Formation method of extra-high-voltage electrode foil

Abstract

The invention discloses a formation method of extra-high-voltage electrode foil, and relates to the technical field of electrode foil. The formation method comprises the following step of 1, digesting corrosion foil in a silicate solution at the temperature of 95 DEG C or above to obtain pretreated foil; 2, conducting formation on the pretreated foil in a boric acid and ammonium pentaborate solution to obtain first-stage formed foil; 3, conducting formation on the first-stage formed foil in a boric acid and ammonium pentaborate solution to obtain second-stage formed foil; and 4, conducting multi-stage formation on the second-stage formed foil in a boric acid, ammonium pentaborate and ammonium pentenedioate solution to obtain a final formed foil product. The formation method has the beneficial effects that electrolyte is simple in composition and easy to produce and control, and wastewater treatment is relatively simple; and sparking voltage is not increased by reducing the conductivity of formation liquid, so that the invalid electric loss in the formation process is greatly reduced, the surface of the formed foil has no sparking spots, the dielectric properties of an oxide film are good, the boosting time of the product is less than 150 seconds, the leakage current is less than 12 [mu]A / cm<2>, and the method meets the production requirement for 1000-1500V extra-high-voltage electrode foil.

Description

technical field [0001] The invention relates to the technical field of electrode foils, in particular to a method for preparing ultra-high voltage electrode foils. Background technique [0002] In recent years, with the rapid development of photovoltaic power generation, automobile charging piles and other industries, the demand for UHV aluminum electrolytic capacitors has increased significantly. UHV aluminum electrolytic capacitors generally refer to capacitors with a withstand voltage exceeding 1000V, and its anode material is UHV aluminum electrode foil. The preparation method is generally divided into two steps. First, the high-purity aluminum is subjected to electrochemical corrosion to obtain a corroded foil, and then the corroded foil is subjected to chemical conversion treatment in a specific electrolyte to obtain an electrode foil. Because the withstand voltage of capacitors often exceeds 1000V, this requires that a voltage of more than 1000V must be applied to th...

AI Technical Summary

Problems solved by technology

Because the withstand voltage of capacitors often exceeds 1000V, this requires that a voltage of more than 1000V must be applied to the electrode foil at the end of the chemical conversion treatment. Under high voltage conditions, the surface of the electrode foil is prone to flash fire, resulting in flash spots on the surface of the electrode foil, which affects The electrical performance of the product

In order to reduce the occurrence of flash spots, the common method is to reduce the conductivity of the electrolyte, thereby increasing the flash voltage of the electrolyte, but this will lead to an increase in the electrolytic pressure drop, insufficient pressure resistance of the forming foil, and in the industrial production process The current can often reach 500-1000A, and the useless power consumption it brings is huge

Chinese invention patent ZL201510549878.5 provides a method for the formation of ultra-high voltage electrode foil, which is formed by adding 2,3-butanediol, sorbitol, benzyl alcohol, polyethylene glycol, polyvinyl alcohol, poly Glycerol monooleate is used to increase the flash voltage of the electrode foil, and there are three disadvantages. First, the composition of the electrolyte is complex, and there are difficulties in the configuration and content control of the electrolyte.

In addition, these organic substances have a high viscosity and are easy to adhere to the surface of the electrode foil. They need to be cleaned with a large amount of ultrapure water, which increases production costs, and there are also major problems in the treatment of wastewater.

The applicable voltage range of the invention is 900-1200V, and it is difficult to meet the production requirements of higher voltage ranges. Therefore, it is necessary to provide a cleaner and more efficient UHV electrode foil formation method