Secondary battery including wound electrode body and battery pack

A secondary battery comprising:

• a wound electrode body including a stack wound around a central axis extending in a first direction, the stack including a positive electrode, a negative electrode, and a separator, the positive electrode and the negative electrode being stacked with the separator interposed therebetween;
• a positive electrode current collector plate disposed to face a first end face of the wound electrode body, the first end face being an end face in the first direction;
• a negative electrode current collector plate disposed to face a second end face of the wound electrode body, the second end face being opposite to the first end face in the first direction;
• an electrolytic solution;
• and
• a battery can containing the wound electrode body, the positive electrode current collector plate, the negative electrode current collector plate, and the electrolytic solution, wherein
• the positive electrode includes
• a positive electrode current collector including
• an inner peripheral surface of the positive electrode current collector located on a side of the central axis of the wound electrode body, and
• an outer peripheral surface of the positive electrode current collector opposite to the inner peripheral surface of the positive electrode current collector,
• an inner periphery side positive electrode active material layer covering a portion or all of the inner peripheral surface of the positive electrode current collector,
• an outer periphery side positive electrode active material layer covering a portion or all of the outer peripheral surface of the positive electrode current collector, and
• a positive electrode exposed part in which the positive electrode current collector is exposed without being covered with the positive electrode active material layer,
• in a state in which the stack is wound around the central axis, the positive electrode exposed part includes a plurality of first edge parts adjacent to each other in a radial direction of the wound electrode body, the plurality of first edge parts being bent toward the central axis and overlapping with each other on the first end face,
• the positive electrode current collector plate is joined to the plurality of first edge parts on the first end face,
• the negative electrode includes
• a negative electrode current collector including
• an inner peripheral surface of the negative electrode current collector located on the side of the central axis of the wound electrode body, and
• an outer peripheral surface of the negative electrode current collector opposite to the inner peripheral surface of the negative electrode current collector,
• an inner periphery side negative electrode active material layer covering a portion or all of the inner peripheral surface of the negative electrode current collector,
• an outer periphery side negative electrode active material layer covering a portion or all of the outer peripheral surface of the negative electrode current collector, and
• a negative electrode exposed part in which the negative electrode current collector is exposed without being covered with the negative electrode active material layer,
• in the state in which the stack is wound around the central axis, the negative electrode exposed part includes a plurality of second edge parts adjacent to each other in the radial direction of the wound electrode body, the plurality of second edge parts being bent toward the central axis and overlapping with each other on the second end face,
• the negative electrode current collector plate is joined to the plurality of second edge parts on the second end face,
• in the wound electrode body, an innermost wind portion of the negative electrode is located on an inner side relative to an innermost wind portion of the positive electrode,
• the outer periphery side negative electrode active material layer has an inner periphery side edge located closer to the central axis of the wound electrode body than an inner periphery side edge of the inner periphery side negative electrode active material layer.