SECONDARY BATTERY

A secondary battery includes an electrode assembly including a first electrode plate, a second electrode plate, and a separator interposed therebetween, a can accommodating the electrode assembly, and a terminal portion including a rivet terminal coupled to one side of the can in a longitudinal direction and electrically connected to the first electrode plate, and an insulator between the can and the rivet terminal to insulate the can from the rivet terminal, and having a stepped structure in an area contacting the rivet terminal. By reducing or minimizing a height difference between the positive electrode terminal and the insulator, shape deformation of the electrode assembly can be reduced or prevented during the manufacturing process. By reducing the thickness and weight of the insulator, the size of the electrode assembly can be increased, and the capacity of the secondary battery can be increased.