Disclosed herein is a battery module including a plurality of battery cells mounted in a module case in a stacked state, wherein cooling members are mounted at interfaces between the battery cells, the module case is configured in a structure in which two opposite sides of the module case are open so that corresponding portions of the battery cell stack are exposed outward through the two open opposite sides of the module case, the cooling members are partially exposed outward through the two open opposite sides of the module case, and a coolant flows along the two open opposite sides of the module case while contacting the outwardly exposed portions of the cooling members.