Battery manufacturing method

Abstract

To increase the productivity of a battery.SOLUTION: A method for manufacturing a battery 2 is a method for manufacturing a battery 2 comprising a wound electrode body 20 wound with a first separator 31, a negative electrode plate 22, a second separator 32, and a positive electrode plate 21. The method for manufacturing the battery 2 has a step A of adsorbing the first separator 31 onto a winding core 140, and a step B of taking up the first separator 31 around the winding core 140. The winding core 140 is formed with a plurality of suction holes 141 for adsorbing the first separator 31. When the outer periphery of the winding core 140 is equally divided into four, with a position facing an end portion of the wound electrode body 20 from which winding of the first separator 31 is started as a starting point, thereby obtaining first to fourth areas (R1 to R4), 80% or more of the suction holes 141, in terms of the opening area ratio, are formed in the first area R1.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a battery. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2006-216520 discloses a winding core used in a winding device used in manufacturing a web-shaped material wound body such as a secondary battery. The winding core disclosed in this publication has a plurality of suction and discharge holes formed at regular intervals on its outer surface. The suction and discharge holes allow separators and other materials to be attracted to the winding core. It is said that using such a winding core makes it possible to wind battery elements without forming folded portions in the battery element material. This makes it possible to omit post-processing steps and reduce costs by eliminating mechanisms and parts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-216520 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have been trying to improve the production efficiency of wound electrode bodies and have found that there is room for improvement in the method of winding negative electrode plates, positive electrode plates, and separators when manufacturing wound electrode bodies. [Means for solving the problem]

[0005] The battery manufacturing method disclosed herein is a method for manufacturing a battery including a wound electrode body in which a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound. The battery manufacturing method includes a step A of adsorbing the first separator onto a winding core, and a step B of winding the first separator onto the winding core. The winding core is formed with a plurality of suction holes for adsorbing the first separator, and when the outer circumference of the winding core is divided into four equal parts, each defined as a first to fourth region, starting from a position opposite the winding start end of the first separator in the wound electrode body, 80% or more of the suction holes are formed in the first region in terms of opening area ratio. This configuration can improve the production efficiency of the wound electrode body.

[0006] The battery manufacturing method may include step C of cutting the first separator and the second separator. In step C, the first separator and the second separator may be cut while wound in a region of 15 to 180 degrees circumferentially around a winding core other than the winding core around which the first separator was wound in step B. In addition, in step C, the first separator may be cut while in contact with a winding core other than the winding core on which the first separator was wound in step B, upstream and downstream of the cutting position of the first separator in the moving path of the first separator. In step C, when the first separator and the second separator are cut, the first separator and the second separator may be pressed by a pressing jig onto a core different from the core onto which the first separator was wound in step B. The pressing jig may be a roller having a plurality of protrusions formed on its surface. In step C, a groove may be formed along the axial direction at the position where the first separator and the second separator are to be cut on a winding core other than the winding core on which the first separator was wound in step B. In step C, the first separator and the second separator may be cut with a blade that moves toward a different winding core from the winding core onto which the first separator was wound in step B. The winding core may be divided into at least two parts in the radial direction of the winding core, and the first separator may be attached to only a part of the winding core. The width of the suction hole formation region in which the plurality of suction holes are formed may be smaller than the width of the first separator. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a vertical cross-sectional plan view of the battery 2. FIG. [Figure 2] FIG. 2 is a schematic diagram of the wound electrode body 20. As shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of the winding machine 100. [Figure 4] FIG. 4 is a schematic diagram of the winding machine 100. [Figure 5] FIG. 5 is a schematic diagram of the winding machine 100. [Figure 6] FIG. 6 is a schematic diagram of the winding machine 100. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows the winding core 140 disposed at the first position P1. [Figure 8] FIG. 8 is a cross-sectional view of the winding core 140. [Figure 9] FIG. 9 is a schematic diagram showing the configuration of the outer peripheral surface of the winding core 140. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the invention disclosed herein will be described. Naturally, the embodiments described herein are not intended to particularly limit the present invention. The present invention is not limited to the embodiments described herein unless otherwise specified. Each drawing is a schematic drawing and does not necessarily reflect the actual product. Furthermore, components and parts that perform the same function are appropriately designated by the same reference numerals, and duplicate explanations will be omitted.

[0009] FIG. 1 is a vertical cross-sectional plan view of a battery 2. In FIG. 1, the wide front surface of a battery case 10 is virtually removed, and the battery 2 is illustrated schematically so that the interior of the battery case 10 can be seen. The battery 2 is one form of a battery manufactured by the manufacturing method disclosed herein, and a wound electrode body 20 is housed inside the battery case 10. The battery manufactured by the manufacturing method disclosed herein is not limited to the form shown in FIG. 1.

[0010] 《Battery 2》 The battery 2 shown in Fig. 1 is a horizontally elongated rectangular battery. As shown in Fig. 1, the battery 2 has a battery case 10, a wound electrode body 20, a positive electrode terminal 50, and a negative electrode terminal 60. The battery case 10 has an exterior body 11 and a sealing plate 12.

[0011] <Exterior body 11> The exterior body 11 is a rectangular case with a bottom, and has a horizontally long rectangular storage space. The exterior body 11 mainly stores the wound electrode body 20. The exterior body 11 has a substantially rectangular bottom surface 11e, a pair of opposing wide surfaces 11a and 11b (not shown) along the long sides of the bottom surface 11e, and a pair of opposing narrow surfaces 11c and 11d along the short sides of the bottom surface 11e. An opening 11f for storing the wound electrode body 20 is formed on the surface opposite the bottom surface 11e. A sealing plate 12 is attached to the opening 11f.

[0012] <Sealing plate 12> The sealing plate 12 is attached to the opening 11f of the battery case 10. The sealing plate 12 is made of a substantially rectangular plate material that can be attached to the opening 11f of the exterior body 11. The sealing plate 12 is a substantially rectangular plate material, and has an attachment hole formed on one side in the longitudinal direction for attaching the positive electrode terminal 50, and attachment holes 12a and 12b formed on the opposite side for attaching the negative electrode terminal 60.

[0013] A liquid inlet 12c and a gas release valve 12d are provided in the center of the sealing plate 12. The liquid inlet 12c is a through-hole provided for injecting non-aqueous electrolyte into the sealed battery case 10. The liquid inlet 12c is sealed by attaching a sealing member 12e after the non-aqueous electrolyte is injected. The gas release valve 12d is a thin-walled portion designed to rupture (open) when a large amount of gas is generated inside the battery case 10, thereby releasing the gas.

[0014] The non-aqueous electrolyte may be any of those used in conventional secondary batteries without any particular limitations. For example, the non-aqueous electrolyte may be prepared by dissolving a supporting salt in a non-aqueous solvent. Examples of non-aqueous solvents include carbonate-based solvents such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Examples of supporting salts include fluorine-containing lithium salts such as LiPF6.

[0015] <Positive terminal 50, negative terminal 60> The positive electrode terminal 50 and the negative electrode terminal 60 are attached to a sealing plate 12. The wound electrode body 20 is housed in an exterior body 11 while attached to the positive electrode terminal 50 and the negative electrode terminal 60. The positive electrode terminal 50 includes an external terminal 51, an axial member 52, an internal terminal 53, a current collecting member 54, a first insulator 71, a second insulator 72, and a gasket 73. The negative electrode terminal 60 includes an external terminal 61, an axial member 62, an internal terminal 63, a current collecting member 64, a first insulator 81, a second insulator 82, and a gasket 83. The first insulators 71, 81, the second insulators 72, 82, and the gaskets 73, 83 are each made of insulating material. The first insulators 71, 81 and the second insulators 72, 82 are each made of a resin having a required rigidity. The gaskets 73 and 83 are members that are attached to the mounting holes 12a and 12b of the sealing plate 12, and have a required flexibility.

[0016] The shaft members 52, 62 of the positive electrode terminal 50 and the negative electrode terminal 60 are attached to the mounting holes 12a, 12b of the sealing plate 12 with gaskets 73, 83 interposed therebetween. External terminals 51, 61 are attached to the outside of the sealing plate 12 with first insulators 71, 81 interposed therebetween. The external terminals 51, 61 have mounting holes and are attached to the outer axial ends of the shaft members 52, 62. Internal terminals 53, 63 are attached to the inside of the sealing plate 12 with second insulators 72, 82 interposed therebetween. The internal terminals 53, 63 have mounting holes and are attached to the inner axial ends of the shaft members 52, 62. The inner axial ends of the shaft members 52, 62 are crimped around the mounting holes of the internal terminals 53, 63. Current collecting members 54, 64 are attached to one end of the internal terminals 53, 63.

[0017] In this manner, the positive electrode terminal 50 and the negative electrode terminal 60 are attached to the sealing plate 12 in a state in which they are electrically insulated via the first insulators 71, 81, the second insulators 72, 82, and the gaskets 73, 83, and in a state in which airtightness is ensured. Furthermore, an electrical conduction path is formed by the external terminals 51, 61, the shaft members 52, 62, the internal terminals 53, 63, and the current collecting members 54, 64. The wound electrode body 20 is attached to the current collecting members 54, 64. The wound electrode body 20 is housed in the exterior body 11 in this state attached to the sealing plate 12. Multiple wound electrode bodies 20 may be attached to one sealing plate 12, and multiple wound electrode bodies 20 may be housed in one battery case 10.

[0018] <Wound electrode body 20> Fig. 2 is a schematic diagram of the wound electrode body 20. In Fig. 2, the wound electrode body 20 is shown with one end unfolded. As shown in Fig. 2, the wound electrode body 20 is formed by, for example, stacking a long, strip-shaped positive electrode plate 21, a first separator 31, a negative electrode plate 22, and a second separator 32 in order with their longitudinal directions aligned, and winding them around a winding axis WL set in the width direction.

[0019] The positive electrode plate 21 includes a positive electrode core 21a, a positive electrode active material layer 21b, a protective layer 21c, and a tab 21d. The positive electrode core 21a is a base material of the positive electrode plate 21. The positive electrode core 21a is formed of a predetermined metal foil (e.g., aluminum foil). The positive electrode active material layer 21b is formed with a constant width on one end of the positive electrode core 21a in the width direction. A protective layer 21c is formed on both sides of the positive electrode plate 21 in a portion of the positive electrode core 21a excluding the portion on which the positive electrode active material layer 21b is formed. Furthermore, a tab 21d protruding in the width direction is formed on the side on which the protective layer 21c is formed on the positive electrode core 21a. The tab 21d protrudes by a predetermined width partially on the side on which the protective layer 21c is formed, exposing the positive electrode core 21a.

[0020] The positive electrode active material layer 21b is a layer containing a positive electrode active material. In a lithium-ion secondary battery, the positive electrode active material is, for example, a material that can release lithium ions during charging and absorb lithium ions during discharging, such as a lithium transition metal composite material. Generally, various positive electrode active materials have been proposed in addition to lithium transition metal composite materials, and the positive electrode active material is not particularly limited. For example, a lithium transition metal composite oxide is preferable. Among the lithium transition metal composite oxides, a lithium transition metal composite oxide containing at least one transition metal selected from the group consisting of nickel (Ni), cobalt (Co), and manganese (Mn) is particularly preferable. Specific examples include lithium nickel cobalt manganese composite oxide (NCM), lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, lithium nickel manganese composite oxide, lithium nickel cobalt aluminum composite oxide (NCA), and lithium iron nickel manganese composite oxide. Furthermore, a suitable example of a lithium transition metal composite oxide that does not contain Ni, Co, or Mn is a lithium iron phosphate composite oxide (LFP).

[0021] In this specification, the term "lithium nickel cobalt manganese composite oxide" refers to oxides containing additive elements in addition to the main constituent elements (Li, Ni, Co, Mn, and O). Examples of such additive elements include transition metal elements and typical metal elements such as Mg, Ca, Al, Ti, V, Cr, Si, Y, Zr, Nb, Mo, Hf, Ta, W, Na, Fe, Zn, and Sn. The additive elements may also be semimetal elements such as B, C, Si, and P, or nonmetal elements such as S, F, Cl, Br, and I. The positive electrode active material layer 21b may contain additives other than the positive electrode active material. Examples of such additives include conductive materials and binders. Specific examples of conductive materials include carbon materials such as acetylene black (AB). Specific examples of binders include resin binders such as polyvinylidene fluoride (PVdF). When the total solid content of the positive electrode active material layer 21b is taken as 100% by mass, the content of the positive electrode active material is generally 80% by mass or more, and typically 90% by mass or more.

[0022] The protective layer 21c is a layer configured to have low electrical conductivity. The protective layer 22c is provided in a region adjacent to the edge of the positive electrode active material layer 21b. This prevents direct contact between the positive electrode substrate 21a and the negative electrode active material layer 22b and an internal short circuit when either of the separators 31 and 32 is damaged. The protective layer 22c preferably includes a layer containing insulating ceramic particles. Examples of such ceramic particles include inorganic oxides such as alumina (Al2O3), magnesia (MgO), silica (SiO2), and titania (TiO2); nitrides such as aluminum nitride and silicon nitride; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; clay minerals such as mica, talc, boehmite, zeolite, apatite, and kaolin; and glass fibers. Considering insulation and heat resistance, alumina, boehmite, aluminum hydroxide, silica, and titania are preferred. The protective layer 22c may also contain a binder for fixing the ceramic particles to the surface of the positive electrode substrate 21a. Examples of such binders include resin binders such as polyvinylidene fluoride (PVdF). A small amount of conductive material (e.g., a carbon material such as carbon black) may be added to the protective layer 22c. The addition of the conductive material may impart slight conductivity. The amount of conductive material added may be adjusted to an amount that achieves the required conductivity. Note that the protective layer is not an essential component of the positive electrode plate. In other words, the secondary battery disclosed herein may also use a positive electrode plate without a protective layer.

[0023] The negative electrode plate 22 includes a negative electrode core 22a, a negative electrode active material layer 22b, and a tab 22d. The negative electrode core 22a is the base material of the negative electrode plate 22. The negative electrode core 22a is formed of a predetermined metal foil (for example, copper foil). The negative electrode active material layer 22b is formed on both sides of the negative electrode core 22a across approximately the entire width. The negative electrode core 22a has a tab 22d formed thereon that protrudes from one side in the width direction. The tab 22d protrudes partially by a predetermined width from one side in the width direction of the negative electrode core 22a.

[0024] The negative electrode active material layer 22b is a layer containing a negative electrode active material. The negative electrode active material is not particularly limited as long as it can reversibly absorb and release charge carriers in relation to the above-mentioned positive electrode active material. Examples of such negative electrode active materials include carbon materials and silicon-based materials. Examples of carbon materials that can be used include graphite, hard carbon, soft carbon, and amorphous carbon. Amorphous carbon-coated graphite, in which the surface of graphite is coated with amorphous carbon, can also be used. Examples of silicon-based materials include silicon and silicon oxide (silica). The silicon-based material may also contain other metal elements (e.g., alkaline earth metals) or their oxides. The negative electrode active material layer 22b may also contain additives other than the negative electrode active material. Examples of such additives include binders and thickeners. Specific examples of binders include rubber-based binders such as styrene butadiene rubber (SBR). Specific examples of thickeners include carboxymethyl cellulose (CMC). The content of the negative electrode active material is generally 30% by mass or more, typically 50% by mass or more, when the total solid content of the negative electrode active material layer 22b is taken as 100% by mass. The negative electrode active material may account for 80% by mass or more, or 90% by mass or more, of the negative electrode active material layer 22b.

[0025] The separators 31 and 32 are, for example, porous resin sheets that have the required heat resistance and allow electrolytes to pass through. Various separators 31 and 32 have been proposed, and no particular limitation is imposed on them. A suitable example of the separators 31 and 32 is a separator including a porous base material layer made of a resin such as a polyolefin resin (e.g., polyethylene (PE) or polypropylene (PP)). A coating layer may be formed on one or both sides of the porous base material layer. The coating layer may include a porous surface layer or an adhesive layer containing an insulating inorganic material. The porous surface layer has excellent heat resistance, thereby preventing the separators 31 and 32 from shrinking or breaking due to temperature rise. Examples of inorganic materials for the porous surface layer include ceramic particles such as alumina, boehmite, aluminum hydroxide, and titania. The porous surface layer also contains a binder that binds the ceramic particles together. Resin binders such as polyvinylidene fluoride (PVdF) and acrylic resins can be used as the binder. The two separators 31 and 32 used in this embodiment may be made of the same material or different materials.

[0026] 2, the negative electrode active material layer 22b of the negative electrode plate 22 may cover the positive electrode active material layer 21b of the positive electrode plate 21 with separators 31 and 32 interposed therebetween. The separators 31 and 32 may further cover the positive electrode active material layer 21b of the positive electrode plate 21 and the negative electrode active material layer 22b of the negative electrode plate 22. Although not shown, the lengths of the positive electrode plate 21, the negative electrode plate 22, and the separators 31 and 32 may be in the order of separators 31 and 32 > negative electrode plate 22 > positive electrode plate 21. The width La of the positive electrode active material layer 21b, the width Ln of the negative electrode active material layer 22b, and the width Ls of the separators 31 and 32 may be in the order of Ls > Ln > La. The area where the positive electrode plate 21 and the negative electrode plate 22 overlap, where the positive electrode active material layer 21b is formed, is covered with the negative electrode active material layer 22b. In addition, the area where the negative electrode active material layer 22b overlaps the positive electrode plate 21, where the positive electrode active material layer 21b does not face, is covered with a protective layer 22c.

[0027] As shown in FIG. 2 , the tab 21d of the positive electrode plate 21 protrudes from one side of the separators 31 and 32 in the width direction. The positive electrode plate 21 has a plurality of tabs 21d provided at a predetermined pitch in the longitudinal direction. The tab 22d of the negative electrode plate 22 protrudes from the separators 31 and 32 on the opposite side in the width direction. The negative electrode plate 22 has a plurality of tabs 22d provided at a predetermined pitch in the longitudinal direction. The plurality of tabs 21d of the positive electrode plate 21 and the plurality of tabs 22d of the negative electrode plate 22 are provided at a predetermined pitch so that they are in approximately the same positions after being wound around the wound electrode body 20. Note that the tabs 21d of the positive electrode plate 21 and the tabs 22d of the negative electrode plate 22 may be formed at the stage when the positive electrode plate 21 and the negative electrode plate 22 are prepared, respectively. The tab 21d of the positive electrode plate 21 and the tab 22d of the negative electrode plate 22 may be cut out after the wound electrode body 20 is wound.

[0028] As shown in FIGS. 1 and 2, the wound electrode body 20 is housed in the exterior body 11 through the opening 11f to which the sealing plate 12 is attached. Therefore, the wound electrode body 20 has a flat shape that matches the shape of the opening 11f. When manufacturing the wound electrode body 20, the electrode body may be wound around a flat shaft. Alternatively, the wound electrode body 20 may be wound around a cylindrical shaft and then press-molded into a flat shape. The wound electrode body 20 and the exterior body 11 are electrically insulated from each other by a resin insulating sheet 90 disposed between the wound electrode body 20 and the exterior body 11. The insulating sheet 90 is a resin sheet that is folded into a box shape to encase the wound electrode body 20. Note that FIG. 1 illustrates the insulating sheet 90 with the wide front surface removed.

[0029] Winding machine 100 Next, the winding machine 100 will be described. Figures 3 to 6 are schematic diagrams of the winding machine 100. The winding machine 100 is an example of a winding machine that embodies the battery manufacturing method disclosed herein. Figures 3 to 6 each show a turret 120 portion of the winding machine 100 as viewed from a distance from the rotation axis C1 of the turret 120.

[0030] Fig. 3 shows a standby state when the winding machine 100 starts winding a new positive electrode plate 21 and a new negative electrode plate 22. Fig. 4 shows a state in which a new positive electrode plate 21 and a new negative electrode plate 22 are being wound on the winding machine 100. Fig. 5 shows a state in which the winding core 140 around which the positive electrode plate 21 and the new negative electrode plate 22 are wound moves from the first position P1 to the second position P2. Fig. 6 shows a state in which the winding core 140 around which the positive electrode plate 21 and the new negative electrode plate 22 are wound moves to the second position P2, a new winding core moves to the first position P1, and the separators 31 and 32 are cut.

[0031] 3, the winding machine 100 is a device for winding the positive electrode plate 21, the negative electrode plate 22, and the separators 31 and 32. The turret 120 is provided with a plurality of winding cores 140(1) to (3) around which the positive electrode plate 21, the negative electrode plate 22, and the separators 31 and 32 are wound.

[0032] As shown in FIG. 3, the winding machine 100 includes movement paths k1 to k4, a turret 120, multiple winding cores 140(1) to (3), a cutter 151, a presser roller 152, multiple fixed rollers 161 to 163, multiple movable rollers 171 to 174, a first chuck 181, a second chuck 182, an index unit 185 provided on the turret 120, index rollers 186 to 188 provided on the index unit 185, a winding stop device 190, and a control device 200. The positive electrode plate 21, the negative electrode plate 22, and the separators 31 and 32 are each prepared in a wound state around a reel (not shown). Each component of the winding machine 100 has a required actuator, as appropriate. The control device 200 is configured to control each component of the winding machine 100 so that required operations are performed at predetermined timing according to a preset program. The control device 200 may be embodied by a computer such as a microcontroller, for example.

[0033] <Travel route k1~k4> Movement path k1 is a path along which the positive electrode plate 21 is fed from the reel toward the turret 120. Movement path k2 is a path along which the negative electrode plate 22 is fed from the reel toward the turret 120. Movement path k3 is a path along which the first separator 31 is fed from the reel toward the turret 120. Movement path k4 is a path along which the second separator 32 is fed from the reel toward the turret 120. The positive electrode plate 21, the negative electrode plate 22, the first separator 31, and the second separator 32 are each strip-shaped and are fed along predetermined movement paths k1 to k4. Movement path k1 of the positive electrode plate 21 merges with movement path k3 of the first separator 31 just before reaching the winding core 140 arranged at the first position P1. The movement path k1 of the negative electrode plate 22 merges with the movement path k4 of the second separator 32 just before reaching the winding core 140 arranged at the first position P1. On the movement paths k1 to k4, dancer roll mechanisms for removing slack from the positive electrode plate 21, negative electrode plate 22, first separator 31, and second separator 32 being fed, tensioners for adjusting tension, and the like are appropriately arranged.

[0034] <Turret 120> The turret 120 is a rotating disk with a rotation axis set at the center C1. Multiple (three in this embodiment) winding cores 140 are arranged on the turret 120. Each of the multiple winding cores 140 has a substantially cylindrical shaft that can rotate independently. In this embodiment, the shafts of the multiple winding cores 140 are arranged parallel to the central axis of the turret 120. The turret 120 is provided with three winding cores 140: a first winding core 140(1), a second winding core 140(2), and a third winding core 140(3). The first winding core 140(1), the second winding core 140(2), and the third winding core 140(3) are arranged at equal intervals in the circumferential direction around the central axis of the turret 120. The first to third winding cores 140(1) to 140(3) are all winding cores having the same configuration. Although not shown, the turret 120 is provided with a required actuator (for example, a servo motor) and rotates at an appropriate angle at an appropriate timing.

[0035] A first position P1, a second position P2, and a third position P3 are set in advance around the axis of the center C1 of the turret 120. In FIG. 3, the first winding core 140(1) is located at the first position P1, the third winding core 140(3) is located at the second position P2, and the second winding core 140(2) is located at the third position P3. The positions of the first winding core to the third winding core 140(1) to (3) are not fixed to the positions shown in FIG. 3. In this embodiment, the turret 120 rotates counterclockwise. The first winding core to the third winding core 140(1) to (3) also rotate counterclockwise. As the turret 120 rotates, the first winding core to the third winding core 140(1) to (3) move sequentially between the first position P1, the second position P2, and the third position P3. Although not shown in the figures, the first to third winding cores 140(1) to (3) are equipped with the required actuators (for example, servo motors) and rotate at appropriate timing and appropriate speeds. Here, the first to third winding cores 140(1) to (3) are referred to as winding cores 140 when no particular distinction is made. Furthermore, when a distinction is made between the first to third winding cores 140(1) to (3), they are appropriately distinguished as winding core 140(1), winding core 140(2), and winding core 140(3).

[0036] <Core 140> FIG. 7 is a cross-sectional view schematically illustrating the winding core 140 disposed at the first position P1. The winding core 140 is a substantially cylindrical member. FIG. 7 illustrates the winding core 140 as viewed from the axial direction, showing the state in which the first separator 31 and the second separator 32 are being wound around the winding core 140 disposed at the first position P1, as shown in FIG. 3. As shown in FIG. 4, the winding core 140 has a function of holding the separators 31 and 32 wound around its circumferential surface. In this embodiment, the winding core 140 has a suction hole 141, a suction path 142, and a groove 143. The suction hole 141 is a hole for attracting the separators 31 and 32 wound around its circumferential surface. The suction path 142 is a flow path formed inside the winding core 140 and communicating with the suction hole 141. The suction path 142 is a flow path for creating a negative pressure in the suction hole 141. The suction path 142 may be configured to be connected to, for example, an externally installed vacuum line (not shown) as appropriate to create a negative pressure. The groove 143 is formed as a receiving portion onto which the blade of the cutter 151 is lowered when the separators 31, 32 are cut. In this embodiment, the groove 143 is formed on the outer peripheral surface of the winding core 140 along the axial direction of the winding core 140. Note that in this embodiment, the winding core 140 has a substantially cylindrical shape, but a flat winding core may be used when winding into a flat shape. Furthermore, the winding core may be divided along the radial direction, and the diameter of the winding core may be variable.

[0037] Cutter 151 The cutter 151 is a cutter that cuts the separators 31, 32. It is configured so that the blade 151a is pressed against the separators 31, 32 held by the winding core 140 arranged at the first position P1. In this embodiment, the cutter 151 is pushed out along a guide to a predetermined position so that the blade is pressed against the separators 31, 32 held by the winding core 140, and is retracted from that position. Although not shown, the cutter 151 is operated by an actuator (for example, a cylinder mechanism) so as to operate at an appropriate timing. The blade 151a may be, for example, a serrated blade (a saw-like blade).

[0038] <Pressure roller 152> The pressure roller 152 presses the separators 31, 32 against the winding core 140 positioned at the first position P1. The pressure roller 152 presses the separators 31, 32 against the winding core 140 positioned at the first position P1 while winding them. The pressure roller 152 functions as a presser jig that presses the separators 31, 32 against the winding core 140 positioned at the first position P1. In this embodiment, as shown in FIG. 7 , the pressure roller 152 has multiple protrusions 152a formed on its outer circumferential surface. As a result, the roller 152 with the protrusions 152a presses the two separators 31, 32 against the winding core 140, and the protrusions 152a locally concentrate force, firmly pressing the separators 31, 32 together. This more effectively presses the separators 31, 32 together. The pressure roller 152 may be, for example, substantially cylindrical, and the outer circumferential surface may be knurled. The pressure roller 152 may be configured to press the separators 31, 32 against the winding core 140 positioned at the first position P1 with an appropriate pressure, for example, by a mechanism incorporating a spring or the like. Although not shown, the pressure roller 152 is moved by a guide and an actuator to a position where it presses against the separators 31, 32 wound around the winding core 140 positioned at the first position P1 (see FIG. 3), and a position where it is separated from the winding core 140 (see FIG. 5). The pressure roller 152 may be provided as a single cylindrical roller in the width direction of the winding core 140, or may be made up of multiple rollers arranged intermittently in the width direction of the winding core 140.

[0039] <Fixed roller 161, movable roller 171> The fixed roller 161 is provided at a position where the movement path k3 of the first separator 31 and the movement path k1 of the positive electrode plate 21 converge. The movable roller 171 is a roller that presses the first separator 31 against the fixed roller 161 to sandwich the first separator 31. The movable roller 171 moves in a predetermined direction by a guide and an actuator. The movement of the movable roller 171 is controlled by the control device 200. The movable roller 171 is configured to move between a position where it presses the first separator 31 against the fixed roller 161 and a position where it moves away from the fixed roller 161. When sandwiching the first separator 31, the movable roller 171 may be configured to sandwich the first separator 31 with a predetermined force using the action of a spring or the like. By being sandwiched with an appropriate force between the fixed roller 161 and the movable roller 171, the first separator 31 is fed without slack toward the winding core 140 placed at the first position P1.

[0040] <Fixed roller 162, movable roller 172> The fixed roller 162 is located at a position where the movement path k4 of the second separator 32 and the movement path k2 of the negative electrode plate 22 converge. The movable roller 172 presses the second separator 32 against the fixed roller 162 to sandwich the second separator 32. The movable roller 172 moves in a predetermined direction using a guide and an actuator. The movement of the movable roller 172 is controlled by the control device 200. The movable roller 172 is configured to move between a position where it presses the second separator 32 against the fixed roller 162 and a position where it moves away from the fixed roller 162. The movable roller 172 may be configured to sandwich the second separator 32 with a predetermined force using the action of a spring or the like when sandwiching the second separator 32. The second separator 32 is sandwiched between the fixed roller 162 and the movable roller 172 with an appropriate force, so that it is fed tightly toward the winding core 140 located at the first position P1.

[0041] <Fixed Roller 163> The fixed roller 163 is disposed at a predetermined position on the movement path k3 of the first separator 31, and is a roller for determining the movement path k3 of the first separator 31.

[0042] <1st Zipper 181> As shown in FIG. 3 , the first chuck 181 is disposed before the pair of rollers 161, 171 that sandwich the first separator 31 on the movement path k1 along which the positive electrode plate 21 is fed. The first chuck 181 is a member that grips the positive electrode plate 21. In this embodiment, the first chuck 181 includes a pair of gripping members. Although not shown, the first chuck 181 includes a cutter for cutting the positive electrode plate 21. Although not shown, the first chuck 181 operates at an appropriate timing using a guide and an actuator (for example, a cylinder mechanism). The operation of the first chuck 181 is configured to be controlled by the control device 200.

[0043] In the state shown in FIG. 3 , the first separator 31 is held by the winding core 140 disposed at the first position P1 and extends along the movement path k3 while being sandwiched between the pair of rollers 161, 171. The first chuck 181 grips the positive electrode plate 21 just before the pair of rollers 161, 171. When the positive electrode plate 21 is wound onto the winding core 140 disposed at the first position P1, as shown in FIG. 4 , the first chuck 181 inserts the held positive electrode plate 21 between the pair of rollers 161, 171 and releases the positive electrode plate 21. As a result, the positive electrode plate 21 is pulled into the pair of rollers 161, 171 together with the first separator 31 and wound onto the winding core 140 disposed at the first position P1. When the positive electrode plate 21 has been fed out by a predetermined length, winding onto the winding core 140 stops. The positive electrode plate 21 is gripped by the first chuck 181 and cut between the first chuck 181 and the pair of rollers 161, 171. The first chuck 181 is configured to move appropriately between a predetermined position where it grips the positive electrode plate 21 and a predetermined position where it inserts the positive electrode plate 21 between the pair of rollers 161, 171.

[0044] <Second zipper 182> As shown in FIG. 3 , the second chuck 182 is disposed on the movement path k2 along which the negative electrode plate 22 is fed, before the pair of rollers 162, 172 that sandwich the second separator 32. The second chuck 182 is a member that grips the negative electrode plate 22. In this embodiment, the second chuck 182 includes a pair of gripping members. Although not shown, the second chuck 182 includes a cutter for cutting the negative electrode plate 22. Although not shown, the second chuck 182 is operated at an appropriate timing by a guide and an actuator (e.g., a cylinder mechanism). The operation of the second chuck 182 is configured to be controlled by the control device 200.

[0045] In the state shown in FIG. 3 , the second separator 32 is held by the winding core 140 disposed at the first position P1 and extends along the movement path k4 while being sandwiched between the pair of rollers 162, 172. The second chuck 182 grips the negative electrode plate 22 just before the pair of rollers 162, 172. When the negative electrode plate 22 is wound onto the winding core 140 disposed at the first position P1, as shown in FIG. 4 , the second chuck 182 inserts the held negative electrode plate 22 between the pair of rollers 162, 172 and releases the negative electrode plate 22. As a result, the negative electrode plate 22 is pulled into the pair of rollers 162, 172 together with the second separator 32 and wound onto the winding core 140 disposed at the first position P1. As described above, when the positive electrode plate 21 is fed out by a predetermined length, the winding onto the winding core 140 stops. In other words, when a predetermined length of the negative electrode plate 22 has been fed out, the winding of the winding core 140 stops. The negative electrode plate 22 is gripped by the second chuck 182 and cut between the second chuck 182 and the pair of rollers 162, 172. The second chuck 182 is configured to move appropriately between a predetermined position where it grips the negative electrode plate 22 and a predetermined position where it inserts the negative electrode plate 22 between the pair of rollers 162, 172.

[0046] The positive electrode plate 21 and the negative electrode plate 22 may be inserted between a pair of rollers 161, 171 and a pair of rollers 162, 172, respectively, after the first separator 31 and the second separator 32 have been wound around the outer peripheral surface of the winding core 140 approximately once.

[0047] <Movable Roller 173> As shown in FIG. 6 , the movable roller 173 is a roller that presses the first separator 31 and the second separator 32 against the winding core 140 that is positioned at the first position P1 when the first separator 31 and the second separator 32 are cut. The movable roller 173 moves in a predetermined direction by a guide and an actuator. The movement of the movable roller 173 is controlled by the control device 200. As shown in FIG. 6 , the movable roller 173 is positioned at a position that presses the first separator 31 and the second separator 32 against the winding core 140 that is positioned at the first position P1 when the first separator 31 and the second separator 32 are cut. At other times, the movable roller 173 moves to a position away from the winding core 140 that is positioned at the first position P1, as shown in FIG. 3 . The movable roller 173 is preferably configured to sandwich the first separator 31 with a predetermined force by the action of a spring or the like when pressing the first separator 31 and the second separator 32 against the core 140.

[0048] As shown in FIG. 6, the cutter 151 is pressed against the winding core 140, which is positioned at the first position P1, thereby cutting the first separator 31 and the second separator 32. In this embodiment, as shown in FIG. 7, a groove 143 is formed in the outer peripheral surface of the winding core 140. When the cutter 151 is pressed against the winding core 140, the groove 143 formed in the outer peripheral surface of the winding core 140 is directed toward the position where the cutter 151 is pressed. With the groove 143 facing the cutter 151, the first separator 31 and the second separator 32 are pressed against the winding core 140 by the movable roller 173. As a result, the first separator 31 and the second separator 32 are adsorbed to the winding core 140. Furthermore, in this state, the cutter 151 is pressed against the first separator 31 and the second separator 32 held by the winding core 140. This cuts the first separator 31 and the second separator 32. Furthermore, because the blade of the cutter 151 fits into the groove 143 of the winding core 140, the first separator 31 and the second separator 32 are cut more reliably and cleanly, the winding core 140 is less likely to be scratched, and foreign matter is less likely to be generated.

[0049] <Movable roller 174> As shown in Fig. 6, the movable roller 174 is a roller for applying tension to the first separator 31 and the second separator 32 when they are cut. The movable roller 174 is moved in a predetermined direction by a guide and an actuator. The movement of the movable roller 174 is controlled by the control device 200.

[0050] For example, as shown in FIG. 4, the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are wound in stacked order by the winding core 140(1) arranged at the first position P1. The winding core 140(1) on which the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 have been wound moves from the first position P1 to the second position P2 as shown in FIG. 5. At this time, another winding core 140(2) moves to the first position P1. Then, as shown in FIG. 6, the first separator 31 and the second separator 32 are attracted to the winding core 140(2) newly arranged at the first position P1, and the first separator 31 and the second separator 32 are held on the outer peripheral surface of the winding core 140(2). At this time, the first separator 31 and the second separator 32 wound around the winding core 140(1) arranged at the second position P2 are held in a connected state on the outer peripheral surface of the winding core 140(2) arranged at the first position P1.

[0051] The movable roller 174 is pushed out toward the first separator 31 and the second separator 32 at an appropriate timing when the winding core 140(1) moves from the first position P1 to the second position P2, and is pressed against the first separator 31 and the second separator 32 as shown in Fig. 6. The movable roller 174 feeds out the first separator 31 and the second separator 32 without slack when the winding core 140(1) moves from the first position P1 to the second position P2. As shown in Figs. 3 to 5, the movable roller 174 is retracted to a position away from the turret 120 except at this timing.

[0052] <Index Unit 185> The index unit 185 is provided at the center of the turret 120. As described above, the three winding cores 140(1) to (3) are evenly spaced around the turret 120. The index unit 185 has a substantially equilateral triangular base that rotates together with the turret 120. Index rollers 186 to 188 are disposed at the vertices of the base, and the index rollers 186 to 188 are disposed between the three winding cores 140(1) to (3), respectively.

[0053] When the winding core 140(1) around which the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are wound moves from the first position P1 to the second position P2, as shown in FIG. 6 , the index roller 186, of the index rollers 186-188, which is arranged between the first position P1 and the second position P2, presses against the first separator 31 and the second separator 32 from their inner diameter sides. The index roller 186 and the movable roller 174 feed the first separator 31 and the second separator 32 without slack between the first position P1 and the second position P2. At the timing shown in FIG. 6 , the index roller 186 presses against the first separator 31 and the second separator 32 from their inner diameter sides, but the index unit 185 rotates together with the rotation of the turret 120. Therefore, the index rollers 186 to 188 of the index unit 185 function in sequence as rollers that press against the first separator 31 and the second separator 32 from the inner diameter side when the winding core 140, on which the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are wound, moves from the first position P1 to the second position P2.

[0054] <Winding device 190> For example, as shown in FIG. 6, the winding core 140(1) on which the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 have been wound moves from the first position P1 to a second position P2 away from the first position P1. Then, after the separators 31 and 32 are cut, the cut separators 31 and 32 are wound up to the cut ends. The winding stop device 190 is disposed at the second position P2. The winding stop device 190 includes a pressure roller 191 and a tape application device 192. The pressure roller 191 is pressed against the outermost second separator 32 wound around the winding core 140(1) when the winding core 140, which has moved to the second position P2, winds up the cut positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 up to the cut ends. As a result, the cut positive electrode plate 21, first separator 31, negative electrode plate 22, and second separator 32 are each wound up without loosening. The tape application device 192 is a device that applies tape to secure the cut end of the outermost second separator 32 or the first separator 31. This winding stop process may be performed, for example, in parallel with the process of winding the first separator 31, positive electrode plate 21, second separator 32, and negative electrode plate 22 around the winding core 140(2) newly arranged at the first position P1.

[0055] Furthermore, in this embodiment, for example, as shown in FIG. 6 , the winding machine 100 performs a winding stop process and winds the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 onto the winding core 140(2) positioned at the first position P1, and then the turret 120 rotates. The winding core 140(1) on which the winding stop process has been performed moves to the third position P3, the winding core 140(2) moves to the second position P2, and another winding core 140(3) is positioned at the first position P1. At this time, the first separator 31 and the second separator 32 wound onto the winding core 140(2) positioned at the second position P2 are held connected to each other on the outer peripheral surface of the winding core 140(3) positioned at the first position P1. Then, after the separators 31 and 32 are cut, the winding stop process is performed on the winding core 140(2) at the second position P2. At the first position P1, the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are newly wound around the winding core 140(3). At the third position P3, the wound body 20a is removed from the winding core 140(1) (see FIG. 3). After being removed, the wound body 20a is pressed flat and can be handled as the wound electrode body 20. In this manner, the winding cores 140(1) to (3) provided on the turret 120 move sequentially between the first position P1 and the third position P3. The positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are then continuously wound around the winding cores 140(1) to (3) in order.

[0056] However, when manufacturing a battery 2 using such a winding machine 100, the inventors have conducted research and found that there is still room for improvement in the adsorption of the separators 31, 32 to the winding core 140 and the cutting of the separators 31, 32. The inventors hope to improve production efficiency by using the winding core 140 described below.

[0057] FIG. 8 is a cross-sectional view of the winding core 140. FIG. 9 is a schematic diagram showing the outer peripheral surface of the winding core 140. FIG. 9 shows a virtual development of the winding core 140 along the circumferential direction so that the entire outer peripheral surface of the winding core 140 is shown in a plane. In this embodiment, as shown in FIG. 8, the winding core 140 includes a first constituent portion 140a and a second constituent portion 140b. The first constituent portion 140a and the second constituent portion 140b have outer peripheral surfaces 140a1 and 140b1, respectively, around which the separators 31 and 32 (see FIG. 7) are wound. The first constituent portion 140a has a shape in which two approximately semi-cylindrical members of different diameters are connected with their inner peripheral surfaces facing each other. The second constituent portion 140b has a substantially semi-cylindrical shape.

[0058] First component 140a has a flat surface 140a2 and a convex surface 140a3 on the surface facing second component 140b. Flat surfaces 140a2 are formed on both sides in the width direction on the surface facing second component 140b. Convex surfaces 140a3 protrude from flat surface 140a2 toward second component 140b. Convex surfaces 140a3 are formed along the axial direction of winding core 140 and are approximately semi-cylindrical.

[0059] The second component 140b has a flat surface 140b2 and an inner circumferential surface 140b3 on the surface facing the first component 140a. The flat surface 140b2 faces the flat surface 140a2 of the first component 140a. The flat surfaces 140a2 and 140b2 are parallel to each other. The diameter of the inner circumferential surface 140b3 is larger than the outer diameter of the convex surface 140a3 of the first component 140a so that the convex surface 140a3 can be accommodated therein.

[0060] A gap 140c is provided between the first component 140a and the second component 140b. That is, the gap 140c is provided between the flat surfaces 140a2 and 140b2 and between the convex surface 140a3 and the inner peripheral surface 140b3. The first component 140a and the second component 140b constituting the winding core 140 are configured to be openable and closable. FIG. 8 shows the winding core 140 in an open state, in which the separators 31 and 32 (see FIG. 7) are wound around the outer peripheral surfaces 140a1 and 140b1. In the closed state, the distance between the flat surfaces 140a2 and 140b2 is narrowed. In this embodiment, when the winding core 140 is in the closed state, the flat surfaces 140a2 and 140b2 are configured to abut against each other. The opening and closing mechanism of the first component 140a and the second component 140b is not particularly limited. The first component part 140a and the second component part 140b may be opened and closed by, for example, a cylinder mechanism or the like.

[0061] The winding core 140 is formed with a plurality of suction holes 141 for suctioning the first separator 31. The suction holes 141 are holes for suctioning the separators 31, 32 wound around the outer peripheral surface. As shown in FIG. 9 , the suction holes 141 are provided at a predetermined pitch along the axial and circumferential directions of the winding core 140. Furthermore, from the viewpoint of reliably suctioning the separators 31, 32, it is preferable that the suction holes 141 be provided in multiple rows along the axial direction of the winding core 140. The shape of the suction holes 141 is not particularly limited and may be, for example, circular or polygonal. From the viewpoint of ease of processing, it is preferable that the shape of the suction holes 141 is circular.

[0062] There are no particular limitations on the size or spacing of the suction holes 141. The suction holes 141 are preferably provided at a pitch of 10 mm or less, and more preferably at a pitch of 5 mm or less. The total opening area of ​​the suction holes 141 is, for example, 200 to 300 mm. 2 It is preferable that the thickness is about 250 to 280 mm. 2Furthermore, when the area of ​​the range of winding core 140 that is in contact with first separator 31 is A and the total area of ​​the openings of suction holes 141 is B, for example, B / A is preferably 5% or less, and more preferably 1% or less.

[0063] As shown in FIG. 8, the winding core 140 has a flow path 142 that communicates with a suction hole 141. The flow path 142 is formed inside the winding core 140. When a negative pressure is created inside the flow path 142, the suction hole 141 can suck the separators 31 and 32 onto the winding core 140. The flow path 142 may be configured to be connected to an external vacuum line (not shown), for example, so that a negative pressure is created. In this embodiment, the suction hole 141 and the flow path 142 are provided in the first component part 140a. The flow path 142 is formed inside the first component part 140a, which is substantially semi-cylindrical and has different inner diameters, and the convex surface 140a3.

[0064] The flow path 142 may be configured so that the pressure inside the flow path 142 can be made positive. For example, an air supply line (not shown) that can be switched to a vacuum line may be connected to the outside of the flow path 142. By making the pressure inside the flow path 142 positive, the separators 31 and 32 can be detached from the outer peripheral surface of the winding core. By switching the pressure inside the flow path 142 between negative and positive pressure, the separators 31 and 32 can be more easily attached to and detached from the outer peripheral surfaces 140a1 and 140b1 of the winding core 140.

[0065] In this embodiment, there is one flow path 142, but this is not limiting, and multiple flow paths may be formed inside the winding core 140. The multiple flow paths may each be connected to a different vacuum line and lead to multiple different suction holes (suction hole groups). This makes it possible to control the suction timing for each suction hole group. With this configuration, even if there is a suction hole group to which the separators 31, 32 are not adsorbed, it is possible to prevent a decrease in the suction force of the suction hole group that is adsorbing the separators 31, 32.

[0066] The multiple flow paths may be divided into a flow path connected to a vacuum line for adsorbing the separators 31 and 32 and a flow path connected to an air supply line for detaching the separators 31 and 32. An air release valve (not shown) may be provided outside the flow path 142 so that the flow path 142 can be opened to atmospheric pressure.

[0067] In this embodiment, as described above, the winding core 140 is divided into a first component part 140a and a second component part 140b. The suction holes 141, the flow paths 142, and the grooves 143 are provided in the first component part 140a. The separators 31 and 32 are configured to be attracted only to the first component part 140a.

[0068] The winding core 140 has a groove 143. The groove 143 is formed as a receiving portion onto which the blade of a cutter 151 (see FIG. 7) is lowered when the separators 31 and 32 are cut. The groove 143 is formed on the outer peripheral surface of the winding core 140 along the axial direction of the winding core 140.

[0069] 9, when the outer periphery of the winding core 140 is divided into four equal parts (R1 to R4) starting from a position (i.e., groove 143) facing the winding start end of the cut first separator 31, the opening area of ​​the suction holes 141 is 80% or more in the first region R1. In other words, when the total opening area of ​​the suction holes 141 formed in the winding core 140 is 100%, the total opening area of ​​the suction holes 141 formed in the first region R1 of the winding core 140 is 80% or more. In this specification, the region on the outer periphery of the winding core 140 that starts from the groove 143 and extends 90 degrees in the direction in which the separators 31 and 32 are wound (also referred to as the winding direction) is referred to as the first region R1. The region from the end of the first region R1 to an angle of 90 degrees in the winding direction is called the second region R2, the region from the end of the second region R2 to an angle of 90 degrees in the winding direction is called the third region R3, and the region from the end of the third region R3 to an angle of 90 degrees in the winding direction is called the fourth region R4. The first region R1 is the region where the cut separators 31 and 32 begin to be wound.

[0070] The suction holes 141 are preferably formed in the first region R1 in an opening area ratio of 90% or more, more preferably 95% or more. Most preferably, 100% of the suction holes 141 are formed in the first region R1. Furthermore, when the first region R1 is divided into two equal circumferential portions, with the region closer to the groove 143 designated as the 1-1 region R11 and the region farther from the groove 143 designated as the 1-2 region R12, it is preferable that the suction holes 141 are formed in the 1-1 region R11 in an opening area ratio of 70% or more. In this manner, it is preferable that substantially all of the suction holes 141 are disposed near the winding start ends of the separators 31 and 32 (i.e., near the portions where the separators 31 and 32 are cut). However, the suction holes 141 may also be formed in regions other than the first region R1, such as the second region R2 and the third region R3. In this embodiment, the width W of the suction hole formation region where the plurality of suction holes 141 are formed is smaller than the width of the first separator 31. In other words, the first separator 31 has a width in the axial direction of the winding core 140 that is sufficient to cover all of the suction holes 141.

[0071] The size of the winding core 140 is not particularly limited, but to facilitate the production of large wound electrode bodies, the diameter is preferably 30 mm or more, and more preferably 40 mm or more. When the winding core has a flat shape, the major axis is preferably 30 mm or more, and more preferably 40 mm or more.

[0072] The winding machine 100 equipped with the winding core 140 described above embodies the following steps A to C in the method for manufacturing a battery 2 equipped with a wound electrode body 20 in which a first separator 31, a negative electrode plate 22, a second separator 32, and a positive electrode plate 21 are wound. Step A: The first separator 31 is attached to the winding core 140 by suction. Step B: The first separator 31 is wound around the winding core 140. Step C: The first separator 31 and the second separator 32 are cut.

[0073] In step A, the first separator 31 is adsorbed onto the winding core 140 arranged at the first position P1. As described above, the separators 31 and 32 are porous resin sheets. Therefore, the suction by the suction holes 141 passes through the holes in the first separator 31 and also adsorbs the second separator 32. The second separator 32 is then adsorbed onto the first separator 31. In other words, the first separator 31 and the second separator 32 are adsorbed onto the winding core 140 in a stacked state.

[0074] In step B, the first separator 31 is wound around the winding core 140 together with the second separator 32. In this embodiment, the first separator 31 and the second separator 32 are wound around the winding core 140 for approximately one turn. 4, the positive electrode plate 21 and the negative electrode plate 22 are fed out from the moving path k1 and the moving path k2. Next, the second separator 32, the negative electrode plate 22, the first separator 31, and the positive electrode plate 21 are stacked in this order and wound up.

[0075] In step C, the first separator 31 and the second separator 32 wound around the winding core 140(1) away from the first position P1 in step B are cut on or near the other winding core 140(2) while being stacked and held on the outer peripheral surface of the other winding core 140(2) placed at the first position P1 in step B (see FIG. 6).

[0076] In the manufacturing method of the battery 2, as shown in FIG. 9, a winding core 140 having a plurality of suction holes 141 formed therein is used as the winding core for adsorbing the separators 31, 32 (see FIG. 7). In the winding core 140, 80% or more of the suction holes 141, in terms of opening area ratio, are formed in the first region R1. The first region R1 is a region facing the portion where the first separator 31 begins to wind. Because the suction holes 141 are concentrated in the portion where the first separator 31 begins to wind, most of the suction holes 141 are covered by the first separator 31 even in the early stages of winding. As a result, air is less likely to leak through the suction holes 141, which prevents a decrease in suction force and improves production efficiency.

[0077] From this perspective, when the first separator 31 and the second separator 32 are cut in step C, the length by which they are wound circumferentially around the winding core 140 arranged at the first position P1 may be set to, for example, a length that allows the first separator 31 and the second separator 32 to be stably wound around the winding core 140. For example, according to the inventor's findings, as shown in FIG. 6, the first separator 31 and the second separator 32 may be cut in a state in which they are wound circumferentially at an angle of 15 to 180 degrees around the winding core (second winding core 140(2)) other than the winding core (first winding core 140(1)) around which the first separator 31 was wound in step B. From the perspective of stable winding, it is desirable that the first separator 31 and the second separator 32 be wound around the winding core 140 for a sufficient length. Preferably, they are cut in a state in which they are wound circumferentially at an angle of 30 degrees or more around the winding core 140(2). Furthermore, from the viewpoint of ease of handling, the first separator 31 and the second separator 32 are preferably cut while wound around the winding core 140 in an angle of, for example, 30 degrees or more, more preferably 45 degrees or more. Furthermore, the first separator 31 and the second separator 32 are preferably cut while wound around the winding core 140 in an angle of 150 degrees or less, more preferably 120 degrees or less. Here, the angle may be defined as an angle centered on the winding center of the winding core 140 when viewed from a distance in the axial direction. The area is a sector arc centered on the winding center and is an area that appears on the outer circumferential surface of the winding core 140. Furthermore, if the area includes a groove 143, the area around which the first separator 31 and the second separator 32 are wound may be set on the outer circumferential surface of the winding core 140 excluding the groove 143.

[0078] In this way, it is preferable that the length by which the first separator 31 and the second separator 32 are wound circumferentially around the winding core 140(2) when they are cut in step C is appropriately set. This allows winding to begin in a stable state around the winding core 140(2) placed at the first position P1 in step B. Note that a groove 143 in the winding core 140 may be arranged in the area where the first separator 31 and the second separator 32 are wound around the winding core 140. In this case, in the area where the first separator 31 and the second separator 32 are wound around the winding core 140, there may be a portion where the first separator 31 and the second separator 32 are not in contact with the winding core 140. Furthermore, the longer the widths of the first separator 31 and the second separator 32, the greater the contact area with the winding core 140, resulting in stable winding. From this viewpoint, for example, the width of the first separator 31 and the second separator 32 is preferably 20 cm or more, and more preferably 25 cm or more.

[0079] In step C, the first separator 31 may be cut while in contact with a winding core (second winding core 140(2)) other than the winding core (first winding core 140(1)) around which the first separator 31 was wound in step B, upstream and downstream of the cutting position of the first separator 31 in the movement path k3 of the first separator 31. This allows the first separator 31 to be cut stably. Furthermore, the winding start position can be stabilized when winding the first separator 31 around the second winding core 140(2). 7, during cutting, the upstream side is preferably pressed by a jig such as a press roller 152. The downstream side is preferably held by suction through suction holes 141 or the like. The downstream side may be pressed by a roller or the like in addition to being held by suction through suction holes 141 or the like. This can make cutting of first separator 31 more stable.

[0080] In step C, when cutting the first separator 31 and the second separator 32, the first separator 31 and the second separator 32 are cut. Alternatively, the first separator 31 may be pressed against a winding core (second winding core 140(2)) other than the winding core (first winding core 140(1)) on which the first separator 31 has been wound in step B by a pressing jig (pressing roller 152 in the embodiment shown in FIG. 3). This more stably holds the first separator 31 and the second separator 32 against the winding core 140. Furthermore, when adsorbing the first separator 31 to the winding core 140, the first separator 31 can be adsorbed in a more stable state. In this case, the pressing jig may be a roller having multiple protrusions 152a formed on its outer circumferential surface, like the above-described pressing roller 152. By using a roller having multiple protrusions 152a formed on its outer circumferential surface, the first separator 31 and the second separator 32 are pressed against the winding core 140 with the multiple protrusions 152a in contact with them, so the first separator 31 can be adsorbed to the winding core 140 in a more stable state.

[0081] In the embodiment described above, a groove 143 is formed along the axial direction at the position where the first separator 31 and the second separator 32 are to be cut on a winding core (first winding core 140(1) in FIG. 3) other than the winding core on which the first separator 31 is wound in step B (second winding core 140(2) in FIG. 3). The groove 143 serves as a receiving portion for receiving the blade of the cutter 151, thereby enabling the separators 31 and 32 to be cut stably. Furthermore, because the blade of the cutter 151 does not come into contact with the winding core 140, damage to the winding core 140 is also reduced. It is preferable that groove 143 is close to suction hole 141. Although not limited thereto, the distance between groove 143 and suction hole 141 is, for example, preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. In this way, by having groove 143 and suction hole 141 close to each other, the vicinity of the cut ends of separators 31 and 32 is held by suction hole 141. As a result, separators 31 and 32 are less likely to break between the cut ends and the portions being sucked by suction hole 141.

[0082] In step C, the first separator 31 and the second separator 32 may be cut with a blade that moves toward a winding core (first winding core 140(1)) around which the first separator 31 was wound in step B and another winding core (second winding core 140(2)). This cutting method ensures that the first separator 31 and the second separator 32 are cut stably. Here, this cutting may be performed at room temperature or with the application of heat.

[0083] As shown in FIG. 8, the winding core 140 may be divided into at least two parts in the radial direction of the winding core 140, and the separators 31 and 32 may be configured to be attracted to only a part of the winding core. In the above-described embodiment, the winding core 140 includes a first component part 140a and a second component part 140b, and is configured to be openable and closable. With this configuration, when the wound body 20a (see FIG. 6) after winding is removed, the diameter of the winding core 140 can be driven to decrease. As a result, the wound body 20a can be easily removed.

[0084] In the above-described embodiment, the width W (see FIG. 9 ) of the suction hole formation region in which the plurality of suction holes 141 are formed is smaller than the width of the first separator 31. By having such a width of the suction hole formation region, the first separator 31 can cover all of the suction holes 141 in the width direction of the first separator 31 (the axial direction of the winding core 140). This prevents air from leaking through some of the suction holes 141. As a result, a decrease in the suction force that attracts the separators 31 and 32 can be suppressed.

[0085] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises. [Explanation of symbols]

[0086] 2 batteries 10 Battery case 11 Exterior body 12 Sealing plate 20 Wound electrode body 20a wound body 21 Positive electrode plate 22 negative electrode plate 31,32 Separator 50 Positive terminal 60 Negative terminal 100 Winding machine 120 Turret 140 core 140a 1st component 140a1 Outer surface 140a2 flat surface 140a3 Convex 140b Second component 140b1 Outer surface 140b2 flat surface 140b3 Inner surface 140c gap 141 Suction hole 142 Flow path (suction path) 143 Groove 151 Cutter 151a blade 152 Laura 152a protrusion 161~163 Fixed roller 171~174 Movable roller 181 First Chuck 182 Second zipper 185 Index Unit 186~188 Index roller 190 Winding stop device 191 Laura 192 Tape application device 200 control device k1~k4 travel route P1 1st position P2 2nd position P3 3rd position R1 1st area R12 1st-2nd area R11 Area 1-1 R2 2nd area R3 3rd area R4 4th area W: Width of the suction hole formation area WL winding shaft

Claims

1. A method for manufacturing a battery including a wound electrode assembly in which a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound together, comprising: a step A of adsorbing the first separator onto a winding core; a step B of winding the first separator around the winding core; and a plurality of suction holes for adsorbing the first separator are formed in the winding core; The outer periphery of the winding core is divided into four equal parts, each of which is defined as a first region to a fourth region, starting from a position facing a portion of the wound electrode body that will be a winding start end of the first separator, When the first region is formed by dividing the outer periphery of the winding core into two equal parts in the circumferential direction, and the first region is designated as a 1-1 region and a 1-2 region in this order from a position facing a portion that becomes a winding start end of the first separator, The method for manufacturing a battery, wherein the suction holes are formed in the 1-1 region with an opening area ratio of 70% or more.

2. A step C of cutting the first separator and the second separator. A method for manufacturing the battery according to claim 1.

3. 3. The method for manufacturing a battery according to claim 2, wherein in the step C, the first separator and the second separator are cut in a state where they are wound in a region of 15 to 180 degrees in the circumferential direction around a winding core different from the winding core around which the first separator is wound in the step B.

4. 4. The method for manufacturing a battery according to claim 2 or 3, wherein in the step C, the first separator is cut in a state in which the first separator is in contact with a winding core different from the winding core around which the first separator was wound in the step B, on the upstream side and downstream side of a cutting position of the first separator in a moving path of the first separator.

5. 5. The method for manufacturing a battery according to claim 2, wherein in step C, a groove extending along the axial direction is formed in a winding core different from the winding core around which the first separator is wound in step B, at a position where the first separator and the second separator are cut.

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