SECONDARY BATTERY

A secondary battery includes: a case; an electrode assembly disposed within the case and including a main body and two tabs; a cap assembly including a cap plate, a lower insulating member and an explosion-proof valve, the explosion-proof valve being disposed on the cap plate, the lower insulating member being disposed on a side of the cap plate close to the electrode assembly and including an inner side surface, an outer side surface, and a concave portion recessed from the inner side surface toward the outer side surface, the concave portion being in position corresponding to the explosion-proof valve, and the concave portion being used to buffer an expansion amount of the main body; and an insulating plate located on a side of the lower insulating member close to the electrode assembly and including a shielding segment which at least partially shields the concave portion.