Electrode manufacturing method and electrode manufacturing system used in the method

Abstract

The present invention provides a method for manufacturing an electrode, and a system for manufacturing an electrode used in the above method, the method comprising the steps of: (a) laminating an active material layer on a surface of a current collector; and (b) removing a portion of the active material layer by irradiating a laser beam to a surface of the active material layer, wherein, before the laser beam is irradiated to the active material layer in step (b), a process of supplying moisture to the active material layer is performed.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0095769, filed on July 21, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for manufacturing an electrode and an electrode manufacturing system used in the above method. Background Technology

[0003] With the increasing demand for mobile devices and electric vehicles, the demand for secondary batteries is growing rapidly. In particular, lithium-ion secondary batteries, which have high energy density and voltage, have been commercialized and are widely used.

[0004] Lithium-ion secondary batteries have a structure in which an electrolyte containing lithium salt is infused into an electrode having an active material applied to a current collector, i.e., an electrode assembly with a porous membrane between the positive and negative electrodes. The electrode is manufactured by forming an active material layer on the current collector via the following processes: a mixing process to prepare a slurry by mixing / dispersing the active material, binder, and conductive material in a solvent; a coating process to apply the active material slurry to a thin-film current collector and dry the slurry; and a pressing process to increase the capacity density of the electrode after the coating process and to enhance the adhesion between the current collector and the active material.

[0005] When an active material slurry is applied to a current collector, it is known that due to the formation of drag lines and / or islands, it is difficult to form a uniform surface at the distal end of the active material layer, such as... Figure 2 As shown in the diagram. Furthermore, at the edges of the active material layer, a sliding portion is formed where the thickness of the active material layer gradually decreases, leading to a reduction in the capacity of the active material layer, as illustrated. Figure 3 As shown in the diagram. Additionally, when the slurry is applied to both surfaces of the current collector, a mismatch occurs where the slurry applied to the upper and lower surfaces does not match, as shown in the diagram. Figure 3 As shown in the diagram. This mismatch causes the active material layers to be misaligned when the positive and negative electrodes face each other, and this misalignment reduces charge / discharge efficiency. In particular, the mismatched portion may cause lithium to deposit on the surface of the negative electrode, and when such lithium deposition occurs over a long period of time, the battery capacity decreases.

[0006] Meanwhile, in order to solve the above problems, laser etching methods have been introduced. However, in this case, there is a problem that the active material deteriorates due to the heat of the laser beam (heat-affected zone).

[0007] Therefore, there is a need for a method that can uniformly form the ends of the active material layer, prevent the formation of slippage and / or mismatch, and prevent the degradation of the active material.

[0008] [Existing Technical Documents]

[0009] Japanese Early Publication Patent No. 2000-251942 Summary of the Invention

[0010] Technical issues

[0011] One object of the present invention is to provide an electrode manufacturing method and an electrode manufacturing system that can uniformly form the ends of an active material layer without slippage and / or mismatch by laser etching. The electrode manufacturing method and the electrode manufacturing system are designed to solve the above-mentioned problems of the prior art.

[0012] Another object of the present invention is to provide an electrode manufacturing method and an electrode manufacturing system that can prevent the problem of degradation of active materials due to the heat of the laser beam during laser etching (the formation of heat-affected zones).

[0013] Technical solution

[0014] To achieve the above objectives, the present invention provides a method for manufacturing an electrode, the method comprising the following steps:

[0015] (a) Laminating an active material layer onto the surface of the current collector; and

[0016] (b) A portion of the active material layer is removed by irradiating the surface of the active material layer with a laser beam.

[0017] In step (b), before the laser beam is irradiated onto the active material layer, a process is performed to supply moisture to the active material layer.

[0018] Additionally, the present invention provides a system for manufacturing electrodes, the system comprising:

[0019] A current collector supply device that supplies a flat-shaped current collector;

[0020] An active material coating apparatus for coating an active material layer on the surface of a supplied current collector;

[0021] A moisture supply device for supplying moisture to an active material layer laminated by an active material coating device; and

[0022] A laser etching apparatus for etching a portion of an active material layer to which moisture is supplied.

[0023] Beneficial effects

[0024] The electrode manufacturing method and electrode manufacturing system of the present invention provide the following effect by using a laser etching method: uniformly forming the ends of the active material layer without slippage and / or mismatch.

[0025] In addition, by supplying moisture during laser etching, the present invention provides the following effect: minimizing the degradation of active materials (heat-affected zone) caused by the heat of the laser beam. Attached Figure Description

[0026] Figure 1 This diagram schematically illustrates the active material coating process during electrode manufacturing in the prior art.

[0027] Figure 2 This is a diagram illustrating the problems that arise when active materials are applied to current collectors according to existing techniques.

[0028] Figure 3 This is a schematic diagram illustrating the sliding and mismatch portions that occur when an active material is applied to a current collector according to existing technology.

[0029] Figure 4 This is a schematic diagram illustrating a laser etching process according to an embodiment of the present invention.

[0030] Figure 5 and Figure 6 These are schematic diagrams illustrating an electrode manufacturing system according to an embodiment of the present invention. Detailed Implementation

[0031] In the following description, embodiments of the invention will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily implement the invention. However, the invention can be embodied in several different forms and is not limited to the embodiments described herein. Throughout this specification, similar reference numerals are assigned to similar parts.

[0032] It should be understood that when any component is referred to as being "connected to, provided with, or installed to" another component, while this component may be directly connected to or installed to the other component, other components may also exist between the two components. On the other hand, it should be understood that when any component is referred to as being "directly connected to, provided with, or installed to" another component, other components do not exist in between. Similarly, other expressions describing the relationship between elements, namely "on" and "directly on," or "between" and "closely between," or "adjacent to" and "directly adjacent to," should be interpreted in the same manner.

[0033] Figure 4This is a schematic diagram illustrating a laser etching process according to an embodiment of the present invention, and Figure 5 and Figure 6 An electrode manufacturing system is exemplarily shown for manufacturing electrodes using a roll-to-roll process, which is an embodiment of the method for manufacturing electrodes according to the present invention. The invention will be described below with reference to the accompanying drawings.

[0034] The method for manufacturing electrodes according to the present invention, such as Figure 5 The diagram shows the following steps:

[0035] (a) Laminating an active material layer 80 onto the surface of the current collector 70; and

[0036] (b) A portion of the active material layer is removed by irradiating the surface of the active material layer 80 with a 40 laser beam (using a laser etching apparatus).

[0037] Before irradiating the active material layer with the laser beam in step (b), a step of supplying 30g of water to the active material layer (using a water supply device) is performed.

[0038] Even when laser etching is used in conventional electrode manufacturing methods, there is a problem of degradation of the active material due to the heat of the laser beam (heat-affected zone). The present invention addresses this problem by supplying moisture to the active material layer before irradiation with a laser beam.

[0039] Examples of the deterioration of active materials due to the heat of the laser beam (heat-affected zone) include, for example, oxidation of the electrode foil surface and the resulting discoloration.

[0040] In one embodiment of the invention, the water supply in step (b) can be carried out in such a way that water permeates into the active material layer before the laser beam is applied. For example, the water supply can be carried out 5 to 30 seconds before the laser is applied. This is because sufficient time is needed to supply water into the active material before the laser is applied. However, it is not limited to the above range, because the time required for water absorption varies depending on the composition of the active material and the amount of layered active material.

[0041] The method of supplying moisture is not particularly limited, and can be, for example, by spraying. However, the invention is not limited thereto, and any method can be used as long as it can adequately supply moisture to the active material.

[0042] In one embodiment of the invention, the laser beam may have a rectangular or linear horizontal cross-section. The horizontal direction refers to the direction relative to the vertical direction from which the laser beam is irradiated.

[0043] In one embodiment of the present invention, a laser etching apparatus known in the art can be used as the laser etching apparatus used in the above method. The laser etching apparatus may include a laser source generator, a transport mirror, a laser beam width adjuster, and a scanner unit and the like. Figure 4 As shown, the scanner unit may include a galvanometer, a theta lens, and the like. The laser source generator may be, for example, a laser source generator that generates an infrared wavelength region, and the wavelength of the laser may be from 700 nm to 1100 nm, preferably from 1000 nm to 1100 nm, but is not limited thereto.

[0044] Typically, lasers oscillate in a circular (Gaussian) shape, but depending on the configuration of the optical system, they can oscillate in a rectangular (flat-topped) or linear beam shape. For example, in the case of a circular or square beam, a laser can be formed using mirrors that can move independently along the X and Y axes, similar to a laser scanner. That is, a beam of the desired shape can be formed by moving two mirrors.

[0045] Rectangular beams can etch larger quantities faster than circular beams. Furthermore, linear beams allow for more precise etching of the active material layer compared to circular beams where the intensity distribution is concentrated at the center.

[0046] In one embodiment of the present invention, the lamination of the active material layer in step (a) can be performed by coating the active material, or additionally by a drying process, a pressing process, and a similar process. In the present invention, step (b) can be performed after coating the active material, preferably after the pressing process. Specifically, step (b) can be performed in a grooving process after the pressing process.

[0047] In one embodiment of the invention, the portion of the active material layer partially removed in step (b) can form an uncoated portion of the active material. Specifically, step (b) can be a process for forming the uncoated portion of the active material by removing the current collector covered by the active material through laser etching, wherein the active material is not laminated on the uncoated portion of the active material, and the uncoated portion of the active material can then be formed into an electrode contact by a process such as stamping.

[0048] In one embodiment of the invention, steps (a) and (b) may be performed on one side of the current collector, or on both the front and back sides.

[0049] In one embodiment of the invention, steps (a) and (b) can be performed by a process for manufacturing electrodes using a roll-to-roll process, such as... Figure 5 and Figure 6 The example provided illustrates this.

[0050] In one embodiment of the invention, prior to step (a), a further step may be included: performing a corona treatment 50 (using a corona treatment device) on the surface of the current collector (on which the active material is laminated), as shown below. Figure 6 As illustrated in the example, and following step (b), a further heat treatment 60 step (using a heat treatment apparatus) for stabilization may be included. Corona treatment on the surface of the current collector is a process used to improve the adhesion of the active material to the surface of the current collector.

[0051] Corona treatment and heat treatment can be performed using methods known in the art.

[0052] In one embodiment of the invention, the electrode manufacturing method can be applied to both the positive and negative electrodes. The current collector can be a positive current collector or a negative current collector, and current collectors known in the art can be used without limitation, and a foil made of, for example, copper, aluminum, gold, nickel, copper alloys, or combinations thereof can be used.

[0053] Additionally, the active material layer can be either a positive or negative electrode active material layer. The active material layer can be formed from a slurry of active materials, which includes either a positive or negative electrode active material and a binder. The slurry of active materials may further contain a conductive material and, if necessary, a dispersant.

[0054] As positive electrode active materials, negative electrode active materials, binders and conductive materials, components known in the art can be used without limitation.

[0055] As positive electrode active materials, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, and LiNi as ternary positive electrode materials can be used. x Mn y Co z O2 (NMC), or lithium composite oxides combining these materials. In the case of lithium-sulfur batteries, sulfur-carbon composites can be included as positive electrode active materials.

[0056] Examples of negative electrode active materials can be LiTi2(PO4)3, Li3V2(PO4)3, LiVP2O7, LiFeP2O7, LiVPO4F, LiVPO4O, and LiFeSO4F. The negative electrode active material may have a carbon coating layer formed on its surface.

[0057] As conductive materials, for example, carbon black such as Super-P, Denca Black, Acetylene Black, Ketjen Black, channel black, furnace black, lamp black, thermal black and carbon black can be used; carbon derivatives such as carbon nanotubes and fullerenes; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorinated carbon, aluminum and nickel powder; or conductive polymers such as polyaniline, polythiophene, polyacetylene and polypyrrole can be used.

[0058] An electrode manufacturing system according to an embodiment of the present invention, such as Figure 5 As shown, it includes:

[0059] The current collector supply device 10 is used to supply a flat-shaped current collector 70;

[0060] An active material coating apparatus 20 is used to coat an active material on the surface of a supplied current collector.

[0061] Moisture supply device 30, the moisture supply device 30 being used to supply moisture to an active material layer 80 laminated by an active material coating device; and

[0062] Laser etching apparatus 40, the laser etching apparatus 40 being used to etch a portion of the active material layer to which moisture is supplied.

[0063] All the contents described in the above methods for manufacturing electrodes can be applied to the electrode manufacturing system of the present invention. Therefore, some repetitive descriptions will be omitted.

[0064] In one embodiment of the invention, the current collector supply device 10 is not particularly limited, as long as it is a device capable of supplying a coating of active material onto the current collector, and equipment known in the art can be used. For example, the device for supplying the current collector to a roll-to-roll process can be a roller 10 on which the current collector is wound, such as... Figure 5 As shown in the image.

[0065] In one embodiment of the present invention, devices known in the art can be used without limitation as the active material coating device 20, the laser etching device 40, and the like. Furthermore, although not shown in the figures, drying devices, pressing devices, and the like may also be included.

[0066] For example, a laser etching apparatus may include a laser source generator, a transport mirror, a laser beam width adjuster, and a scanner unit, such as Figure 4As shown, the scanner unit may include a galvanometer lens, a theta lens, and the like. The laser source generator may be, for example, an IR laser source generator, and the wavelength of the laser generated by the laser source generator may be from 700 nm to 1100 nm, preferably from 1000 nm to 1100 nm, but is not limited thereto.

[0067] In one embodiment of the invention, the laser beam irradiated from the laser etching apparatus 40 may have a rectangular or linear shape in terms of its horizontal cross-section. The horizontal direction refers to the direction based on the vertical direction of the irradiating laser.

[0068] In one embodiment of the present invention, the electrode manufacturing system may further include a corona treatment device 50 positioned in front of the active material coating device 10 and a heat treatment device 60 positioned behind the laser etching device 40, such as Figure 6 As shown in the image.

[0069] As the corona treatment apparatus 50 and the heat treatment apparatus 60, any apparatus known in the art may be used without limitation.

[0070] In one embodiment of the present invention, a water spray device or the like can be used as the water supply device 30, but it is not limited to this, and any device can be used as long as such device can provide sufficient water to the active material.

[0071] Although the invention has been described in conjunction with the preferred embodiments described above, various modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims are intended to cover such modifications and variations, provided they fall within the scope of the invention.

[0072] [Symbol Explanation]

[0073] 10: Unwinding Roller

[0074] 12: Support roller

[0075] 14: Rewinding Roller

[0076] 20: Active material coating device

[0077] 30: Moisture supply device

[0078] 40: Laser Etching Device

[0079] 50: Corona Treatment Device

[0080] 60: Heat treatment equipment

[0081] 70: Current collector

[0082] 80: Active material layer

Claims

1. A method for manufacturing an electrode, the method comprising the following steps: (a) Laminating an active material layer onto the surface of the current collector; and (b) A portion of the active material layer is removed by irradiating the surface of the active material layer with a laser beam. In step (b), before irradiating the active material layer with the laser beam, a process of supplying moisture to the active material layer is performed, and The steps of performing corona treatment on the surface of the current collector to which the active material layer is to be laminated before step (a), and the steps of heat treatment for stabilization after step (b).

2. The method for manufacturing an electrode according to claim 1, wherein the supply of water in step (b) is carried out in such a manner that water permeates into the active material layer before the laser beam is irradiated.

3. The method for manufacturing an electrode according to claim 2, wherein the supply of moisture is carried out by a spraying method.

4. The method for manufacturing an electrode according to claim 1, wherein the horizontal cross-section of the laser beam has a rectangular or linear shape.

5. The method for manufacturing an electrode according to claim 1, wherein the laser beam is infrared radiation and has a wavelength of 700 nm to 1100 nm.

6. The method for manufacturing an electrode according to claim 1, wherein the step of laminating the active material layer in step (a) is performed by coating the active material.

7. The method for manufacturing an electrode according to claim 1, wherein in step (b) a portion of the active material layer is partially removed to form an uncoated portion of the active material.

8. The method for manufacturing an electrode according to claim 1, wherein steps (a) and (b) are performed on both the front and back sides of the current collector.

9. The method for manufacturing an electrode according to claim 1, wherein steps (a) and (b) are performed in a process of manufacturing the electrode by a roll-to-roll process.

10. A system for manufacturing electrodes, comprising: A current collector supply device that supplies the current collector in a flat shape; An active material coating apparatus for coating an active material layer on the surface of the supplied current collector; A moisture supply device for supplying moisture to the active material layer laminated by the active material coating device; and A laser etching apparatus for etching a portion of the active material layer to which moisture is supplied, and The system for manufacturing electrodes further includes a corona treatment device positioned in front of the coating apparatus and a heat treatment device positioned behind the laser etching apparatus.

11. The system for manufacturing electrodes according to claim 10, wherein the moisture supply device is a moisture injection device.

12. The system for manufacturing electrodes according to claim 10, wherein the current collector supply device is a roll-to-roll device.

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