Secondary battery

A secondary battery comprising:

• a wound electrode body in which a positive electrode sheet comprising a long sheet-shaped positive electrode current collector and a positive electrode active material layer formed on a surface of the positive electrode current collector, and a negative electrode sheet comprising a long sheet-shaped negative electrode current collector and a negative electrode active material layer formed on a surface of the negative electrode current collector are wound in a longitudinal direction, with a separator being interposed therebetween;
• and
• a non-aqueous electrolytic solution,
• wherein
• at least one end portion of the positive electrode sheet in the longitudinal direction is provided with
• an insulating tape that covers the end portion and is attached onto the positive electrode active material layer, and
• a coating that is provided on the positive electrode active material layer along an edge of the insulating tape and is inactive to a battery reaction,
• and
• a thickness of the coating decreases gradually as a distance between the coating and the edge of the insulating tape increases gradually.