Electrolyte for driving of aluminum electrolytic capacitor and preparation method of main solute of electrolyte

Abstract

The invention discloses electrolyte for driving of an aluminum electrolytic capacitor and a preparation method of dicarboxylic acid with branches in an alpha position and salt of the dicarboxylic acid. The electrolyte comprises solutes, solvents and various additives, wherein the solutes comprise major solutes and auxiliary solutes; the solvents comprise major solvents and auxiliary solvents; and the additives comprise a sparking voltage improver, a waterproof mixture and a hydrogen eliminating agent. According to the weight ratio, the major solutes account for 2%-18%, the auxiliary solutes account for 3.5%-7.5%, the main solvents account for 54.5%-82%, the auxiliary solvents account for 3%-8%, the sparking voltage improver accounts for 2%-8%, the waterproof mixture accounts for 1.5%-3%, and the hydrogen eliminating agent accounts for 1.5%-2.5%. The electrolyte has the characteristics of relatively high sparking voltage, good low-low-temperature stability and large ripple current resistance, thus being capable of prolonging the service life of the capacitor.

Description

technical field [0001] The invention relates to the field of aluminum electrolytic capacitors, in particular to a method for preparing an electrolytic solution for driving an aluminum electrolytic capacitor and a main solute thereof. Background technique [0002] At present, the working electrolytes of known or in-use medium and high voltage aluminum electrolytic capacitors have gone through the following development processes: 1. Ethylene glycol is used as the main solvent, and inorganic compounds such as boric acid or ammonium pentaborate are used as the main solute. The working electrolyte prepared in this way has the problem of low conductivity, and boric acid and its salts are easy to undergo esterification reaction with ethylene glycol at high temperature to generate a large amount of condensed water, which causes the moisture content inside the electrolyte to increase, and the electrolyte's The vapor pressure increases, and the internal pressure of the capacitor incre...

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Problems solved by technology

The working electrolyte prepared in this way has the problem of low conductivity, and boric acid and its salts are easy to undergo esterification reaction with ethylene glycol at high temperature to generate a large amount of condensed water, which causes the moisture content inside the electrolyte to increase, and the electrolyte's The vapor pressure increases, and the internal pressure of the capacitor increases, causing the capacitor to open the valve and fail; 2. Using ethylene glycol as the main solvent, using direct-linked hydrocarbon saturated dicarboxylic acids such as azelaic acid, sebacic acid or dodecanedioic acid and their Salt is the electrolyte of the electrolyte. Although this type of electrolyte avoids a part of the esterification reaction, due to the low solubility of this type of straight-chain alkanes in ethylene glycol, the impedance of the product is large and the ripple is large. It is easy to generate heat under high temperature and make the solvent volatilize, thus creating a vicious cycle, causing the capacitor to dry out and fail. At the same time, linear alkanes are prone to amidation side reactions at high temperatures to generate water, which is also easy to cause early failure of the capacitor; 3. Use some branched chains Acids or their salts, such as reported 1,6-DDA and its salts and 2-butylsuberic acid and its salts, such branched carboxylic acids and their salts have improved solubility in solvents compared to straight-chain alkanes , thus producing effects to a certain extent, but at the same time, this kind of acid or its salt mainly relies on imports, so the cost is high and there are many constraints

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