SECONDARY BATTERY

A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case including a first side having an opening to accommodate the electrode assembly; a cap plate sealing the first side of the case; a first current collector plate arranged between the electrode assembly and the cap plate and electrically connecting the first electrode plate and the cap plate; a terminal arranged on a second side of the case; a second current collector plate electrically connecting the second electrode plate and the terminal; a first welding portion on an outer surface of the cap plate and welding the cap plate and the first current collector plate; and a second welding portion on the outer surface of the cap plate and welding the case and the cap plate.