A secondary battery including an electrode assembly, the electrode assembly including a separator between a positive electrode and a negative electrode; current collectors, the current collectors being electrically connected to the positive electrode and the negative electrode, respectively; a case, the case accommodating the electrode assembly and the current collectors; a cap plate, the cap plate coupled to an opening in the case; and an insulating film, the insulating film insulating the electrode assembly and the electrode collectors from the case, wherein the insulating film includes a protuberance pattern on at least one surface thereof to compensate for vibration of the electrode assembly current collectors with respect to the case.