Electrode assembly manufacturing method

Abstract

To provide a method for manufacturing an electrode body which can suppress positional displacement of an electrode from a separator while reducing the number of steps necessary to manufacture a plurality of electrodes.SOLUTION: A method for manufacturing an electrode 100 includes the steps of: preparing a separator 130; arranging a plurality of positive electrodes 110 on the separator; forming a folding unit 132 for determining the positions of the positive electrodes with respect to the separator by folding back the separator and arranging the separator on the positive electrodes; arranging a plurality of negative electrodes 120 on the separator arranged on the positive electrodes; forming a folding unit 132 for determining the positions of the negative electrodes with respect to the separator by folding back the separator and arranging the separator on the negative electrodes; and cutting the separator in a position which passes among the positive electrodes and among the negative electrodes, thereby forming a plurality of electrode bodies 100.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electrode assembly. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2018-166080 discloses a method for manufacturing a secondary battery, which includes a step of winding a stack of a positive electrode sheet, a negative electrode sheet, and a separator to form a flat wound body, and a step of cutting a part of the flat wound body to form a laminate. The flat wound body includes a bent portion formed by bending the positive electrode sheet, the negative electrode sheet, and the separator, and the laminate is formed by cutting the bent portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-166080 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for a simpler manufacturing method for so-called stacked electrode assemblies.

[0005] An object of the present disclosure is to provide a method for manufacturing an electrode assembly that allows for easy manufacturing of a stacked electrode assembly. [Means for solving the problem]

[0006] A method for manufacturing an electrode assembly according to one aspect of the present disclosure includes a winding step of forming a wound assembly by winding a positive electrode and a negative electrode with a separator interposed therebetween; a compression step of forming a compressed wound assembly by compressing the wound assembly from both radial sides of the wound assembly; and a cutting step of cutting the compressed wound assembly by moving a cutting member from the inside to the outside of the compressed wound assembly along an orthogonal direction that is orthogonal to both the direction in which the wound assembly is compressed in the compression step and the central axis of the wound assembly. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a method for manufacturing an electrode assembly that allows for easy manufacturing of a stacked electrode assembly. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically illustrating a storage cell according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of the storage cell shown in FIG. [Figure 3] 1A to 1C are diagrams schematically showing a method for manufacturing an electrode body. [Figure 4] 1A to 1C are diagrams schematically showing a method for manufacturing an electrode body. [Figure 5] 1A to 1C are diagrams schematically showing a method for manufacturing an electrode body. [Figure 6] 10A to 10C are diagrams schematically showing a modified example of the method for manufacturing the electrode body. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0010] Fig. 1 is a perspective view schematically illustrating a storage cell according to an embodiment of the present disclosure, and Fig. 2 is a cross-sectional view of the storage cell shown in Fig. 1.

[0011] As shown in FIGS. 1 and 2, the energy storage cell 1 includes an electrode assembly 100, a cell case 200, a pair of external terminals 300, a pair of connecting members 400, and an insulating member 500.

[0012] The electrode assembly 100 is a so-called laminated type. The electrode assembly 100 includes a plurality of electrodes 110, 120 and a separator .

[0013] The plurality of electrodes 110, 120 are arranged to line up in one direction (a direction perpendicular to the paper surface in FIG. 2). The plurality of electrodes 110, 120 include a plurality of positive electrodes 110 and a plurality of negative electrodes 120.

[0014] Each positive electrode 110 is formed in a rectangular shape that is long in the width direction (a direction perpendicular to both one direction and the up-down direction). Each positive electrode 110 has a positive electrode current collector foil and positive electrode active material layers provided on both sides of the positive electrode current collector foil. As shown in FIG. 2, the positive electrode current collector foil has a positive electrode tab 112p on which no positive electrode active material layer is provided. The positive electrode tab 112p protrudes toward one side in the width direction.

[0015] Each negative electrode 120 is formed in a rectangular shape that is elongated in the width direction. Each negative electrode 120 has a negative electrode current collector foil and negative electrode active material layers provided on both sides of the negative electrode current collector foil. As shown in FIG. 2, the negative electrode current collector foil has a negative electrode tab 122n on which no negative electrode active material layer is provided. The negative electrode tab 122n protrudes toward the other side in the width direction.

[0016] The separator 130 provides insulation between the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ions to pass through.

[0017] The cell case 200 houses the electrode assembly 100. The cell case 200 houses an electrolyte (not shown). The cell case 200 is sealed. The cell case 200 has a case body 210 and a lid 220.

[0018] The case body 210 has an opening that opens upward. The case body 210 is made of a metal such as aluminum. As shown in FIG. 2, the case body 210 has a bottom wall 212 and a peripheral wall 214. The bottom wall 212 is formed in a rectangular, flat plate shape. The peripheral wall 214 stands upright from the bottom wall 212. The peripheral wall 214 is formed in a square cylindrical shape. The length of the peripheral wall 214 in the width direction is longer than the length of the peripheral wall 214 in the thickness direction. The length of the peripheral wall 214 in the height direction is longer than the length of the peripheral wall 214 in the thickness direction.

[0019] The lid 220 closes the opening of the case body 210. The lid 220 is connected to the opening by welding or the like. The lid 220 is formed in a flat plate shape. The lid 220 is made of a metal such as aluminum. The lid 220 has a pressure release valve 222 and a sealing member 224.

[0020] Pressure release valve 222 is formed in the center of lid 220. Pressure release valve 222 is formed to rupture when the internal pressure of cell casing 200 reaches or exceeds a predetermined pressure. When pressure release valve 222 ruptures, gas within cell casing 200 is released to the outside of cell casing 200 through pressure release valve 222, thereby reducing the internal pressure of cell casing 200.

[0021] The sealing member 224 seals a liquid filling port h formed in the lid 220. The liquid filling port h is a through-hole for injecting an electrolyte into the cell case 200 during the manufacturing process of the energy storage cell 1. The liquid filling port h is sealed by the sealing member 224 after the electrolyte is injected into the case body 210 through the liquid filling port h.

[0022] A pair of external terminals 300 are fixed on the cell case 200. One of the pair of external terminals 300 is a positive electrode external terminal, and the other is a negative electrode external terminal. Each external terminal 300 is fixed to the upper surface of the lid 220 via an upper insulating part 510, which will be described later. Each external terminal 300 is made of a metal such as aluminum. Each external terminal 300 is formed, for example, in the shape of a rectangular parallelepiped. A bus bar (not shown) is connected to each external terminal 300 by welding or the like.

[0023] The pair of connecting members 400 connect the plurality of electrode tabs 112p, 122n to the external terminals 300. One connecting member 400 connects the plurality of positive electrode tabs 112p to the positive electrode external terminals 300, and the other connecting member 400 connects the plurality of negative electrode tabs 122n to the negative electrode external terminals 300. Since the pair of connecting members 400 have substantially the same structure, only one of the connecting members 400 will be described below.

[0024] The connecting member 400 includes a current collecting tab 410 , a sub-tab 420 , and a connecting pin 430 .

[0025] The current collecting tab 410 has a side portion 412 and an upper portion 414. The side portion 412 is located on a side of the electrode assembly 100 in the width direction. The upper portion 414 is located above the electrode assembly 100. The upper portion 414 extends from the upper end of the side portion 412 toward the inside in the width direction.

[0026] The subtabs 420 connect the multiple positive electrode tabs 112p to the current collecting tab 410. One end 422 of the subtab 420 is connected to the multiple positive electrode tabs 112p by welding or the like, and the other end 424 of the subtab 420 is connected to the side portion 412 of the current collecting tab 410 by welding or the like.

[0027] The connecting pin 430 connects the current collecting tab 410 and the external terminal 300. The connecting pin 430 connects the upper part 414 and the external terminal 300. Specifically, the lower end of the connecting pin 430 is inserted into a through hole provided in the upper part 414 and connected to the upper part 414 by welding or the like, and the upper end of the connecting pin 430 is inserted into a through hole provided in the external terminal 300 and connected to the external terminal 300 by welding, crimping or the like.

[0028] The insulating member 500 provides insulation between the cell casing 200 and the connecting member 400. The insulating member 500 has an upper insulating portion 510, a lower insulating portion 520, an insulator 530, and an insulating plate 540.

[0029] The upper insulating part 510 is fixed to the upper surface of the lid 220. The upper insulating part 510 is disposed between the lid 220 and the external terminal 300. The upper insulating part 510 has an insertion hole through which the connecting pin 430 is inserted.

[0030] The lower insulating part 520 is fixed to the lower surface of the lid 220. The lower insulating part 520 is disposed between the lid 220 and the upper part 414 and the lower part of the connecting pin 430. The lower insulating part 520 has an insertion hole through which the connecting pin 430 is inserted.

[0031] The insulator 530 is disposed between the connecting pin 430 and the lid 220. The insulator 530 is formed in a cylindrical shape and surrounds the connecting pin 430.

[0032] The insulating plate 540 is fixed to the lower surface of the upper part 414. The insulating plate 540 is disposed above the electrode assembly 100. Through holes are provided in the insulating plate 540 in a portion located below the pressure release valve 222 and a portion located below the liquid injection port h.

[0033] Next, the manufacturing process of the electrode assembly 100 will be described with reference to Figures 3 to 5. The manufacturing method of the electrode assembly 100 includes a winding step, a compression step, and a cutting step.

[0034] In the winding step, the positive electrode 110 and the negative electrode 120 are wound with the separator 130 interposed therebetween to form the wound body 101.

[0035] In the compression step, as shown by arrows AR3 in Fig. 3, the wound body 101 is compressed from both sides in the radial direction of the wound body 101 to form a compressed wound body 102 (see Fig. 4). The compression of the wound body 101 is performed by a compression jig (not shown).

[0036] In the cutting step, the compressed wound body 102 is cut by moving a cutting member 10 such as a blade from the inside to the outside of the compressed wound body 102 along an orthogonal direction (the left-right direction in FIG. 4 ) that is orthogonal to both the direction in which the wound body 101 is compressed in the compression step and the central axis C of the wound body 101. In this way, the electrode body 100 is formed. The cutting step may be performed in a state in which the compressed wound body 102 is compressed by the compression jig. Note that FIG. 5 shows the electrode body 100 formed in the cutting step.

[0037] In the cutting step, it is preferable to cut the compressed wound body 102 with the cutting member 10 while collecting dust on the outside of the compressed wound body 102 in the orthogonal direction (the moving direction of the cutting member 10). Dust collection may be performed by, for example, a dust collector 20 (see FIG. 4).

[0038] In the winding step, it is preferable to form a wound body 101 having slits formed so as to align radially with a portion 101A (see FIG. 3 ) of the compressed wound body 102 that is to be cut in the cutting step by forming slits in at least one of the positive electrode 110, the negative electrode 120, and the separator 130 using a laser or the like at predetermined positions while winding the positive electrode 110, the negative electrode 120, and the separator 130. Note that slits may be formed in at least one of the positive electrode 110, the negative electrode 120, and the separator 130 before the winding step, and then the wound body 101 may be wound in the winding step.

[0039] As described above, in the manufacturing method of the electrode body 100 in this embodiment, by cutting the compressed wound body 102 with the cutting member 10, a laminated electrode body 100 in which the positive electrode 110 and the negative electrode 120 are stacked with the separator 130 interposed therebetween is easily formed.

[0040] In the cutting step, the cutting member 10 may be moved along the orthogonal direction and the compressed wound body 102 may be spread from the inside of the compressed wound body 102 in the direction opposite to the direction in which the wound body 101 is compressed in the compression step, as shown by arrow AR6 in Fig. 6. The operation of spreading the compressed wound body 102 is performed by a jig (not shown).

[0041] In the compression step, a portion to be cut 102A (see FIG. 4 ) of the compressed wound body 102 that is to be cut in the cutting step may be pressed from the inside of the compressed wound body 102, thereby forming an outward recess in the perpendicular direction in advance in the portion to be cut 102A. Note that the pressing of the portion to be cut 102A is performed by a pressing jig (not shown).

[0042] Furthermore, if a slit is formed in the portion 101A of the wound body 101, the wound body 101 may be compressed in the compression step so that the portion 101A breaks starting from the slit. In this case, the cutting step is omitted.

[0043] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0044] [Aspect 1] a winding step of winding the positive electrode and the negative electrode with a separator interposed therebetween to form a wound body; a compressing step of compressing the wound body from both sides in the radial direction of the wound body to form a compressed wound body; a cutting step of cutting the compressed wound body by moving a cutting member from the inside to the outside of the compressed wound body along an orthogonal direction that is orthogonal to both the direction in which the wound body is compressed in the compression step and the central axis of the wound body.

[0045] In this method of manufacturing an electrode assembly, a laminated electrode assembly in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween is easily formed by cutting the compressed wound body with a cutting member.

[0046] [Aspect 2] In the method for manufacturing an electrode assembly according to aspect 1, in the winding step, the positive electrode, the negative electrode, and the separator are wound while making slits at predetermined positions in at least one of the positive electrode, the negative electrode, and the separator, thereby forming the wound body having the slits formed so as to be aligned in the radial direction at a portion of the compressed wound body that will be cut in the cutting step.

[0047] In this embodiment, the compressed wound body can be easily cut in the cutting step.

[0048] [Aspect 3] Aspect 3. The method for manufacturing an electrode assembly according to aspect 1 or 2, wherein in the cutting step, the compressed wound body is cut with the cutting member while dust is collected on the outside of the compressed wound body in the orthogonal direction.

[0049] In this embodiment, even if cut pieces (foreign matter) are generated when the compressed wound body is cut by the cutting member, the cut pieces are prevented from scattering or being mixed into the electrode body.

[0050] [Aspect 4] Aspect 4. The method for manufacturing an electrode assembly according to any one of aspects 1 to 3, wherein in the cutting step, the cutting member is moved along the orthogonal direction, and the compressed wound body is expanded from inside the compressed wound body in a direction opposite to a direction in which the wound body is compressed in the compressing step.

[0051] In this embodiment, cutting of the compressed wound body in the cutting step is facilitated.

[0052] [Aspect 5] A method for manufacturing an electrode assembly according to any one of aspects 1 to 4, wherein in the compression step, a portion of the compressed wound body to be cut in the cutting step is pressed from inside the compressed wound body, thereby forming an outward recess in the orthogonal direction in advance in the portion to be cut.

[0053] In this aspect, the portion to be cut is more reliably cut by the cutting member in the cutting step.

[0054] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 1 storage cell, 10 cutting member, 20 dust collector, 100 electrode body, 101 wound body, 102 compressed wound body, 110 positive electrode, 112 positive electrode current collector foil, 112p positive electrode tab, 114 positive electrode active material layer, 120 negative electrode, 122 negative electrode current collector foil, 122n negative electrode tab, 130 separator, 200 cell case, 210 case body, 220 lid, 300 external terminal, 400 connecting member, 410 current collector tab, 420 sub-tab, 430 connecting pin, 500 insulating member, 510 upper insulating part, 520 lower insulating part, 530 insulator, 540 insulating plate.

Claims

1. a winding step of winding the positive electrode and the negative electrode with a separator interposed therebetween to form a wound body; a compressing step of compressing the wound body from both sides in the radial direction of the wound body to form a compressed wound body; a cutting step of cutting the compressed wound body by moving a cutting member from the inside to the outside of the compressed wound body along an orthogonal direction that is orthogonal to both the direction in which the wound body is compressed in the compression step and the central axis of the wound body.

2. 2. The method for manufacturing an electrode assembly according to claim 1, wherein in the winding step, the positive electrode, the negative electrode, and the separator are wound while making slits at predetermined positions in at least one of the positive electrode, the negative electrode, and the separator, thereby forming the wound body having the slits formed so as to be aligned in the radial direction at a portion of the compressed wound body that is cut in the cutting step.

3. The method for manufacturing an electrode assembly according to claim 1 , wherein in the cutting step, the compressed wound body is cut with the cutting member while dust is collected on the outside of the compressed wound body in the orthogonal direction.

4. 2. The method for manufacturing an electrode body according to claim 1, wherein in the cutting step, the cutting member is moved along the orthogonal direction, and the compressed wound body is pushed open from inside the compressed wound body in a direction opposite to a direction in which the wound body is compressed in the compressing step.

5. 2. The method for manufacturing an electrode body according to claim 1, wherein in the compression step, a portion of the compressed wound body to be cut in the cutting step is pressed from the inside of the compressed wound body, thereby forming an outward recess in the orthogonal direction in advance in the portion to be cut.

Images