BATTERY PACK

A battery pack includes a plurality of battery cells arranged in a longitudinal direction, a heat insulating sheet between two adjacent battery cells of the plurality of battery cells, a first friction sheet located between the heat insulating sheet and a first battery cell of the two adjacent battery cells and including non-adhesive surfaces in direct contact with the heat insulating sheet and the first battery cell, and a restrainer configured to provide a compressive force in the longitudinal direction from opposite ends of the plurality of battery cells.