Preparation method for anode foil of medium-high voltage aluminum electrolytic capacitor and capacitor

Abstract

A preparation method for an anode foil of a medium-high voltage aluminum electrolytic capacitor comprises the following steps: 1) performing powder deoxidation: carrying out vacuum annealing on aluminum powder or aluminum alloy powder or annealing for 1-3 hours under the protection of inert gas; 2) performing slurry mixing: uniformly mixing a binder with the aluminum powder or aluminum alloy powder obtained in the step 1); 3) forming a film on an aluminum foil substrate; 4) performing sintering: sintering the aluminum foil prepared in the step 3) at the temperature of 560-660 DEG C; 5) etchingthe sintered aluminum foil in weak acid such as organic acid or low-concentration inorganic acid, wherein the time is 3 min to 2 h; 6) performing formation. According to the method, the anode foil issubjected to weak acid corrosion for a period of time after being sintered, and bulges and spines in the sintered film are corroded to a certain extent, so that gaps in the sintered film are uniformto a certain extent, the current is uniformly distributed during formation, and an oxide film formed on the sintered film is uniform as much as possible; therefore, the formation quality is ensured.

Description

technical field [0001] The invention relates to a medium-high voltage aluminum electrolytic capacitor, in particular to a method for preparing an anode foil of a medium-high voltage aluminum electrolytic capacitor and the capacitor. Background technique [0002] At present, most of the anode foils of high-voltage aluminum electrolytic capacitors in China are corroded foils, and high-voltage corroded foils have the following disadvantages. Because the film thickness of medium and high-voltage anode foils is relatively thick, the holes of the corrosion pits formed on the corroded foils are relatively large. , thus affecting the surface area of ​​the anode foil. At the same time, low-concentration inorganic acids, sulfuric acid, nitric acid and other aqueous solutions are required in the corrosion process. These acids have strong environmental damage capabilities, and the treatment of these acids also affects the production cost and the anode foil. The production process, becau...

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Problems solved by technology

[0004] However, it was found during the production process that when the anode foil of Japan Toyo Aluminum Co., Ltd. was anodized on the surface, which is what we usually call chemical formation, due to the many protrusions and spikes inside the sintered film, the sintered film The resistance of the surface varies greatly, resulting in the anodic oxidation process and the uneven current distribution during the formation process, which brings great difficulties to the formation process.

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