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] This disclosure relates to a method for manufacturing electrodes. [Background technology]

[0002] Various techniques have been proposed regarding the manufacturing method of electrodes, such as the one disclosed in Patent Document 1. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-029256 [Overview of the project] [Problems that the invention aims to solve]

[0004] In conventional technology, the electrode body is irradiated with a laser, dried, and then cut. Depending on the drying conditions, the binder may migrate to the upper part of the electrode where moisture is more easily removed, potentially affecting the performance of the electrode, such as reducing the peel strength of the electrode.

[0005] This disclosure has been made in view of the above circumstances, and its main purpose is to provide a method for manufacturing electrodes that can suppress the movement of the binder. [Means for solving the problem]

[0006] In a first embodiment of this disclosure, a method for manufacturing an electrode comprising an electrode layer containing an active material and a binder, A preparation step of preparing a workpiece having a current collector and an electrode layer disposed on the first surface of the current collector and having through holes, The present invention provides a method for manufacturing an electrode, comprising a drying step of drying the electrode layer after the preparation step.

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

[0008] In a third embodiment of the present disclosure, in the first or second embodiment, the electrode layer may be dried in the drying step while conveying the workpiece using a conveyor having pores, and while sucking the workpiece through the pores of the conveyor.

[0009] In a fourth embodiment of this disclosure, an electrode comprising an electrode layer containing an active material and a binder, The electrode comprises a current collector and an electrode layer disposed on the first surface of the current collector and having through holes. The present invention provides an electrode in which the diameter of the through-hole in the electrode layer is 55 μm or more.

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

[0011] The electrode manufacturing method of this disclosure can suppress the movement of the binder. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram illustrating an example of a first embodiment of the present disclosure. [Figure 2] This is a schematic diagram illustrating an example of a third embodiment of the present disclosure. [Figure 3] This is a schematic diagram illustrating another example of a third embodiment of the present disclosure. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments according to the present disclosure will be described. Note that matters other than those particularly mentioned in this specification and necessary for the implementation of the present disclosure (for example, general configurations and manufacturing processes of electrodes that do not characterize the present disclosure) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The present disclosure can be implemented based on the content disclosed in this specification and common technical knowledge in the relevant field. Also, the dimensional relationships (length, width, thickness, etc.) in the figures do not reflect actual dimensional relationships.

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

[0015] Conventionally, in the drying step, since drying was only performed toward the upper surface of the electrode layer, vapor could only escape from the upper surface of the electrode layer, resulting in migration where the binder in the electrode layer segregated toward the upper surface of the electrode layer. FIG. 1 is a schematic diagram showing an example of the first embodiment of the present disclosure. s According to the first embodiment, due to the presence of fine through-holes 20 in the electrode layer 10 containing the active material 30 and the binder 40, moisture in the electrode layer 10 can escape not only upward but also laterally. Therefore, moisture can be evaporated from surfaces other than the upper surface of the electrode layer 10, the movement of the binder 40 in the electrode layer 10 can be suppressed, the drying time can be shortened, and the quality can be improved.

[0016] The electrode obtained by the manufacturing method of the present disclosure includes 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, etc.

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

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

[0019] Examples of binders 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, and conductive polymers. Examples of carbon materials include particulate carbon materials such as acetylene black (AB) and Ketjenblack (KB); and fibrous carbon materials such as carbon fibers, carbon nanotubes (CNTs), and carbon nanofibers (CNFs).

[0021] Examples of thickening agents 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 a solid electrolyte containing Li element, X element (X is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, In), and S element. Further, the sulfide solid electrolyte may further contain at least one of O element and halogen element. Examples of the halogen element include F element, Cl element, Br element, and I element.

[0023] Examples of the oxide solid electrolyte 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 Si 0.6 P 0.4 O4, Li4SiO4, Li3PO4, Li3PO 4-3 / 2x N x (x ≦ 1).

[0024] (1) Preparation step The preparation step is a step of preparing a workpiece having a current collector and the electrode layer disposed on the first surface of the current collector and having through holes.

[0025] The current collector may be a negative electrode current collector, a positive electrode current collector, a bipolar current collector, etc. Examples of the material of 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 shape, a roll shape, etc.

[0026] The electrode layer is disposed on the 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 the first surface and the second surface which is the back surface of the first surface of the current collector. The electrode layer can be prepared by coating the first surface of the current collector with an electrode paste, which is prepared by mixing the aforementioned binder, active material, conductive material, electrolyte, thickener, etc., with a solvent such as water. The electrode paste may be a positive electrode paste or a negative electrode paste. The amount of electrode paste applied to the current collector is, for example, 30 to 80 mg / cm³. 2 The viscosity of the electrode paste may be, for example, 5000 to 50000 mPa·s.

[0027] The electrode layer has through holes. Methods for creating through-holes in the electrode layer include, for example, irradiating the electrode layer with a laser. The wavelength and energy density of the irradiated laser are not particularly limited and can be set as appropriate, as long as the conditions for creating through-holes in the electrode layer are met. The diameter of the through-hole may be such that the coated electrode paste does not block the through-hole and does not drip from it, and may be greater than or equal to 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 direction of workpiece transport, or 176 or more in the direction of workpiece transport. The pitch of the through-holes may be, for example, 5.7 mm or more. The pitch is calculated from (total width of through-holes) ÷ (number of through-holes - 1). By providing through-holes evenly, the occurrence of wrinkles in the electrode can be suppressed.

[0028] (1-1) First step In a second embodiment of the present disclosure, the preparation step may include a first step of providing the through hole in the current collector. Methods for providing through holes in the current collector can be the same as those for providing 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 described above.

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

[0030] While adjusting the laser output is necessary to directly create fine through-holes in the electrode layer, according to the second embodiment, by providing through-holes in the current collector and then applying electrode paste to the first surface of the current collector, it is not necessary to directly create fine through-holes in the electrode layer, and an electrode layer having through-holes can be easily created.

[0031] (2) Drying process The drying step is a step of drying the electrode layer after the preparation step. Typically, a drying apparatus is used in the drying process to dry the electrode layer. Conventional known devices capable of drying the electrode layer, such as hot air devices and laser devices, can be used as the drying apparatus. The drying method and drying conditions are not particularly limited and can be set as appropriate.

[0032] In a third embodiment of this disclosure, the electrode layer may be dried in the drying step while conveying the workpiece using a conveyor having pores, and while sucking the workpiece through the pores of the conveyor. Figure 2 is a schematic diagram showing an example of a third embodiment of the present disclosure. Figure 3 is a schematic diagram illustrating another example of a third embodiment of the present disclosure. According to the third embodiment, by using a conveying roll 50 or conveying plate 51 having pores 60 as a conveying body and sucking air from below the workpiece 100, capillary force is generated in the direction of the conveying body, and a path is created for moisture in the electrode layer to escape not only from the upward and sideways directions but also from the downward direction (current collector side), thereby suppressing biased movement in the direction of the binder. The shape of the conveying body may be roll-shaped or plate-shaped. The transporter has pores. Methods for providing pores in the transport body include those similar to the method for providing through-holes in the electrode layer described above. The diameter, number, and pitch of the pores provided in the conveyor may be the same as, or different from, the diameter, number, and pitch of the through holes provided in the electrode layer described above. The air velocity drawn in through the pores of the conveyor may be such that the workpiece is drawn in and adheres to the conveyor, and may be, for example, 5.0 m / s or less. The conveying speed of the workpiece by the conveyor may be, for example, 34 m / min or less.

[0033] 2.Electrode In a fourth embodiment of this disclosure, an electrode comprising an electrode layer containing an active material and a binder, The electrode comprises a current collector and an electrode layer disposed on the first surface of the current collector and having through holes. The present invention provides an electrode in which the diameter of the through-hole in the electrode layer is 55 μm or more. In the fifth embodiment of this disclosure, the current collector may have the through hole having a diameter of 55 μm or more. According to the electrode of this disclosure, it is possible to create an electrode in which the binder is less likely to move during manufacturing.

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

[0035] The electrode layer may be either a positive electrode layer or a negative electrode layer. The electrode layer contains either a positive electrode active material or a negative electrode active material, a binder, and may also 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, thickness, and shape of the current collector are as described above.

[0037] The type of battery using electrodes is not particularly limited, but lithium-ion secondary batteries are an example. Applications of batteries include powering vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline cars, and diesel cars. In particular, they may be used as power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). Batteries may also be used as power sources for mobile devices other than vehicles (e.g., trains, ships, aircraft), and as power sources for electrical products such as information processing devices. [Explanation of Symbols]

[0038] 10. Electrode layer 20. Through hole 30.Active material 40. Binder 50. Conveyor Roll 51. Conveyor board 60. Velocity of the transport body 100. Work

Claims

1. A method for manufacturing an electrode comprising an electrode layer containing an active material and a binder, A preparation step of preparing a workpiece having a current collector and an electrode layer disposed on the first surface of the current collector and having through holes with a particle size greater than or equal to the largest particle contained in the electrode material, A method for manufacturing an electrode, comprising a drying step of drying the electrode layer after the preparation step.

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

3. The method for manufacturing an electrode according to claim 1 or 2, wherein in the drying step, the electrode layer is dried while the workpiece is being transported using a transporter having pores, and the workpiece is being sucked out from the pores of the transporter.

4. An electrode comprising an electrode layer containing an active material and a binder, The electrode comprises a current collector and an electrode layer disposed on the first surface of the current collector and having through holes. An electrode in which the diameter of the through-holes in the electrode layer is 55 μm or more, and the pitch of the through-holes is 5.7 mm or more.

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

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