Disclosed is a battery module having improved safety against fire or thermal runaway. A battery module according to the present invention to achieve the above purpose comprises: a cell assembly including at least two battery cells; a module housing having an internal space for accommodating the cell assembly and a communication port for connecting the internal space with outside; a mesh member having a mesh structure and provided on the communication port of the module housing; and a sealing member provided on a location facing the mesh member and configured to seal mesh holes of the mesh member when the volume thereof expands at a certain temperature or higher.