A battery module includes: first and second sub-battery modules, respectively comprising a cell stack including a plurality of battery cells, and a bus bar assembly disposed at least one side of the cell stack; and a central wall disposed between the first and second sub-battery modules, wherein the central wall includes a hollow venting passage formed in a direction intersecting the direction that the first and second sub-battery modules are disposed such that gas or flames occurring in the first or second sub-battery modules are allowed to flow from inside the battery module through the hollow venting passage to the outside of the battery module.