Electrode body

Abstract

To provide an electrode body in which positional displacements of electrodes to a separator can be suppressed.SOLUTION: An electrode body 100 includes a plurality of electrode bodies 110, 120 arranged in one direction; and a separator 130 formed in a winding pattern for insulating a plurality of electrodes from one another. The separator 130 includes: a plurality of inclusions 132a intervening between a pair of electrodes; an upper folded part 132b; and a lower folded part 132a. At least one of the upper folded part 132b and the lower folded part 132c is connected to an electrode.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This disclosure relates to an electrode body.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2022-100813 discloses a so-called laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated with a separator interposed therebetween.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electrode body described in Japanese Patent Application Laid-Open No. 2022-100813, there is a concern that the electrodes may be displaced with respect to the separator when the electrode body is transported or inserted into the cell case of the electrode body.

[0005] An object of this disclosure is to provide an electrode body capable of suppressing displacement of the electrodes with respect to the separator.

Means for Solving the Problems

[0006] An electrode body according to one aspect of the present disclosure 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, wherein the separator includes a plurality of intervening portions interposed between a pair of electrodes adjacent to each other in the unidirectional direction, an upper folded portion connecting the upper end of one of the plurality of intervening portions and the upper end of an intervening portion adjacent to the one intervening portion on one side in the unidirectional direction, and a lower folded portion connecting the lower end of the one intervening portion and the lower end of an intervening portion adjacent to the one intervening portion on the other side in the unidirectional direction, wherein at least one of the upper folded portion and the lower folded portion is connected to the electrodes. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an electrode body that can suppress misalignment of the electrode relative to the separator. [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 cross-sectional view of the electrode body. [Figure 4] This is a plan view of the separator before it is formed into a zigzag shape. [Figure 5] This is a perspective view illustrating the connection process between the electrode tab and the current collector tab. [Figure 6] This is a schematic perspective view showing the process of bending the electrode tabs and current collector tabs. [Figure 7] This is a schematic perspective view showing the process of inserting the electrode into the case 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 cross-sectional view of the electrode body. As shown in Figure 3, the electrode body 100 comprises a plurality of electrodes 110, 120, a separator 130, and an insulating film 140 (see Figure 7).

[0013] As shown in Figure 3, the multiple electrodes 110, 120 are arranged in a unidirectional direction (left-right direction in Figure 3). The multiple electrodes 110, 120 consist of multiple positive electrodes 110 and multiple negative electrodes 120.

[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). 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. As shown in Figures 2 and 5, the positive electrode current collector foil 112 has a positive electrode tab 112p on which the positive electrode active material layer 114 is not provided. The positive electrode tab 112p protrudes toward one side in the width direction (a direction perpendicular to the plane of the paper in Figure 3).

[0015] Each negative electrode 120 is formed in a rectangular shape that is long in the width direction. Each negative electrode 120 has a negative electrode current collector foil 122 and negative electrode active material layers 124 provided on both surfaces of the negative electrode current collector foil 122. As shown in FIGS. 2 and 5, etc., the negative electrode current collector foil 122 has a negative electrode tab 122n where the negative electrode active material layer 124 is not provided. The negative electrode tab 122n protrudes toward the other side in the width direction.

[0016] 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. 3, the separator ione 130 is formed in a zigzag shape.

[0017] FIG. 4 is a plan view of the separator in a state before being formed in a zigzag shape. As shown in FIG. 4, the separator 130 has a rectangular shape in a state before being formed in a zigzag shape. The separator 130 is arranged while being formed in a zigzag shape between the respective electrodes 110, 120. The separator 130 has a plurality of intervening portions 132a, a plurality of upper folding-back portions 132b, a plurality of lower folding-back portions 132c, and an outermost covering portion 132d.

[0018] Each intervening portion 132a intervenes between a pair of electrodes 110, 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.

[0019] Each upper folding-back portion 132b connects the upper end portion of one intervening portion 132a among the plurality of intervening portions 132a and the upper end portion of an intervening portion 132a that is adjacent to the one intervening portion 132a on one side in one direction among the plurality of intervening portions 1, 32a. In the present embodiment, the upper folding-back portion 132b is arranged above the positive electrode 110.

[0020] 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.

[0021] Each lower turning-back portion 132c is connected to the lower end portion of the negative electrode 120, more specifically, the lower end portion of the negative electrode current collector foil 122. Specifically, heat is applied to the lower turning-back portion 132c from the outside of the lower turning-back portion 132c by irradiation with a laser or the like as indicated by the arrow in FIG. 3. Thereby, the lower turning-back portion 132c is connected (welded) to the lower end portion of the negative electrode current collector foil 122.

[0022] The outermost covering portion 132d collectively covers each upper turning-back portion 132b and each lower turning-back portion 132c. More specifically, the outermost covering portion 132d collectively covers all the electrodes 110, 120, all the intervening portions 132a, all the upper turning-back portions 132b, and all the lower turning-back portions 132c while winding them around a central axis parallel to the width direction. The terminal 132e (see FIGS. 3 and 4) of the outermost covering portion 132d is set in a range that does not overlap the positive electrode active material layer 114 and the negative electrode active material layer 124 in one direction. In the present embodiment, the terminal 132e of the outermost covering portion 132d is provided below each of the electrodes 110, 120.

[0023] As shown in FIG. 3, the outermost covering portion 132d is connected to each lower turning-back portion 132c. Specifically, heat is applied to the portion of the outermost covering portion 132d that overlaps each lower turning-back portion 132c from the outside of the portion by irradiation with a laser or the like as indicated by the arrow in FIG. 3. Thereby, the outermost covering portion 132d is connected (welded) to each lower turning-back portion 132c. At this time, each lower turning-back portion 132c is connected (welded) to the lower end portion of the negative electrode current collector foil 122.

[0024] Furthermore, the outermost covering portion 132d is connected to each upper folded portion 132b. Specifically, heat is applied to the portion of the outermost covering portion 132d that overlaps with each upper folded portion 132b from the outside, by laser irradiation or the like, as indicated by the arrows in Figure 3. As a result, the outermost covering portion 132d is connected (welded) to each upper folded portion 132b.

[0025] As shown in Figure 3, the multiple negative electrodes 120 include the outermost negative electrode 120E, which is positioned furthest out in one direction. The lower end of the outermost negative electrode 120E is connected to the outermost covering portion 132d. The upper end of the outermost negative electrode 120E is connected to the outermost covering portion 132d. The connection of the lower and upper ends of the outermost negative electrode 120E to the outermost covering portion 132d is performed by laser irradiation or the like, as described above.

[0026] Furthermore, the upper end of the positive electrode 110, or more specifically, the upper end of the positive electrode current collector foil 112, may be connected to the upper folded portion 132b. Similarly, the lower end of the positive electrode current collector foil 112 may be connected to the outermost covering portion 132d.

[0027] The insulating film 140 covers the circumferential and bottom surfaces of the multiple electrodes 110, 120 and the separator 130. In Figure 7, the insulating film 140 has a dot pattern.

[0028] The cell case 200 houses the electrode body 100. The cell case 200 contains an electrolyte solution (not shown). The cell case 200 is sealed. The cell case 200 has a case body 210 and a lid 220.

[0029] 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 Figure 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 shape. The peripheral wall 214 rises from the bottom wall 212. The peripheral wall 214 is formed in a rectangular tubular 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] A pair of connecting members 400 (see Figure 2) 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, while 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, one of the connecting members 400 will be described below.

[0035] The connecting member 400 includes a current collection tab 410, a sub-tab 420, and a connecting pin 430.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Next, the manufacturing process of the energy storage cell 1 will be explained with reference to Figures 5 to 7, etc.

[0045] First, the separator 130 is formed in a zigzag pattern, with the electrodes 110 and 120 alternately arranged between the pair of intervening portions 132a. Then, after winding the outermost covering portion 132d of the separator 130, the lower folded portions 132c are connected (welded) to the outermost covering portion 132d by, for example, irradiating the outermost covering portion 132d with a laser, and the lower ends of the negative electrode current collector foils 122 are connected (welded) to the lower folded portions 132c, the upper folded portions 132b are connected (welded) to the outermost covering portion 132d, and the lower and upper ends of the outermost negative electrode electrodes 120E are connected (welded) to the outermost covering portion 132d.

[0046] Next, as shown in Figure 5, one end 422 of the sub-tab 420 is connected to the multiple electrode tabs 112p, 122n by welding or the like. Then, as shown by the arrow in Figure 6, 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 collector tab 410.

[0047] Next, as shown in Figure 7, the peripheral and bottom surfaces of the multiple electrodes 110, 120 and the separator 130 are covered together with an insulating film 140, 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.

[0048] 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.

[0049] As described above, in the electrode body 100 of this embodiment, the separator 130 is formed in a zigzag shape, and each lower folded portion 132c is connected to the negative electrode 120, so at least the misalignment of the negative electrode 120 relative to the separator 130 is suppressed.

[0050] Furthermore, since each lower folded portion 132c is connected to the outermost covering portion 132d, relative displacement between the lower folded portions 132c is suppressed. In addition, since the positive electrode 110 is positioned in the space enclosed by a pair of adjacent lower folded portions 132c and upper folded portion 132b, misalignment of the positive electrode 110 relative to the separator 130 is also suppressed.

[0051] In the above embodiment, an example was shown in which the negative electrode 120 is placed on the lower folded portion 132c and the lower folded portion 132c is connected to the lower end of the negative electrode 120. However, the positive electrode 110 may be placed on the lower folded portion 132c and the lower folded portion 132c may be connected to the lower end of the positive electrode 110.

[0052] Furthermore, even when either the positive electrode 110 or the negative electrode 120 is positioned on the lower folded portion 132c, each upper folded portion 132b may be connected to the upper end of each electrode 110, 120. In this case, each lower folded portion 132c does not need to be connected to each electrode 110, 120.

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

[0054] [Aspect 1] 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, A plurality of intervening portions interposed between a pair of electrodes adjacent to each other in one direction, An upper folded portion that connects the upper end of one of the plurality of intervening portions and the upper end of an intervening portion adjacent to the first intervening portion on one side in the same direction, It includes a lower folded portion that connects the lower end of one of the plurality of intervening portions and the lower end of an intervening portion adjacent to the one intervening portion on the other side in the same direction, An electrode body in which at least one of the upper folded portion and the lower folded portion is connected to the electrode.

[0055] In this electrode body, the separator is formed in a zigzag pattern, and at least one of the upper folded portion and the lower folded portion is connected to the electrode, thereby suppressing misalignment of the electrode relative to the separator.

[0056] [Aspect 2] The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The negative electrode is positioned on the lower folded portion, The electrode body according to embodiment 1, wherein the lower folded portion is connected to the lower end of the negative electrode.

[0057] In this embodiment, misalignment of the negative electrode relative to the separator is suppressed.

[0058] [Aspect 3] The separator further has an outermost covering portion that covers the upper folded portion and the lower folded portion together, The electrode body according to embodiment 1 or 2, wherein the lower folded portion is connected to the outermost covering portion.

[0059] In this embodiment, relative displacement between the lower folded portions is suppressed.

[0060] [Aspect 4] The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The electrode body according to embodiment 3, wherein the upper end of the negative electrode is connected to the outermost covering portion.

[0061] In this embodiment, misalignment of the negative electrode relative to the separator is more reliably suppressed.

[0062] [Aspect 5] The electrode body according to embodiment 3 or 4, wherein the upper folded portion is connected to the outermost covering portion.

[0063] [Aspect 6] The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The plurality of negative electrodes include the outermost negative electrode located on the outermost side in the one direction, The electrode body according to any one of embodiments 3 to 5, wherein the lower end of the outermost negative electrode is connected to the outermost covering portion.

[0064] 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]

[0065] 1 Energy storage cell, 100 Electrode body, 110 Positive electrode, 112 Positive electrode current collector foil, 112p Positive electrode tab, 114 Positive electrode active material layer, 120 Negative electrode, 120E Outermost 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, 132d Outermost covering part, 140 Insulating film, 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. 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, A plurality of intervening portions interposed between a pair of electrodes adjacent to each other in one direction, An upper folded portion that connects the upper end of one of the plurality of intervening portions and the upper end of an intervening portion adjacent to the first intervening portion on one side in the same direction, It includes a lower folded portion that connects the lower end of one of the plurality of intervening portions and the lower end of an intervening portion adjacent to the one intervening portion on the other side in the same direction, An electrode body in which at least one of the upper folded portion and the lower folded portion is connected to the electrode.

2. The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The negative electrode is positioned on the lower folded portion, The electrode body according to claim 1, wherein the lower folded portion is connected to the lower end of the negative electrode.

3. The separator further has an outermost covering portion that covers the upper folded portion and the lower folded portion together, The electrode body according to claim 1, wherein the lower folded portion is connected to the outermost covering portion.

4. The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The electrode body according to claim 3, wherein the upper end of the negative electrode is connected to the outermost covering portion.

5. The electrode body according to claim 3, wherein the upper folded portion is connected to the outermost covering portion.

6. The plurality of electrodes have a plurality of positive electrodes and a plurality of negative electrodes, The plurality of negative electrodes include the outermost negative electrode located on the outermost side in the one direction, The electrode body according to claim 3, wherein the lower end of the outermost negative electrode is connected to the outermost covering portion.

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