Method for producing electrochemical capacitor

Abstract

A process for producing an electrochemical capacitor including an organic electrolytic solution and electrode bodies immersed in the organic electrolytic solution, each comprising a polarizing electrode (composed mainly of a carbon material containing a partially oxidized, graphite-like microcrystalline carbon), a separator and a collector, in which capacitor each polarizing electrode gives rise to volume expansion when charged and volume contraction when discharged, is provided. The process includes: a step of placing each electrode body and the organic electrolytic solution in a cell container to form a unit cell, a step of placing the unit cell or a cell integrate obtained by electrically connecting a plurality of such unit cells, in a first capacitor container to constitute a first electrochemical capacitor, a step of subjecting the first electrochemical capacitor to charging-discharging cycles until the maximum value of the stress caused by the volume expansion of each polarizing electrode during charging becomes almost constant, and a step of transferring, after the maximum value of the stress has become almost constant, the unit cell or the cell integrate into a second capacitor container to constitute a second electrochemical capacitor. The process can provide an electrochemical capacitor which causes no plastic deformation of the capacitor container and which is superior in durability and reliability.