Conductive electrolyte for high voltage capacitors

Abstract

The present invention is directed to a conductive electrolyte for use in high voltage electrolytic capacitors and to an electrolytic capacitor impregnated with the electrolyte of the present invention for use in an implantable cardioverter defibrillator (ICD). The electrolyte according to the present invention is composed of a two solvent mixture of ethylene glycol and an alkoxy-substituted alcohol, such as 2-methoxyethanol, 2-ethoxyethanol, or 2-butoxyethanol. Dissolved in this mixture is a combination of acids including at least one straight chain aliphatic dicarboxylic acid of carbon chain length from eight to thirteen (C8 to C13) and a longer chain dicarboxylic acid, where the acid functional groups are separated by 34 carbons (referred to as “dimer acid”). As further additives, boric acid and hypophosphorous acid can be added, with the former providing corrosion inhibition in the finished capacitor, and the latter resulting in lower leakage currents and better voltage droop characteristics. Also, a cathode depolarizer, or degassing agent, from the group of nitro-substituted aromatic compounds (nitroaromatics) can be added to reduce the amount of gas produced during capacitor life. The solution is neutralized with an amine.

Dependencies are inferred from the claim text.