Method for manufacturing energy storage cells and electrodes

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 a storage battery cell and an electrode body.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2001-102050 discloses a laminated battery including a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated with a separator interposed therebetween, and a case for housing the laminated electrode body. A positioning portion for positioning the electrodes is formed in the separator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the laminated battery described in Japanese Unexamined Patent Application Publication No. 2001-102050, there is a concern that the separators may be displaced relative to each other within the cell case due to vibration or the like.

[0005] An object of the present disclosure is to provide a method for manufacturing a storage battery cell and an electrode body capable of suppressing both displacement of the electrodes relative to the separator and displacement of the separators relative to each other.

Means for Solving the Problems

[0006] A storage cell according to one aspect of the present disclosure comprises an electrode body and a cell case housing the electrode body, wherein the electrode body comprises a plurality of electrodes arranged in a unidirectional direction and a separator formed in a zigzag shape that insulates each of the plurality of electrodes, the separator having an intervening portion interposed between a pair of electrodes adjacent to each other in the unidirectional direction and a pair of positioning projections protruding from the intervening portion in the unidirectional direction and determining the position of the electrodes relative to the intervening portion. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a method for manufacturing an energy storage cell and an electrode body that can suppress both the misalignment of electrodes relative to the separator and the misalignment of separators relative to each other. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of an energy storage cell in one embodiment of the present disclosure. [Figure 2] Figure 1 is a cross-sectional view of the energy storage cell. [Figure 3] This is a schematic front view showing the electrode body. [Figure 4] Figure 3 shows a cross-sectional view along line IV-IV. [Figure 5] This is a schematic cross-sectional view showing a modified electrode body. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a schematic perspective view of an energy storage cell in one embodiment of the present disclosure. Figure 2 is a cross-sectional view of the energy storage cell shown in Figure 1.

[0011] As shown in Figures 1 and 2, the energy storage cell 1 comprises an electrode body 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] Figure 3 is a schematic front view showing the electrode body. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. As shown in Figures 3 and 4, the electrode body 100 comprises a plurality of electrodes 110, 120 and a separator 130.

[0013] Multiple electrodes 110, 120 are arranged in a unidirectional direction (up and down in Figure 4). Each set of electrodes 110, 120 comprises multiple positive electrodes 110 and multiple negative electrodes 120. In Figure 3, the outer diameter of the negative electrode 120 is shown by the dashed line.

[0014] Each positive electrode 110 is formed in a rectangular shape that is elongated in the width direction (a direction perpendicular to both the unidirectional and vertical directions). As shown in Figure 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 Figures 2 and 3, the positive electrode current collector foil 112 has a main region 112a and a positive electrode tab 112p. The main region 112a is the region where the positive electrode active material layer 114 is provided. In Figure 3, the main region 112a and the positive electrode active material layer 114 are shown with diagonal lines. The main region 112a is formed in a rectangular shape. The main region 112a is in contact with the positioning projection 134, which will be described later. The positive electrode tab 112p is the 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 one direction. In this embodiment, the positive electrode tab 112p protrudes toward one side (right side) in the width direction (left-right direction in Figure 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 negative electrode active material layers 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 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 the permeation of ions. As shown in FIG. 4, the separator 130 is formed in a zigzag shape. The separator 130 is arranged while being formed in a zigzag shape between the electrodes 110 and 120.

[0018] As shown in FIG. 4, the separator 130 has a plurality of intervening portions 132a, a plurality of upward folding portions 132b, a plurality of downward folding portions 132c, and a positioning protrusion 134.

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

[0020] Each upward folding portion 132b connects the upper end of one intervening portion 132a among the plurality of intervening portions 132a and the upper end of an intervening portion 132a adjacent to the one intervening portion 132a on one side in one direction among the plurality of intervening portions 132a. In the present embodiment, the upward folding portion 132b is arranged above the positive electrode 110.

[0021] Each lower turning-back portion 132c connects the lower end portion of the one intervening portion among the plurality of intervening portions 132a and the lower end portion of the intervening portion 132a adjacent to the one intervening portion on the other side in one direction among the plurality of intervening portions 132a to each other. In the present embodiment, the lower turning-back portion 132c is disposed below the negative electrode 120. In other words, the negative electrode 120 is disposed on the lower turning-back portion 132c.

[0022] The pair of positioning protrusions 134 determines the positions of the electrodes 110 and 120 with respect to the intervening portion 132a. Each positioning protrusion 134 protrudes in one direction from the intervening portion 132a. Each positioning protrusion 134 is formed by embossing or the like. In the present embodiment, the pair of positioning protrusions 134 determines the position of the positive electrode 110. As shown in FIG. 3, each positioning protrusion 134 has a shape along the corners located on the diagonal line of the positive electrode 110 among the positive electrodes 110. As shown in FIG. 3, the pair of positioning protrusions 134 is in contact with the main region 112a of the positive electrode 110. Each positioning protrusion 134 is spaced apart from the positive electrode tab 112p. As shown in FIG. 4, the top surface 134a of each positioning protrusion 134 is adhered to the portion of the intervening portion 132a facing the top surface 134a.

[0023] The cell case 200 houses the electrode body 100. The cell case 200 contains an electrolytic solution (not shown). 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 and flat plate shape. The peripheral wall 214 stands up from the bottom wall 212. The peripheral wall 214 is formed in a square 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 relief valve 222 and a sealing member 224.

[0026] The pressure relief valve 222 is formed in the center of the lid 220. The pressure relief valve 222 is designed to rupture when the internal pressure of the cell case 200 exceeds a predetermined pressure. When the pressure relief valve 222 ruptures, the gas inside the cell case 200 is released to the outside of the cell case 200 through the pressure relief valve 222, causing the internal pressure of the cell case 200 to decrease.

[0027] The sealing member 224 seals the liquid injection port h formed in the lid 220. The liquid injection port h is a through-hole for injecting electrolyte into the cell case 200 during the manufacturing process of the energy storage cell 1. After the electrolyte is injected into the case body 210 through the liquid injection port h, it is sealed by the sealing member 224.

[0028] A pair of external terminals 300 are fixed on the cell case 200. One of the pair of external terminals 300 is the positive terminal, and the other is the negative terminal. Each external terminal 300 is fixed to the upper surface of the cover 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 a rectangular parallelepiped shape. A busbar, not shown in the figure, is connected to each external terminal 300 by welding or the like.

[0029] A pair of connecting members 400 connect multiple electrode tabs 112p, 122n to the external terminal 300. One connecting member 400 connects multiple positive electrode tabs 112p to the positive electrode external terminal 300, and the other connecting member 400 connects 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 the other, one of the connecting members 400 will be described below.

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

[0031] The current collector tab 410 has a lateral portion 412 and an upper portion 414. The lateral portion 412 is located laterally to the electrode body 100 in the width direction. The upper portion 414 is located above the electrode body 100. The upper portion 414 extends inward in the width direction from the upper end of the lateral portion 412.

[0032] The sub-tab 420 connects multiple positive electrode tabs 112p to the current collection tab 410. One end 422 of the sub-tab 420 is connected to the multiple 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 collection tab 410 by welding or the like.

[0033] The connecting pin 430 connects the current collection tab 410 and the external terminal 300. The connecting pin 430 also 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 insulates the cell case 200 from 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 portion 510 is fixed to the upper surface of the lid 220. The upper insulating portion 510 is positioned between the lid 220 and the external terminal 300. The upper insulating portion 510 is provided with an insertion hole for inserting the connecting pin 430.

[0036] The lower insulating portion 520 is fixed to the lower surface of the lid 220. The lower insulating portion 520 is positioned between the lid 220 and the upper portion 414 and the lower part of the connecting pin 430. The lower insulating portion 520 is provided with an insertion hole for inserting the connecting pin 430.

[0037] The insulator 530 is positioned between the connecting pin 430 and the cover 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 portion 414. The insulating plate 540 is positioned above the electrode body 100. Through holes are provided in the portion of the insulating plate 540 located below the pressure relief valve 222 and below the liquid injection port h.

[0039] Next, the manufacturing process for the energy storage cell 1 will be described. This manufacturing method includes a protrusion formation step, a placement step, and a folding step.

[0040] In the protrusion formation process, a long, strip-shaped separator 130 is transported, and a pair of positioning protrusions 134 are formed on the portion of the separator 130 on which the positive electrode 110 is placed by embossing.

[0041] In the mounting process, the positive electrode 110 is placed inside the pair of positioning protrusions 134.

[0042] In the folding process, the separator 130 is folded back so that it overlaps the positive electrode 110, which is placed inside the pair of positioning protrusions 134. This process forms the upper folded portion 132b.

[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 projection 134 and is removed after the separator 130 is folded. In Figure 4, the jig 5 is shown by a dashed line. The roller is formed in a crown shape. That is, the roller is formed in a shape that widens from the end towards the center in the direction of the roller's rotation axis. This prevents wrinkles from forming in the center of the separator 130 in the width direction (parallel to the roller's rotation axis) when the separator 130 is folded.

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

[0045] Subsequently, a pair of positioning protrusions 134 are formed on the portion of the separator 130 on which the positive electrode 110 is placed, and the separator 130 is folded back so that this portion overlaps the negative electrode 120. This process forms the lower folded portion 132c. The jig 5 and rollers are also used in this process.

[0046] The electrode body 100 is formed by repeating the above process.

[0047] Next, one end 422 of the sub-tab 420 is connected to the multiple electrode tabs 112p, 122n by welding or the like. Then, the one end 422 of the sub-tab 420 and the multiple electrode tabs 112p, 122n are bent so that the one end 422 of the sub-tab 420 is in contact with the side portion 412 of the current collection tab 410.

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

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

[0050] As described above, in the energy storage cell 1 of this embodiment, the positional misalignment of the positive electrode 110 relative to the separator 130 is suppressed by the pair of positioning protrusions 134, and furthermore, because the separator 130 is formed in a zigzag shape, positional misalignment of the intervening portions 132a within the cell case 200 is also suppressed.

[0051] As shown in Figure 5, each positioning projection 134 is constructed separately from the intervening portion 132a and may be fixed to the intervening portion 132a. The positioning projection 134 is formed from, for example, an insulating material. The thickness of the positioning projection 134 in one direction is set to be less than or equal to the thickness of the positive electrode 110.

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

[0053] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0054] [Aspect 1] Electrode body and The cell case comprises the electrode body, The electrode body is Multiple electrodes arranged in a single direction, It comprises a separator formed in a zigzag shape that insulates each of the plurality of electrodes, The aforementioned separator is, An intervening portion between a pair of electrodes adjacent to each other in one direction, A storage cell having a pair of positioning protrusions that project from the intervening portion in one direction and determine the position of the electrode relative to the intervening portion.

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

[0056] [Aspect 2] The energy storage cell according to embodiment 1, wherein the top surface of each positioning projection is bonded to the portion of the intervening portion that faces the top surface.

[0057] In this embodiment, a space is formed surrounding the electrode by a pair of adjacent intervening portions and a positioning projection, thereby more reliably suppressing misalignment of the electrode relative to the separator.

[0058] [Aspect 3] The electrode is formed in a rectangular shape, The energy storage cell according to embodiment 1 or 2, wherein each positioning projection has a shape that follows the corners of the electrodes that are located diagonally opposite each other.

[0059] In this embodiment, misalignment of the electrodes relative to the separator in a direction perpendicular to one direction is suppressed.

[0060] [Aspect 4] Each of the positioning protrusions is constructed separately from the intervening portion and is fixed to the intervening portion, as described in embodiment 3 of the energy storage cell.

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

[0062] [Aspect 5] The plurality of electrodes each have a positive electrode and a negative electrode. The positive electrode is, Positive electrode current collector foil, The positive electrode current collector foil has a positive electrode active material layer provided on it, The aforementioned positive electrode current collector foil is The positive electrode active material layer is provided, and a main region is in contact with the pair of positioning protrusions, The positive electrode active material layer is not provided, and the positive electrode tab protrudes from the main region in a direction perpendicular to the aforementioned one direction, The energy storage cell according to any one of embodiments 1 to 4, wherein the positive electrode tab is spaced apart from each of the positioning protrusions.

[0063] [Aspect 6] A positioning projection formation step in which a pair of positioning projections are formed on the separator while the separator is being transported, to determine the position of the electrodes relative to the separator, A mounting step of placing the electrodes inside the pair of positioning protrusions, A method for manufacturing an electrode body, comprising a folding step of folding the separator so that it overlaps the electrode placed on the inside of the pair of positioning protrusions.

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

[0065] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0066] 1 Energy storage cell, 100 Electrode body, 110 Positive electrode, 112 Positive electrode current collector foil, 112a Main region, 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, 132a Intervening part, 132b Upper folded part, 132c Lower folded part, 134 Positioning projection, 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 part, 520 Lower insulating part, 530 Insulator, 540 Insulating plate.

Claims

1. Electrode body and The cell case comprises the electrode body, The electrode body is Multiple electrodes arranged in a single direction, It comprises a separator formed in a zigzag shape that insulates each of the plurality of electrodes, The aforementioned separator is, An intervening portion between a pair of electrodes adjacent to each other in one direction, It has a pair of positioning protrusions that project from the intervening portion in one direction and determine the position of the electrode relative to the intervening portion, The top surface of each positioning projection is bonded to the portion of the intervening portion that faces the top surface, in a power storage cell.

2. 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 follows the corners of the electrodes that are located diagonally opposite each other.

3. Each of the positioning protrusions is constructed separately from the intervening portion and is fixed to the intervening portion, as described in claim 2.

4. The plurality of electrodes each have a positive electrode and a negative electrode. The positive electrode is, Positive electrode current collector foil, The positive electrode current collector foil has a positive electrode active material layer provided on it, The aforementioned positive electrode current collector foil is The positive electrode active material layer is provided, and a main region is in contact with the pair of positioning protrusions, The positive electrode active material layer is not provided, and the positive electrode tab protrudes from the main region in a direction perpendicular to the aforementioned one direction, The energy storage cell according to claim 1, wherein the positive electrode tab is spaced apart from each of the positioning protrusions.

5. A positioning projection formation step in which a pair of positioning projections are formed on the separator while the separator is being transported, to determine the position of the electrodes relative to the separator, A mounting step of placing the electrodes inside the pair of positioning protrusions, The process includes a folding step of folding the separator so that it overlaps the electrodes placed inside the pair of positioning protrusions, A method for manufacturing an electrode body, wherein the positioning projection formation step involves forming the pair of positioning projections by embossing.

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