Process for producing aluminum electrode plate for electrolytic capacitor

Abstract

In the production of an aluminum etched plate (1) for an electrolytic capacitor having a high level of capacitance by subjecting an aluminum plate to alternating current etching in an etching liquid to enlarge the face, an aluminum plate having an aluminum purity of not less than 99.98% by mass, a copper content of less than 30 ppm, and an iron content of 5 to 50 ppm is subjected to alternating current etching in an etching liquid containing not less than 0.01 ppm and less than 100 ppm of an additive such as diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, or diethylhexyl phthalate mixed therein.

Description

technical field [0001] The present invention relates to a method for manufacturing an aluminum electrode plate for an electrolytic capacitor obtained by etching an aluminum plate. Background technique [0002] In recent years, with the digitalization and high frequency of personal computers and information equipment, electrolytic capacitors are required to be thinner, lower in impedance, and lower in ESR, and lower in ESL and higher in capacity. In response to these demands, development of solid aluminum electrolytic capacitors is underway. However, in order to increase the capacity of electrolytic capacitors, it is necessary to increase the etching ratio of aluminum foil. [0003] Therefore, it has been proposed to increase the capacitance by thickening the aluminum foil and performing deep etching (see Patent Document 1). [0004] Patent Document 1: Japanese Patent Laid-Open No. 2005-150705 [0005] However, when a thick aluminum foil is used and the etched portion is d...

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Problems solved by technology

[0005] However, when a thick aluminum foil is used and the etched part is deepened, there is a problem in the conventional etching technology that when the etched pit is grown (growth), the etched part is dissolved and the etching magnification cannot be increased.

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