Patent ID: 8804310

Claim:
An electrochemical device having a structure wherein a capacitor element is sealed in a package, said capacitor element having a configuration in which two or more electrode sheets, each having a collector electrode layer and a polarizable electrode layer formed on at least one side of the collector electrode layer, are stacked to form a laminate with a separation sheet inserted between the polarizable electrode layers of adjacent different electrode sheets, said laminate being folded along a single common reference line, to be superposed, wherein the collector electrode layers, the polarizable electrode layers, and the separation sheets are continuous through the respective folded locations, and the polarizable electrode layers entirely contact the collector electrode layers and the separation sheets, wherein, of the two or more electrode sheets, provided on both ends of the collector electrode layer of each electrode sheet having one polarity are lead connection parts that face each other in the aforementioned configuration and these lead connection parts are directly joined and are disposed opposite to the folded end of the laminate; and provided on both ends of the collector electrode layer of each electrode sheet having the opposite polarity are lead connection parts that face each other at positions not contacting the lead connection parts of the aforementioned electrode sheet in the aforementioned configuration and these lead connection parts are directly joined and are disposed opposite to the folded end of the laminate, wherein, of the two or more electrode sheets, at least one electrode sheet having one polarity is such that its collector electrode layer has anti-displacement projections on its outer periphery, which anti-displacement projections extend from the outer periphery beyond the adjacent polarizable electrode layer and bite into the adjacent separation sheet without piercing therethrough, and at least one electrode sheet having the opposite polarity is such that its collector electrode layer has anti-displacement projections on its outer periphery, which anti-displacement projections extend from the outer periphery beyond the adjacent polarizable electrode layer and bite into the adjacent separation sheet without piercing therethrough.