The present invention provides a battery module comprising: a battery cells- stacked body in which a plurality of battery cells, each of which having a structure in which an electrode assembly and an electrolyte are sealed together in a battery case, are arranged in such a manner that the sides of the battery cells are in contact with each other; and a buffering and cooling member mounted under the battery cells-stacked body so as to be able to support the weight thereof, and having a porous structure so as to enable the heat generated from the battery cells-stacked body during the processes of charging and discharging to be discharged through the bottom of the battery cells-stacked body.