A battery module includes a cell assembly including a plurality of battery cells, and a module housing having an arrangement space for accommodating the cell assembly and a cover plate covering a top surface of the cell assembly. The cover plate has at least one discharge hole for discharging gas generated in the cell assembly. A blocking member is disposed between the top surface of the cell assembly and the cover plate to block flame or a combustion material from being discharged externally of the module housing through the discharge hole.