A rechargeable battery includes: an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; a case having an opening and housing the electrode assembly; and a cap assembly sealing the opening of the case, and the cap assembly includes: a cap plate bonded to the case and covering the opening; a terminal plate bonded to the cap plate; and a thermal fusion member between the terminal plate and the cap plate and thermally fused with the terminal plate and the cap plate.