Secondary battery

摘要

A secondary battery capable of improving charge-discharge cycle characteristics in the case where an alloy material is used as an anode active material is provided. An exposed cathode region is disposed in an outer end portion of a cathode. The exposed cathode region includes an insulating protective member on at least one of an outer side and an inner side of the exposed cathode region in a position opposed to an outer end portion of an anode active material layer in one turn inside the outer end portion. In a cathode active material layer, a central angle between an outer end portion and a central end portion at the center of the spirally wound body is preferably within a range from 0° to -90° inclusive from the central end portion in a winding direction.