Electrode manufacturing method

Abstract

To provide an electrode manufacturing method that can suppress binder migration.SOLUTION: A manufacturing method for an electrode having an electrode layer containing an active material and a binder includes a preparation step of preparing a workpiece having a current collector and an electrode layer disposed on a first surface of the current collector and having a through hole, and a drying step of drying the electrode layer after the preparation step.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Various techniques have been proposed for producing electrodes such as those disclosed in Patent Document 1. [Prior art documents] [Patent documents]

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

[0004] In the conventional technology, after the electrode body is irradiated with a laser, the electrode body is dried and then cut. Depending on the drying conditions, the binder in the electrode may move to the upper part where moisture is more likely to escape, which may affect the performance of the electrode, such as reducing the peel strength of the electrode.

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

[0006] In a first embodiment of the present disclosure, there is provided a method for producing an electrode having an electrode layer including an active material and a binder, comprising: A preparation step of preparing a workpiece including a current collector and the electrode layer disposed on a first surface of the current collector and having a through hole; The method for producing an electrode further comprises a drying step of drying the electrode layer after the preparing step.

[0007] In a second embodiment of the present disclosure, in the first embodiment, the preparation step may include a first step of providing the through holes in the current collector, and after the first step, a second step of creating the electrode layer having the through holes by applying an electrode paste to the first surface of the current collector.

[0008] In a third embodiment of the present disclosure, in the first or second embodiment, in the drying process, the electrode layer may be dried while transporting the workpiece using a transport body having air holes and sucking the workpiece through the air holes of the transport body.

[0009] In a fourth embodiment of the present disclosure, there is provided an electrode comprising an electrode layer including an active material and a binder, the electrode includes a current collector and the electrode layer is disposed on a first surface of the current collector and has a through hole; The electrode includes a through hole of the electrode layer having a diameter of 55 μm or more.

[0010] In a fifth embodiment of the present disclosure, in the fourth embodiment, the current collector may have the through holes having a diameter of 55 μm or more. Effect of the Invention

[0011] The electrode manufacturing method of the present disclosure can suppress the migration of the binder. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an example of a first embodiment of the present disclosure. [Diagram 2] FIG. 13 is a schematic diagram showing an example of a third embodiment of the present disclosure. [Diagram 3] FIG. 13 is a schematic diagram showing another example of the third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, 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 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.

[0014] 1. Electrode manufacturing method In a first embodiment of the present disclosure, there is provided a method for producing an electrode having an electrode layer including an active material and a binder, comprising: A preparation step of preparing a workpiece including a current collector and the electrode layer disposed on a first surface of the current collector and having a through hole; The method for producing an electrode further comprises a drying step of drying the electrode layer after the preparing step.

[0015] Conventionally, in the drying process, drying was only performed toward the top surface of the electrode layer, and steam could only escape from the top surface of the electrode layer, causing migration of the binder in the electrode layer to segregate to the top surface of the electrode layer. FIG. 1 is a schematic diagram showing an example of the first embodiment of the present disclosure. According to the first embodiment, the electrode layer 10 containing the active material 30 and the binder 40 has minute through holes 20, which allows moisture in the electrode layer 10 to escape not only upward but also laterally. This allows moisture to evaporate from surfaces other than the top surface of the electrode layer 10, suppresses movement of the binder 40 in the electrode layer 10, shortens the drying time, and improves quality.

[0016] The electrode obtained by the production method of the present disclosure comprises an electrode layer and a current collector. The electrode layer contains an active material and a binder, and may further contain a conductive material, an electrolyte, a thickener, and the like.

[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 inorganic 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] (1) Preparation process The preparation step is a step of preparing a workpiece including a current collector and the electrode layer that is disposed on a first surface of the current collector and has a through hole.

[0025] 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 roll.

[0026] The electrode layer is disposed on a first surface of the current collector. The electrode layer may be disposed only on the first surface of the current collector, or may be disposed on both the first surface and a second surface of the current collector that is the opposite surface to the first surface. The electrode layer can be prepared by applying an electrode paste, which is prepared by mixing the electrode material including the above-mentioned binder, active material, conductive material, electrolyte, thickener, etc. with a solvent such as water, onto the first surface of the current collector. The electrode paste may be a positive electrode paste or a negative electrode paste. The amount of the electrode paste applied to the current collector is, for example, 30 to 80 mg / cm. 2 The viscosity of the electrode paste may be, for example, 5,000 to 50,000 mPa·S.

[0027] The electrode layer has a through hole. Examples of a method for providing through-holes in the electrode layer include a method of irradiating the electrode layer with a laser. The wavelength and energy density of the irradiated laser are not particularly limited as long as the conditions are such that through-holes can be provided in the electrode layer, and can be appropriately set. The diameter of the through hole may be a size that does not block the applied electrode paste and does not drip from the through hole, and may be equal to or larger than the particle size of the largest particle contained in the electrode material, for example, 55 μm or more. The number of through holes may be one or more, and may be 100 or more in the workpiece conveying direction, or may be 176 or more in the workpiece conveying direction. The pitch at which the through holes are provided may be, for example, 5.7 mm or more. The pitch is calculated by (total width of the through holes)÷(number of through holes-1). By providing the through holes evenly, it is possible to suppress the occurrence of wrinkles in the electrode.

[0028] (1-1) First step In the second embodiment of the present disclosure, the preparation step may include a first step of providing the through holes in the current collector. The method for providing the through holes in the current collector can be the same as the method for providing the through holes in the electrode layer described above. The diameter, number and pitch of the through holes provided in the current collector may be the same as or different from the diameter, number and pitch of the through holes provided in the electrode layer.

[0029] (1-2)Second process In a second embodiment of the present disclosure, the preparation step may include a second step of creating the electrode layer having the through holes by applying an electrode paste to the first surface of the current collector after the first step.

[0030] In order to drill fine through holes directly in an electrode layer, adjustment of the laser output, etc. is necessary. However, according to the second embodiment, by providing through holes in a current collector and then applying an electrode paste to a first surface of the current collector, it is possible to easily produce an electrode layer having through holes without the need to drill fine through holes directly in the electrode layer.

[0031] (2) Drying process The drying step is a step of drying the electrode layer after the preparation step. In general, in the drying step, a drying device is used to dry the electrode layer. The drying device may be a conventional device capable of drying the electrode layer, such as a hot air device or a laser device. The drying method and drying conditions are not particularly limited and may be appropriately set.

[0032] In a third embodiment of the present disclosure, in the drying step, the electrode layer may be dried while transporting the workpiece using a transport body having air holes and sucking the workpiece through the air holes of the transport body. FIG. 2 is a schematic diagram illustrating an example of the third embodiment of the present disclosure. FIG. 3 is a schematic diagram showing another example of the third embodiment of the present disclosure. According to the third embodiment, a conveying roll 50 or a conveying plate 51 having pores 60 is used as a conveying body to suck air from below the workpiece 100, thereby generating a capillary force in the direction of the conveying body, and creating a path for moisture in the electrode layer to escape not only from the upward and lateral directions but also from the downward direction (collector side), thereby suppressing biased movement in the direction of the binder. The shape of the carrier may be a roll or a plate. The carrier has pores. The method for providing pores in the carrier can be the same as the method for providing through holes in the electrode layer described above. The diameter, number and pitch of the pores provided in the carrier may be the same as or different from the diameter, number and pitch of the through holes provided in the electrode layer. The wind speed of the air sucked through the holes of the conveying body may be a wind speed at which the workpiece is sucked in and adheres to the conveying body, for example, 5.0 m / s or less. The transport speed of the workpiece by the transport body may be, for example, 34 m / min or less.

[0033] 2.Electrode In a fourth embodiment of the present disclosure, there is provided an electrode comprising an electrode layer including an active material and a binder, the electrode includes a current collector and the electrode layer is disposed on a first surface of the current collector and has a through hole; The electrode includes a through hole of the electrode layer having a diameter of 55 μm or more. In the fifth embodiment of the present disclosure, the current collector may have the through holes having a diameter of 55 μm or more. According to the electrode of the present disclosure, it is possible to provide an electrode in which the binder is less likely to move during production.

[0034] The electrodes of the present disclosure are typically used in the manufacture of batteries. The electrodes may be positive or negative electrodes.

[0035] The electrode layer may be a positive electrode layer or a negative electrode layer. The electrode layer contains one of a positive electrode active material and a negative electrode active material, a binder, and may further contain a conductive material, an electrolyte, etc. These materials are as described above.

[0036] 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.

[0037] The type of battery in which the electrode is used is not particularly limited, and may be, for example, a lithium ion secondary battery. Examples of uses of the battery include 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]

[0038] 10. Electrode layer 20.Through hole 30.Active material 40. Binder 50.Transport roll 51.Transport plate 60.Carrier pores 100. Work

Claims

1. 1. A method for producing an electrode comprising an electrode layer including an active material and a binder, comprising: A preparation step of preparing a workpiece including a current collector and the electrode layer disposed on a first surface of the current collector and having a through hole; A drying step of drying the electrode layer after the preparing step.

2. 2. The method for manufacturing an electrode according to claim 1, wherein the preparation step includes: a first step of providing the through holes in the current collector; and a second step of creating the electrode layer having the through holes by applying an electrode paste to the first surface of the current collector after the first step.

3. 3 . The method for manufacturing an electrode according to claim 1 , wherein in the drying step, the electrode layer is dried while transporting the workpiece using a transport body having air holes and sucking the workpiece through the air holes of the transport body.

4. An electrode comprising an electrode layer including an active material and a binder, The electrode includes a current collector and the electrode layer is disposed on a first surface of the current collector and has a through hole, An electrode, wherein the through holes of the electrode layer have a diameter of 55 μm or more.

5. The electrode of claim 4 , wherein the current collector has the through holes having a diameter of 55 μm or more.

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