Corrosion foil for aluminum electrolytic capacitor and preparation method thereof
By forming a graphene layer on the surface of the aluminum foil, laser drilling and corrosion treatment, and removing the raised parts on the graphene layer, the problem of thickness uniformity of corroded foil caused by laser drilling is solved, the flatness and performance of the foil are improved, the process is simplified, and the cost is reduced.
Patent Information
- Application Number
- CN202411820838.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-02-28
AI Technical Summary
When laser drilling of aluminum foil is performed, melt splashes to the outer peripheral edge of the laser hole to form a pile, resulting in poor thickness uniformity of the corroded foil.
A graphene layer is formed on the surface of the aluminum foil, laser drilling is performed to form a uniformly distributed laser hole group, and then corrosion treatment is performed to form corrosion holes, and the raised portions accumulated on the graphene layer are removed.
By removing the raised portions formed by splashing in laser drilling, the surface flatness and thickness uniformity of the corrosion foil are improved, while utilizing the thermal conductivity and corrosion resistance of the graphene layer, the corrosion process is simplified and the preparation cost is reduced.
Smart Images
Figure CN119542032A_ABST
Abstract
Description
Technical Field
[0001] The present invention generally relates to the technical field of capacitors, and in particular to an aluminum electrolytic capacitor corrosion foil and a preparation method thereof. Background Art
[0002] The etched foil is formed by etching aluminum foil. After the etching treatment, the surface of the etched foil will form etched holes, which can increase the surface area of the aluminum foil. In order to achieve uniform distribution of etched holes, a uniformly distributed laser hole group can be formed on the aluminum foil by laser drilling, and then the laser hole group is corroded and expanded.
[0003] However, when laser drilling is performed on aluminum foil, the melt will splash to the peripheral edge of the laser hole and form an accumulation at the peripheral edge of the laser hole, resulting in poor thickness uniformity of the etched foil. Summary of the invention
[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide an aluminum electrolytic capacitor corrosion foil and a preparation method thereof.
[0005] In a first aspect, the present application provides a method for preparing a corrosion foil for an aluminum electrolytic capacitor, comprising: S100: forming a graphene layer on the surface of the aluminum foil; S200: laser drilling is performed on the surface of the aluminum foil to form a uniformly distributed laser hole group, wherein the laser holes in the laser hole group penetrate the graphene layer and extend into the aluminum foil, and the diameter of the laser holes is 1-2 μm; S300: etching the aluminum foil to corrode and expand the laser hole to form an etching hole; S400: removing the raised portion of the graphene layer that is deposited on the outer periphery of the corrosion hole.
[0006] Furthermore, S400 specifically includes: S410: forming a negative photoresist layer on the surface of the graphene layer, wherein the height of the photoresist layer is higher than the height of the protruding portion; S420: performing an exposure process on the photoresist layer according to a preset pattern to form a plurality of unexposed set areas on the photoresist layer, wherein the plurality of set areas and each etching hole are arranged in a one-to-one correspondence, wherein along the exposure direction, the etching hole and the convex portion of the outer peripheral edge thereof are all located within the projection range of the set area; S430: performing a development process on the photoresist layer to remove the photoresist in a set area; S440: performing etching and removal processing on the portion of the graphene layer located in the set area.
[0007] Furthermore, the etching process in the etching removal treatment is a plasma etching process.
[0008] Furthermore, the setting area is circular.
[0009] Furthermore, the thickness of the aluminum foil is 100-150 μm, and the thickness of the graphene layer is 400-600 nm.
[0010] In a second aspect, the present application also provides a corrosion foil for an aluminum electrolytic capacitor, which is prepared based on the above-mentioned preparation method.
[0011] The aluminum electrolytic capacitor corrosion foil and preparation method provided by the present application form a graphene layer on the surface of the aluminum foil, perform laser drilling on the surface of the aluminum foil to form a laser hole group that passes through the graphene layer and is evenly distributed, then perform corrosion treatment on the aluminum foil to form corrosion holes, and then remove the raised portions of the graphene layer that are accumulated on the outer periphery of the corrosion holes. On the one hand, the raised portions formed by splashing during laser drilling are removed, so that the surface of the corrosion foil is relatively flat, and the overall thickness uniformity of the corrosion foil is improved. On the other hand, by arranging a graphene layer on the surface of the aluminum foil, the thermal and electrical conductivity of the corrosion foil is improved, and the high corrosion resistance of the graphene layer is used to make it act as a surface protective layer of the aluminum foil in the hole expansion corrosion treatment, without the need to additionally arrange an aluminum foil corrosion protection layer, thereby simplifying the corrosion process steps of the corrosion foil, thereby improving the performance of the corrosion foil and reducing the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 This is a flow chart of the method for preparing the etching foil for aluminum electrolytic capacitors provided in this embodiment. DETAILED DESCRIPTION
[0013] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.
[0014] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0015] Please refer to the attached Figure 1 The present application embodiment provides a method for preparing a corrosion foil for an aluminum electrolytic capacitor, comprising: S100: forming a graphene layer on the surface of the aluminum foil; S200: laser drilling is performed on the surface of the aluminum foil to form a uniformly distributed laser hole group, wherein the laser holes in the laser hole group penetrate the graphene layer and extend into the aluminum foil, and the diameter of the laser holes is 1-2 μm; S300: etching the aluminum foil to corrode and expand the laser hole to form an etching hole; S400: removing the raised portion of the graphene layer that is deposited on the outer periphery of the corrosion hole.
[0016] In step S100, the graphene layer is formed on the surface of the aluminum foil by, but not limited to, growing the graphene layer by an existing chemical vapor deposition (CVD) process. Since forming a graphene layer by CVD is an existing process, this application will not go into details. Preferably, the thickness of the aluminum foil is 100-200 μm, and the thickness of the graphene layer is 400-600 nm. The number of layers of the graphene layer can be one or more layers. The graphene layer has excellent corrosion resistance and a dense structure. It can protect the surface of the aluminum foil during the corrosion process and prevent the portion where the aluminum foil and the graphene layer are combined from being corroded. In addition, the graphene layer also has excellent thermal and electrical conductivity, which improves the performance of the corrosion foil.
[0017] In step S200, the laser hole group can be distributed in a matrix so that the corrosion holes formed subsequently are evenly distributed. The diameter of the laser hole can be selected to be 1-2μm, and the drilling depth can be 5-10μm. The laser holes in the laser hole group penetrate the graphene layer and extend into the aluminum foil, that is, the laser holes pass through the graphene layer and penetrate into the aluminum foil. During the laser drilling process, the melt will accumulate on the outer edge of the laser hole through splashing and form a convex portion surrounding the laser hole after cooling. The convex portion is formed by cooling the graphene melt and the aluminum foil melt, and the aluminum foil melt covers the outer surface of the graphene melt. The height of the convex portion is usually within 0.5μm, and the distance from the outer peripheral edge to the outer peripheral edge of the laser hole is usually within 1μm (i.e., the radial width). The laser drilling parameters can be selected as follows: in laser drilling, the laser wavelength is 1030~1064nm, and the laser energy density is 1~10 J / cm 2 , pulse frequency 1~10kHz.
[0018] In step S300, the aluminum foil is corroded. Specifically, the aluminum foil is placed in a corrosive solution for electrochemical corrosion (direct current corrosion) to corrode and expand the laser hole and finally form a corrosion hole. The depth of the corrosion hole does not exceed half of the thickness of the aluminum foil. For example, when the thickness of the aluminum foil is 100 μm, the depth of the corrosion hole can be 30-40 μm. The corrosion current density is 0.1 A / cm 2 ~0.2A / cm 2 During the etching process, the molten aluminum foil portion in the raised portion is also etched away to reduce the height of the raised portion.
[0019] In step S400, the raised portion of each etching hole accumulated on the graphene layer at the outer periphery of the etching hole is removed, so as to improve the surface flatness of the etching foil and enhance the overall thickness uniformity of the etching foil.
[0020] In this embodiment, a graphene layer is formed on the surface of the aluminum foil, and the surface of the aluminum foil is laser-drilled to form a group of laser holes that pass through the graphene layer and are evenly distributed. The aluminum foil is then corroded to form corrosion holes, and then the raised portions of the graphene layer accumulated on the outer periphery of the corrosion holes are removed. On the one hand, the raised portions formed by splashing during laser drilling are removed, so that the surface of the corrosion foil is relatively flat, thereby improving the uniformity of the overall thickness of the corrosion foil. On the other hand, by providing a graphene layer on the surface of the aluminum foil, the thermal and electrical conductivity of the corrosion foil is improved, and the high corrosion resistance of the graphene layer is utilized to make it act as a surface protective layer of the aluminum foil in the hole expansion corrosion treatment, without the need to provide an additional corrosion protection layer of the aluminum foil, thereby simplifying the corrosion process steps of the corrosion foil, thereby improving the performance of the corrosion foil and reducing the preparation cost.
[0021] Preferably, in step S100, a graphene coating may be formed on both surfaces of the aluminum foil, in step S200, laser drilling may be performed on both surfaces of the aluminum foil in succession, and in step S400, protrusion removal treatment may be performed on both surfaces of the aluminum foil in succession.
[0022] In some embodiments of the present application, step S400 specifically includes: S410: forming a negative photoresist layer on the surface of the graphene layer, wherein the height of the photoresist layer is higher than the height of the protruding portion; S420: performing an exposure process on the photoresist layer according to a preset pattern to form a plurality of unexposed set areas on the photoresist layer, wherein the plurality of set areas and each etching hole are arranged in a one-to-one correspondence, wherein along the exposure direction, the etching hole and the convex portion of the outer peripheral edge thereof are all located within the projection range of the set area; S430: performing a development process on the photoresist layer to remove the photoresist in a set area; S440: performing etching and removal processing on the portion of the graphene layer located in the set area.
[0023] In step S410, this embodiment uses a negative photoresist layer, such as polyvinyl cinnamate negative photoresist. The photoresist layer covers the surface of the etching foil, including the protruding portion. For example, the height of the photoresist can be 1-2 μm.
[0024] In step S420 and step S430, a preset pattern with the same distribution as the laser hole group is provided on the mask, and the photoresist layer is exposed using the mask to form a plurality of unexposed set areas on the photoresist layer, wherein the plurality of set areas and each etching hole are arranged one by one, wherein the etching hole and the convex portion of the outer peripheral edge thereof are all located within the projection range of the set area along the exposure direction. The photoresist layer is then developed using a developer so that the photoresist in the set area is removed to expose the etching hole and a portion of the graphene layer located at the outer periphery of the etching hole, wherein the exposed portion of the graphene layer includes the convex portion. The shape of the set area is preferably circular, and its radius R=R1+R2+R3, R1 is the radius of the laser hole, R2 is the radial width of the convex portion, and R3 is the radial compensation width. R2 can be set to 1μm, and R3 can be set to 0.2μm, that is, the radius R of the set area=(R1+1.2)μm.
[0025] In step S440, the etching process in the etching removal process can adopt an existing plasma etching process, such as oxygen plasma etching, etc. The above-mentioned plasma etching process is an existing process, and this application will not repeat them here. After etching is completed, the remaining photoresist layer is removed. Wherein, the part of the corrosion hole located in the aluminum foil is the first hole segment and the part located in the graphene layer is the second hole segment. After chemical etching, the first hole segment is usually expanded, that is, the aperture of one end of the first hole segment close to the opening is slightly larger than the aperture of the bottom of the corrosion hole, and the second hole segment is slightly smaller than the aperture of the opening end in the first hole segment. Through the range setting of the above-mentioned setting area, after the etching removal process, the second hole segment expands and can basically expose the opening end of the second hole segment, which helps subsequent chemical formation treatment.
[0026] The embodiment of the present application also provides a corrosion foil for aluminum electrolytic capacitors, which is prepared based on the above-mentioned preparation method.
[0027] It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used above to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; the orientation words "inside" and "outside" refer to the inside and outside relative to the contours of the components themselves. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.
[0028] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.
[0029] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.
Claims
1. A method for preparing an etching foil for an aluminum electrolytic capacitor, characterized in that: include: S100: forming a graphene layer on the surface of the aluminum foil; S200: performing laser drilling on the surface of the aluminum foil to form a uniformly distributed laser hole group, wherein the laser holes in the laser hole group penetrate the graphene layer and extend into the aluminum foil, and the diameter of the laser holes is 1-2 μm; S300: performing an etching process on the aluminum foil to corrode and expand the laser hole to form an etching hole; S400: removing the raised portion of the graphene layer accumulated on the outer periphery of the corrosion hole.
2. The method for preparing the etching foil for aluminum electrolytic capacitor according to claim 1, characterized in that: The S400 specifically includes: S410: forming a negative photoresist layer on the surface of the graphene layer, wherein the height of the photoresist layer is higher than the height of the protruding portion; S420: performing exposure processing on the photoresist layer according to a preset pattern to form a plurality of unexposed set areas on the photoresist layer, wherein the plurality of set areas and each of the etching holes are arranged in a one-to-one correspondence, wherein along the exposure direction, the etching holes and the convex portions of their outer peripheral edges are all located within the projection range of the set areas; S430: performing a development process on the photoresist layer to remove the photoresist in the set area; S440: performing etching and removal processing on the portion of the graphene layer located in the set area.
3. The method for preparing the etching foil for aluminum electrolytic capacitor according to claim 2, characterized in that: The etching process in the etching removal process is a plasma etching process.
4. The method for preparing the etching foil for aluminum electrolytic capacitor according to claim 2, characterized in that: The setting area is circular.
5. The method for preparing the etching foil for aluminum electrolytic capacitor according to claim 1, characterized in that: The thickness of the aluminum foil is 100-150 μm, and the thickness of the graphene layer is 400-600 nm.
6. An etched foil for an aluminum electrolytic capacitor, characterized in that: The method is prepared based on any one of claims 1 to 5.