BATTERY MODULE

A battery module includes a cell assembly(200) comprising a plurality of cells(210); a module housing(100) including an upper housing(110) having a closed inner space accommodating the cell assembly and a lower housing(120) air-tightly attached to a lower end of the upper housing; and an air vent member(130) air-tightly disposed at one side of the module housing to discharge inner gas of the module housing to the outside, the air vent member being configured to block external gas from entering into the module housing.