A conductive member including an opening portion is connected to a positive terminal and is integrally secured to a sealing plate together with an outer insulating member and a second insulating member. The conductive member opening portion is sealed by a deformable plate. A base portion of a positive electrode current collector is connected to the deformable plate. A first insulating member that is disposed between the deformable plate and the base portion of the positive electrode current collector includes a pair of first catch portions that are disposed so as to be aligned in a longitudinal direction of the sealing plate and a pair of second catch portions that are disposed so as to be aligned in a transverse direction of the sealing plate. The first catch portions and the second catch portions are connected to the second insulating member disposed between the sealing plate and the conductive member.