A battery pack includes: a battery cell including a terminal surface on which an electrode terminal is located, a bottom surface opposite the terminal surface, and a lateral surface between the terminal surface and the bottom surface; a first tank facing the terminal surface of the battery cell; a second tank extending from the first tank and facing the lateral surface of the battery cell; and a third tank extending from the second tank and facing the bottom surface of the battery cell, and a cavity is defined in the first and second tanks to extend across the first and second tanks, the cavity being filled with a first cooling medium and being fluidically isolated from an outside of the battery pack; and a flow path is defined in the third tank to receive a flow of a second cooling medium which is different from the first cooling medium.