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CN-115831613-B - Preparation method of porous anode aluminum foil for electrolytic capacitor based on laser additive manufacturing

CN115831613BCN 115831613 BCN115831613 BCN 115831613BCN-115831613-B

Abstract

The invention provides a preparation method of a porous anode aluminum foil for an electrolytic capacitor based on laser additive manufacturing, which comprises the following steps of selecting aluminum foil with the thickness of 30 mu m and aluminum powder particles with the average particle diameter of 5-6 mu m as raw materials, adding the aluminum powder particles onto the aluminum foil through a feeding bin, controlling the thickness of the aluminum powder particles by utilizing a scraper vibrating below the feeding bin to enable the aluminum powder particles to be basically paved on the aluminum foil in a single layer, ensuring the single-layer distribution of aluminum balls, adding a dispersing agent into the raw materials to prevent the balls from agglomerating, adding high-frequency vibration with the amplitude micron level on the scraper at the outlet of the feeding bin, facilitating the single-layer paving of the balls and being capable of paving the whole plane, and utilizing linear laser to weld the aluminum powder particles to completely weld the covered aluminum metal particles. After one side of the aluminum foil is completely welded with the aluminum powder particles, the aluminum foil is turned upside down by a turning device, and then the other side of the aluminum foil is covered and welded with the aluminum powder particles. The preparation method provided by the invention solves the problems of reduced specific surface area and reduced porosity or capacitance of the electrode foil in the process of the electrode foil.

Inventors

  • Han Wangshu
  • YU SHAOMEI
  • XIAO ZHENDONG
  • LONG HUIHUI

Assignees

  • 长沙联超科技有限公司

Dates

Publication Date
20260505
Application Date
20221122

Claims (10)

  1. 1. A preparation method of a porous anode aluminum foil for an electrolytic capacitor based on laser additive manufacturing is characterized by comprising the following steps of (1) tiling the aluminum foil on a conveying device, adding aluminum foil particles to the aluminum foil through a charging bin when the aluminum foil passes through a first charging bin, then welding the aluminum foil particles by utilizing linear laser, completely welding a single-layer aluminum metal particle to the aluminum foil, (2) moving the aluminum foil along with the conveying device, continuously covering the single-layer aluminum powder particle above through a next charging bin, welding the aluminum foil particles by utilizing linear laser, repeating the steps until aluminum metal particles with the thickness of 50 mu m are welded on one side of the aluminum foil, (3) enabling one side which is not welded by the aluminum powder particles to be located above through a turnover device, repeating the steps (1) and (2), finally obtaining the porous anode aluminum foil for the electrolytic capacitor, adding the aluminum powder particles to the aluminum foil through the charging bin, controlling the thickness of the aluminum powder particles by utilizing a scraper vibrated below the charging bin, so that the aluminum powder particles are basically distributed in a single-layer manner.
  2. 2. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing of claim 1, wherein the thickness of the aluminum foil in the step (1) is 30 μm, the average particle size of aluminum powder particles is 5-6 μm, and a dispersing agent is added into the aluminum powder particles to prevent the aggregation of spheres.
  3. 3. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing according to claim 1, wherein the conveying device in the step (1) is a belt conveyor, a roller conveyor or a plate-chain conveyor.
  4. 4. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing of claim 1, wherein a scraper is attached to the outlet of the feeding bin in the step (1), and high-frequency vibration with the amplitude of micrometers is added.
  5. 5. The method of claim 1, wherein the turning device in the step (2) mainly comprises three guide rollers, and after the aluminum foil bypasses the three guide rollers from top to bottom, one side of the welded aluminum metal particles originally located above is located below, and one side of the non-welded aluminum metal particles originally located below is located above, so that the turning is realized.
  6. 6. The method of claim 1, wherein the anode aluminum foil for electrolytic capacitors finally formed in the step (3) has a thickness of 130. Mu.m.
  7. 7. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing of claim 1, wherein the linear laser in the step (1) is a semiconductor laser.
  8. 8. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing according to claim 1, wherein the wavelength of the linear laser in the step (1) is 880 nanometers.
  9. 9. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing of claim 1, wherein the wavelength of the linear laser in the step (1) is 915 nanometers.
  10. 10. The method for preparing the porous anode aluminum foil for the electrolytic capacitor based on laser additive manufacturing according to claim 1, wherein the wavelength of the linear laser in the step (1) is 976 nanometers.

Description

Preparation method of porous anode aluminum foil for electrolytic capacitor based on laser additive manufacturing Technical Field The invention relates to the technical field of capacitors, in particular to a preparation method of a porous anode aluminum foil for an electrolytic capacitor based on laser additive manufacturing. Background The capacitor includes a film capacitor, a ceramic capacitor, and an electrolytic capacitor. Among them, the electrolytic capacitor mainly uses tantalum electrolytic capacitor and aluminum electrolytic capacitor, and the aluminum electrolytic capacitor is widely used because of its large volume specific capacity and low cost per unit capacity. The electrode aluminum foil of the aluminum electrolytic capacitor is prepared by adopting an electrochemical corrosion method, so that a porous structure is obtained, and an aluminum oxide film grows on the surface of the corroded aluminum foil through anodic oxidation, so that the dielectric property of the aluminum foil is exerted. The degree of corrosion of the aluminum foil adopts different corrosion conditions according to the difference of the use voltage. Specifically, in the case of a medium-high voltage capacitor, when the oxide film is thick, a tunnel hole is often formed by direct current corrosion, and in the case of a low voltage capacitor, a sponge hole is often formed by alternating current corrosion in order to obtain a high specific surface area. However, both direct current corrosion and alternating current corrosion require the use of corrosive liquids containing hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc., which place a great burden on the environment and post-treatment of the corrosive liquids places a great burden on the process and economy. According to the literature investigation, patent document CN103563028a proposes an electrode foil for electrolytic capacitors having a sintered body of aluminum powder on one or both sides of an aluminum base material without requiring electrochemical corrosion treatment. In patent document CN104620342a, an electrode foil is proposed, which is characterized in that a porous layer composed of sintered aluminum powder is formed on the surface of an aluminum material. Patent document CN105874549a proposes an electrode foil for an aluminum electrolytic capacitor, which comprises a porous sintered body formed by aluminum and aluminum alloy powder with a gap maintained therebetween and a supporting base material. Patent document CN103688327a proposes an electrolytic capacitor electrode material characterized by comprising an aluminum base and a powder sintered body obtained by pressing a film made of aluminum or aluminum alloy powder and sintering the film. Patent document CN104919552a proposes a porous aluminum foil for electrolytic capacitors obtained by attaching a paste containing aluminum powder to an aluminum base material and sintering the paste. In patent document CN104094370a, a method for producing an electrode material is proposed, which is characterized in that a laminate of a mold and a base material is sandwiched from both sides on an aluminum base material, and aluminum powder is attached to the aluminum base material and sintered. In the above method, the porous structure is changed only by changing the structure of the powder of aluminum or aluminum alloy, but there is a problem that the specific surface area of the sintered aluminum foil is limited because the aluminum powder particles used are too fine, regardless of whether the aluminum powder is directly sintered or the film is formed in advance and then sintered. This is because the finer the aluminum powder, the larger the surface energy, causing fusion of the aluminum powder during sintering, filling of voids between aluminum powder particles, and a decrease in specific surface area, leading to a limited or even decreased increase in electrostatic capacity. The electrode foil obtained in the above document is suitable for high-voltage foils with low porosity requirements. In patent document CN105393320a, an improvement method of an electrode material of an aluminum electrolytic capacitor is proposed, in which aluminum and aluminum alloy powder and electrically insulating particles are sintered together to form a sintered layer, so that the sintered layer has a high electrostatic capacity when used in a piezoelectric capacitor. However, the addition of insulating particles makes it difficult to sinter the electrode foil, and the insulating particles reduce the conductivity, which affects the efficiency of the subsequent anodizing process. In summary, in the process of sintering aluminum powder to obtain an electrode foil, it is necessary to sinter aluminum powder finer in order to obtain an electrode foil with a high specific volume, but the preparation of an electrode foil using aluminum powder of fine particles suffers from the following problems: (1) The fine-particle aluminum po