A rechargeable battery according to an exemplary embodiment of the present invention includes an electrode assembly, a case containing the electrode assembly, and a cap assembly. The electrode assembly includes a first electrode, a second electrode, and a separator between the first and second electrodes. The cap assembly is coupled to the case. The cap assembly includes a tab that is electrically connected to the first electrode and a deformable plate that is electrically connected to the second electrode. The deformable plate also includes a notch that is opened due to an increase of pressure. The deformable plate deforms as a result of increased pressure and electrically contacts the first tab, short circuiting the rechargeable battery.