SECONDARY BATTERY

A secondary battery includes an electrode assembly configured to have a wound structure including a first electrode, a second electrode and a separator between the first electrode and the second electrode; a case having an open area in a first side thereof, the open area being configured to accommodate the electrode assembly; and a cap assembly coupled to the first side of the case and configured to close the open area, wherein the cap assembly includes a cap plate seated in and coupled to the open area of the case and having a through-hole; and a terminal plate including a body and an insertion portion extending through the through-hole of the cap plate, and wherein the first electrode includes an electrode tab having a first end connected to the terminal plate.