Manufacturing method of power storage cell

Abstract

To increase manufacturing efficiency.SOLUTION: A manufacturing method for a power storage cell includes the following steps (a) to (c) in this order: (a) preparing a square cylindrical case having a rectangular opening and a bottom; (b) pouring an electrode body and an electrolyte into the case through the opening; and (c) manufacturing the power storage cell by closing the opening. The case includes a square cylindrical peripheral wall and a rectangular bottom wall. The peripheral wall stands upright from the bottom wall. The opening is closed by folding the peripheral wall inward of the case.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing an energy storage cell. [Background technology]

[0002] JP 2012-156002 A discloses a method for manufacturing an alkaline battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-156002 A Summary of the Invention [Problem to be solved by the invention]

[0004] The case of the energy storage cell houses the electrode body and the electrolyte. Generally, the case includes a bottomed container (main body) and a lid. The main body has an opening. The lid is joined to the main body. The lid closes the opening. An injection hole is provided in the lid. The electrolyte is injected through the injection hole. Because the cross-sectional area of ​​the injection hole is small, it tends to take a long time to inject and impregnate the electrolyte.

[0005] For example, it is possible to pour the electrolyte from the opening of the main body before joining the lid. The electrolyte is poured into the gap between the electrode body and the main body. Since the clearance between the electrode body and the main body is small, the electrolyte may overflow from the opening. In order to prevent the electrolyte from overflowing, it is required to adjust the inflow rate of the electrolyte from the opening in accordance with the impregnation rate of the electrolyte into the electrode body. Since the impregnation of the electrolyte into the electrode body is the rate-limiting step, it is possible that the desired manufacturing efficiency cannot be achieved.

[0006] An objective of the present disclosure is to improve manufacturing efficiency. [Means for solving the problem]

[0007] The technical configuration and the effects of the present disclosure will be described below. However, the mechanism of action includes assumptions. The mechanism of action does not limit the technical scope of the present disclosure.

[0008] The method for producing a storage cell includes the following steps (a) to (c) in this order. (a) A square cylindrical case having a rectangular opening and a bottom is prepared. (b) The electrode body and electrolyte are placed into the case through the opening. (c) The opening is sealed to produce a storage cell. The case includes a peripheral wall having a rectangular cylindrical shape and a bottom wall having a rectangular shape. The peripheral wall stands upright from the bottom wall. The above (c) includes folding the peripheral wall inward of the case to close the opening.

[0009] The case has a lidless structure. The peripheral wall of the case has a fold portion. The fold portion is folded inward to block the opening. When the fold portion is not folded, the electrolyte is poured in through the opening. Since the fold portion acts as a buffer, it is believed that the electrolyte is less likely to spill out. Since the desired amount of electrolyte can be poured in at once, it is expected that manufacturing efficiency will be improved.

[0010] For example, after the above (b), notches may be made in the four corners of the peripheral wall. The formation of the notches is expected to make it easier to fold the peripheral wall.

[0011] For example, after the above (c), the gaps between the peripheral walls (the tips of the peripheral walls after bending) may be joined by laser processing. That is, the case may be sealed by laser processing.

[0012] Hereinafter, an embodiment of the present disclosure (hereinafter, may be abbreviated as "the present embodiment") will be described. However, the present embodiment does not limit the technical scope of the present disclosure. The present embodiment is illustrative in all respects. The present embodiment is non-restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the description of the claims. For example, it is also intended from the beginning that any configuration may be extracted from the present embodiment and arbitrarily combined. [Brief description of the drawings]

[0013] [Figure 1] 2 is a schematic flowchart of a method for producing a storage cell in the present embodiment. [Diagram 2] FIG. 4 is a schematic diagram showing an example of a case in the present embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing an example of liquid injection in the present embodiment. [Figure 4] FIG. 2 is a schematic cross-sectional view showing an example of an electrode body in the present embodiment. [Diagram 5] FIG. 2 is a first schematic diagram showing an example of a sealing hole in the present embodiment. [Figure 6] FIG. 2 is a second schematic diagram showing an example of a sealing hole in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Manufacturing method of storage cell Fig. 1 is a schematic flow chart of the method for producing a storage cell in this embodiment. Hereinafter, the "method for producing a storage cell in this embodiment" may be abbreviated as "this production method". This production method includes "(a) preparation of a case", "(b) liquid injection", and "(c) sealing".

[0015] (a) Case preparation 2 is a schematic diagram showing an example of a case in this embodiment. The manufacturing method includes preparing a case 200. The case 200 has a height direction (H direction), a width direction (W direction), and a thickness direction (T direction). The H direction, W direction, and T direction are perpendicular to each other. The H direction may be parallel to the vertical direction, for example. The W direction and T direction may be parallel to the horizontal direction, for example.

[0016] The case 200 has a bottomed rectangular tube shape. The case 200 may be made of, for example, a metal. The case 200 may be made of, for example, an Al alloy. The case 200 may be prepared by any method. For example, the case 200 may be formed by deep drawing. For example, the case 200 may be assembled by joining multiple metal plates together by laser welding.

[0017] The case 200 includes a peripheral wall 210 and a bottom wall 220. The case 200 has an opening 230. The opening 230 is open in the H direction. The bottom wall 220 and the opening 230 are rectangular. The bottom wall 220 and the opening 230 may be, for example, rectangular. The bottom wall 220 may have a similar shape to the opening 230. For example, a positive electrode terminal portion (not shown) and a negative electrode terminal portion (not shown) may be provided on the bottom wall 220.

[0018] The peripheral wall 210 stands from the bottom wall 220. The peripheral wall 210 includes a pair of main walls 211 and a pair of side walls 212. The main wall 211 and the side walls 212 are rectangular. The main wall 211 and the side walls 212 may be, for example, rectangular. The main wall 211 has an area larger than the bottom wall 220 and the side walls 212. The side walls 212 may have an area smaller than the bottom wall 220, for example.

[0019] The peripheral wall 210 has a folding line portion 213. The folding line portion 213 runs around the peripheral wall 210 in parallel with the opening 230. The main wall 211 and the side wall 212 are folded inward along the folding line portion 213 to close the opening 230. The folding line portion 213 may include a groove (recess) extending linearly. It is expected that the folding work will be simplified by forming a groove along the folding line. For example, the groove may be formed by laser processing. For example, when laser processing (groove formation) is performed after deep drawing, the case 200 may be cleaned after the laser processing. Metal pieces and the like generated by the laser processing can be removed by cleaning. For example, when the case 200 is assembled by joining multiple metal plates, the groove may be formed at the stage of the metal plates.

[0020] (b) Liquid injection 3 is a schematic diagram showing an example of liquid injection in this embodiment. This manufacturing method includes pouring the electrode body 100 and the electrolyte solution 10 from the opening 230. The order of pouring is arbitrary. For example, the electrode body 100 may be poured into the case 200 first. For example, the electrode body 100 and a terminal portion (not shown) may be joined inside the case 200. For example, the electrolyte solution 10 may be poured into the case 200 first.

[0021] The "first aspect ratio" refers to the ratio of the W-direction dimension to the H-direction dimension in the electrode body 100. The first aspect ratio may be, for example, 1 or more, 1.5 or more, 2 or more, 2.5 or more, 3 or more, 5 or more, or 10 or more. The first aspect ratio may be, for example, 10 or less, 5 or less, 3 or less, 2.5 or less, 2 or less, or 1.5 or less. The "second aspect ratio" refers to the ratio of the T-direction dimension to the H-direction dimension in the electrode body 100. The second aspect ratio may be, for example, 0.1 or more, 0.2 or more, 0.3 or more, 0.5 or more, or 1 or more. The second aspect ratio may be, for example, 1 or less, 0.5 or less, 0.3 or less, or 0.2 or less.

[0022] The electrode body 100 has an arbitrary structure. The electrode body 100 may be, for example, a wound type. The electrode body 100 may be, for example, a laminated type. FIG. 4 is a schematic cross-sectional view showing an example of an electrode body in this embodiment. The electrode body 100 includes one or more positive electrodes 110, one or more negative electrodes 120, and one or more separators 130. In the T direction, the positive electrodes 110 and the negative electrodes 120 are alternately laminated. That is, the T direction is parallel to the lamination direction of the positive electrodes 110 and the negative electrodes 120. The number of the positive electrodes 110 and the negative electrodes 120 may be any of 2 or more, 5 or more, 10 or more, 50 or more, or 100 or more. The number of the positive electrodes 110 and the negative electrodes 120 may be any of 200 or less, 100 or less, 50 or less, 10 or less, or 5 or less.

[0023] The positive electrode 110 may include, for example, a positive electrode current collector 112 and a positive electrode active material layer 114. The positive electrode current collector 112 may include, for example, an Al foil or the like. The positive electrode active material layer 114 is disposed on a surface of the positive electrode current collector 112. The positive electrode active material layer 114 may be disposed on only one side of the positive electrode current collector 112. The positive electrode active material layer 114 may be disposed on both sides of the positive electrode current collector 112. The positive electrode active material layer 114 includes a positive electrode active material. The positive electrode active material may include, for example, a lithium nickel composite oxide or the like.

[0024] The negative electrode 120 may include, for example, a negative electrode current collector 122 and a negative electrode active material layer 124. The negative electrode current collector 122 may include, for example, Cu foil or the like. The negative electrode active material layer 124 is disposed on a surface of the negative electrode current collector 122. The negative electrode active material layer 124 may be disposed on only one side of the negative electrode current collector 122. The negative electrode active material layer 124 may be disposed on both sides of the negative electrode current collector 122. The negative electrode active material layer 124 includes a negative electrode active material. The negative electrode active material may include, for example, graphite, SiO, Si, or the like.

[0025] The negative electrode active material layer 124 may have the same area as the positive electrode active material layer 114, or may have a different area. For example, the area of ​​the negative electrode active material layer 124 may be larger than the area of ​​the positive electrode active material layer 114. The ratio of the area of ​​the negative electrode active material layer 124 to the area of ​​the positive electrode active material layer 114 may be, for example, any of 1.01 or more, 1.05 or more, or 1.1 or more. The ratio of the area of ​​the negative electrode active material layer 124 to the area of ​​the positive electrode active material layer 114 may be, for example, any of 1.1 or less, 1.05 or less, or 1.01 or less.

[0026] The separator 130 has electrical insulation properties. The separator 130 is porous. The separator 130 may include, for example, a microporous film made of polyolefin. The thickness of the separator 130 may be, for example, 5 to 50 μm, 5 to 30 μm, or 5 to 15 μm. The separator 130 separates the positive electrode 110 from the negative electrode 120. The separator 130 may be, for example, two or more sheets. For example, the separator 130 may be inserted between each of the positive electrode 110 and the negative electrode 120.

[0027] Separator 130 may be, for example, a single sheet. For example, separator 130 may include zigzag fold portion 135. Separator 130 is folded in a zigzag shape at zigzag fold portion 135. The zigzag shape may also be expressed as, for example, a "bellows shape" or an "accordion shape."

[0028] The zigzag fold portion 135 includes a planar portion 131 and a folded portion 132. In the planar portion 131, the separator 130 extends in a planar shape. In the folded portion 132, the separator 130 is folded. The folded portion 132 is disposed at both ends in the H direction. The separator 130 is folded so as to alternately sandwich the positive electrode 110 or the negative electrode 120. The planar portion 131 sandwiches the positive electrode 110 or the negative electrode 120. The separator 130 may further include, for example, an outer peripheral portion 136. The outer peripheral portion 136 may be wound so as to wrap the zigzag fold portion 135. Note that the zigzag fold portion may be formed by folding the separator 130 at both ends in the W direction. When the zigzag fold portion 135 is formed, the electrolyte 10 is less likely to permeate into the electrode body 100, so that the present manufacturing method may be particularly effective.

[0029] (c) Sealing FIG. 5 is a first schematic diagram showing an example of sealing in this embodiment. This manufacturing method includes manufacturing the energy storage cell 1 by closing the opening 230. The opening 230 is closed by folding the peripheral wall 210. The peripheral wall 210 is folded toward the inside of the case 200 along the folding line 213. For example, after the liquid is poured, before folding the peripheral wall 210, the incisions 214 may be made in the four corners of the peripheral wall 210. The incisions 214 extend from the opening 230 toward the folding line 213 in parallel with the H direction. The incisions 214 may reach the folding line 213. It is expected that the formation of the incisions 214 will facilitate folding of the peripheral wall 210.

[0030] 6 is a second schematic diagram showing an example of a sealing in this embodiment. After the peripheral walls 210 are folded, the gaps between the peripheral walls 210 may be joined by, for example, laser processing. For example, the case 200 can be sealed by scanning the laser 20 along the gaps 215 between the peripheral walls 210. It is expected that the laser processing will improve airtightness. [Explanation of symbols]

[0031] 1 storage cell, 10 electrolyte, 20 laser, 100 electrode body, 110 positive electrode, 112 positive electrode current collector, 114 positive electrode active material layer, 120 negative electrode, 122 negative electrode current collector, 124 negative electrode active material layer, 130 separator, 131 flat portion, 132 folded portion, 135 zigzag folded portion, 136 outer periphery, 200 case, 210 peripheral wall, 211 main wall, 212 side wall, 213 fold line portion, 214 notch, 215 gap, 220 bottom wall, 230 opening.

Claims

[Claim 1] (a) preparing a case having a rectangular opening and a bottomed rectangular cylindrical shape; (b) inserting an electrode assembly and an electrolyte into the case through the opening; and (c) producing an energy storage cell by closing the opening; in that order, The case includes a cylindrical peripheral wall and a rectangular bottom wall, The peripheral wall stands upright from the bottom wall, (c) includes folding the peripheral wall toward the inside of the case to close the opening; A method for manufacturing a storage cell.

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