Since electrochemical capacitors including an electric double-layer capacitor can be easily made small in size and light in weight, they are expected as, for example, backup power sources for the power sources of portable equipment (small-sized electronic equipment) etc., and auxiliary power sources for an electric automobile and a hybrid vehicle, and various studies have been made for enhancing the performances of the electrochemical capacitors. Especially in a case where a large capacity is required as in the power source for the electric automobile, it has been desired to develop an electrochemical capacitor in which a capacitance per unit volume of electrodes (hereinbelow, termed “volume capacitance”) is high.
Each electrode for use in such an electrochemical capacitor has a laminated structure which includes a current collector and a polarizable electrode layer, and it can be fabricated by coating the front surface of the sheet-like current collector with a solution which is to become the material of the polarizable electrode layer, and which is subjected to drying (refer to Patent Document 1). Since, however, the density of the polarizable electrode layer to be formed is low merely by coating the front surface of the current collector with such a solution and then drying the solution, a sufficient volume capacitance cannot be attained. In order to attain a higher volume capacitance, therefore, the polarizable electrode layer needs to be compressed by roll press or the like after the formation thereof by the coating.
[Patent Document 1] JP-A-2000-106332