The present invention is to provide a positive tab lead capable of being connected with each other with a sufficient connection strength at a low energy cost. It is constituted such that a partial coating layer (13) made of nickel, tin or solder is formed on at least a part of a region of an aluminum plate (11) exposed to an outside of an outer cover. It is preferable to form a chitosan layer (14) containing one or more compounds selected from the group consisting of chitosan and chitosan derivatives on the surface of the tab lead.