Battery pack having current blocking device using bimetal and operating method thereof

The present disclosure relates to a battery pack and an operation method thereof. The battery pack includes a pack case, a plurality of cylindrical battery cells in the pack case, and a current breaking device in the pack case to connect the plurality of cylindrical battery cells and having a portion including a bimetal. The current breaking device includes a fixed end contacting an electrode terminal of the cylindrical battery cell, a free end contacting an electrode terminal of the surrounding cylindrical battery cell, and a flexible member configured to elastically press the free end toward the surrounding cylindrical battery cell. The battery pack may include a current breaking device using bimetal that is capable of quickly restoring a connection with a surrounding cylindrical battery cell when a state of a battery cell separated from the surroundings in case of an abnormal state thereof is recovered.