Apparatus and method for manufacturing electrode and electrode manufactured thereby

Abstract

Disclosed are an apparatus and a method for manufacturing an electrode and an electrode manufactured thereby. An electrode manufacturing apparatus includes: rollers including a first roller including at least one first surface treatment area on at least a portion of a surface thereof, and a second roller spaced apart from the first roller and rotatable in a different direction from the first roller; a film conveyor that conveys the self-supporting film toward the first roller; and a current collector conveyor that conveys a current collector toward a gap between the first roller and the second roller to stack the self-supporting film on a surface of the current collector through the rollers.

Description

Technical Field

[0001] Aspects of embodiments of the present invention relate to an apparatus and method for manufacturing an electrode and an electrode manufactured by the apparatus and / or method. Background Art

[0002] In recent years, with the rapid popularization of electronic devices using batteries (such as mobile phones, notebook computers and electric vehicles), the demand for high energy density and high capacity secondary batteries has been rapidly growing. Therefore, various research and development have been actively carried out to improve lithium secondary batteries.

[0003] The lithium secondary battery includes positive and negative electrodes containing active materials that allow intercalation and deintercalation of lithium ions and an electrolyte, and generates electric energy through oxidation and reduction of lithium ions when intercalated / deintercalated in the positive and negative electrodes.

[0004] Here, the positive electrode and / or the negative electrode generally includes a current collector and an active material layer coated on the current collector. The active material layer is generally prepared in the form of a slurry. The method of coating the active material layer in the form of a slurry on the current collector is called a wet process. The wet process allows metals to be easily extracted from waste batteries. However, the wet process requires high-temperature heat treatment to dry the active material layer having a slurry phase. As a result, the wet process has the problem of high manufacturing cost and difficulty in improving productivity.

[0005] Therefore, a dry process for forming an active material layer using a dry mixture has emerged in recent years. However, the dry process can only produce a film-shaped dry electrode through a continuous process by roll calendaring, resulting in limitations in applying the dry electrode to various single form factors.

[0006] Therefore, there is a need to develop techniques for applying dry electrodes to various monomer form factors. Summary of the invention

[0007] According to an aspect of an embodiment of the present invention, there is provided an electrode having a pattern formed on a side thereof.

[0008] According to another aspect of an embodiment of the present invention, a manufacturing apparatus and / or a manufacturing method capable of producing a dry electrode applicable to various monomer form factors is provided.

[0009] The above and other aspects and features of the present invention will become apparent from the following description of some embodiments of the present invention.

[0010] According to one or more embodiments of the present invention, an electrode manufacturing device includes: rollers, including a first roller and a second roller, the first roller including at least one first surface treatment area on at least a portion of its surface, the second roller being spaced apart from the first roller and rotatable in a direction different from the first roller; a film conveyor, conveying a self-supporting film toward the first roller; and a current collector conveyor, conveying the current collector toward a gap between the first roller and the second roller to stack the self-supporting film on the surface of the current collector through the rollers.

[0011] According to one or more embodiments of the present invention, an electrode manufacturing method includes: applying a shear force to a dry mixture to produce a self-supporting film; conveying the self-supporting film toward a first roller including a surface treatment area thereon to form a pattern on the self-supporting film; and conveying a current collector toward the first roller and a second roller adjacent to the first roller to stack the self-supporting film on the current collector.

[0012] According to one or more embodiments of the present invention, an electrode manufactured by the electrode manufacturing apparatus and / or the electrode manufacturing method includes: a current collector; and a self-supporting film stacked on the current collector and having a pattern formed on a surface thereof.

[0013] According to an aspect of one or more embodiments, the electrode manufacturing apparatus and / or the electrode manufacturing method can manufacture an electrode having a pattern formed thereon.

[0014] According to another aspect of one or more embodiments, the electrode manufacturing apparatus and / or the electrode manufacturing method can manufacture electrodes applicable to various single form factors.

[0015] According to another aspect of one or more embodiments, the electrode may have a pattern formed on at least one side thereof.

[0016] However, aspects and features of the present invention are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the detailed description provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings attached to this specification illustrate some exemplary embodiments of the present invention and, together with the detailed description of the present invention, further describe aspects and features of the present invention. However, the present invention should not be interpreted as being limited to the accompanying drawings:

[0018] Figures 1 to 4 is a schematic diagram of a lithium secondary battery according to some embodiments of the present invention;

[0019] Figure 5 is a view of an electrode manufacturing apparatus according to an embodiment of the present invention;

[0020] Figure 6is a flow chart showing a method for manufacturing an electrode according to one embodiment of the present invention;

[0021] 7A to 7C is a raised view according to some embodiments of the present invention;

[0022] FIG. 8A to FIG. 8C is a raised view according to some embodiments of the present invention;

[0023] 9A to 9C is a view of a roller and a surface treatment area according to some embodiments of the present invention;

[0024] Fig.10 is a view of an electrode manufacturing apparatus according to an embodiment of the present invention; and

[0025] Fig.11A and Fig. 11B is a diagram of an electrode according to some embodiments of the present invention. DETAILED DESCRIPTION

[0026] Here, some example embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, it will be understood that the following embodiments are provided by way of illustration and the present invention is not limited thereto and is defined by the appended claims and their equivalents.

[0027] When an arbitrary element is referred to as being disposed (or positioned or placed) "on" (or "below") or "on" (or "under") a component, this may mean that the arbitrary element is disposed in contact with the upper (or lower) surface of the component, or it may mean that another component may be interposed between the component and any arbitrary element disposed (or positioned or placed) on (or under) the component.

[0028] Throughout the specification, unless otherwise specified, each element may be singular or plural. In addition, throughout the specification, when "A and / or B" is stated, this means A, B, or A and B, unless otherwise specified.

[0029] As used herein, "combinations thereof" may refer to mixtures, stacks, composites, copolymers, alloys, blends, and reaction products of the components.

[0030] Unless otherwise defined herein, the particle size may refer to the average particle size. In addition, the particle size represents the average particle size (D50), which refers to the particle size corresponding to 50% by volume in the volume cumulative distribution of the corresponding particles. The average particle size can be measured by any method known in the art (e.g., by a particle size analyzer, a transmission electron microscope image, or a scanning electron microscope image). Alternatively, the average particle size (D50) can be measured by counting the number of particles in each particle size range using a device using a dynamic light scattering method to analyze the data, and then calculating the average particle size (D50) based on the analyzed data. Alternatively, the average particle size (D50) can be measured by laser diffraction. More specifically, in the measurement by laser diffraction, the target particles are dispersed in a dispersant, introduced into a commercially available laser diffraction particle analyzer (e.g., MicrotracMT 3000), and irradiated with an ultrasonic wave of about 28kHz at a power of 60W, and then the average particle size (D50) corresponding to 50vol% by volume in the cumulative volume distribution of the particles in the measuring device is calculated.

[0031] Figures 1 to 4 is a schematic diagram of a lithium secondary battery according to some embodiments of the present invention.

[0032] Lithium secondary battery 100

[0033] Lithium secondary batteries may be classified into cylindrical secondary batteries, polyhedral or prismatic secondary batteries, pouch-type secondary batteries, coin-type secondary batteries, and the like based on their shapes. Figures 1 to 4 is a schematic diagram of a lithium secondary battery according to some embodiments of the present invention, wherein Figure 1 A cylindrical secondary battery is shown, Figure 2 A polyhedral or prismatic secondary battery is shown, Figure 3 and Figure 4 A pouch type secondary battery is shown. Figures 1 to 4 , the lithium secondary battery 100 may include an electrode assembly 40 in which a separator 30 is interposed between a positive electrode 10 and a negative electrode 20, and a case 50 in which the electrode assembly 40 is accommodated. The positive electrode 10, the negative electrode 20, and the separator 30 may be embedded in an electrolyte (not shown). Figure 1 As shown, the lithium secondary battery 100 may include a sealing member 60 that seals the housing 50. In one embodiment, as shown in FIG. Figure 2 As shown, the lithium secondary battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. Figure 3 and Figure 4 As shown, the lithium secondary battery 100 may include an electrode tab 70 including a positive electrode tab 71 and a negative electrode tab 72 , and the electrode tab 70 serves as an electrical path for conducting current formed in the electrode assembly 40 to the outside.

[0034] Cathode Materials

[0035] As the positive electrode material, a compound that allows reversible insertion and extraction of lithium (lithiated insertion compound) may be used. In one embodiment, the positive electrode material may be at least one composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and a combination thereof.

[0036] The composite oxide may be a lithium transition metal composite oxide. In one embodiment, the composite oxide may be lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate compound, cobalt-free nickel manganese oxide or a combination thereof.

[0037] For example, the composite oxide may be a compound represented by any one of the following chemical formulas: Li a A 1- b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O 2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NeG b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG bO 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 2 G b O 4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO 4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe 2 (PO 4 ) 3 (0≤f≤2); and Li a FePO 4 (0.90≤a≤1.8).

[0038] In the above chemical formula, A is Ni, Co, Mn or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; L 1 It is Mn, Al or a combination thereof.

[0039] In one embodiment, the positive electrode material can be a positive electrode material with a high nickel content, and the positive electrode material with a high nickel content comprises 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% to 99 mol% nickel relative to 100 mol% of the metal other than lithium in the lithium transition metal composite oxide. The positive electrode material with a high nickel content can achieve high capacity and can therefore be applied to high capacity / high density lithium secondary batteries.

[0040] Positive electrode 10

[0041] The positive electrode 10 for the lithium secondary battery 100 may include a current collector and a positive active material layer formed on the current collector. The positive active material layer includes a positive electrode material and may further include a binder and / or a conductive material.

[0042] In one embodiment, the positive electrode may further include an additive capable of acting as a sacrificial positive electrode.

[0043] In one embodiment, the positive electrode material may be present in an amount of 90 wt % to 99.5 wt % based on 100 wt % of the positive electrode active material layer, and each of the binder and the conductive material may be present in an amount of 0.5 wt % to 5 wt % based on 100 wt % of the positive electrode active material layer.

[0044] The binder is used to attach the positive electrode material particles to each other and to attach the positive electrode material to the current collector.

[0045] The binder may include, for example, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc., but is not limited thereto.

[0046] In another embodiment, the binder may include any binder that becomes a fiber under shear. For example, the binder may include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polyolefin, or a mixture thereof.

[0047] The conductive material imparts conductivity to the electrode and may be any conductive material that does not cause chemical changes in the monomer when constructed. The conductive material may include, for example: carbon materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials in the form of metal powder or metal fiber, including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives, etc.; and mixtures thereof.

[0048] In one embodiment, the current collector may be Al, but is not limited thereto.

[0049] Anode Materials

[0050] The negative electrode material includes a material that allows reversible intercalation / deintercalation of lithium ions, lithium metal, a lithium metal alloy, a material capable of being doped into and dedoped from lithium, or a transition metal oxide.

[0051] The material that allows reversible insertion / deinsertion of lithium ions may include a carbon-based negative electrode material, such as crystalline carbon, amorphous carbon, or a combination thereof. Crystalline carbon may include, for example, graphite (such as natural graphite or artificial graphite) in an amorphous form, a plate form, a flake form, a spherical form, or a fiber form, and amorphous carbon may include, for example, soft carbon, hard carbon, mesoporous pitch carbide, calcined coke, etc.

[0052] The lithium metal alloy can be an alloy of lithium and can use metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0053] In one embodiment, the material that can be incorporated into lithium and de-doped therefrom can be a Si-based anode material or a Sn-based anode material. The Si-based anode material can be silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-Q alloy (where Q is selected from alkali metals, alkaline earth metals, Group XIII elements, Group XIV elements (excluding Si), Group XV elements, Group XVI elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based anode material can be Sn, SnO 2 , a Sn alloy, or a combination thereof.

[0054] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite can be prepared in the form of silicon particles with an amorphous carbon coating formed on their surface. For example, the silicon-carbon composite can include secondary particles (cores) composed of primary silicon particles and an amorphous carbon coating (shells) formed on the surface of the secondary particles. Amorphous carbon can also be located between the primary silicon particles such that, for example, the primary silicon particles are coated with amorphous carbon. The secondary particles can be dispersed in an amorphous carbon matrix.

[0055] The silicon-carbon composite can also include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating formed on the core.

[0056] In one embodiment, the Si-based anode material or the Sn-based anode material can be used in combination with a carbon-based anode material.

[0057] Anode 20

[0058] The anode 20 for the lithium secondary battery 100 can include a current collector and an anode active material layer formed on the current collector. The anode active material layer includes anode material and can also include a binder and / or a conductive material.

[0059] In one embodiment, for example, the anode active material layer can include 90 wt% to 99 wt% of anode material, 0.5 wt% to 5 wt% of binder, and 0 wt% to 5 wt% of conductive material.

[0060] The binder is used to attach the anode material particles to each other while attaching the anode material to the current collector. The binder can be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0061] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0062] The aqueous binder can be selected from the group consisting of styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluorinated rubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and combinations thereof.

[0063] When a water binder is used as a negative electrode binder, a cellulose compound capable of imparting viscosity may be further included. The cellulose compound may be carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose or a mixture of alkali metal salts thereof. The alkali metal may be Na, K or Li.

[0064] The dry binder may be a fibrous polymeric material and may include, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or combinations thereof.

[0065] The conductive material imparts conductivity to the electrode and may be any conductive material that does not cause chemical changes in the monomer when constructed. In one embodiment, the conductive material may include, for example: a carbon material such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; a metal-based material in the form of a metal powder or metal fiber, including copper, nickel, aluminum, silver, etc.; a conductive polymer such as a polyphenylene derivative, etc.; or a mixture thereof.

[0066] In one embodiment, the negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a conductive metal-coated polymer matrix, and combinations thereof.

[0067] Electrolyte (not shown)

[0068] In one embodiment, the electrolyte for the lithium secondary battery 100 includes a non-aqueous organic solvent and a lithium salt.

[0069] The nonaqueous organic solvent serves as a medium through which ions participating in the electrochemical reaction of the monomer can move.

[0070] The non-aqueous organic solvent may be a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent, a non-amphoteric solvent or a combination thereof.

[0071] The carbonate-based solvent may include any one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).

[0072] The ester solvent may include any one of methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonolactone, valerolactone, caprolactone, and the like.

[0073] The ether solvent may include any one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. In addition, the ketone solvent may include cyclohexanone, etc. The alcohol solvent may include any one of ethanol, isopropanol, etc., and the non-amphoteric solvent may include: nitrile, such as R-CN (wherein R is a linear, branched or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring or an ether group); amide, such as dimethylformamide; dioxolane, such as 1,3-dioxolane, 1,4-dioxolane; cyclopentane; and the like.

[0074] The nonaqueous organic solvent may be used alone or as a mixture thereof.

[0075] When the carbonate-based solvent is used, a mixture of a cyclic carbonate and a chain carbonate may be used, and in one embodiment, the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of 1:1 to 1:9.

[0076] Lithium salts are substances that are soluble in organic solvents and serve as a source of lithium ions in batteries, enabling alkaline lithium secondary batteries to operate while facilitating the transfer of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts may include LiPF 6 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiClO 4 、LiAlO 2 、LiAlCl 4 、LiPO 2 F 2 、LiCl、LiI、LiN(SO 3 C 2 F 5 ) 2 、Li(FSO 2 ) 2 N (Lithium bis(fluorosulfonyl)imide (LiFSI)), LiC 4 F 9SO 3 、LiN(C x F 2x+1 SO 2 )(C y F 2y+1 SO 2 ) (wherein x and y are integers of 1 to 20), at least one selected from lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB) and lithium bis(oxalato)borate (LiBOB).

[0077] Diaphragm 30

[0078] Depending on the type of the lithium secondary battery 100, the separator 30 may be interposed between the positive electrode 10 and the negative electrode 20. For such a separator 30, polyethylene, polypropylene, polyvinylidene fluoride, or two or more layers thereof, and a mixed layer (such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polyethylene / polyethylene / polypropylene three-layer separator, etc.) may be used.

[0079] The separator 30 may include a porous substrate and a coating on one or both surfaces of the porous substrate, the coating including an organic material, an inorganic material, or a combination thereof.

[0080] The porous substrate can be a polymer layer formed from a polymer selected from the following: polyolefins (such as polyethylene, polypropylene, etc.), polyesters (such as polyethylene terephthalate, polybutylene terephthalate, etc.), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, Teflon and polytetrafluoroethylene, copolymers thereof, or mixtures thereof.

[0081] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0082] Inorganic materials can include Al 2 O 3 、SiO 2 、TiO 2 SnO 2 、CeO 2 , MgO, NiO, CaO, GaO, ZnO, ZrO 2 , Y 2 O 3 、SrTiO 3 、BaTiO 3 Mg(OH) 2 , boehmite and combinations thereof, but are not limited thereto.

[0083] The organic material and the inorganic material may exist in a mixed state in one coating layer, or may exist in the form of a stacked structure of a coating layer including an organic material and a coating layer including an inorganic material.

[0084] exist Figures 1 to 4 , a lithium secondary battery 100 according to some embodiments is shown. Here, an electrode included in such a secondary battery 100 will be described. An electrode manufacturing apparatus, an electrode manufacturing method, and an electrode manufactured by an apparatus and / or method for manufacturing an electrode will be described here. Here, the electrode described herein may include Figures 1 to 4 The positive electrode 10 and the negative electrode 20 are shown as either or both thereof. For ease of description, the electrodes will be collectively referred to as the electrode 300 rather than being referred to as the positive electrode 10 or the negative electrode 20 individually.

[0085] Figure 5 FIG. 1 is a diagram of an electrode manufacturing apparatus according to an embodiment of the present invention.

[0086] exist Figure 5 In the figure, reference numeral 200 indicates an electrode manufacturing device according to an embodiment of the present invention. Figure 5 In the figure, reference numerals 311 and 312 denote self-supporting films. Figure 5 , reference numeral 320 denotes a current collector.

[0087] The electrode manufacturing apparatus 200 according to this embodiment of the present invention manufactures the electrode 300. The electrode 300 includes Figures 1 to 4 The electrode manufacturing apparatus 200 performs, for example, roll-rolling and / or lamination.

[0088] Here, roll calendering is a process for producing a powder mixture into a self-supporting film, which is a dry electrode sheet. Lamination is a process for stacking a self-supporting film on at least one surface of a current collector. These processes will be described in more detail below.

[0089] In one embodiment, to perform these processes, the electrode manufacturing apparatus 200 includes a film conveyor (201, 202), a current collector conveyor 203, and a roller 210 having a surface treatment area 220 formed thereon. However, it will be understood that the electrode manufacturing apparatus 200 is not limited to Figure 5 The electrode manufacturing apparatus 200 may include, in addition to Figure 5 More components than those shown and / or may be omitted Figure 5 At least some of the components shown.

[0090] The film conveyors ( 201 , 202 ) convey the self-supporting films 311 , 312 from some components of the electrode manufacturing apparatus 200 toward other components thereof.

[0091] In one embodiment, the self-supporting films 311, 312 are formed by applying a shear force to the dry mixture. For example, the roller 210 can apply a shear force to the dry mixture to form the self-supporting films 311, 312. In another embodiment, Figure 5 Rollers not shown in the figure can apply shear force to the dry mixture to form self-supporting films 311, 312. In one embodiment, the dry mixture is prepared by mixing the electrode material, the binder and the conductive material without a liquid medium (such as a solvent or a dispersant). The electrode material, the binder and the conductive material can be mixed with Figures 1 to 4 The same or similar to those shown.

[0092] The self-supporting film includes a first film 311 conveyed toward the first roller 211 in the first direction P1 and a second film 312 conveyed toward the second roller 212 in the second direction P2. However, in one embodiment, for the self-supporting film, only at least one of the first film 311 and the second film 312 may be conveyed to the roller 210 by the film conveyor (201, 202). In this case, the self-supporting films 311, 312 may be stacked on one surface of the current collector 320. However, for ease of description, reference will be made to Figure 5 The following description is given regarding a process of stacking the self-supporting films 311 , 312 on both surfaces of the current collector 320 by way of example.

[0093] For example, the film conveyor may include a first film conveyor 201 and / or a second film conveyor 202. For example, the first film conveyor 201 conveys the first film 311 toward the first roller 211. For example, the second film conveyor 202 conveys the second film 312 toward the second roller 212.

[0094] The current collector conveyor 203 conveys the current collector 320 from some components of the electrode manufacturing apparatus 200 toward other components thereof. Figures 1 to 4 The current collectors shown are the same or similar.

[0095] For example, the current collector conveyor 203 may convey the current collector 320 toward the roller 210 in the third direction P3. In one embodiment, the third direction P3 may be a direction perpendicular to the first direction P1 and / or the second direction P2. The first direction P1 and the second direction P2 may be opposite directions. The current collector conveyor 203 conveys the current collector 320 toward the gap between the first roller 211 and the second roller 212.

[0096] The roller 210 performs roller calendering and / or lamination of the self-supporting films 311, 312 and / or the current collector 320. To this end, the roller 210 includes a first roller 211 and a second roller 212. The roller 210 has at least one surface treatment region 220 on at least a portion of a surface thereof.

[0097] The first roller 211 and the second roller 212 are spaced apart from each other. In one embodiment, the first roller 211 and the second roller 212 are spaced apart from each other by a distance equal to the combined thickness of one or both self-supporting films 311, 312 and the current collector 320. However, the gap between the first roller 211 and the second roller 212 can be adjusted based on the rolling pressure applied by the roller 210 to the electrode 300. For example, when the roller 210 applies a high rolling pressure to the electrode 300, the gap between the first roller 211 and the second roller 212 can be narrowed. In one embodiment, when the roller 210 applies a low rolling pressure to the electrode 300, the gap between the first roller 211 and the second roller 212 can be widened.

[0098] The first roller 211 and the second roller 212 are spaced apart from each other (as described above) while being positioned adjacent to each other. In addition, the first roller 211 and the second roller 212 rotate in opposite directions. For example, the first roller 211 rotates in a first rotation direction "a", and the second roller 212 rotates in a second rotation direction "b". For example, when the first rotation direction "a" is a clockwise direction, the second rotation direction "b" is a counterclockwise direction.

[0099] As described above, the current collector conveyer 203 conveys the current collector 320 toward the gap between the first roller 211 and the second roller 212. The current collector conveyer 203 conveys the current collector 320 toward the gap between the first self-supporting film 311 conveyed by the first roller 211 and the second self-supporting film 312 conveyed by the second roller 212.

[0100] As such, the roll 210 may perform a lamination process by which the first self-supporting film 311 is stacked on a surface of the current collector 320 and the second self-supporting film 312 is stacked on the other surface of the current collector 320 through the first roll 211 and the second roll 212 adjacent to each other.

[0101] Roller 210 includes a surface treatment area 220 on at least a portion of its surface. For example, first roller 211 may have a first surface treatment area 221 formed on at least a portion of its surface. For example, second roller 212 may have a second surface treatment area 222 formed on at least a portion of its surface.

[0102] The surface treatment area 220 may induce an anchoring phenomenon with respect to the self-supporting films 311 , 312 .

[0103] For example, when the roller 210 rotates, the surface treatment area 220 moves in a direction close to the self-supporting films 311, 312 to adhere to the self-supporting films 311, 312. In one embodiment, the surface treatment area 220 includes one or more protrusions to increase the adhesion to the self-supporting films 311, 312. The one or more protrusions may have, for example, an uneven shape, a dome shape, etc. 7A to 9C The protrusions are described in more detail.

[0104] In addition, for example, when the roller 210 rotates, the surface treatment area 220 moves in a direction away from the self-supporting films 311, 312 to be separated from the self-supporting films 311, 312. As a result, the surface treatment area 220 forms a pattern on at least a portion of the self-supporting films 311, 312 when separated from the self-supporting films 311, 312. For example, the surface treatment area 220 may form a non-coating area on at least a portion of the self-supporting films 311, 312.

[0105] In one embodiment, one of the first roller 211 and the second roller 212 may not have a surface treatment area 220 on at least a portion of its surface. In addition, the first surface treatment area 221 and the second surface treatment area 222 may include protrusions having the same shape, pitch, and size, or may include protrusions having different shapes, pitches, and / or sizes.

[0106] In this way, the roll 210 may perform roll calendering through the rolls 211 , 212 adjacent to each other and the surface treatment area 220 on the roll 210 to form the self-supporting films 311 , 312 and patterns on the self-supporting films 311 , 312 .

[0107] In this manner, the electrode manufacturing apparatus 200 according to an embodiment of the present invention can form a dry electrode having a pattern formed on at least a portion of its surface. In addition, the electrode manufacturing apparatus 200 can form a dry electrode applicable to various single form factors.

[0108] Figure 6 : is a flowchart showing a method for manufacturing an electrode according to one embodiment of the present invention.

[0109] Figure 6 Show use Figure 5 The electrode manufacturing apparatus 200 shown in the figure is a method for manufacturing an electrode. Figure 6 Each task or step shown may not be completed by Figure 5 For example, the electrode manufacturing method can be performed by an electrode manufacturing device 200 capable of performing Figure 6 Each task or step shown is performed by a facility, equipment, or system including the same.

[0110] The electrode manufacturing method according to one embodiment includes a task or step of applying a shear force to the dry mixture to form a self-supporting film 311, 312 (S101). Figure 5 As shown, roller 210 can apply shear force to the dry mixture to form self-supporting films 311, 312. The description of task or step S101 can be similar to Figure 5 The contents shown are the same or similar.

[0111] The electrode manufacturing method according to an embodiment includes a task or step (S102) of transferring the self-supporting films 311 and 312 toward the roller 210 to form a pattern on the self-supporting films 311 and 312. The surface treatment area 220 formed on the surface of the roller 210 can form a pattern on the self-supporting films 311 and 312 through an anchoring effect. The description of the task or step S102 can be the same as Figure 5 The contents shown are the same or similar.

[0112] The electrode manufacturing method according to an embodiment includes a task or step of stacking self-supporting films 311, 312 on the current collector 320 (S103). The roller 210 applies pressure to the current collector 320 and the self-supporting films 311, 312 placed on both surfaces (or one surface) of the current collector 320 through the first roller 211 and the second roller 212. As a result, the roller 210 stacks the self-supporting films 311, 312 on one or both surfaces of the current collector 320 to form the electrode 300. The description of the task or step S103 can be the same as Figure 5 The contents shown are the same or similar.

[0113] However, depending on the location of the surface treatment area 220 on the surface of the roller 210 , tasks or steps S102 and S103 may be performed sequentially, simultaneously (eg, at the same time), and / or in reverse order.

[0114] In this manner, the electrode manufacturing method according to an embodiment of the present invention can form a dry electrode having a pattern formed on at least a portion of its surface. In addition, the electrode manufacturing method can form a dry electrode applicable to various single form factors.

[0115] 7A to 7C is a raised view according to some embodiments of the present invention.

[0116] FIG. 8A to FIG. 8C is a raised view according to some embodiments of the present invention.

[0117] As reference Figure 5 and Figure 6 As described above, the surface treatment area 220 includes one or more protrusions 230. For example, the surface treatment area 220 may be formed into an uneven shape and / or a dome shape by the one or more protrusions 230.

[0118] In one embodiment, the protrusion 230 has at least one of the following shapes: a polygonal cone shape including at least one of a triangular cone shape, a pyramid shape, a pentagonal cone shape, and a hexagonal cone shape; a spiral shape; and a conical shape.

[0119] However, the protrusion 230 is not limited thereto and may be formed in any shape tapering from its lower portion toward its upper portion. In another embodiment, even if the protrusion 230 does not taper from its lower portion toward its upper portion, the protrusion 230 may be formed in any shape as long as the protrusion 230 has a pointed upper end.

[0120] In this way, the protrusion 230 may have a pointed shape or a shape narrower at the upper portion than at the lower portion to increase the adhesion to the self-supporting films 311, 312. Here, the lower portion refers to a portion close to the surface of the roller 210, and the upper portion refers to a portion located away from the surface of the roller 210. Since the upper portion is located away from the surface of the roller 210, the upper portion may be located closer to the self-supporting film 311, 312 facing the roller 210 than the lower portion. That is, the upper portion of the protrusion 230 may contact the self-supporting films 311, 312, and then the lower portion thereof may contact the self-supporting films 311, 312.

[0121] 7A to 7C and FIG. 8A to FIG. 8C Various shapes of protrusions 230 are shown. FIG. 7A to FIG. 7C is a schematic top view of the protrusion 230, FIG. 8A to FIG. 8C is a schematic side view of the protrusion 230 .

[0122] Reference Fig. 7A For example, the protrusion 230a may be formed in a pyramid shape. For example, the first protrusion 231a and the second protrusion 232a may have the same pyramid shape and may be spaced apart from each other by a distance (eg, a predetermined distance).

[0123] In one embodiment, the protrusion 230a may be formed to have a portion biased toward the first side, such as Fig. 8A The expression "formed to have an offset portion" means that the center of gravity of the protrusion 230a is not on the same vertical line with the center of gravity of the bottom surface of the protrusion 230a relative to the surface of the roller 210. In another embodiment, for example, when the upper portion of the protrusion 230a includes a pointed tip, as shown in FIG. Fig. 8A As shown, the tip of the upper portion of the protrusion 230a and the center of gravity of the bottom surface of the protrusion 230a are not on the same vertical line relative to the surface of the roller 210a.

[0124] Here, the direction in which the protrusion 230a is biased toward the first side is, for example, the rotation direction of the roller 210. Figure 5In the illustrated first roller 211 , the direction in which the protrusion 230 a is biased toward the first side is the first rotation direction “a”.

[0125] In another embodiment, the protrusion 230b may be formed into a hexagonal cone, for example. Figure 7B For example, the first protrusion 231b and the second protrusion 232b may have the same hexagonal cone shape and may be spaced apart from each other by a distance (eg, a predetermined distance). In addition, like the protrusion 230a, the protrusion 230b may be formed to have a portion biased toward the first side, such as Figure 8B shown.

[0126] In another embodiment, Figure 7C As shown, for example, the protrusion 230c may be formed in a spiral shape. For example, the first protrusion 231c and the second protrusion 232c have the same spiral shape and may be spaced apart from each other by a distance (e.g., a predetermined distance) in the lateral direction. In addition, like the protrusion 230a and / or the protrusion 230b, the protrusion 230c may be formed to have a portion biased toward the first side, such as Figure 8C shown.

[0127] like FIG. 7A to FIG. 7C and FIG. 8A to FIG. 8C As shown, in one embodiment, the protrusion 230 may be formed to have a portion offset in the rotation direction of the roller 210. With such a shape, the protrusion 230 can further improve the adhesion (eg, mechanical adhesion) to the self-supporting films 311 and 312. However, as described above, FIG. 7A to FIG. 7C and FIG. 8A to FIG. 8C The illustrated shapes of the protrusions 230 are provided for illustration purposes, and thus all or some of one or more protrusions 230 may not be formed to have a portion biased toward the first side.

[0128] In one embodiment, although there is no Figures 5 to 8C , but the surface treatment area 220 may further include a cutting portion (not shown) at its proximal and / or distal ends to cut the self-supporting films 311, 312. In one embodiment, the cutting portion may be formed as a knife-shaped hurdle. With this structure, the cutting portion allows the surface treatment area 220 to more easily form a pattern on the self-supporting films 311, 312.

[0129] Reference 7A to 7C and FIG. 8A to FIG. 8C , the shape of the protrusion 230 is described above. Next, refer to 9A to 9C , the relationship between the surface processed areas 220 and the relationship between the protrusions 230 will be described.

[0130] 9A to 9C are views of rollers and surface treatment areas according to some embodiments of the present invention.

[0131] According to an embodiment, the roller 210 may include one or more surface treatment areas 220 on at least a portion of its surface.

[0132] For example, Fig. 9A As shown, roller 210 may include a single surface treatment area 220 .

[0133] In another embodiment, for example, Fig. 9B As shown, the roller 210 may include a plurality of surface treatment areas 220. In one embodiment, when the roller 210 includes a plurality of surface treatment areas 220, the surface treatment areas 220 may be arranged at the same intervals. In one embodiment, for example, the plurality of surface treatment areas 220 include surface treatment areas 220a, surface treatment areas 220b, and surface treatment areas 220c. In one embodiment, the distance between the surface treatment areas 220a and 220b may be the same as the distance between the surface treatment areas 220a and 220c and the distance between the surface treatment areas 220b and 220c. However, in all or at least some of the surface treatment areas, the distances between the surface treatment areas 220 may be different from each other.

[0134] Reference above Figure 5 The first roller 211 and the second roller 212 are described as including a structure having protrusions 230 of different shapes. In one embodiment, the first roller 211 and the second roller 212 may have different numbers of surface treatment areas 220 on their surfaces. For example, the first roller 211 may include a surface treatment area 220 (such as Fig. 9A As shown, the second roller 212 may include a plurality of surface treatment areas 220 (such as Fig. 9B As shown). Thus, for the electrode manufacturing apparatus 200, various shapes and numbers of surface treatment regions 220 and / or protrusions 230 may be provided depending on the characteristics of the electrode 300 to be manufactured (for example, depending on the length of the non-coated region of the electrode 300 corresponding to the negative electrode 10).

[0135] Fig. 9C 2 is a schematic enlarged view of the protrusion 230 formed on the roller 210. Fig. 9C , the protrusions 230 in the surface treatment area 220 and the relationship between two or more protrusions 230 will be described.

[0136] like Fig. 9C As shown, the protrusion 230 is formed to a height (eg, a predetermined height) "h" from the surface of the roller 210. In one embodiment, the height "h" is in a range of, for example, 2 μm to 150 μm.

[0137] In addition, if Fig. 9C As shown, the plurality of protrusions are formed to be spaced apart from each other by a distance (e.g., a predetermined distance) "d". For example, the first protrusion 231 and the second protrusion 232 are spaced apart from each other by a distance "d". Here, the distance between the first protrusion 231 and the second protrusion 232 refers to the distance between the side of the first protrusion 231 and the side of the second protrusion 232. Here, the side of the first protrusion 231 refers to the side close to the second protrusion 232, and the side of the second protrusion 232 refers to the side close to the first protrusion 231. That is, the distance between the first protrusion 231 and the second protrusion 232 is the closest straight-line distance between the first protrusion 231 and the second protrusion 232. In one embodiment, the distance "d" is in the range of, for example, 1 μm to 100 μm.

[0138] With this structure, the protrusions 230 are patterned on the self-supporting films 311, 312 without damaging the self-supporting films 311, 312 and / or the current collector 320. However, the height "h" may vary depending on the thickness of the electrode 300 to be manufactured and / or the thickness and properties of the self-supporting films 311, 312.

[0139] Fig.10 FIG. 1 is a diagram of an electrode manufacturing apparatus according to an embodiment of the present invention.

[0140] As reference Figures 5 to 9C As described above, the electrode manufacturing apparatus 200 according to an embodiment includes a roller 210. In addition, the roller 210 may have a surface treatment area 220 formed on its surface. In addition, the surface treatment area 220 may include one or more protrusions 230, such as Figures 5 to 9C With this configuration, the electrode manufacturing apparatus 200 forms patterns on the self-supporting films 311 and 312 .

[0141] In one embodiment, the roller 210 is attached to the self-supporting films 311 , 312 by an anchoring effect and then released from the self-supporting films 311 , 312 , so that at least some portions of the self-supporting films 311 , 312 are separated from the self-supporting films 311 , 312 to be transferred to the surface of the roller 210 .

[0142] For example, the first surface treatment area 221 allows the first transfer film 311f to be transferred from the first self-supporting film 311 to the first roller 211. In addition, the second surface treatment area 222 allows the second transfer film 312f to be transferred from the second self-supporting film 312 to the second roller 212. In this way, the transfer films 311f, 312f, which are parts of the self-supporting films 311, 312, are separated from the self-supporting films 311, 312 to form patterns on the self-supporting films 311, 312.

[0143] Here, a method of processing the transfer films 311f, 312f transferred to the roller 210 is required.

[0144] In one embodiment, the electrode manufacturing apparatus 200 further includes a film collector 240 including a first film collector 241 and a second film collector 242. The first film collector 241 and the second film collector 242 remove the transfer films 311f, 312f from the roller 210 and / or collect the transfer films 311f, 312f.

[0145] The first film collector 241 and the second film collector 242 are, for example, disposed below the roller 210. In one embodiment, the film collector 240 is disposed below the roller 210 to be spaced a certain distance from the electrode 300. Here, the film collector 240 may be disposed at a position that facilitates collecting the transfer films 311f, 312f from the roller 210.

[0146] In one embodiment, for example, the first film collector 241 is disposed under the first roller 211 and collects the first transfer film 311f transferred to the first roller 211, and the second film collector 242 is disposed under the second roller 212 and collects the second transfer film 312f transferred to the second roller 212. In an embodiment in which the surface treatment area 220 is formed on only one of the two rollers, the film collector 240 may be formed only under the roller on which the surface treatment area 220 is formed.

[0147] In one embodiment, each of the film collectors 241, 242 includes a suction device that sucks the transfer film 311f, 312f, for example, via vacuum. In one embodiment, each of the film collectors 241, 242 includes, for example, a brush that sweeps the transfer film 311f, 312f to collect the transfer film 311f, 312f in a specific direction. However, it will be understood that the film collectors 241, 242 are not limited thereto and may have any suitable configuration capable of removing or collecting the transfer film 311f, 312f from the roller 210.

[0148] With this configuration, the electrode manufacturing apparatus 200 according to an embodiment allows the roller 210 to operate continuously without being stopped or blocked by the transfer films 311f, 312f. In addition, the electrode manufacturing apparatus 200 allows the transfer films 311f, 312f to be collected and recycled for use in manufacturing the self-supporting films 311, 312. In other words, the electrode manufacturing apparatus 200 enables resource recycling, thereby contributing to environmental and cost-effectiveness.

[0149] Fig.11A and Fig. 11B is a diagram of an electrode according to some embodiments of the present invention.

[0150] FIG. 11A to FIG. 11B Shown by Figures 5 to 10 The electrode 300 is manufactured by the electrode manufacturing apparatus 200 and / or the electrode manufacturing method shown.

[0151] Reference FIG. 11A to FIG. 11B , the electrode 300 according to this embodiment includes a current collector 320 and self-supporting films 311, 312 formed on one or both surfaces of the current collector 320. Here, each of the self-supporting films 311, 312 has a pattern on a surface thereof.

[0152] In one embodiment, for example, FIG. 11A to FIG. 11B As shown, the pattern 310p may be formed only on the self-supporting film 312 stacked on one surface of the current collector 320 among the self-supporting films 311 and 312 stacked on both surfaces of the current collector 320. In one embodiment, the distance between the patterns 310p formed on the self-supporting films 311 and 312 and / or the shape of the patterns 310p corresponds to Fig.10 In another embodiment, the distance between the patterns 310p formed on the self-supporting films 311 and 312 and / or the shape of the patterns 310p corresponds to 7A to 9C The distance between the protrusions 230 and / or the shape of the protrusions 230 are shown. In another embodiment, the pattern may be formed on the self-supporting films 311 , 312 stacked on both surfaces of the current collector 320 among the self-supporting films 311 , 312 formed on both surfaces of the current collector 320 .

[0153] As such, the electrode 300 according to an embodiment may include a pattern on a surface thereof. Therefore, the electrode 300 according to an embodiment may be applied to a variety of single form factors.

[0154] Thus, the electrode manufacturing apparatus 200 and / or the electrode manufacturing method according to one or more embodiments of the present invention provides a dry electrode having a pattern formed on its surface. In addition, the battery cell 100 (including, for example, a secondary battery, such as in Figures 1 to 11B In addition, the battery cell 100 and / or the battery module including the battery cell 100 according to an embodiment of the present invention may be applied to automobiles, mobile phones and / or various forms of electrical devices, etc., without being limited thereto.

[0155] Although the present invention has been described with reference to some example embodiments and the accompanying drawings showing aspects thereof, the present invention is not limited thereto. Various modifications and changes may be made by those skilled in the art within the technical spirit of the present invention and the scope of the claims and their equivalents.

[0156] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0163396 filed in the Korean Intellectual Property Office on November 22, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. An electrode manufacturing device, comprising: a roller comprising a first roller comprising at least one first surface treatment area on at least a portion of a surface thereof and a second roller spaced apart from the first roller and rotatable in a different direction than the first roller; a film conveyor for conveying the self-supporting film toward the first roller; as well as A current collector conveyer conveys a current collector toward a gap between the first roller and the second roller to stack the self-supporting film on a surface of the current collector through the rollers. 2 . The electrode manufacturing apparatus of claim 1 , wherein the at least one first surface treatment region comprises a plurality of protrusions to form a pattern on at least a portion of the self-supporting film. 3 . The electrode manufacturing apparatus according to claim 2 , wherein each of the protrusions tapers from a lower portion thereof toward an upper portion thereof. 4 . The electrode manufacturing apparatus according to claim 2 , wherein the protrusion has a height of 2 μm to 150 μm. 5 . The electrode manufacturing apparatus according to claim 2 , wherein the protrusions are arranged at intervals of 1 μm to 100 μm.

6. The electrode manufacturing device according to claim 2, wherein the protrusion is formed in at least one of a polygonal cone, a spiral shape and a cone shape, and the polygonal cone includes at least one of a triangular cone, a pyramid shape, a pentagonal cone and a hexagonal cone. 7 . The electrode manufacturing apparatus according to claim 2 , wherein the protrusion includes an upper portion biased toward the first side. 8 . The electrode manufacturing apparatus according to claim 7 , wherein the first side is a rotation direction of the roller. 9 . The electrode manufacturing apparatus of claim 1 , wherein the second roller includes a second surface treatment region on at least a portion of a surface thereof, the second surface treatment region forming a pattern on at least a portion of the self-supporting film. 10 . The electrode manufacturing apparatus according to claim 1 , further comprising a film collector which collects a transfer film separated from the self-supporting film and transferred to the roller. 11 . The electrode manufacturing apparatus according to claim 10 , wherein the film collector comprises at least one of a suction device that sucks the transfer film and a brush that sweeps the transfer film.

12. An electrode manufactured by the electrode manufacturing apparatus according to claim 1, the electrode comprising: current collector; and a self-supporting film stacked on the current collector and having a pattern formed on a surface thereof.

13. A method for manufacturing an electrode, comprising: applying shear force to the dry mixture to form a self-supporting film; forming a pattern on the self-supporting film by conveying the self-supporting film toward a first roller including a surface treatment area thereon; as well as The current collector is conveyed toward the first roller and a second roller positioned adjacent to the first roller to stack the self-supporting film on the current collector.

14. The electrode manufacturing method according to claim 13, wherein forming the pattern on the self-supporting film comprises: attaching the surface treatment region to the self-supporting film; as well as The surface treatment area is separated from the self-supporting film to form the pattern.

15. The electrode manufacturing method according to claim 14, further comprising: The transfer film separated from the self-supporting film through the surface treatment area is collected.

16. An electrode manufactured by the electrode manufacturing method according to claim 13, the electrode comprising: current collector; and a self-supporting film stacked on the current collector and having a pattern formed on a surface thereof.

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