface 24A opposite to the surface on which the slit 24C is formed is housed in the can body 12 so as to face the bottom 12B of the can body 12.

[0027] Furthermore, in this embodiment, the depth of the slit 24C is set to about half the total thickness of the thermal conductive resin sheet 24. If the depth of the slit 24C is shallow, it is difficult to obtain the effect of the slit 24C, so it is preferable to set the depth of the slit 24C to 15% or more of the thickness of the thermal conductive resin sheet 24.

[0028] The steps shown in Figures 2 and 3 involve placing the heat-conductive resin sheet 24 into the bottom 12B of the can body 12. Following this step, the electrode body 16 is inserted into the can body 12 while compressing the heat-conductive resin sheet 24 between the can body 12 and the electrode body 16, resulting in the state shown in Figure 4.

[0029] Figure 4 is a cross-sectional view showing the state after the thermal conductive resin sheet 24 has been compressed from the state shown in Figure 2. In Figure 4, the thermal conductive resin sheet 24 before compression is shown by a dashed line, and the thermal conductive resin sheet 24 after compression is shown by a solid line.

[0030] The heat-conductive resin sheet 24 is stretched by compression and is stretched almost uniformly toward the edge of the can body 12.

[0031] (action) Next, the operation of the manufacturing method for the battery cell 10 according to this embodiment will be explained.

[0032] The manufacturing method for the battery cell 10 according to this embodiment includes the steps of housing the thermal conductive resin sheet 24 in the bottom 12B of the outer casing, which is a can body 12, and compressing the thermal conductive resin sheet 24 between the can body 12 and the electrode body 16 while inserting the electrode body 16 into the can body 12. Here, as shown in Figure 3, a plurality of unidirectional slits 24C are formed on the upper surface 24B of the thermal conductive resin sheet 24. As a result, when the thermal conductive resin sheet 24 is compressed, the crushed portion deforms so that it enters the slits 24C, allowing the thermal conductive resin sheet 24 to be stretched more uniformly compared to a structure without slits 24C.

[0033] This effect will be explained in comparison with the structure of the comparative example. Figure 6 is a schematic diagram showing the state of the thermal conductive resin sheet before and after compression in the comparative example. As shown in Figure 6, the battery cell 100 in the comparative example is equipped with a thermal conductive resin sheet 102.

[0034] In Figure 6, the shape of the thermal conductive resin sheet 102 before compression is shown by a dashed line, and the shape of the thermal conductive resin sheet 102 after compression is shown by a solid line. Furthermore, the thermal conductive resin sheet 102 in the comparative example is formed to the same shape as the thermal conductive resin sheet 24 in the embodiment, and differs from the embodiment in that it does not have slits.

[0035] In the comparative example, the heat-conducting resin sheet 102 does not have slits, so when compressed, the heat-conducting resin sheet 102 is not stretched uniformly and becomes roughly elliptical. In this case, a gap is created between the corner of the can body 12 and the heat-conducting resin sheet 102, which may reduce the efficiency of heat conduction.

[0036] In contrast, as shown in Figure 4, in the battery cell 10 according to this embodiment, the gap between the compressed thermal conductive resin sheet 24 and the corner of the can body 12 is small, which suppresses a decrease in the efficiency of heat conduction.

[0037] Furthermore, in this embodiment, as shown in Figure 3, the lower surface 24A of the heat-conductive resin sheet 24, where the slit 24C is not formed, is in contact with the bottom 12B of the can body 12. Therefore, the contact area with the bottom 12B is larger than when the upper surface 24B, where the slit 24C is formed, is positioned on the bottom 12B side, making it easier to position the heat-conductive resin sheet 24.

[0038] Furthermore, in this embodiment, by forming multiple slits 24C along the longitudinal direction of the thermal conductive resin sheet 24, more slits 24C can be formed. Also, since the length of the slits 24C is shorter than when the slits 24C extend in the longitudinal direction, they are more easily stretched in the desired direction during compression. In other words, the shape of the thermal conductive resin sheet 24 is easier to control. Thus, according to the manufacturing method of the battery cell 10 of this embodiment, it is possible to suppress the uneven stretching of the thermal conductive resin sheet 24.

[0039] In this embodiment, the thickness of the thermal conductive resin sheet 24 is kept constant, but this is not limited to this. For example, the modified configuration shown in Figure 5 may be adopted.

[0040] (modified version) Figure 5 is a cross-sectional view corresponding to Figure 3, showing a modified battery cell 50. As shown in Figure 5, the battery cell 50 according to this modified example is equipped with a thermal conductive resin sheet 52 instead of the thermal conductive resin sheet 24.

[0041] The thermal conductive resin sheet 52 is composed of a lower surface 52A that contacts the bottom 12B of the can body 12 and an upper surface 52B that contacts an electrode body (not shown), and a plurality of slits 52C are formed on the upper surface 52B. The pitch and shape of the slits 52C are the same as the slits 24C in the embodiment, but they may be different shapes.

[0042] In this modified example, the thickness of the thermal conductive resin sheet 52 differs between the central part and the peripheral edges. Specifically, the upper surface 52B of the thermal conductive resin sheet 52 is formed in a shape that is slightly concave in the central part. As a result, the thermal conductive resin sheet 52 is thinner in the central part than at the peripheral edges.

[0043] In this modified example, because the thickness of the central part of the heat-conducting resin sheet 52 is thin, the peripheral edges are compressed to the electrode body first, allowing the heat-conducting resin sheet 52 to be stably stretched all the way to the corners of the can body 12.

[0044] Although embodiments and modified versions of a battery manufacturing method have been described above, the invention is not limited thereto and can be implemented in various forms without departing from the spirit of the present invention. For example, in the above embodiment, as shown in Figure 3, a slit 24C was formed on the upper surface 24B of the thermal conductive resin sheet 24, but the invention is not limited thereto, and a slit may be formed on the lower surface 24A. Also, slits may be formed on both the upper and lower surfaces of the thermal conductive resin sheet 24. In this case, the pitch and groove width may be changed between the slits on the upper surface and the slits on the lower surface.

[0045] Furthermore, although the pitch of the slits 24C is kept constant in this embodiment, the invention is not limited to this. For example, the spacing between adjacent slits 24C may be varied between the central part and the peripheral edge of the heat-conductive resin sheet 24. Also, although the heat-conductive resin sheet 24 is formed in a substantially rectangular sheet shape in this embodiment, the invention is not limited to this, and the shape of the slits may be changed to match the shape of the bottom 12B of the can body 12.

[0046] The following additional information is disclosed regarding the above embodiment.

[0047] (Note 1) A step of housing a heat-conductive resin sheet, having multiple slits extending in one direction on at least one surface, at the bottom of the exterior body, A step of inserting the electrode body into the outer casing while compressing the heat conductive resin sheet between the outer casing and the outer casing, A method for manufacturing a battery having [a certain characteristic]. (Note 2) The slit is formed on only one side of the heat-conducting resin sheet. The method for manufacturing a battery according to Appendix 1, wherein the battery is housed in the outer casing such that the side opposite to the side on which the slit is formed faces the bottom of the outer casing. (Note 3) The heat-conducting resin sheet is formed in a rectangular shape with the shorter side being one of the directions, A method for manufacturing a battery according to Appendix 1 or 2, wherein a plurality of slits are formed at predetermined intervals in a direction perpendicular to the aforementioned one direction. (Note 4) The method for manufacturing a battery according to any one of the appendices 1 to 3, wherein the heat-conducting resin sheet is formed in a shape in which the thickness is thinner in the center than at the peripheral edges. [Explanation of Symbols]

[0048] 10 Battery cells (batteries) 12 cans (outer packaging) 12B Bottom 16 Electrode body 24 Thermal conductive resin sheet 24C Slit 50 battery cells (batteries) 52 Thermal conductive resin sheet 52C Slit

Claims

1. A step of housing a heat-conductive resin sheet, having multiple slits extending in one direction on at least one surface, at the bottom of the exterior body, A step of inserting the electrode body into the outer casing while compressing the heat conductive resin sheet between the outer casing and the outer casing, A method for manufacturing a battery having [a certain characteristic].

2. The slit is formed on only one side of the heat-conducting resin sheet. The method for manufacturing a battery according to claim 1, wherein the battery is housed in the outer casing such that the side opposite to the side on which the slit is formed faces the bottom of the outer casing.

3. The heat-conducting resin sheet is formed in a rectangular shape with the shorter side being one of the directions, The method for manufacturing a battery according to claim 1, wherein a plurality of slits are formed at predetermined intervals in a direction perpendicular to the aforementioned one direction.

4. The method for manufacturing a battery according to claim 1, wherein the heat-conductive resin sheet is formed in a shape in which the thickness is thinner in the center than at the peripheral edges.

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