Method for manufacturing a battery

Abstract

To provide a battery manufacturing method that can eliminate defects such as separator winding misalignment and improve productivity in battery manufacturing by a simpler method.SOLUTION: A method includes a step (step A) of adsorbing a first separator 31 and a second separator 32 in a stacked state onto a winding core 140, and a step (step B) of winding the first separator and the second separator onto a winding core, and the first separator and the second separator each have a porous base layer made of resin and a surface layer formed on at least one side of the base layer.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2009-193750 discloses a method for manufacturing an electrode plate group for a non-aqueous secondary battery in which a strip-shaped positive electrode plate and a negative electrode plate are wound in a spiral shape while alternately stacking two separators. In the manufacturing method disclosed in this publication, the tip portion of the separator is adsorbed while being pressed against the winding core, and the positive electrode plate and the negative electrode plate are sandwiched and wound in a spiral shape.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in such a manufacturing method, as a separator used for the wound electrode body, a separator having a base material layer and a surface layer may be used. Since such a separator having a base material layer and a surface layer is expensive, reducing the separators that are disposed of due to winding displacement or the like can contribute to improving productivity. Therefore, the inventor of the present invention desires to eliminate problems such as winding displacement by a simpler method and improve productivity.

Means for Solving the Problems

[0005] The method for manufacturing a battery disclosed herein is a method for manufacturing a battery including a wound electrode body, and includes the following steps. Step A: A step of adsorbing a first separator and a second separator to a winding core in a stacked state Step B: A step of winding the first separator and the second separator around the winding core Here, the first separator and the second separator each have a porous base material layer made of resin and a surface layer formed on at least one surface of the base material layer.

[0006] According to such a manufacturing method, the productivity of the wound electrode body can be improved.

[0007] In each of the first separator and the second separator, when the surface layer is formed on both surfaces of the base material layer, the surface layer may be a three-dimensional network structure containing polyvinylidene fluoride (PVdF). Further, the mass ratio of PVdF in the surface layer may be 10% by mass or more, and furthermore, it may contain inorganic particles in addition to PVdF.

[0008] In each of the first separator and the second separator, when the surface layer is formed on only one surface of the base material layer, the surface layer may contain inorganic particles and a binder. The mass ratio of the inorganic particles in the surface layer may be 90% by mass or more. Also, in step B, the first separator and the second separator may be wound around the winding core with the base material layer of the first separator facing the base material layer of the second separator.

[0009] In step B, the first separator and the second separator may be pressed with a jig having a plurality of protrusions formed on its surface.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the invention disclosed herein will be described. The embodiments described here are not, of course, intended to particularly limit the present invention. The present invention is not limited to the embodiments described here unless otherwise particularly mentioned. Each drawing is schematically drawn and does not necessarily reflect the actual object. Also, members and parts having the same function are appropriately given the same reference numerals, and duplicate explanations are omitted.

[0012] FIG. 1 is a longitudinal sectional plan view of the battery 2. In FIG. 1, the battery 2 is schematically shown such that the wide surface on the front side of the battery case 10 is virtually removed and the inside of the battery case 10 can be seen. The battery 2 is one form of a battery manufactured by the manufacturing method disclosed here, and a wound electrode body 20 is accommodated inside the battery case 10. The battery manufactured by the manufacturing method disclosed here is not limited to the form shown in FIG. 1.

[0013] 《Battery 2》 The battery 2 shown in FIG. 1 is a horizontally long 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.

[0014] 〈Exterior body 11〉 The exterior body 11 is a bottomed rectangular case and has a horizontally long rectangular accommodation space. The exterior body 11 mainly accommodates the wound electrode body 20. The exterior body 11 has a substantially rectangular bottom surface 11e, a pair of wide surfaces 11a, 11b (not shown) facing each other along the long side of the bottom surface 11e, and a pair of narrow surfaces 11c, 11d facing each other along the short side of the bottom surface 11e. An opening 11f for accommodating the wound electrode body 20 is formed in the surface facing the bottom surface 11e. A sealing plate 12 is attached to the opening 11f.

[0015] 〈Sealing Plate 12〉 The sealing plate 12 is attached to the opening 11f of the battery case 10. The sealing plate 12 is composed 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 mounting holes for attaching the positive electrode terminal 50 are formed on one side in the longitudinal direction, and mounting holes 12a, 12b for attaching the negative electrode terminal 60 are formed on the opposite side.

[0016] A liquid injection hole 12c and a gas discharge valve 12d are provided in the central portion of the sealing plate 12. The liquid injection hole 12c is a through hole provided for injecting a non-aqueous electrolyte into the interior of the battery case 10 after sealing. The liquid injection hole 12c is sealed by attaching a sealing member 12e after injecting the non-aqueous electrolyte. Further, the gas discharge valve 12d is a thin-walled portion designed to break (open) when a large amount of gas is generated in the battery case 10 and discharge the gas.

[0017] As the non-aqueous electrolyte, those conventionally known and used in secondary batteries can be used without particular limitation. For example, the non-aqueous electrolyte is prepared by dissolving a supporting salt in a non-aqueous solvent. Examples of the non-aqueous solvent include carbonate solvents such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Examples of the supporting salt include fluorine-containing lithium salts such as LiPF6.

[0018] 〈Positive Electrode Terminal 50, Negative Electrode Terminal 60〉 The positive electrode terminal 50 and the negative electrode terminal 60 are attached to the sealing plate 12. The wound electrode body 20 is accommodated in the exterior body 11 while being attached to the positive electrode terminal 50 and the negative electrode terminal 60. The positive electrode terminal 50 includes an external terminal 51, a shaft 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, a shaft 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 an insulating material. The first insulators 71, 81 and the second insulators 72, 82 are each a resin having required rigidity. The gaskets 73, 83 are members that are mounted in the mounting holes 12a, 12b of the sealing plate 12 and have required flexibility.

[0019] The shaft members 52, 62 of the positive electrode terminal 50 and the negative electrode terminal 60 are mounted in the mounting holes 12a, 12b of the sealing plate 12 with the gaskets 73, 83 interposed therebetween. The external terminals 51, 61 are attached to the outside of the sealing plate 12 with the first insulators 71, 81 interposed therebetween. The external terminals 51, 61 have mounting holes and are mounted on the outer shaft ends of the shaft members 52, 62. The internal terminals 53, 63 are attached to the inside of the sealing plate 12 with the second insulators 72, 82 interposed therebetween. The internal terminals 53, 63 have mounting holes and are mounted on the inner shaft ends of the shaft members 52, 62. The inner shaft ends of the shaft members 52, 62 are caulked around the mounting holes of the internal terminals 53, 63. The current collecting members 54, 64 are attached to one ends of the internal terminals 53, 63.

[0020] In this way, the positive electrode terminal 50 and the negative electrode terminal 60 are attached to the sealing plate 12 in a state of being electrically insulated via the first insulators 71, 81, the second insulators 72, 82, and the gaskets 73, 83, and in a state where airtightness is ensured. Also, 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. And the wound electrode body 20 is attached to the current collecting members 54, 64. The wound electrode body 20 is accommodated in the exterior body 11 in a state of being attached to the sealing plate 12 in this way. A plurality of wound electrode bodies 20 may be attached to one sealing plate 12, or a plurality of wound electrode bodies 20 may be accommodated in one battery case 10.

[0021] 〈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 in a state where one end is unfolded. The wound electrode body 20 is, for example, as shown in FIG. 2, a long strip-shaped positive electrode plate 21, a first separator 31, a negative electrode plate 22, and a second separator 32 are sequentially stacked with their longitudinal directions aligned, and are wound around a winding axis WL set in the width direction.

[0022] 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 the base material of the positive electrode plate 21. The positive electrode core 21a is formed of a predetermined metal foil (for example, aluminum foil). The positive electrode active material layer 21b is formed on the positive electrode core 21a at one end on one side in the width direction with a certain width. Protective layers 21c are formed on both sides of the positive electrode plate 21 on the portions of the positive electrode core 21a excluding the portion where the positive electrode active material layer 21b is formed. Further, on the side of the positive electrode core 21a where the protective layer 21c is formed, a tab 21d protruding in the width direction is formed. The tab 21d partially protrudes with a predetermined width on the side where the protective layer 21c is formed, and the positive electrode core 21a is exposed.

[0023] The positive electrode active material layer 21b is a layer containing a positive electrode active material. The positive electrode active material is, for example, in a lithium-ion secondary battery, a material such as a lithium transition metal composite material that can release lithium ions during charging and absorb lithium ions during discharging. The positive electrode active material has generally been proposed in various forms other than lithium transition metal composite materials and is not particularly limited. The positive electrode active material is preferably, for example, a lithium transition metal composite oxide. Among the above lithium transition metal composite oxides, a lithium transition metal composite oxide containing at least one kind from the group consisting of nickel (Ni), cobalt (Co), and manganese (Mn) as the transition metal is particularly suitable. Specific examples include lithium nickel cobalt manganese-based composite oxides (NCM), lithium nickel-based composite oxides, lithium cobalt-based composite oxides, lithium manganese-based composite oxides, lithium nickel manganese-based composite oxides, lithium nickel cobalt aluminum-based composite oxides (NCA), lithium iron nickel manganese-based composite oxides, and the like. Further, preferred examples of lithium transition metal composite oxides not containing Ni, Co, and Mn include lithium iron phosphate-based composite oxides (LFP) and the like.

[0024] Note that the "lithium nickel cobalt manganese-based composite oxide" in this specification is a term encompassing oxides containing additional elements in addition to the main constituent elements (Li, Ni, Co, Mn, O). Examples of such additional 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, Sn, etc. Further, the additional element may be a semi-metal element such as B, C, Si, P, etc., or a non-metal element such as S, F, Cl, Br, I, etc. The positive electrode active material layer 21b may contain additives other than the positive electrode active material. Examples of such additives include conductive materials, binders, and the like. Specific examples of the conductive material include carbon materials such as acetylene black (AB). Specific examples of the binder include resin binders such as polyvinylidene fluoride (PVdF). Note that when the total solid content of the positive electrode active material layer 21b is 100% by mass, the content of the positive electrode active material is generally 80% by mass or more, and typically may be 90% by mass or more.

[0025] The protective layer 21c is a layer configured to have low electrical conductivity. Such a protective layer 22c is provided in a region adjacent to the edge of the positive electrode active material layer 21b. When either of the separators 31, 32 is damaged, direct contact between the positive electrode core 21a and the negative electrode active material layer 22b can be prevented, and internal short circuit can be avoided. Preferably, the protective layer 22c is formed of 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, among the above, alumina, boehmite, aluminum hydroxide, silica, and titania are preferred. Further, the protective layer 22c may contain a binder for fixing the ceramic particles to the surface of the positive electrode core 21a. Examples of such a binder include resin binders such as polyvinylidene fluoride (PVdF). A small amount of a conductive material (for example, a carbon material such as carbon black) may be added to the protective layer 22c. By adding the conductive material, a slight conductivity may be provided. The addition amount of the conductive material is preferably adjusted to an amount at which the required conductivity is exhibited. Note that the protective layer is not an essential component of the positive electrode plate. That is, in the secondary battery disclosed herein, a positive electrode plate without a protective layer may also be used.

[0026] 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 a base material of the negative electrode plate 22. The negative electrode core 22a is formed of a predetermined metal foil (for example, a copper foil). The negative electrode active material layer 22b is formed on both surfaces of the negative electrode core 22a over substantially the entire width. A tab 22d protruding to one side in the width direction is formed on the negative electrode core 22a. The tab 22d protrudes partially with a predetermined width on one side in the width direction of the negative electrode core 22a.

[0027] 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 occlude and release charge carriers in relation to the positive electrode active material described above. Examples of such negative electrode active materials include carbon materials and silicon-based materials. As the carbon material, for example, graphite, hard carbon, soft carbon, amorphous carbon, etc. can be used. Also, amorphous carbon-coated graphite in which the surface of graphite is coated with amorphous carbon can also be used. Examples of the silicon-based materials include silicon and silicon oxide (silica). Further, the silicon-based material may contain other metal elements (e.g., alkaline earth metals) and their oxides. Also, the negative electrode active material layer 22b may contain additives other than the negative electrode active material. Examples of such additives include binders and thickeners. Specific examples of the binder include rubber-based binders such as styrene-butadiene rubber (SBR). Specific examples of the thickener include carboxymethyl cellulose (CMC). Note that when the total solid content of the negative electrode active material layer 22b is 100% by mass, the content of the negative electrode active material is generally 30% by mass or more, typically 50% by mass or more. The negative electrode active material may occupy 80% by mass or more, or 90% by mass or more of the negative electrode active material layer 22b.

[0028] For the separators 31 and 32, for example, a porous resin sheet through which an electrolyte having required heat resistance can pass is used. Various proposals have been made for the separators 31 and 32 as well, and they are not particularly limited. Preferred examples of the separators 31 and 32 include separators including a porous base material layer made of a polyolefin resin (for example, polyethylene (PE), polypropylene (PP), etc.). Further, a coating layer may be appropriately formed on one or both surfaces of this porous base material layer. The coating layer may include a porous surface layer containing an insulating inorganic material, an adhesive layer, and the like. Since this porous surface layer is excellent in heat resistance, shrinkage and breakage of the separators 31 and 32 due to temperature rise can be suppressed. Examples of the inorganic material of such a porous surface layer include ceramic particles such as alumina, boehmite, aluminum hydroxide, and titania. Further, the porous surface layer contains a binder for binding the ceramic particles. As the binder, resin binders such as polyvinylidene fluoride (PVdF) and acrylic resins can be used. Note that the two separators 31 and 32 used in this embodiment may be made of the same material or different materials.

[0029] As shown in FIG. 2, the negative electrode active material layer 22b of the negative electrode plate 22 preferably covers the positive electrode active material layer 21b of the positive electrode plate 21 with the separators 31 and 32 interposed therebetween. The separators 31 and 32 preferably 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. Also, although not shown, the lengths of the positive electrode plate 21, the negative electrode plate 22, and the separators 31 and 32 are preferably such that 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 are preferably such that Ls > Ln > La. At the portion where the positive electrode plate 21 and the negative electrode plate 22 overlap, the portion where the positive electrode active material layer 21b is formed is covered with the negative electrode active material layer 22b. Also, at the portion where the negative electrode active material layer 22b overlaps the positive electrode plate 21, a protective layer 22c is formed at the portion where the positive electrode active material layer 21b does not face.

[0030] As shown in FIG. 2, the tab 21d of the positive electrode plate 21 protrudes beyond one side in the width direction of the separators 31 and 32. A plurality of tabs 21d are provided on the positive electrode plate 21 at a predetermined pitch in the longitudinal direction. The tab 22d of the negative electrode plate 22 protrudes beyond the separators 31 and 32 on the opposite side in the width direction. A plurality of tabs 22d are provided on the negative electrode plate 22 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 as to be generally in the same position after being wound around the wound electrode body 20. Note that the tab 21d of the positive electrode plate 21 and the tab 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. 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.

[0031] As shown in FIGS. 1 and 2, the wound electrode body 20 is housed in the exterior body 11 from the opening 11f to which the sealing plate 12 is attached. For this reason, it has a flat shape according to the shape of the opening 11f. When manufacturing the wound electrode body 20, it may be wound around an axis having a flat shape when being wound. Further, when manufacturing the wound electrode body 20, it may be wound around a cylindrical axis and then press-formed into a flat shape. The wound electrode body 20 and the exterior body 11 are electrically insulated 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 and is bent into a box shape so as to wrap the wound electrode body 20. Note that in FIG. 1, the wide surface on the front side of the insulating sheet 90 is also shown in a removed state.

[0032] 《Winding Machine 100》 Next, the winding machine 100 will be described. FIGS. 3 to 6 are schematic views of the winding machine 100. The winding machine 100 is an example of a winding machine that embodies the battery manufacturing method disclosed herein. FIGS. 3 to 6 each show a view of the turret 120 of the winding machine 100 as seen from a distance from the rotation axis C1 of the turret 120.

[0033] In FIG. 3, a standby state is shown when the winding machine 100 newly starts winding the positive electrode plate 21 and the negative electrode plate 22. In FIG. 4, a state is shown in which the positive electrode plate 21 and the negative electrode plate 22 are newly being wound by the winding machine 100. In FIG. 5, a state is shown in which the wound core 140 formed by winding the positive electrode plate 21 and the negative electrode plate 22 moves from the first position P1 to the second position P2. In FIG. 6, a state is shown in which the wound core 140 formed by winding the positive electrode plate 21 and the negative electrode plate 22 moves to the second position P2, a new core moves to the first position P1, and the separators 31 and 32 are cut.

[0034] As shown in FIG. 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. A plurality of 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 are provided on the turret 120.

[0035] As shown in FIG. 3, the winding machine 100 includes movement paths k1 to k4, a turret 120, a plurality of cores 140(1) to (3), a cutter 151, a pressing roller 152, a plurality of fixed rollers 161 to 163, a plurality of 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 stopper 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 state of being wound around a reel (not shown). Each component of the winding machine 100 appropriately has a required actuator. The control device 200 is configured to control each component of the winding machine 100 so that required operations are executed at a predetermined timing according to a preset program. The control device 200 can be embodied by a computer such as a microcontroller, for example.

[0036] 〈Movement paths k1 to k4〉 The moving path k1 is the path along which the positive electrode plate 21 is sent out from the reel toward the turret 120. The moving path k2 is the path along which the negative electrode plate 22 is sent out from the reel toward the turret 120. The moving path k3 is the path along which the first separator 31 is sent out from the reel toward the turret 120. The moving path k4 is the path along which the second separator 32 is sent out 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 in a strip shape and are sent out along the predetermined moving paths k1 to k4. The moving path k1 of the positive electrode plate 21 merges with the moving path k3 of the first separator 31 before reaching the core 140 disposed at the first position P1. The moving path k2 of the negative electrode plate 22 merges with the moving path k4 of the second separator 32 before reaching the core 140 disposed at the first position P1. In the moving paths k1 to k4, a dancer roll mechanism for removing the slack of the positive electrode plate 21, the negative electrode plate 22, the first separator 31, and the second separator 32 sent out, a tensioner for adjusting the tension, etc. are respectively arranged as appropriate.

[0037] 〈Turret 120〉 The turret 120 is a rotating disk with a rotation axis set at the center C1. A plurality (three in this embodiment) of cores 140 are arranged on the turret 120. The plurality of cores 140 are each a substantially cylindrical shaft that can rotate independently. In this embodiment, the axes of the plurality of cores 140 are provided parallel to the central axis of the turret 120. The turret 120 is provided with three cores 140: the first core 140(1), the second core 140(2), and the third core 140(3). The first core 140(1), the second core 140(2), and the third core 140(3) are arranged at equal intervals in the circumferential direction around the central axis of the turret 120. The first to third cores 140(1) to (3) are 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.

[0038] Around the axis of the center C1 of the turret 120, a first position P1, a second position P2, and a third position P3 are preset. In FIG. 3, a first core 140(1) is arranged at the first position P1, a third core 140(3) is arranged at the second position P2, and a second core 140(2) is arranged at the third position P3. The positions of the first core to the third 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 core to the third core 140(1) to (3) also rotate counterclockwise respectively. The first core to the third core 140(1) to (3) move through the first position P1, the second position P2, and the third position P3 in order due to the rotation of the turret 120. Although not shown, the first core to the third core 140(1) to (3) are provided with required actuators (for example, servo motors) and rotate at an appropriate speed at an appropriate timing. Here, when the first core to the third core 140(1) to (3) are not particularly distinguished, they are referred to as the core 140. When the first core to the third core 140(1) to (3) are distinguished, they are appropriately distinguished as the core 140(1), the core 140(2), and the core 140(3).

[0039] 〈Core 140〉 FIG. 7 is a cross-sectional view schematically showing the core 140 disposed at the first position P1. The core 140 is a substantially cylindrical member. In FIG. 7, a view seen from the axial direction of the core 140 is shown, and as shown in FIG. 3, the state when the first separator 31 and the second separator 32 are wound around the core 140 disposed at the first position P1 is shown. The core 140 has a function of holding the separators 31 and 32 wound around the side peripheral surface as shown in FIG. 4. In this embodiment, the core 140 has a suction hole 141, a suction path 142, and a groove 143. The suction hole 141 is a hole for adsorbing the separators 31 and 32 wound around the side peripheral surface. The suction path 142 is a flow path formed inside the core 140 and communicating with the suction hole 141. The suction path 142 is a flow path for forming a negative pressure in the suction hole 141. The suction path 142 may be configured to be appropriately connected to a vacuum line (not shown) installed outside to form a negative pressure. The groove 143 is formed as a receiving portion where the blade of the cutter 151 is lowered when the separators 31 and 32 are cut. In this embodiment, the groove 143 is formed along the axial direction of the core 140 on the outer peripheral surface of the core 140. Note that in this embodiment, the core 140 has a substantially cylindrical shape, but a flat core may be used when wound in a flat shape. Also, the core may be a core divided along the radial direction, or the diameter of the core may be variable.

[0040] 〈Cutter 151〉 The cutter 151 is a cutter for cutting the separators 31 and 32. The cutter 151 is configured such that the blade 151a is pressed against the separators 31 and 32 held by the core 140 disposed at the first position P1. In this embodiment, the cutter 151 is pushed out or retracted along a guide to a position determined such that the blade is pressed against the separators 31 and 32 held by the core 140. The cutter 151 is operated by an actuator (for example, a cylinder mechanism) at an appropriate timing, although not shown. The blade 151a may be, for example, a wave blade (a saw-tooth-like blade).

[0041] <Pressing Roller 152> The pressing roller 152 is a roller that presses the separators 31 and 32 against the core 140 disposed at the first position P1. By such a pressing roller 152, the separators 31 and 32 are wound while being pressed against the core 140 disposed at the first position P1. The pressing roller 152 functions as a pressing jig that presses the separators 31 and 32 against the core 140 disposed at the first position P1. In this embodiment, as shown in FIG. 7, a plurality of protrusions 152a are formed on the outer peripheral surface of the pressing roller 152. By the roller 152 having such protrusions 152a, when the two separators 31 and 32 are pressed against the core 140, the force is locally concentrated by the protrusions 152a and the separators 31 and 32 are strongly pressed. For this reason, the separators 31 and 32 are more suitably crimped to each other. The pressing roller 152 is, for example, substantially cylindrical, and it is preferable that knurling is performed on the circumferential side surface. The pressing roller 152 is configured, for example, by a mechanism with a spring or the like, to press the separators 31 and 32 against the core 140 disposed at the first position P1 with an appropriate pressure. Further, although not shown, the pressing roller 152 is moved by a guide and an actuator to a position where it presses against the separators 31 and 32 wound around the core 140 disposed at the first position P1 (see FIG. 3) and a position away from the core 140 (see FIG. 5). The pressing roller 152 may be provided as a single cylindrical roller in the width direction of the core 140, or may be composed of a plurality of rollers intermittently arranged in the width direction of the core 140.

[0042] <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 merge. The movable roller 171 is a roller that presses the first separator 31 against the fixed roller 161 and sandwiches 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 the movable roller 171 sandwiches the first separator 31, it may be configured to sandwich the first separator 31 with a predetermined force by the action of a spring or the like. The first separator 31 is sent out toward the core 140 arranged at the first position P1 without looseness by being sandwiched between the fixed roller 161 and the movable roller 171 with an appropriate force.

[0043] 〈Fixed roller 162, Movable roller 172〉 The fixed roller 162 is provided at a position where the movement path k4 of the second separator 32 and the movement path k2 of the negative electrode plate 22 merge. The movable roller 172 is a roller that presses the second separator 32 against the fixed roller 162 and sandwiches the second separator 32. The movable roller 172 moves in a predetermined direction by 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. When the movable roller 172 sandwiches the second separator 32, it may be configured to sandwich the second separator 32 with a predetermined force by the action of a spring or the like. The second separator 32 is sent out toward the core 140 arranged at the first position P1 without looseness by being sandwiched between the fixed roller 162 and the movable roller 172 with an appropriate force.

[0044] 〈Fixed roller 163〉 The fixed roller 163 is arranged at a predetermined position on the movement path k3 of the first separator 31 and is a roller for defining the movement path of the movement path k3 of the first separator 31.

[0045] <The first chuck 181> As shown in FIG. 3, the first chuck 181 is disposed in front of a pair of rollers 161 and 171 that sandwich the first separator 31 in the movement path k1 along which the positive electrode plate 21 is fed out. 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 by 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.

[0046] In the state shown in FIG. 3, the first separator 31 is held by the core 140 disposed at the first position P1 and is sandwiched between the pair of rollers 161 and 171 and extends along the movement path k3. The first chuck 181 grips the positive electrode plate 21 in front of the pair of rollers 161 and 171. When the positive electrode plate 21 is wound around the 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 and 171 and releases the positive electrode plate 21. Thereby, the positive electrode plate 21 is drawn into the pair of rollers 161 and 171 together with the first separator 31 and is wound around the core 140 disposed at the first position P1. When the positive electrode plate 21 is fed out by a predetermined length, the winding of the core 140 stops. The positive electrode plate 21 is gripped by the first chuck 181 and is cut between the first chuck 181 and the pair of rollers 161 and 171. The first chuck 181 is configured to move appropriately between a predetermined position for gripping the positive electrode plate 21 and a predetermined position for inserting the positive electrode plate 21 between the pair of rollers 161 and 171.

[0047] <The second chuck 182> As shown in FIG. 3, the second chuck 182 is disposed in front of a pair of rollers 162 and 172 that sandwich the second separator 32 in the movement path k2 along which the negative electrode plate 22 is fed out. 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. The second chuck 182, although not shown, operates 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.

[0048] In the state shown in FIG. 3, the second separator 32 is held by the bobbin 140 disposed at the first position P1 and is sandwiched between the pair of rollers 162 and 172, and extends along the movement path k4. The second chuck 182 grips the negative electrode plate 22 in front of the pair of rollers 162 and 172. When the negative electrode plate 22 is wound around the bobbin 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 and 172 and releases the negative electrode plate 22. Thereby, the negative electrode plate 22 is drawn into the pair of rollers 162 and 172 together with the second separator 32 and is wound around the bobbin 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 of the bobbin 140 stops. In other words, when the negative electrode plate 22 is fed out by a predetermined length, the winding of the bobbin 140 stops. The negative electrode plate 22 is gripped by the second chuck 182 and is cut between the second chuck 182 and the pair of rollers 162 and 172. The second chuck 182 is configured to move appropriately between a predetermined position for gripping the negative electrode plate 22 and a predetermined position for inserting the negative electrode plate 22 between the pair of rollers 162 and 172.

[0049] The positive electrode plate 21 and the negative electrode plate 22 may be inserted between the pair of rollers 161 and 171 and between the pair of rollers 162 and 172, respectively, for example, after the first separator 31 and the second separator 32 are wound around the outer peripheral surface of the bobbin 140 for about one turn.

[0050] <Movable roller 173> As shown in FIG. 6, when the first separator 31 and the second separator 32 are cut, the movable roller 173 is a roller for pressing the first separator 31 and the second separator 32 against the core 140 disposed at the first position P1. 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, when the first separator 31 and the second separator 32 are cut, the movable roller 173 is disposed at a position where it presses the first separator 31 and the second separator 32 against the core 140 disposed at the first position P1. At other times, as shown in FIG. 3, the movable roller 173 moves to a position away from the core 140 disposed at the first position P1. When the movable roller 173 presses the first separator 31 and the second separator 32 against the core 140, it may be configured to sandwich the first separator 31 with a predetermined force by the action of a spring or the like.

[0051] As shown in FIG. 6, when the cutter 151 is pressed against the core 140 disposed at the first position P1, the first separator 31 and the second separator 32 are cut. In this embodiment, as shown in FIG. 7, a groove 143 is provided on the outer peripheral surface of the core 140. When the cutter 151 is pressed against the core 140, the groove 143 provided on the outer peripheral surface of the core 140 is directed toward the position where the cutter 151 is pressed. With the groove 143 directed toward the cutter 151, the first separator 31 and the second separator 32 are pressed against the core 140 by the movable roller 173. As a result, the first separator 31 and the second separator 32 are adsorbed to the core 140. Further, in this state, the cutter 151 is pressed against the first separator 31 and the second separator 32 held by the core 140. Thereby, the first separator 31 and the second separator 32 are cut. Further, since the blade of the cutter 151 enters the groove 143 of the core 140, the first separator 31 and the second separator 32 are cut more reliably and neatly, the core 140 is less likely to be damaged, and foreign matters are less likely to be generated.

[0052] 〈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 the first separator 31 and the second separator 32 are cut. The movable roller 174 moves in a predetermined direction by a guide and an actuator. The movement of the movable roller 174 is controlled by the control device 200.

[0053] 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 up while being stacked in order by the core 140(1) disposed at the first position P1. The 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. 5. At this time, another 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 adsorbed to the newly disposed core 140(2) at the first position P1, and the first separator 31 and the second separator 32 are held on the outer peripheral surface of the core 140(2). At this time, the first separator 31 and the second separator 32 wound around the core 140(1) disposed at the second position P2 are held on the outer peripheral surface of the core 140(2) disposed at the first position P1 in a connected state.

[0054] The movable roller 174 is pushed out toward the first separator 31 and the second separator 32 at an appropriate timing when the 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. By the movable roller 174, the first separator 31 and the second separator 32 are fed out without loosening when the core 140(1) moves from the first position P1 to the second position P2. The movable roller 174 is retracted to a position away from the turret 120 except at this timing as shown in FIGS. 3 to 5.

[0055] 〈Index Unit 185〉 The index unit 185 is provided at the center of the turret 120. As described above, three cores 140(1) to (3) are evenly arranged in the circumferential direction on the turret 120. The index unit 185 has a substantially equilateral triangle base that rotates together with the turret 120. Index rollers 186 to 188 are respectively arranged at the vertices of the base, and the index rollers 186 to 188 are respectively arranged between the three cores 140(1) to (3).

[0056] When the wound core 140(1) obtained by winding the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 moves from the first position P1 to the second position P2, as shown in FIG. 6, among the index rollers 186 to 188, the index roller 186 arranged from the first position P1 to the second position P2 presses against the first separator 31 and the second separator 32 from the inner diameter side. By such an index roller 186 and the movable roller 174, the first separator 31 and the second separator 32 are fed out without looseness 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 the inner diameter side, but the index unit 185 rotates together with the rotation of the turret 120. For this reason, when the wound core 140 obtained by winding the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 moves from the first position P1 to the second position P2, the index rollers 186 to 188 of the index unit 185 function in order as rollers that press against the first separator 31 and the second separator 32 from the inner diameter side.

[0057] <Winding stopper device 190> For example, as shown in FIG. 6, the wound core 140(1) obtained by winding the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 moves from the first position P1 to the second position P2 away from the first position P1. After the separators 31 and 32 are cut, the cut separators 31 and 32 are wound up to the cut ends. The winding stopper 190 is disposed at the second position P2. The winding stopper 190 includes a pressing roller 191 and a tape attaching device 192. The pressing roller 191 is pressed against the outermost second separator 32 wound around the wound core 140(1) when the wound core 140 that 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 to the cut ends. Thereby, the cut positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are wound up without being loosened respectively. The tape attaching device 192 is a device for attaching a tape for stopping the cut end of the outermost second separator 32 or the first separator 31. Such a winding stopping process may be performed in parallel with, for example, a process of winding the first separator 31, the positive electrode plate 21, the second separator 32, and the negative electrode plate 22 around a wound core 140(2) newly disposed at the first position P1.

[0058] Furthermore, in this embodiment, for example, as shown in FIG. 6, after the winding prevention process is performed on the winder 100 and the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are newly wound around the core 140(2) disposed at the first position P1, the turret 120 rotates. The core 140(1) on which the winding prevention process has been performed moves to the third position P3, the core 140(2) moves to the second position P2, and yet another core 140(3) is disposed at the first position P1. At this time, the first separator 31 and the second separator 32 wound around the core 140(2) disposed at the second position P2 are held on the outer peripheral surface of the core 140(3) disposed at the first position P1 in a connected state. Then, after the separators 31 and 32 are cut, at the second position P2, the winding prevention process for the core 140(2) is performed. 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 core 140(3). At the third position P3, the wound body 20a is taken out from the core 140(1) (see FIG. 3). After being taken out, the wound body 20a is pressed flat and can be handled as the wound electrode body 20. In this way, the cores 140(1) to (3) provided on the turret 120 sequentially move between the first position P1 and the third position P3. Then, the positive electrode plate 21, the first separator 31, the negative electrode plate 22, and the second separator 32 are continuously wound around the cores 140(1) to (3) in order.

[0059] Here, the winder 100 relates to a method for manufacturing the battery 2 provided with the wound electrode body 20, and implements the following steps A and B. Step A: In step A, the first separator 31 and the second separator 32 respectively fed out along the predetermined movement paths k1 to k4 are adsorbed in a stacked state on the core 140(1) disposed at the first position P1 (see FIG. 3). Step B: In step B, the first separator 31 and the second separator 32 adsorbed in a stacked state in step A are wound around the core 140(1) (see FIG. 3). Here, the first separator 31 and the second separator 32 each have a base material layer 33 and a surface layer 34 formed on at least one surface of the base material layer 33. According to the manufacturing method disclosed herein, even when each of the first separator 31 and the second separator 32 includes the base material layer 33 and the surface layer 34, the deviation of each separator with respect to the winding core 140 can be effectively suppressed by a simple method, and continuous winding of the electrode body 20 can be achieved. Thereby, productivity is improved. Note that the surface layer 34 may be provided on only one surface of the base material layer 33 or may be provided on both surfaces. Hereinafter, the case where the surface layer 34 is formed on both surfaces of the base material layer 33 and the case where the surface layer 34 is formed on only one surface of the base material layer 33 will be described.

[0060] First, the case where the surface layer 34 is formed on both surfaces of the base material layer 33 will be described. FIG. 8 is a schematic diagram of the winding machine 100 (more specifically, the winding core 140) and the separators 31 and 32. As shown in FIG. 8, in the separators 31 and 32, surface layers 34a are formed on both surfaces of the base material layer 33. The base material layer 33 is typically composed of a porous sheet (film) made of resin. For example, a porous sheet (film) made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a polyvinyl chloride resin, a polyvinyl acetate resin, a polyimide resin, a polyamide resin, or a resin such as celluloses can be mentioned. Among them, a porous sheet made of polyethylene (PE) is preferable because its shutdown temperature is sufficiently lower than the heat resistance temperature of the battery and it has an appropriate shutdown function. The base material layer 33 may have a single-layer structure composed of a single material, or may have a laminated structure in which two or more porous sheets made of resins having different materials and properties (for example, average thickness and porosity) are laminated (for example, a structure in which PP is laminated on both sides of PE).

[0061] The average thickness of the base material layer 33 is not particularly limited, but is usually 5 μm or more, typically 8 μm or more, for example, 10 μm or more. On the other hand, the thickness of the base material layer 33 can usually be 40 μm or less, for example, 30 μm or less, for example, 25 μm or less. Although not particularly limited, the porosity of the base material layer 33 is about 30 to 60%.

[0062] When the surface layers 34 are formed on both surfaces of the base material layer 33, the surface layer 34a is a layer having a three-dimensional network structure containing PVdF. The surface layer 34a typically has a structure (three-dimensional network structure) formed by randomly laminating a plurality of fibrous PVdFs so as to have a large number of pores (voids). By bringing the surface layers 34 having such a three-dimensional network structure into contact with each other, electrostatic charges are preferably generated, and the separators 31 and 32 can be prevented from shifting. Further, the electrostatic charges can prevent each separator from shifting with respect to the winding core 140. Thereby, it is possible to suppress the occurrence of problems at the start of winding of the separator, and the wound electrode body 20 can be continuously manufactured. That is, according to the above configuration, even when the separator has the base material layer 33 and the surface layers 34 on both surfaces of the base material layer 33, the winding displacement of the separators 31 and 32 with respect to the winding core 140 can be effectively suppressed by a simple method, and the productivity can be improved.

[0063] The surface layer 34a has many pores formed by the PVdF constituting the surface layer 34a. The porosity of the surface layer 34a is preferably higher than that of the base material layer 33, and is typically 40% or more, for example, about 50 to 70%. The average thickness of the surface layer 34a is not particularly limited, but the average thickness of the surface layer 34a may be, for example, 0.1 μm or more and 5 μm or less, and may be 0.5 μm or more and 3 μm or less. With the surface layer 34a having such an average thickness and porosity, it is easily attracted to the suction holes 141, and the winding core 140 can preferably adsorb the separators 31 and 32.

[0064] The surface layer 34a contains at least PVdF as a resin component constituting a three-dimensional network structure. More preferably, when the surface layer 34a is 100% by mass, it contains 10% by mass or more of PVdF. According to the findings of the present inventors, when the surface layer 34a contains 10% by mass or more of PVdF, it can function as an adhesive layer having appropriate adhesiveness. Thereby, the slippage of the separators 31 and 32 with respect to the winding core 140 is more preferably suppressed. From such a viewpoint, the mass ratio of PVdF contained in the surface layer 34a is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more when the surface layer 34a is 100% by mass. The upper limit of the mass ratio of PVdF contained in the surface layer 34a is not particularly limited, but may be, for example, 50% by mass or less, 45% by mass or less, or 40% by mass or less. When the PVdF contained in the surface layer 34a is within the above range, a three-dimensional network structure with a homogeneous property (such as pore distribution and average thickness) can be formed. Thereby, in the separators 31 and 32, a state in which static electricity is more preferably likely to be generated is achieved, and the slippage with respect to the winding core 140 is suppressed.

[0065] The surface layer 34a may contain one or more other resin components in addition to the above PVdF as long as the effects of the present invention are not significantly impaired. Such other resin components are not particularly limited, but are preferably resins that do not dissolve in the non-aqueous electrolyte and do not inhibit the insertion and extraction of charge carriers (such as lithium ions). Examples of other resin components contained in the surface layer 34a include fluorine-based resins such as polytetrafluoroethylene (PTFE); acrylic resins such as polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), and polyvinyl alcohol (PVA); polyester resins such as polyethylene terephthalate; polyamide-based resins; polyimide-based resins; and the like. When the surface layer 34a contains other resin components in addition to PVdF, the ratio of the other resin components is preferably 45% by mass or less, more preferably 30% by mass or less, based on the total resin components contained in the surface layer 34a.

[0066] The surface layer 34a preferably contains one or more inorganic particles in addition to the above PVdF for the purpose of improving the strength of the surface layer 34a or the like. The material of the inorganic particles may be the inorganic materials exemplified as those that can be contained in the separators 31 and 32. Among them, alumina, boehmite, silica, and titania, which have stable quality, are inexpensive, and are easily available, are preferably used. The inorganic particles are preferably arranged (i.e., dispersed) substantially uniformly in the three-dimensional network structure composed of the resin such as PVdF described above. Thereby, more suitable static electricity is likely to be generated in the separators 31 and 32, the deviation with respect to the core 140 is eliminated, and the core 140 easily adsorbs the separators 31 and 32.

[0067] The properties of the inorganic particles are not particularly limited. For example, the aspect ratio may be 1 or more and 5 or less (typically 2 or less, preferably 1.5 or less). Here, the aspect ratio refers to the ratio of the length of the longest side to the length of the shortest side of the inorganic particles. Further, the average particle diameter of the inorganic particles is not particularly limited, but in consideration of dispersibility and the like, it may be 0.01 μm or more (for example, 0.05 μm or more, typically 0.1 μm or more) and 10 μm or less (for example, 5 μm or less, typically 3 μm or less). In this specification, the "average particle diameter" refers to the particle diameter (also referred to as D50, median diameter) corresponding to a cumulative frequency of 50% by volume from the side of fine particles with a small particle diameter in the volume-based particle size distribution based on the general laser diffraction / scattering method.

[0068] The mass ratio of the inorganic particles contained in the surface layer 34a is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more when the surface layer 34a is 100% by mass. The upper limit of the mass ratio of the inorganic particles contained in the surface layer 34a is not particularly limited, but may be, for example, 90% by mass or less, 85% by mass or less, or 80% by mass or less.

[0069] The surface layer 34a may contain materials other than the above resin component and inorganic particles as long as the effects of the present invention are not significantly impaired. Examples of such materials include various additives such as oxidation stabilizers. In a preferred embodiment, when the surface layer 34a is 100% by mass, the total mass ratio of the resin component (PVdF and other resin components) and inorganic particles contained in the surface layer 34a is approximately 90% by mass (for example, 95% by mass or more). The surface layer 34a may be substantially composed of only the resin component and inorganic particles.

[0070] Next, the case where the surface layer 34 is formed only on one surface of the base material layer 33 will be described. FIG. 9 is a schematic diagram of the winder 100 (more specifically, the core 140) and the separators 31 and 32. As shown in FIG. 9, on the first separator 31 and the second separator 32, a surface layer 34b is formed only on one surface of the base material layer 33. At this time, the base material layer 33 of the first separator 31 and the base material layer 33 of the second separator 32 may be arranged in a facing direction. According to the findings of the present inventors, it is easier to crimp the separators when the base material layers 33 are opposed to each other rather than the surface layers 34b being opposed to each other. Therefore, displacement is less likely to occur, and the core 140 can preferably wind the first separator 31 and the second separator 32. According to the above configuration, even when the separator has the base material layer 33 and the surface layer 34 only on one surface of the base material layer 33, the winding displacement of the separators 31 and 32 with respect to the core 140 can be suppressed by a simple method, and a wound electrode body 20 with a stable shape can be produced. Thereby, productivity can be improved.

[0071] When the surface layer 34 is formed only on one surface of the base material layer 33, the surface layer 34b contains inorganic particles and a binder. The inorganic particles may be the same as those exemplified as being capable of being included in the surface layer 34a. When the surface layer 34 is formed on one surface of the base material layer 33, the surface layer 34b is preferably a porous insulating layer having heat resistance. For example, the surface layer 34b may have a porous structure capable of allowing charge carriers to permeate and have heat resistance with respect to a shutdown temperature (typically 80 to 140 °C). Therefore, as the inorganic particles, those having such heat resistance and insulating properties are particularly preferable. Specifically, alumina, boehmite, and magnesia are preferably used. Since these have a high melting point, they can exhibit excellent heat resistance. The mass ratio of the inorganic particles contained in the surface layer 34b is preferably 90% by mass or more, more preferably 95% by mass or more, when the surface layer 34b is 100% by mass. The upper limit of the mass ratio of the inorganic particles contained in the surface layer 34b is not particularly limited, but may be, for example, 99% by mass or less, or 98% by mass or less.

[0072] As the binder contained in the surface layer 34b, one of the resin components exemplified as being capable of being included in the surface layer 34a can be used alone, or two or more thereof can be mixed at an appropriate ratio and used. Among them, an acrylic resin is preferable because it has suitable adhesiveness and is electrochemically stable, and thus can exhibit high shape retention.

[0073] When the surface layer 34 is formed only on one surface of the base material layer 33, the three-dimensional network structure as described above may not be formed in the surface layer 34b. That is, the binder may be contained to such an extent that it can bind the inorganic particles. From such a viewpoint, the mass ratio of the inorganic particles contained in the surface layer 34b may be, for example, 1% by mass or more and 10% by mass or less, or 2% by mass or more and 8% by mass or less.

[0074] The average thickness of the surface layer 34b is not particularly limited, and may be, for example, 0.1 μm or more and 5 μm or less, or may be 0.5 μm or more and 3 μm or less. With the surface layer 34b having such an average thickness, it is easily attracted to the suction holes 141, and the core 140 can suitably adsorb the separators 31 and 32.

[0075] The surface layer 34b may contain materials other than the inorganic particles and the binder as long as the effects of the present invention are not significantly impaired. Examples of such materials include various additives such as oxidation stabilizers. In a preferred embodiment, when the surface layer 34b is 100% by mass, the total mass ratio of the inorganic particles and the binder contained in the surface layer 34b is generally 90% by mass (for example, 95% by mass or more). The surface layer 34b may be substantially composed of only inorganic particles and a binder.

[0076] Hereinafter, in the first separator 31 and the second separator 32, matters common to the case where the surface layer 34 is formed on both surfaces of the base material layer 33 and the case where it is formed on only one surface will be described.

[0077] The separators 31 and 32 are preferably configured to be pressed by the pressing roller 152 when wound around the core 140 (see FIG. 7). In particular, a plurality of protrusions 152a are preferably formed on the outer peripheral surface of the pressing roller 152. The surface layer 34 can exhibit adhesiveness by being pressed by the pressing roller 152. Thereby, the winding displacement of the separators 31 and 32 with respect to the core 140 is further suppressed.

[0078] The widths Ls of the first separator 31 and the second separator 32 (see FIG. 2) are preferably 25 cm or more, and more preferably 30 cm or more. By making the widths Ls of the first separator 31 and the second separator 32 relatively large, the adhesion area with the core 140 increases, and the area where the suction holes 141 can adsorb also increases. Thereby, the separators 31 and 32 are prevented from shifting from the core 140, and a winding electrode body 20 with a more stable shape can be produced.

[0079] According to the above-described configuration, even when each of the first separator 31 and the second separator 32 has a base material layer 33 and a surface layer formed on at least one surface of the base material layer 33, the steps A and B are carried out in a state where the displacement of each separator with respect to the winding core 140 is effectively suppressed. That is, it is possible to continuously manufacture a wound electrode body 20 with a more stable shape (high quality) by a simple method, and an improvement in productivity is achieved.

[0080] In addition, after the first separator 31 and the second separator 32 are wound around the outer peripheral surface of the winding core 140 about once in the step B, the positive electrode plate 21 and the negative electrode plate 22 are respectively inserted between a pair of rollers 161 and 171 and between a pair of rollers 162 and 172 and wound. It is preferably configured as such (see FIG. 6).

[0081] As described above, the method for manufacturing a battery disclosed herein and the winding machine 100 that embodies the method for manufacturing the battery have been described. The winding machine 100 is merely one form of a winding machine that embodies the method for manufacturing a battery, and unless otherwise specified, the winding machine that embodies the method for manufacturing a battery is not limited to the above-described form. For example, in the above-described embodiment, three winding cores 140 are provided on the turret 120 and are configured to move simultaneously by the rotation of the turret 120. The turret 120 may be further provided with a plurality of winding cores and configured such that a plurality of processes are performed in parallel at a plurality of positions. Also, unless otherwise specified, the plurality of winding cores may not be provided on the turret and may be configured to move independently. Also, each step of the above-described method for manufacturing a battery may be started at the same timing or may be appropriately shifted even when performed in parallel.

[0082] In addition, although the cylindrical pressing roller 152 is exemplified as the pressing jig, the pressing jig is preferably a member that presses the first separator 31 and the second separator 32 against the winding core 140 disposed at the first position P1, and is not necessarily limited to the form of a roller.

[0083] The invention disclosed herein has been variously described above. Unless otherwise specified, the embodiments recited herein do not limit the present invention. Further, the embodiments of the invention disclosed herein can be variously modified, and unless otherwise particularly problematic, each component and each process recited herein can be omitted as appropriate or combined as appropriate.

Description of Reference Numerals

[0084] 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 Separator (first separator) 32 Separator (second separator) 33 Base material layer 34 Surface layer 34a Surface layer 34b Surface layer 50 Positive electrode terminal 60 Negative electrode terminal 100 Winder 120 Turret 140 Spindle 141 Suction hole 142 Suction path 143 Groove 151 Cutter 151a Blade 152 Roller 152a Protrusion 161 - 163 Fixed rollers 171 - 174 Movable rollers 181 First chuck 182 Second chuck 185 Index unit 186 - 188 Index rollers 190 Winding stopper 191 Roller 192 Tape - attaching device 200 Control device k1 - k4 Movement paths P1 Position 1 P2 Position 2 P3 Position 3 WL Winding shaft

Claims

1. 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 method comprising: a step A of adsorbing a first separator and a second separator on a winding core in a state where the first separator and the second separator are stacked, and cutting the first separator and the second separator; a step B of winding the first separator and the second separator cut in the state of being adsorbed on the winding core in step A around the winding core; and having the first separator and the second separator each have a porous base material layer made of resin and a surface layer formed on at least one surface of the base material layer; In step B, with the negative electrode plate and the positive electrode plate not being supplied to the winding core, after the first separator and the second separator are wound around the winding core at least once, the negative electrode plate and the positive electrode plate are supplied to the winding core, and the first separator, the negative electrode plate, the second separator, and the positive electrode plate are wound around the winding core. A method for manufacturing a battery.

2. 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 method comprising: a step A of adsorbing a first separator and a second separator on a winding core in a state where the first separator and the second separator are stacked, and cutting the first separator and the second separator; a step B of winding the first separator and the second separator cut in the state of being adsorbed on the winding core in step A around the winding core; and having the first separator and the second separator each have a porous base material layer made of resin and a surface layer formed on at least one surface of the base material layer; the surface layer has a three-dimensional network structure containing polyvinylidene fluoride (PVdF); In step A, the first separator and the second separator are arranged on the winding core such that the surface layer of the first separator and the surface layer of the second separator are in contact with each other. A method for manufacturing a battery.

3. In each of the first separator and the second separator, the surface layer is formed on both surfaces of the base material layer; The method for manufacturing a battery according to claim 1, wherein the surface layer has a three-dimensional network structure containing polyvinylidene fluoride (PVdF).

4. In each of the first separator and the second separator, the mass ratio of PVdF in the surface layer is 10% by mass or more. The method for manufacturing a battery according to claim 2 or 3.

5. The method for manufacturing a battery according to any one of claims 2 to 4, wherein in each of the first separator and the second separator, the surface layer contains inorganic particles.

6. In each of the first separator and the second separator, the surface layer is formed only on one surface of the base material layer, the surface layer contains inorganic particles and a binder, the mass ratio of the inorganic particles in the surface layer is 90% by mass or more, In the step B, the first separator and the second separator are wound around the winding core with the base material layer of the first separator and the base material layer of the second separator facing each other. The method for manufacturing a battery according to claim 1.

7. The surface layer of the first separator and the surface layer of the second separator are each an adhesive layer, In the step B, the first separator and the second separator are pressed by a jig having a plurality of protrusions formed on the surface. The method for manufacturing a battery according to any one of claims 1 to 6.

8. The method for manufacturing a battery according to any one of claims 1 to 7, wherein the widths of the first separator and the second separator are each 25 cm or more.

Images