Power storage cell, and manufacturing method of electrode body

Abstract

To provide a power storage cell capable of controlling both the positional misalignment of the electrodes relative to the separators and the positional misalignment of the separators themselves.SOLUTION: The power storage cell includes: an electrode body; and a cell case that houses the electrode body. The electrode body is formed in a zigzag shape together with multiple electrodes 110 and 120, and includes a separator 130 for insulating between the multiple electrodes. The separator 130 includes: an intervening portion 132a interposed between a pair of electrodes adjacent to each other in one direction; and a pair of positioning protrusions 134 protruding from the intermediate portion in one direction and determining the position of the electrode relative to the intermediate portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Japanese Patent Application Laid-Open No. 2001-102050 discloses a stacked battery including a stacked electrode assembly in which multiple positive electrodes and multiple negative electrodes are alternately stacked with separators interposed therebetween, and a case for housing the stacked electrode assembly. The separator is formed with a positioning portion for positioning the electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-102050 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the stacked battery described in JP 2001-102050 A, there is a concern that the separators may become misaligned relative to one another within the cell case due to vibration or the like.

[0005] An object of the present disclosure is to provide a manufacturing method for an energy storage cell and an electrode assembly that is capable of suppressing both misalignment of the electrodes relative to the separators and misalignment of the separators themselves. [Means for solving the problem]

[0006] A storage cell according to one aspect of the present disclosure comprises an electrode body and a cell case that houses the electrode body, wherein the electrode body comprises a plurality of electrodes arranged in a line in one direction, and a separator formed in a zigzag shape that provides insulation between each of the plurality of electrodes, and the separator has an intervening portion interposed between a pair of electrodes adjacent to each other in the one direction, and a pair of positioning protrusions that protrude from the intervening portion in the one direction and determine the position of the electrode relative to the intervening portion. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a manufacturing method for an energy storage cell and an electrode assembly that is capable of suppressing both misalignment of the electrodes relative to the separators and misalignment of the separators themselves. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view illustrating a storage cell according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the storage cell shown in FIG. [Diagram 3] FIG. 2 is a front view showing a schematic view of an electrode body. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 11 is a cross-sectional view illustrating a schematic modification of the electrode body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0010] Fig. 1 is a perspective view that illustrates a schematic configuration of a storage cell according to an embodiment of the present disclosure, and Fig. 2 is a cross-sectional view of the storage cell illustrated 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, an electrolyte (not shown), a pair of external terminals 300, a pair of connecting members 400, and an insulating member 500.

[0012] Fig. 3 is a front view showing a schematic view of the electrode assembly. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. As shown in Fig. 3 and Fig. 4, the electrode assembly 100 includes a plurality of electrodes 110, 120 and a separator 130.

[0013] The multiple electrodes 110, 120 are arranged to line up in one direction (the up-down direction in FIG. 4). The multiple electrodes 110, 120 include multiple positive electrodes 110 and multiple negative electrodes 120. In FIG. 3, the outer diameter of the negative electrode 120 is indicated by a two-dot chain line.

[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). As shown in FIG. 4, each positive electrode 110 has a positive electrode current collector foil 112 and a positive electrode active material layer 114 provided on both sides of the positive electrode current collector foil 112.

[0015] As shown in FIG. 2 and FIG. 3, the positive electrode current collector foil 112 has a main region 112a and a positive electrode tab 112p. The main region 112a is a region where the positive electrode active material layer 114 is provided. In FIG. 3, the main region 112a and the positive electrode active material layer 114 are indicated by diagonal lines. The main region 112a is formed in a rectangular shape. The main region 112a is in contact with a positioning protrusion 134 described below. The positive electrode tab 112p is a region where the positive electrode active material layer 114 is not provided. The positive electrode tab 112p protrudes from the main region 112a in a direction perpendicular to the one direction. In this embodiment, the positive electrode tab 112p protrudes toward one side (the right side) in the width direction (the left-right direction in FIG. 3).

[0016] Each negative electrode 120 is formed in a rectangular shape that is long in the width direction. The outer shape of each negative electrode 120 is slightly larger than the outer shape of each positive electrode 110. Each negative electrode 120 has a negative electrode current collector foil 122 and a negative electrode active material layer 124 provided on both sides of the negative electrode current collector foil 122. As shown in Figs. 2 and 3, the negative electrode current collector foil 122 has a negative electrode tab 122n on which the negative electrode active material layer 124 is not provided. The negative electrode tab 122n protrudes toward the other side in the width direction.

[0017] The separator 130 insulates the positive electrode 110 from the negative electrode 120. The separator 130 is made of an insulating material and has minute gaps that allow ion permeation. As shown in Fig. 4, the separator 130 is formed in a zigzag shape. The separator 130 is disposed between the electrodes 110, 120 while being formed in a zigzag shape.

[0018] As shown in FIG. 4, the separator 130 has a plurality of intermediate portions 132a, a plurality of upper folded portions 132b, a plurality of lower folded portions 132c, and a positioning protrusion 134.

[0019] Each interposed portion 132a is interposed between a pair of electrodes 110, 120 adjacent to each other in one direction. That is, each interposed portion 132a has a function of insulating between the positive electrode 110 and the negative electrode 120. Each interposed portion 132a is formed of a rectangular region.

[0020] Each upper folded portion 132b connects an upper end portion of one of the plurality of intermediate portions 132a to an upper end portion of the intermediate portion 132a adjacent to the one intermediate portion 132a on one side in one direction among the plurality of intermediate portions 132a. In this embodiment, the upper folded portion 132b is disposed above the positive electrode 110.

[0021] Each lower folded portion 132c connects a lower end of one of the plurality of intermediate portions 132a to a lower end of another intermediate portion 132a adjacent to the one intermediate portion on the other side in one direction. In this embodiment, the lower folded portion 132c is disposed below the negative electrode 120. In other words, the negative electrode 120 is disposed on the lower folded portion 132c.

[0022] The pair of positioning protrusions 134 determine the positions of the electrodes 110, 120 relative to the interposition portion 132a. Each positioning protrusion 134 protrudes in one direction from the interposition portion 132a. Each positioning protrusion 134 is formed by embossing or the like. In this embodiment, the pair of positioning protrusions 134 determine the position of the positive electrode 110. As shown in FIG. 3, each positioning protrusion 134 has a shape that follows the corners of the positive electrode 110 that are located diagonally opposite each other. As shown in FIG. 3, the pair of positioning protrusions 134 contact the main region 112a of the positive electrode 110. Each positioning protrusion 134 is spaced from the positive electrode tab 112p. As shown in FIG. 4, the top surface 134a of each positioning protrusion 134 is bonded to a portion of the interposition portion 132a that faces the top surface 134a.

[0023] The cell case 200 houses the electrode assembly 100. An electrolyte (not shown) is housed in the cell case 200. The cell case 200 is sealed. The cell case 200 has a case body 210 and a lid 220.

[0024] 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 up from the bottom wall 212. The peripheral wall 214 is formed in a rectangular tube 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.

[0025] 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.

[0026] The pressure release valve 222 is formed in the center of the lid 220. The pressure release valve 222 is formed to break when the internal pressure of the cell case 200 reaches or exceeds a predetermined pressure. When the pressure release valve 222 breaks, gas within the cell case 200 is released to the outside of the cell case 200 through the pressure release valve 222, and the internal pressure of the cell case 200 decreases.

[0027] 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 in 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.

[0028] A pair of external terminals 300 are fixed on the cell case 200. One of the pair of external terminals 300 is a positive external terminal, and the other is a negative external terminal. Each external terminal 300 is fixed to the upper surface of the lid 220 via an upper insulating part 510 described later. Each external terminal 300 is made of a metal such as aluminum. Each external terminal 300 is formed, for example, in a rectangular parallelepiped shape. A bus bar (not shown) is connected to each external terminal 300 by welding or the like.

[0029] The pair of connecting members 400 connect the multiple electrode tabs 112p, 122n to the external terminal 300. One connecting member 400 connects the multiple positive electrode tabs 112p to the positive electrode external terminal 300, and the other connecting member 400 connects the multiple negative electrode tabs 122n to the negative electrode external terminal 300. Since each of the pair of connecting members 400 has substantially the same structure as each other, one connecting member 400 will be described below.

[0030] The connecting member 400 has a current collecting tab 410 , a sub-tab 420 , and a connecting pin 430 .

[0031] 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.

[0032] The sub-tab 420 connects the positive electrode tabs 112p to the current collecting tab 410. One end 422 of the sub-tab 420 is connected to the positive electrode tabs 112p by welding or the like, and the other end 424 of the sub-tab 420 is connected to the side portion 412 of the current collecting tab 410 by welding or the like.

[0033] 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.

[0034] 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.

[0035] 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 is provided with an insertion hole through which the connecting pin 430 is inserted.

[0036] 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 is provided with an insertion hole through which the connecting pin 430 is inserted.

[0037] 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.

[0038] 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 at a portion located below the pressure release valve 222 and at a portion located below the liquid injection port h.

[0039] Next, a description will be given of a manufacturing process for the energy storage cell 1. This manufacturing method includes a projection forming step, a mounting step, and a folding step.

[0040] In the projection forming step, while the long, strip-like separator 130 is being transported, a pair of positioning projections 134 are formed by embossing at the portion of the separator 130 on which the positive electrode 110 is to be placed.

[0041] In the placing step, the positive electrode 110 is placed on the inner side of the pair of positioning protrusions 134 .

[0042] In the folding step, the separator 130 is folded back so that the separator 130 overlaps the positive electrode 110 placed on the inside of the pair of positioning protrusions 134. Through this step, an upper folded portion 132b is formed.

[0043] In the folding process, a folding jig 5 and a roller (not shown) are used. The jig 5 is placed on the outside of the positioning protrusion 134, and is pulled out after the separator 130 is folded. In FIG. 4, the jig 5 is indicated by a two-dot chain line. The roller is formed in a crown shape. That is, the roller is formed in a shape that expands in diameter from the end portion toward the center portion in the rotation axis direction of the roller. In this way, when the separator 130 is folded back, the formation of wrinkles in the center portion of the separator 130 in the width direction (the direction parallel to the rotation axis of the roller) is suppressed.

[0044] Then, the negative electrode 120 is placed on the separator 130 (intervening portion 132a) placed on the positive electrode 110. At this time, the negative electrode 120 is placed at a position where it overlaps with the pair of positioning protrusions 134, as shown in Figures 3 and 4.

[0045] Thereafter, a pair of positioning protrusions 134 are formed in the portion of separator 130 where positive electrode 110 is to be placed, and separator 130 is folded back so that the positioning protrusions 134 overlap negative electrode 120. This step forms bottom folded portion 132c. In this step, jig 5 and rollers are also used.

[0046] The above steps are repeated to form the electrode body 100.

[0047] Next, one end 422 of the subtab 420 is connected to the multiple electrode tabs 112p, 122n by welding or the like. Thereafter, the one end 422 and the multiple electrode tabs 112p, 122n are bent so that the one end 422 of the subtab 420 contacts the side portion 412 of the current collecting tab 410.

[0048] Next, the peripheral and bottom surfaces of the multiple electrodes 110, 120 and the separator 130 are collectively covered with an insulating film (not shown), and then the electrode body 100 is inserted into the case body 210. Then, the peripheral portion of the lid 220 is connected to the opening of the case body 210 by welding or the like.

[0049] Thereafter, the electrolyte is supplied into the cell case 200 through the liquid injection port h, and the liquid injection port h is sealed with the sealing member 224.

[0050] As described above, in the storage cell 1 of this embodiment, the pair of positioning protrusions 134 suppresses misalignment of the positive electrode 110 relative to the separator 130, and further, since the separator 130 is formed in a zigzag shape, misalignment of the interposed portions 132a relative to each other within the cell case 200 is also suppressed.

[0051] 5, each positioning protrusion 134 may be configured separately from the intermediate portion 132a and fixed to the intermediate portion 132a. The positioning protrusion 134 is formed of, for example, an insulating material. The thickness of the positioning protrusion 134 in one direction is set to be equal to or smaller than the thickness of the positive electrode 110.

[0052] In this embodiment, the separator can be folded back so as to wrap around the positioning protrusion, thereby reducing the distance between the folded back portion of the separator and the positioning protrusion.

[0053] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0054] [Aspect 1] An electrode body; A cell case that houses the electrode assembly, The electrode body is A plurality of electrodes arranged in one direction; a separator formed in a zigzag shape and insulating each of the plurality of electrodes; The separator is an interposition portion interposed between a pair of electrodes adjacent to each other in the one direction; a pair of positioning protrusions protruding from the intermediate portion in the one direction and determining the position of the electrode relative to the intermediate portion.

[0055] In this energy storage cell, the pair of positioning protrusions suppresses misalignment of the electrodes relative to the separator, and further, because the separator is formed in a zigzag shape, misalignment of the interposed portions within the cell case is also suppressed.

[0056] [Aspect 2] 2. The energy storage cell according to claim 1, wherein a top surface of each of the positioning protrusions is adhered to a portion of the intermediate portion that faces the top surface.

[0057] In this aspect, a space surrounding the electrode is formed by a pair of adjacent intermediate portions and the positioning protrusion, so that misalignment of the electrode with respect to the separator is more reliably suppressed.

[0058] [Aspect 3] The electrode is formed in a rectangular shape, 3. The energy storage cell according to aspect 1 or 2, wherein the positioning protrusions have a shape that fits along corners of the electrodes that are diagonally opposite to each other.

[0059] In this embodiment, the positional deviation of the electrodes with respect to the separator in the direction perpendicular to the one direction is suppressed.

[0060] [Aspect 4] 4. The energy storage cell according to aspect 3, wherein each of the positioning protrusions is configured separately from the intermediate portion and fixed to the intermediate portion.

[0061] In this embodiment, the separator can be folded back so as to wrap around the positioning protrusion, thereby reducing the distance between the folded back portion of the separator and the positioning protrusion.

[0062] [Aspect 5] The plurality of electrodes includes a positive electrode and a negative electrode, The positive electrode is A positive electrode current collecting foil; A positive electrode active material layer provided on the positive electrode current collector foil, The positive electrode current collector foil is a main region in which the positive electrode active material layer is provided and which contacts the pair of positioning protrusions; a positive electrode tab that is not provided with the positive electrode active material layer and that protrudes from the main region in a direction perpendicular to the one direction, Aspects 5. The energy storage cell of any one of aspects 1 to 4, wherein the positive electrode tab is spaced apart from each of the positioning protrusions.

[0063] [Aspect 6] a positioning protrusion forming step of forming a pair of positioning protrusions on the separator while transporting the separator, the pair of positioning protrusions determining positions of the electrodes relative to the separator; a placing step of placing the electrodes on the inner sides of the pair of positioning protrusions; a folding step of folding back the separator so that the separator overlaps the electrodes placed inside the pair of positioning protrusions.

[0064] [Aspect 7] 7. The method for manufacturing an electrode assembly according to aspect 6, wherein in the positioning protrusion forming step, the pair of positioning protrusions are formed by embossing.

[0065] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] 1 storage cell, 100 electrode body, 110 positive electrode, 112 positive current collector foil, 112a main region, 112p positive electrode tab, 114 positive electrode active material layer, 120 negative electrode, 122 negative current collector foil, 122n negative electrode tab, 130 separator, 132a interposition portion, 132b upper folded portion, 132c lower folded portion, 134 positioning protrusion, 134a top surface, 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 portion, 520 lower insulating portion, 530 insulator, 540 insulating plate.

Claims

1. An electrode body; A cell case that houses the electrode assembly, The electrode body is A plurality of electrodes arranged in one direction; a separator formed in a zigzag shape and insulating each of the plurality of electrodes; The separator is an interposition portion interposed between a pair of electrodes adjacent to each other in the one direction; a pair of positioning protrusions protruding from the intermediate portion in the one direction and determining the position of the electrode relative to the intermediate portion.

2. The energy storage cell according to claim 1 , wherein a top surface of each of the positioning protrusions is adhered to a portion of the intermediate portion that faces the top surface.

3. The electrode is formed in a rectangular shape, The energy storage cell according to claim 1 , wherein each of the positioning protrusions has a shape that fits along corners of the electrodes that are located diagonally opposite each other.

4. The energy storage cell according to claim 3 , wherein each of the positioning protrusions is formed separately from the intermediate portion and fixed to the intermediate portion.

5. The plurality of electrodes includes a positive electrode and a negative electrode, The positive electrode is A positive electrode current collecting foil; A positive electrode active material layer provided on the positive electrode current collector foil, The positive electrode current collector foil is a main region in which the positive electrode active material layer is provided and which contacts the pair of positioning protrusions; a positive electrode tab that is not provided with the positive electrode active material layer and that protrudes from the main region in a direction perpendicular to the one direction, The storage cell of claim 1 , wherein the positive electrode tab is spaced from each of the positioning protrusions.

6. a positioning protrusion forming step of forming a pair of positioning protrusions on the separator while transporting the separator, the pair of positioning protrusions determining positions of the electrodes relative to the separator; a placing step of placing the electrodes on the inner sides of the pair of positioning protrusions; a folding step of folding back the separator so that the separator overlaps the electrodes placed inside the pair of positioning protrusions.

7. The method for manufacturing an electrode assembly according to claim 6 , wherein in the positioning protrusion forming step, the pair of positioning protrusions are formed by embossing.

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