RECHARGEABLE BATTERY

摘要

PURPOSE: A secondary battery is provided to improve safety by maintaining a short state of a fuse element by a valve element when a short is generated due to overcurrent. CONSTITUTION: A secondary battery(101) comprises an electrode assembly(10) which comprises a positive electrode(11) and a negative electrode; a case(26) comprising an empty space for accepting the electrode assembly; a cap plate(31) which comprises a short hole(37) and connected to the case; a short element(57) which is placed in the short hole and electrically connects the positive electrode to the negative electrode through a deformation; and a valve element(70) between the short element and electrode assembly. The valve element comprises a first part with a first thickness and a second part with a second thickness. The second thickness is thicker than the first thickness.