To obtain large capacity and high breakdown voltage by equipping a cell container for accommodating an electrode construct and an electrolyte with a stress relaxation structure.
A cell container 60 of a unit cell 70 is provided with a bellows part 60a as structure for relaxing stress being generated by the inflation of a polarizable electrode (carbon material). In this case, the cell container 60 is preferably made of stainless steel or the like. The bellows part 60a may be provided at the center of the cell container 60 or at an end part. Also, the cell container is equipped with a leaf spring as the stress relaxation structure. Also, in an electrode construct, a collector is composed by an elastic body. Also, as the elastic body being used as the collector is preferably made of elastically deformable porous conductive rubber sheet. As a separator, an insulation porous body should be selected to electrically separate a positive electrode from a negative one and can transmit the ions of a dissolved substance.
YOSHIDA HITOSHI
KATSUKAWA HIROYUKI
