Electric double-layer capacitor

Abstract

An electric double-layer capacitor is provided, which prevents the apparent capacitance decrease on operation or use at a large discharge current. This capacitor includes at least one basic cell and a pair of external terminals electrically connected to ends of the at least one basic cell, respectively. Each of the at least one basic cell has a tubular electrically-insulating gasket having a tubular inner space and opening ends, a pair of polarizable electrodes placed in the inner space of the gasket, a porous separator sandwiched between the pair of electrodes and placed in the inner space of the gasket, and a pair of collectors placed to close the opening ends of the gasket, respectively. An electrolyte solution is stored in the inner space of the gasket. The solution is absorbed to the pair of electrodes. Each of the pair of electrodes has an inner surface contacted with an opposing surface of the separator and an outer surface contacted with a corresponding one of the pair of collectors. Each of the pair of electrodes is formed by stacked sub-electrodes having at least one interface extending along the pair of collectors. The at least one interface allows ions of the electrolyte solution to diffuse.