Manufacturing method for electrode body

Abstract

To provide a manufacturing method for an electrode body that can improve productivity.SOLUTION: A manufacturing method for an electrode body includes a drying step of drying an electrode material while conveying a work in which the electrode material is applied on at least one surface of a current collector. The work has a penetration hole that penetrates the current collector in a part where the electrode material is not applied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing an electrode assembly. [Background technology]

[0002] Various techniques have been proposed for manufacturing an electrode assembly as disclosed in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-029256 A [Patent Document 2] JP 2009-238924 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, when electrode material is transported and dried in a limited space, it is difficult to achieve ventilation between the front and back surfaces of the workpiece, and it is difficult to generate airflow that passes between the front and back surfaces of the workpiece, resulting in poor drying efficiency (low productivity).

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a method for manufacturing an electrode assembly that can improve productivity. [Means for solving the problem]

[0006] That is, the present disclosure includes the following aspects. <1> A method for manufacturing an electrode assembly, comprising the steps of: a drying step of drying the electrode material while transporting a workpiece having an electrode material applied on at least one surface of a current collector; The method for manufacturing an electrode assembly, wherein the workpiece has a through hole penetrating the current collector in an uncoated portion of the electrode material. This makes it easier for the workpiece to ventilate from the front to the back, and allows it to be dried under favorable conditions without steam or the like remaining.

[0007] <2> The workpiece is for a bipolar electrode. <1> A method for producing the electrode assembly according to claim 1. If the workpiece is for a bipolar electrode, with electrode material on both the front and back, the drying conditions on both sides of the workpiece can be considered. Effect of the Invention

[0008] The manufacturing method of the electrode assembly according to the present disclosure can improve productivity. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of the manufacturing method of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram showing an example of the welding process of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described. Note that matters other than those specifically mentioned in this specification and necessary for implementing the present disclosure (for example, the general configuration and manufacturing process of the electrode body that do not characterize the present disclosure) can be understood as design matters of a person skilled in the art based on the prior art in the field. The present disclosure can be implemented based on the contents disclosed in this specification and the technical common sense in the field. Furthermore, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect the actual dimensional relationships.

[0011] The present disclosure provides a method for producing an electrode assembly, comprising: A drying step of transporting and drying a workpiece having an electrode material applied on at least one surface of a current collector, The workpiece has a through hole penetrating the current collector in an uncoated portion of the electrode material, thereby providing a method for manufacturing an electrode assembly.

[0012] In the present disclosure, the current collector has a structure in which there are slits (through holes) in the uncoated parts of the electrode material. The through holes can create airflow between the back and front surfaces, improving the drying efficiency of the electrode material and improving the productivity of the electrode body.

[0013] (drying process) The method for producing an electrode assembly according to the present disclosure includes a drying step. The drying step is a step of drying the electrode material while transporting a workpiece having a current collector with the electrode material applied on at least one surface thereof. In the drying process, a drying device may be used to dry the electrode material. The drying device may be a conventionally known device capable of drying the electrode material, such as a hot air device, a laser device, or an IR (infrared) device, and these may be used in combination. In the drying process, the electrode material may be completely dried until the moisture content is several hundred ppm or less. In the drying process, the upper and lower surfaces of the workpiece may be dried by creating an air flow by supplying hot air from a hot air device under conditions suitable for each surface. In the drying step, the electrode material may be dried in a drying furnace. In the drying step, the workpiece may be placed on a carrier and transported. The transport speed may be, for example, 30 m / min or more. The drying temperature for the electrode material may be 100°C to 200°C. The drying time of the electrode material is not particularly limited. After the drying step, the electrode material becomes an electrode layer, and an electrode body including a current collector and an electrode layer formed on at least one surface of the current collector is obtained.

[0014] The workpiece includes a current collector and an electrode material applied to at least one surface of the current collector. The workpiece may be for a bipolar electrode having a current collector coated on both sides with electrode material, where the electrode material coated on one side of the current collector is a positive electrode material and the electrode material coated on the other side of the current collector is a negative electrode material.

[0015] The current collector may be a negative electrode current collector, a positive electrode current collector, a bipolar current collector, or the like. Examples of materials for the current collector include metals such as aluminum, copper, SUS, and nickel. The thickness of the current collector is, for example, 0.1 μm or more and 100 μm or less. The shape of the current collector may be a sheet or the like.

[0016] The electrode material is applied to at least one of the surfaces of the current collector, that is, a first surface. The electrode material may be applied only to the first surface of the current collector, or may be applied to both the first surface and a second surface opposite to the first surface of the current collector. The electrode material can be prepared by mixing a mixture containing an active material, a binder, a conductive material, an electrolyte, a thickener, etc., together with a solvent. The electrode material may be a positive electrode material or a negative electrode material. The electrode material may contain moisture of about 10,000 ppm or less.

[0017] The active material may be a positive electrode active material. Examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include LiCoO2, LiMnO2, LiNiO2, LiVO2, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc., rock salt layered active materials, LiMn2O4, Li(Ni 0.5 Mn 1.5 )O4 and the like; and olivine type active materials such as LiFePO4, LiMnPO4, LiNiPO4, and LiCuPO4.

[0018] The active material may be a negative electrode active material. Examples of the negative electrode active material include carbon active materials, oxide active materials, and metal active materials. Examples of the carbon active material include mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), hard carbon, and soft carbon. Examples of the oxide active material include Nb2O5, Li4Ti5O 12 and SiO. Examples of the metal active material include In, Al, Si, Sn, and the like.

[0019] Examples of the binder include fluorine-containing binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), rubber-based binders such as butadiene rubber, and acrylic-based binders.

[0020] Examples of conductive materials include carbon materials, metal particles, conductive polymers, etc. Examples of carbon materials include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as carbon fibers, carbon nanotubes (CNT), and carbon nanofibers (CNF).

[0021] Examples of thickeners include polysaccharides such as carboxymethylcellulose and methylcellulose.

[0022] Examples of the electrolyte include solid electrolytes such as sulfide solid electrolytes and oxide solid electrolytes. Examples of the sulfide solid electrolyte include solid electrolytes containing Li, X (X is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In), and S. The sulfide solid electrolyte may further contain at least one of O and halogen elements. Examples of the halogen elements include F, Cl, Br, and I.

[0023] Examples of oxide solid electrolytes include Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li 3.6 S 0.6 P 0.4 O4, Li4SiO4, Li3PO4, Li3PO 4-3 / 2x N x (x≦1).

[0024] Examples of the solvent include aqueous solvents and organic solvents. The aqueous solvent means water or a mixed solvent containing water and a polar organic solvent. For example, an appropriate solvent can be selected depending on the types of active material, binder, etc. As the aqueous solvent, water is preferably used because of its ease of handling. Examples of polar organic solvents that can be used in the mixed solvent include alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone, and ethers such as tetrahydrofuran. An example of the organic solvent is N-methyl-2-pyrrolidone (NMP).

[0025] (Through hole formation process) The method for producing an electrode assembly according to the present disclosure may include, prior to the drying step, a through-hole forming step of providing through-holes penetrating the current collector in uncoated portions of the electrode material. The workpiece has through holes that penetrate the current collector in the uncoated areas of the electrode material. The through holes create an air flow between the front and back sides of the workpiece in a drying furnace, allowing the electrode material to be dried efficiently. At least one through hole is sufficient, but multiple through holes may be provided. For example, one through hole may be provided when the workpiece cut surface is crossed, and two through holes may be provided at the front and rear in the conveying direction when the workpiece cut surface is not crossed. In addition, through holes may be provided on both sides in the conveying direction, mainly for weight reduction. The through holes may be drilled by reel-to-reel transport of the workpiece before the drying process. The through holes may be provided by laser cutting the current collector or by punching using a die.

[0026] (Welding process) The manufacturing method of the electrode assembly of the present disclosure may include a welding step of sealing the through holes with a resin sealant after the drying step. The through-holes may be closed with a resin sealant after the drying process. If the through-holes remain when the electrode body is modularized and liquid is poured, a liquid short circuit occurs between the electrode layers. Therefore, the through-holes may be provided at a location where a resin sealant that joins the electrode layers is heat-sealed in a process after the drying process. The through-holes can also be used to locate the resin sealant. For example, a convex portion that fits into the through-hole may be provided in the resin sealant, and the convex portion may be disposed in the through-hole. The height of the convex portion may be the same as the depth of the through-hole, i.e., the thickness of the current collector. In addition, the amount of metal punched out by the through-hole is reduced, thereby improving the energy density per weight of the battery. The resin sealing material may be a conventionally known thermoplastic resin or the like. A plurality of laminated electrode assemblies may be welded together with the resin sealing material by heating the resin sealing material.

[0027] FIG. 1 is a schematic diagram showing an example of the manufacturing method of the present disclosure. 1, the workpiece 1 has a current collector coated with an electrode material 6 and has an uncoated portion 7 of the electrode material 6. The workpiece 1 is transported in the transport direction, and a through hole 2 is formed in the uncoated portion 7 of the electrode material 6 of the workpiece 1 by a laser device 11 in a through hole forming process. In the drying process, hot air 50 is supplied from the front side of the workpiece 1 into the drying furnace 20 by the hot air device 22, and the workpiece 1 is heated by the laser device 21 in the drying furnace 20. The hot air 50 passes through the through hole 2, moves to the back side of the workpiece 1, and is exhausted from the exhaust hole 23. In the drying process, instead of the laser device 21, an IR device or the like may be used.

[0028] FIG. 2 is a schematic diagram showing an example of the welding process of the present disclosure. 2, after the drying process, the workpiece 1 is cut into sheets, and the through holes 2 of the workpiece 1 are blocked by the protrusions 4 of the resin sealant 3. A stack 5 formed by stacking a plurality of workpieces 1 is welded by the resin sealant 3. The through holes 2 provided on both sides in the conveying direction are provided mainly for weight reduction.

[0029] The electrode assembly obtained by the manufacturing method of the present disclosure includes a current collector and an electrode layer formed by drying an electrode material coated on at least one surface of the current collector. The electrode layer may be a positive electrode layer or a negative electrode layer. The electrode layer may contain one of a positive electrode active material and a negative electrode active material, and may further contain a binder, a conductive material, an electrolyte, etc. These materials are as described above. The current collector may be a negative electrode current collector, a positive electrode current collector, a bipolar current collector, etc. The material of the current collector, the thickness of the current collector, and the shape of the current collector are as described above.

[0030] The electrode assembly of the present disclosure is typically used in the manufacture of batteries. The electrode assembly may be a positive electrode, a negative electrode, or a bipolar electrode. A bipolar electrode comprises a positive electrode layer on one side of a current collector and a negative electrode layer on the other side of the current collector. The type of battery in which the electrode body is used is not particularly limited, and may be, for example, a lithium ion secondary battery. The battery may be a liquid battery using an electrolytic solution as an electrolyte, or a solid battery using a solid electrolyte as an electrolyte. Applications of the battery include, for example, power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline automobiles, and diesel automobiles. In particular, the battery may be used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery may also be used as a power source for moving objects other than vehicles (for example, railways, ships, and aircraft), and may also be used as a power source for electrical appliances such as information processing devices. [Explanation of symbols]

[0031] 1. Work 2.Through holes 3. Resin sealing materials 4. Convex part 5.Laminate 6. Electrode material 7. Uncoated area 11. Laser equipment 20.Drying oven 21. Laser equipment 22.Hot air device 23. Exhaust vent 50. Hot air

Claims

1. A method for manufacturing an electrode assembly, comprising the steps of: a drying step of drying the electrode material while transporting a workpiece having an electrode material applied on at least one surface of a current collector; The method for manufacturing an electrode assembly, wherein the workpiece has a through hole penetrating the current collector in an uncoated portion of the electrode material.

2. The method for manufacturing an electrode assembly according to claim 1 , wherein the workpiece is for a bipolar electrode.

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