Battery cell

Abstract

To provide a manufacturing method for a battery cell capable of preventing a connecting piece from falling in a direction away from a winding core during winding.SOLUTION: A manufacturing method for a storage cell 1 includes: a preparation step for preparing an electrode sheet including a current collecting foil and an active material layer; a cutting step for forming a plurality of cuts 114c in the current collecting foil; and a winding step for winding the electrode sheet around a winding core 10. The current collecting foil includes an end part area 114 on which no active material layer is provided. In the cutting step, a plurality of cuts 114c is formed in an end part area 114 so that a connecting part 114d is formed in the end part area 114. In the winding step, by winding the electrode sheet around the winding core 10, the connecting part 114d is broken along the cuts 114c, and a connecting piece 114a formed in the end part 114 by the breaking of the connecting part 114d falls toward the winding core 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Japanese Patent Publication No. 4401634 discloses a storage battery including a plate assembly including positive and negative plates and a separator, and a battery case that houses the plate assembly. The strip-shaped current collector of each plate has multiple notches. The strip-shaped current collector has multiple connecting pieces formed between the notches. The plate assembly is formed by spirally winding the plates with the separator interposed therebetween. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4401634 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacturing method of a storage cell described in Patent Publication No. 4401634, when each electrode plate is spirally wound with a separator interposed therebetween, the connecting piece may fall in a direction away from the winding core (outward in the radial direction of the winding core).

[0005] An object of the present disclosure is to provide a method for manufacturing an energy storage cell that can prevent the connection pieces from tipping in a direction away from the winding core during winding, and the energy storage cell. [Means for solving the problem]

[0006] a winding step of winding the electrode sheet around a winding core, the winding step being configured to wind ...

[0007] an end region in which the active material layer is not provided, the end region being formed outside the main region in the axial direction of the winding; and the end region having a plurality of connection pieces separated from each other in the circumferential direction and leaning inward in the radial direction of the winding; and each connection piece having a cut end surface formed by cutting the current collecting foil and an active material layer provided on a surface of the current collecting foil, the end region being formed outside the main region in the axial direction of the winding, the end region having a plurality of connection pieces leaning inward in the radial direction of the winding; and and, [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a method for manufacturing an energy storage cell and an energy storage cell that can prevent the connection piece from tipping in a direction away from the winding core during winding. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a partial cross-sectional view schematically illustrating a storage cell according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view schematically showing a positive electrode sheet before being wound. [Figure 3] FIG. 10 is a perspective view schematically illustrating a winding step in which an electrode sheet is wound around a winding core. [Figure 4] FIG. 10 is a diagram schematically illustrating a modified example of the incision. [Figure 5] FIG. 10 is a diagram schematically illustrating a modified example of the incision. [Figure 6] 10A and 10B are diagrams schematically showing modified examples of connecting portions and notches. [Figure 7] 10A and 10B are diagrams schematically showing modified examples of connecting portions and notches. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] 1 is a partial cross-sectional view schematically illustrating an energy storage cell according to an embodiment of the present disclosure. The energy storage cell 1 is preferably mounted on a vehicle.

[0012] As shown in FIG. 1, the energy storage cell 1 includes an electrode assembly 100, a cell case 200, a positive electrode current collector plate 310, a negative electrode current collector plate 320, and a connecting lead 330.

[0013] The electrode body 100 has a positive electrode sheet 110, a negative electrode sheet 120, and a separator 130. The electrode body 100 is configured as a wound body in which the positive electrode sheet 110 and the negative electrode sheet 120 are wound with the separator 130 interposed therebetween.

[0014] 1 and 2, a positive electrode sheet 110 includes a positive electrode current collector foil 112 and a positive electrode active material layer 116.

[0015] The positive electrode current collector foil 112 is made of a metal such as aluminum, and has a main region 113 and an end region 114.

[0016] The main region 113 is a region of the positive electrode current collector foil 112 where the positive electrode active material layer 116 is provided. The main regions 113 are arranged so as to overlap each other in the radial direction of the wound body (electrode body 100).

[0017] The edge region 114 is a region of the positive electrode current collector foil 112 where the positive electrode active material layer 116 is not provided. As shown in Fig. 1, the edge region 114 is formed outside (on the upper side in Fig. 1) the main region 113 in the axial direction of the electrode body 100 (the vertical direction in Fig. 1).

[0018] The end region 114 has a plurality of connection pieces 114a (see FIG. 3) that are separated from one another in the circumferential direction of the electrode body 100. Each connection piece 114a leans inward in the radial direction. The upper surface of each connection piece 114a forms a substantially flat surface.

[0019] 3, each connection piece 114a has a notched end surface S1 and a broken end surface S2. The broken end surface S2 is an end surface formed by breaking the end region 114 of the positive electrode current collector foil 112. The broken end surface S2 is formed inside the notched end surface S1 in the radial direction.

[0020] The negative electrode sheet 120 has a negative electrode current collector foil 122 made of a metal such as copper, and a negative electrode active material layer 126 provided on the surface of the negative electrode current collector foil 122 .

[0021] The structure of the negative electrode current collector foil 122 is substantially the same as that of the positive electrode current collector foil 112. Therefore, only a brief description of the negative electrode current collector foil 122 will be given. That is, the negative electrode current collector foil 122 has a main region 123 in which a negative electrode active material layer 126 is provided, and an end region 124 formed outside the main region 123 in the axial direction (the lower side in FIG. 1 ). The end region 124 has a plurality of connecting pieces leaning inward in the radial direction, and each connecting piece has a notched end face and a broken end face.

[0022] The separator 130 is disposed between the positive electrode sheet 110 and the negative electrode sheet 120. More specifically, the separator 130 is disposed only between the main region 113 of the positive electrode sheet 110 and the main region 123 of the negative electrode sheet 120, which are adjacent to each other in the radial direction. The separator 130 is made of an insulating material and allows ions to pass through.

[0023] The cell case 200 houses the electrode assembly 100. The cell case 200 also houses an electrolyte (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 is open upward. The case body 210 is made of a metal such as aluminum. The case body 210 has a bottom wall 212 and a peripheral wall 214. The bottom wall 212 is formed in a disk shape. The peripheral wall 214 stands up from the edge of the bottom wall 212 and is formed in a cylindrical shape.

[0025] The lid 220 closes the opening of the case body 210. The lid 220 is connected to the case body 210 via a sealing member 215.

[0026] The positive current collector plate 310 is disposed above the electrode assembly 100. The positive current collector plate 310 is connected to the upper surface of each connection piece 114a of the positive current collector foil 112 by welding or the like.

[0027] The negative electrode current collector 320 is disposed below the electrode assembly 100. The negative electrode current collector 320 is connected to the upper surface of each connection piece of the negative electrode current collector foil 122 by welding or the like.

[0028] The connecting lead 330 connects the positive electrode current collector plate 310 and the lid 220 together.

[0029] Next, a manufacturing method of the energy storage cell 1 will be described with reference to FIGS. 2 and 3. This manufacturing method includes a preparation step, a cutting step, and a winding step. Hereinafter, the positive electrode sheet 110 and the negative electrode sheet 120 will be referred to as "electrode sheets," the positive electrode current collector foil 112 and the negative electrode current collector foil 122 will be referred to as "current collector foils," and the positive electrode active material layer 116 and the negative electrode active material layer 126 will be referred to as "active material layers." Note that FIGS. 2 and 3 show the positive electrode sheet 110 as an example. Also, the separator 130 is not shown in FIG. 3.

[0030] In the preparation step, an electrode sheet is prepared. Specifically, in the preparation step, an electrode sheet is prepared that includes a current collector foil having a shape that extends elongated in one direction (the vertical direction in FIG. 2) and an active material layer provided on the surface of the current collector foil. The current collector foil of each of the electrode sheets 110, 120 prepared in the preparation step has a main region 113, 123 and an end region 114, 124. The regions 113, 123 are formed, for example, by providing an active material layer on a current collector foil transported by transport rolls. The end regions 114, 124 are adjacent to the main regions 113, 123 in an orthogonal direction (left-right direction in FIG. 2 ) that is orthogonal to both one direction and the thickness direction of the current collector foil. The length of the main regions 113, 123 in the orthogonal direction is set to, for example, 80 mm, and the length of the end regions 114, 124 in the orthogonal direction is set to, for example, 5 mm. The end regions 114, 124 have a shape that is continuously connected in one direction. The end regions 114, 124 include edges 114b in the orthogonal direction.

[0031] In the cutting step, a plurality of cuts 114c (see FIG. 2) are formed in the current collector foil, spaced apart from one another in one direction. Specifically, in the cutting step, a plurality of cuts 114c are formed, each of which is spaced apart from the edge 114b in the orthogonal direction and spaced apart from one another in one direction. As a result, a connecting portion 114d that includes the edge 114b in the orthogonal direction and extends along one direction is formed in the end regions 114, 124. In other words, in the cutting step, a plurality of cuts 114c are formed in the end regions 114, 124 so that the connecting portion 114d is formed in the end regions 114, 124. More specifically, in the cutting step, a plurality of cuts 114c are formed in the end regions 114, 124 so that the connecting portion 114d is formed that is continuously connected from one end of the end regions 114, 124 to the other end of the end regions 114, 124 in one direction. Each cut 114c may be formed parallel to the orthogonal direction. For example, each incision 114c may be formed by a laser emitted from a laser irradiation unit 20 as shown in Fig. 2, or may be formed by a blade. Fig. 2 shows the positive electrode sheet 110 of the electrode sheet after the incision process.

[0032] In the winding process, the electrode sheet and the separator 130 are wound around the winding core 10. As shown in Figures 2 and 3, the electrode sheet is wound around the winding core 10 at a position where the active material layer overlaps the winding core 10. The separator 130 is positioned so as to overlap only the main regions 113, 123.

[0033] When the electrode sheet is wound around the winding core 10, a surface pressure acts on the end regions 114, 124 toward the winding core 10. If this surface pressure is P [MPa], the tension of the electrode sheet is T [N], the length (width) of the end regions 114, 124 in the orthogonal direction is W [mm], and the winding radius is R [mm], the surface pressure P can be expressed by the following equation:

[0034] P=T / (WR)

[0035] 3, in the winding step, by winding the electrode sheet and separator 130 around the winding core 10, the connecting portion 114d breaks along the slit 114c, and the breaking of the connecting portion 114d causes the connecting pieces 114a formed in the end regions 114, 124 to collapse toward the winding core 10. More specifically, when a surface pressure toward the winding core 10 acts on the end regions 114, 124 during winding of the electrode sheet, the inner portion in the winding direction (the upper portion in FIG. 2) of the pair of portions sandwiching the slit 114c begins to collapse toward the winding core 10 first, and a shear force acts on the portion of the pair of portions that is on the outer side of the slit 114c in the orthogonal direction, i.e., the connecting portion 114d. As a result, the connecting portion 114d breaks so that the notch 114c reaches the edge 114b of the end region 114, and the connecting piece 114a formed by the breakage falls toward the winding core 10 due to the surface pressure. Each connecting piece 114a formed in this manner has a notched end surface S1 formed by the notch made in the notching step and a broken end surface S2 formed by the breakage in the winding step.

[0036] As described above, in the method for manufacturing the storage cell 1 according to this embodiment, when the electrode sheet is wound around the winding core 10 in the winding step, the end regions 114 and 124 are connected. Because the end regions 114 and 124 have the connecting portions 114d, a surface pressure toward the winding core 10 acts on the end regions 114 and 124 when the electrode sheet is wound. This surface pressure causes the connecting portions 114d to break, and the connecting pieces 114a formed by the breakage to fall toward the winding core 10. This prevents the connecting pieces 114a from falling in a direction away from the winding core 10 (outward in the radial direction) when the electrode sheet is wound.

[0037] In the above embodiment, as shown in FIGS. 4 and 5, the cutting step may form a cut 114c including an inclined portion c1 that gradually inclines toward the outside in the orthogonal direction (to the left in FIG. 4) as it approaches the outside in the winding direction (to the bottom in FIG. 4). In the example shown in FIG. 4, the cut 114c is composed of only the inclined portion c1. In the example shown in FIG. 5, the cut 114c has the inclined portion c1 and an inner portion c2 formed inside the inclined portion c1 in the orthogonal direction. The inner portion c2 is formed parallel to the orthogonal direction. The angle θ between the one direction and the inclined portion c1 is preferably set to be equal to or greater than 10 degrees and equal to or less than 80 degrees, and more preferably equal to or greater than 30 degrees and equal to or less than 75 degrees.

[0038] 6, the multiple notches 114c may include cutting notches 114e that extend to the edge portion 114b. The cutting notches 114e divide the connecting portion 114d. The cutting notches 114e are formed at intervals that are equal to or greater than the length of one circumference of the electrode sheet wound around the winding core 10 (the product of the diameter of the electrode sheet and pi). In this example, although the connecting portion 114d is interrupted by the cutting notches 114e, the length of the connecting portion 114d in one direction is equal to or greater than the length of one circumference of the electrode sheet wound around the winding core 10, and therefore the surface pressure acts effectively on the end regions 114, 124 during the winding process.

[0039] Also, as shown in FIG. 7, in the cutting step, a plurality of cuts 114c may be formed so that the length of the connecting portion 114d in the orthogonal direction gradually decreases toward the outside in the winding direction (the lower side in FIG. 7).

[0040] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0041] [Aspect 1] a preparation step of preparing an electrode sheet including a current collector foil having a shape that extends elongated in one direction and an active material layer provided on a surface of the current collector foil; a cutting step of forming a plurality of cuts in the current collecting foil spaced apart from one another in the one direction; a winding step of winding the electrode sheet around a winding core, the current collecting foil of the electrode sheet prepared in the preparing step includes an end region where the active material layer is not provided, the end region including an edge portion in an orthogonal direction that is orthogonal to both the one direction and a thickness direction of the current collecting foil, and having a shape that is continuously connected in the one direction; In the cutting step, the plurality of cuts are formed in the end region so that a connecting portion is formed in the end region, the connecting portion including the edge portion in the orthogonal direction and extending along the one direction; In the winding step, the electrode sheet is wound around the winding core, whereby the connecting portion breaks along the notch, and the breaking of the connecting portion causes the connecting piece formed in the end region to fall toward the winding core.

[0042] In this method for manufacturing a storage cell, when the electrode sheet is wound around the winding core in the winding step, the end region has a connecting portion, so that when the electrode sheet is wound, a surface pressure acts on the end region toward the winding core. As a result, of a pair of portions of the end region sandwiching the notch, the inner portion in the winding direction starts to collapse toward the winding core first, and a shear force acts on the outer portion of the pair of portions of the notch in the perpendicular direction, i.e., the connecting portion. As a result, the connecting portion breaks so that the cut reaches the edge of the end region, and the connecting piece formed by the break falls toward the winding core due to the surface pressure, thereby preventing the connecting piece from falling outward during winding.

[0043] [Aspect 2] 2. The method for manufacturing a storage cell according to aspect 1, wherein in the cutting, the cuts are formed to include inclined portions that gradually incline outward in the orthogonal direction as they extend outward in the winding direction.

[0044] In this embodiment, air resistance acting on the connection pieces during the winding process is reduced, so that each connection piece effectively falls toward the winding core even when the winding core is rotated at high speed during the winding process.

[0045] [Aspect 3] In the cutting step, the plurality of cuts are formed in the end region so as to form the connecting portion that is continuously connected from one end of the end region to the other end of the end region in the one direction.

[0046] In this embodiment, the surface pressure acts stably on the connecting portions in the winding process, so that each connecting piece falls stably toward the winding core.

[0047] [Aspect 4] Aspect 4. The method for manufacturing a storage cell according to any one of aspects 1 to 3, wherein in the cutting, the plurality of cuts are formed such that the length of the connecting portion in the orthogonal direction gradually decreases toward the outside in the winding direction.

[0048] In this embodiment, the connecting portion breaks stably in the winding step even at the outer portion of the end region in the winding direction.

[0049] [Aspect 5] an electrode body including a positive electrode sheet, a negative electrode sheet, and a separator, the electrode body being configured as a wound body in which the positive electrode sheet and the negative electrode sheet are wound with the separator interposed therebetween; Each of the positive electrode sheet and the negative electrode sheet is A current collecting foil; an active material layer provided on the surface of the current collecting foil, The current collecting foil is main regions provided with the active material layer and arranged so as to overlap each other in the radial direction of the wound body; an end region formed outside the main region in the axial direction of the wound body, and in which the active material layer is not provided; the end region has a plurality of connecting pieces that are separated from each other in the circumferential direction of the winding body and that are inclined toward the inside in the radial direction, Each connecting piece is a cut end surface formed by cutting the current collecting foil; a broken end surface formed inside the cut end surface in the radial direction and formed by breaking the current collecting foil.

[0050] In this energy storage cell, each connection piece has a broken end surface, so an increase in contact resistance at the welded portion between each connection piece and the current collector plate is suppressed compared to when each connection piece is composed of only a notched end surface. For example, when connection pieces are formed only by cutting with a laser, molten material may adhere to the edge of the cut surface, and when connection pieces are formed only by cutting with a blade, burrs may form on the edge of the cut surface, which may increase the contact resistance between each connection piece and the current collecting plate. In contrast, no molten material or burrs are formed on the fractured end surface, so the increase in contact resistance is suppressed.

[0051] [Aspect 6] An electrode sheet that is wound together with a separator to form an electrode body consisting of a wound body, a current collecting foil having a shape that extends elongated in one direction; an active material layer provided on the surface of the current collecting foil, The current collecting foil is a main region in which the active material layer is provided; an end region that includes an edge portion in an orthogonal direction that is orthogonal to both the one direction and the thickness direction of the current collecting foil and is continuous in the one direction, and in which the active material layer is not provided; An electrode sheet, wherein the end region has a plurality of notches formed therein, each of which is spaced apart from the edge in the orthogonal direction and spaced apart from one another in the one direction.

[0052] 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]

[0053] 1 storage cell, 100 electrode body, 110 positive electrode sheet, 112 positive electrode current collector foil, 113 main region, 114 end region, 114a connecting piece, 114b edge portion, 114c notch, 114d connecting portion, 114e cutting notch, 116 positive electrode active material layer, 120 positive electrode sheet, 122 negative electrode current collector foil, 123 main region, 124 end region, 200 cell case, 210 case body, 220 lid, 310 positive electrode current collector plate, 320 negative electrode current collector plate, 330 Connecting lead, c1 inclined part, c2 inner part.

Claims

1. a preparation step of preparing an electrode sheet including a current collector foil having a shape that extends elongated in one direction and an active material layer provided on a surface of the current collector foil; a cutting step of forming a plurality of cuts in the current collecting foil spaced apart from one another in the one direction; a winding step of winding the electrode sheet around a winding core, the current collecting foil of the electrode sheet prepared in the preparing step includes an end region where the active material layer is not provided, the end region including an edge portion in an orthogonal direction that is orthogonal to both the one direction and a thickness direction of the current collecting foil, and having a shape that is continuously connected in the one direction; In the cutting step, the plurality of cuts are formed in the end region so that a connecting portion is formed in the end region, the connecting portion including the edge portion in the orthogonal direction and extending along the one direction; In the winding step, the electrode sheet is wound around the winding core, whereby the connecting portion breaks along the notch, and the breaking of the connecting portion causes the connecting piece formed in the end region to fall toward the winding core.

2. The method for manufacturing a storage cell according to claim 1 , wherein in the cutting, the cuts are formed to include inclined portions that gradually incline outward in the orthogonal direction as they extend outward in the winding direction.

3. 2. The method for manufacturing a storage cell according to claim 1, wherein in the cutting step, the plurality of cuts are formed in the end region so as to form the connecting portion that is continuously connected from one end of the end region to the other end of the end region in the one direction.

4. The method for manufacturing a storage cell according to claim 1 , wherein in the cutting step, the plurality of cuts are formed so that the length of the connecting portion in the orthogonal direction gradually decreases toward the outside in the winding direction.

5. an electrode body including a positive electrode sheet, a negative electrode sheet, and a separator, the electrode body being configured as a wound body in which the positive electrode sheet and the negative electrode sheet are wound with the separator interposed therebetween; Each of the positive electrode sheet and the negative electrode sheet is A current collecting foil; an active material layer provided on the surface of the current collecting foil, The current collecting foil is main regions provided with the active material layer and arranged so as to overlap each other in the radial direction of the wound body; an end region formed outside the main region in the axial direction of the wound body, and in which the active material layer is not provided; the end region has a plurality of connecting pieces that are separated from each other in the circumferential direction of the winding body and that are inclined toward the inside in the radial direction, Each connecting piece is a cut end surface formed by cutting the current collecting foil; a broken end surface formed inside the cut end surface in the radial direction and formed by breaking the current collecting foil.

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