Electrochemical element having an ellipsoidal assembly configured for high power input

Abstract

The electrochemical element includes an electrode assembly accommodated in a case with an electrolyte. The electrode assembly is formed into a flat shape by winding positive and negative electrodes with a separator interposed therebetween. The positive electrode includes an exposed positive current collector portion uncoated with an active material and formed in one end in the width direction of a strip-shaped positive current collector, and a positive lead is attached to the exposed positive current collector portion. The negative electrode includes an exposed negative current collector portion uncoated with an active material and formed in the other end in the width direction of a strip-shaped negative current collector, and a negative lead is attached to the exposed current collector portion. The exposed positive current collector portion on the one end is pressed and welded, and the exposed negative current collector portion on the other end is pressed and welded to form the electrode assembly. This implements a current collection structure for providing stable conductive connection with high quality in a simple manner for an electrochemical element requiring high power.