Method for manufacturing a secondary battery and secondary battery

Abstract

To provide a method for manufacturing a secondary battery that reduces residue inside the housing and injects the electrolyte into the housing without the electrolyte adhering to the joint between the housing and the lid. [Solution] A method for manufacturing a secondary battery comprises an electrode body, a housing for housing the electrode body, and a lid joined to the housing, and comprises a placement step, a sealing step, and a melting step. In the placement step, the frozen electrolyte, which is an electrolyte solution, is placed inside the housing. In the sealing step, the lid is joined to the housing, and the housing is sealed. In the melting step, the housing is heated, and the frozen electrolyte melts.

Description

Technical Field

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

Background Art

[0002] In a method for manufacturing a secondary battery, a method is taken in which an electrolytic solution is injected into a battery case so that an electrode body is immersed, and the inside of the case is filled with the electrolytic solution. Patent Document 1 describes a method in which a bag body containing an electrolytic solution is disposed in a case, the case is sealed with a lid body, and then the bag body is ruptured to fill the inside of the case with the electrolytic solution.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the invention described in Patent Document 1, by rupturing the bag body inside the case after the case is sealed, the inside of the case can be filled with the electrolytic solution without the electrolytic solution adhering to the joint portion of the case and the joint portion of the lid body. However, in the invention described in Patent Document 1, the ruptured bag body may remain inside the case.

[0005] In view of the above problems, the present disclosure provides a method for manufacturing a secondary battery that reduces residues inside the case and injects the electrolytic solution into the case without allowing the electrolytic solution to adhere to the joint portions of the case and the lid body.

Means for Solving the Problems

[0006] A method for manufacturing a secondary battery according to one aspect of the present disclosure comprises an electrode body, a housing for housing the electrode body, and a lid joined to the housing, and comprises a placement step, a sealing step, and a melting step. In the placement step, the frozen electrolyte, which is an electrolyte, is placed inside the housing. In the sealing step, the lid is joined to the housing, and the housing is sealed. In the melting step, the housing is heated, and the frozen electrolyte melts.

[0007] In the above-described method for manufacturing a secondary battery, the frozen electrolyte may be placed adjacent to the end face of the electrode body during the arrangement step.

[0008] In the above-described method for manufacturing a secondary battery, during the melting process, the housing may be positioned so that the surface in contact with the electrode body is at the bottom, and the housing may be heated from above.

[0009] In the above-described method for manufacturing a secondary battery, the secondary battery may be a battery for use in a vehicle.

[0010] A secondary battery according to one aspect of the present disclosure comprises an electrode body and a housing for housing the electrode body, wherein a frozen electrolyte is disposed inside the housing. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a method for manufacturing a secondary battery that reduces residue inside the housing and injects the electrolyte into the housing without the electrolyte adhering to the joint between the housing and the lid. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a method for manufacturing a secondary battery according to Embodiment 1. [Figure 2] This is a flow chart of the manufacturing method for a secondary battery according to Embodiment 1. [Figure 3] This is a schematic diagram showing a method for manufacturing a secondary battery according to Embodiment 2. [Modes for carrying out the invention]

[0013] The present invention will be described below through embodiments of the invention, but the invention claimed is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means of solving the problem. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations have been omitted where necessary.

[0014] <Embodiment 1> A method for manufacturing a secondary battery according to Embodiment 1 will be described with reference to Figure 1. Figure 1 is a schematic diagram showing a method for manufacturing a secondary battery 10 according to Embodiment 1. Figure 1(A) is a cross-sectional view of the secondary battery 10 seen from the side (-z direction). Figure 1(B) is a plan view of the secondary battery 10 seen from above (+z direction). Note that Figure 1(B) shows only the internal structure of the secondary battery 10. In Figure 1(A), the secondary battery 10 comprises a housing 11, a cover 12, an electrode body 13, at least two terminals 14, and a frozen electrolyte 15. Multiple secondary batteries 10 may be combined and used as a single secondary battery with a larger capacity.

[0015] The housing 11 has an internal space in which the electrode body 13, terminals 14, and frozen electrolyte 15 are housed. The housing 11 has an opening. The housing 11 is sealed by joining a lid 12 to the opening. The housing 11 may be, for example, a rectangular box shape with a rectangular parallelepiped-shaped storage space inside. The housing 11 may also be cylindrical with an open top and a cylindrical storage space inside. In Figure 1, the housing 11 is a rectangular box shape with an opening in the +y direction.

[0016] The lid 12 is joined to the housing 11, sealing the housing 11. The lid 12 is made of the same material as the housing 11, for example, and is a plate that fits into the opening of the housing 11. The method of joining the housing 11 and the lid 12 is not particularly limited, but methods such as welding, brazing, or adhesive can be used. In Figure 1, the lid 12 is connected to the housing 11 from the +y direction, sealing the housing 11.

[0017] The housing 11 and lid 12 are constructed from metal materials such as aluminum or steel. Alternatively, the housing 11 and lid 12 may be constructed from resin materials such as polyphenylene sulfide resin (PPS) or polyimide resin.

[0018] The electrode body 13 is a structure that includes the positive and negative electrodes of the secondary battery 10. The electrode body 13 comprises multiple electrodes. The electrode body 13 is connected to the terminal 14. More specifically, the multiple electrodes of the electrode body 13 are connected to the positive terminal 141 or the negative terminal 142. The electrodes may also be connected to the terminal 14 via lead wires (not shown).

[0019] The electrode body 13 is, for example, a laminate in which positive electrode sheets coated with positive electrode material and negative electrode sheets coated with negative electrode material are alternately stacked with separators in between. Alternatively, the electrode body 13 may be a wound body in which positive electrode sheets coated with positive electrode material and negative electrode sheets coated with negative electrode material are stacked with separators in between and wound up. Here, the positive electrode sheets are connected to the positive electrode terminal 141, and the negative electrode sheets are connected to the negative electrode terminal 142. The combination of positive and negative electrode materials can be, for example, lithium transition metal oxide and graphite, sodium transition metal oxide and carbon, or nickel hydroxide and hydrogen storage alloy. In Figure 1, the electrode body 13 is a laminate in which multiple electrodes are stacked in the z direction. The electrode body 13 is also connected to the positive electrode terminal 141 and the negative electrode terminal 142 at its ends in the -x and +x directions, respectively.

[0020] The terminal 14 electrically connects the plurality of electrodes constituting the electrode body 13 and the outside of the housing 11. The terminal 14 is connected to the electrode body 13. More specifically, the terminal 14 consists of a positive terminal 141 and a negative terminal 142. The positive terminal 141 is connected to the electrode that is the positive electrode of the electrode body 13. The negative terminal 142 is connected to the electrode that is the negative electrode of the electrode body 13. The terminal 14 may penetrate the housing 11 or the lid body 12. Also, the terminal 14 may be integrally formed with the housing 11 or the lid body 12. Thereby, the terminal 14 enables electrical connection between the plurality of electrodes constituting the electrode body 13 and the outside of the housing 11. Note that the secondary battery 10 may include a plurality of positive terminals 141 and negative terminals 142.

[0021] The frozen electrolyte 15 is obtained by freezing the electrolyte. The frozen electrolyte 15 is heated and melted into an electrolyte when the temperature exceeds the melting point. Here, the electrolyte varies depending on the positive electrode material and the negative electrode material, and for example, is an organic electrolyte in which salts and additives are added to an organic solvent, or an alkaline solution or the like. The frozen electrolyte 15 is disposed within the housing 11. In FIG. 1, the frozen electrolyte 15 is disposed on the -x side and the +x side with respect to the electrode body 13. Also, the frozen electrolyte 15 may be formed into a predetermined shape during or after freezing. In FIG. 1(B), the frozen electrolyte 15 is formed in a C-shaped cross section when viewed from above (+z direction) so as not to interfere with the terminal 14.

[0022] The frozen electrolyte 15 melts when the housing 11 is heated after the lid body 12 is joined to the housing 11 and the housing 11 is sealed. The electrolyte obtained by melting the frozen electrolyte 15 impregnates the electrode body 13 and fills the space between the electrodes of the electrode body 13. More specifically, the electrolyte obtained by melting the frozen electrolyte 15 impregnates the separator disposed between the electrodes of the electrode body 13. Thereby, when the positive terminal 141 and the negative terminal 142 are connected by a conducting wire (not shown), the positive terminal 141 and the negative terminal 142 are energized through the electrode body 13.

[0023] Next, the manufacturing flow of the secondary battery according to Embodiment 1 will be explained with reference to Figure 2. Figure 2 is a flow chart of the manufacturing method of the secondary battery according to Embodiment 1. The manufacturing method of the secondary battery according to Embodiment 1 includes steps S11 to S13.

[0024] In step S11, the frozen electrolyte 15 is placed inside the housing 11. Step S11 is also called the placement step. In step S12, the lid 12 is joined to the housing 11. This seals the housing 11. Step S12 is also called the sealing step.

[0025] In step S13, the housing 11 is heated. This causes the frozen electrolyte 15 to melt. The melted electrolyte fills the inside of the housing 11 and impregnates the electrode body 13. As a result, the secondary battery 10 can conduct electricity by electrically connecting the terminals 14. Step S13 is also called the melting process. Step S13 may be performed simultaneously with step S12. The manufacturing of the secondary battery 10 according to this embodiment is completed upon completion of step S13.

[0026] As described above, the process from step S11 to step S13 allows the electrolyte to be injected into the housing 11 without adhering to the joint between the housing 11 and the lid 12. Furthermore, the manufacturing method of the secondary battery 10 according to this embodiment leaves no residue inside the housing 11. Therefore, even if the secondary battery 10 according to Embodiment 1 is used as an in-vehicle battery that is prone to vibration and shock, no residue will move inside the housing 11.

[0027] <Embodiment 2> Next, with reference to Figure 3, the manufacturing method of the secondary battery 10 according to Embodiment 2 will be described. Figure 3 is a schematic diagram showing the manufacturing method of the secondary battery 10 according to Embodiment 2. In Figure 3, the secondary battery 10 is shown as a cross-sectional view seen from the side (-z direction). Here, the manufacturing method of the secondary battery 10 according to Embodiment 2 is applied to the secondary battery 10 in Figure 1. The secondary battery 10 shown in Figure 3 has some of the same configuration as the secondary battery 10 described with reference to Figure 1. Therefore, redundant explanations of the configuration of the secondary battery 10 will be omitted.

[0028] As shown in Figure 3, the frozen electrolyte 15 is placed adjacent to the end face of the electrode body 13. More specifically, in the placement process described with reference to Figure 2, the frozen electrolyte 15 is placed adjacent to the end face of the electrode body 13. With this arrangement, the electrolyte is impregnated from the end face of the electrode body 13, allowing the frozen electrolyte 15 to suitably impregnate the electrode body 13 with the thawed electrolyte. Here, "adjacent" means being placed next to each other, and they do not necessarily have to be in contact with each other. The end face of the electrode body 13 is the surface on which the multiple electrodes contained in the electrode body 13 are exposed.

[0029] As shown in Figure 3, the housing 11 is positioned so that the surface in contact with the electrode body 13 is at the bottom (located in the -y direction) and is heated from the top (+y direction). Specifically, in the melting process described with reference to Figure 2, the housing 11 is positioned so that the surface in contact with the electrode body 13 is at the bottom (located in the -y direction) and is heated from the top (+y direction). The method of heating the housing 11 is not particularly limited, but a method that allows the heating position to be arbitrarily selected is preferred. The housing 11 may be heated by, for example, an electric heating wire, or by far-infrared radiation. In Figure 3, the housing 11 is heated from the top using a heater 20. The housing 11 may also be heated from the top by welding it to the lid 12 located at the top.

[0030] The electrolyte is impregnated into the electrode body 13 by capillary action. When the electrolyte is injected, it rises from the liquid surface to the top of the electrode body by capillary action. However, if the amount of electrolyte injected is insufficient, the electrolyte may not reach the top of the electrode body. On the other hand, as in this embodiment, by thawing the frozen electrolyte 15 from near the top of the electrode body 13, which is the least likely to be immersed in the electrolyte, the thawed electrolyte sequentially impregnates the electrode body 13 from near the top, as shown by the white arrows in Figure 3. This allows the electrolyte to be impregnated even near the top of the electrode body 13, and the electrode body 13 can be suitably impregnated with the electrolyte.

[0031] As described above, the manufacturing method of the secondary battery 10 according to Embodiment 2 allows the electrolyte to be suitably impregnated into the electrode body 13 without the electrolyte adhering to the joint between the housing 11 and the lid 12.

[0032] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the frozen electrolyte may be melted by the heat of reaction from a chemical reaction. Also, the housing may be placed in a position where it is exposed to sunlight and heated by sunlight. Furthermore, the housing may be heated naturally during transportation or other means. [Explanation of Symbols]

[0033] 10 Secondary battery 11 cabinets 12 Lid 13 Electrode body 14 terminals 15 Frozen electrolyte 20 Heaters 141 Positive terminal 142 Negative terminal

Claims

1. A method for manufacturing a secondary battery comprising an electrode body, a housing for housing the electrode body, and a lid joined to the housing, A placement step in which the frozen electrolyte, obtained by freezing the electrolyte, is placed inside the housing, A sealing step in which the lid is joined to the housing and the housing is sealed, The casing is heated up, and the frozen electrolyte melts in a melting step, A method for manufacturing a secondary battery, comprising the following features.

2. The method for manufacturing a secondary battery according to claim 1, wherein in the arrangement step, the frozen electrolyte is arranged adjacent to the end face of the electrode body.

3. In the melting process, The housing is positioned such that the surface in contact with the electrode body is at the bottom. The aforementioned enclosure is heated from the top. A method for manufacturing a secondary battery according to claim 2.

4. The method for manufacturing a secondary battery according to any one of claims 1 to 3, wherein the secondary battery is an in-vehicle battery.

5. It comprises an electrode body and a housing for housing the electrode body. A frozen electrolyte solution, obtained by freezing an electrolyte solution, is placed inside the housing. Secondary battery.

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