BATTERY MODULE, BATTERY RACK COMPRISING SAME, AND POWER STORAGE DEVICE

Disclosed is a battery module with reduced risk of fire propagation or explosion. To achieve the above-described object, the battery module according to the present disclosure includes a cell assembly including a plurality of secondary batteries, a module housing in which the cell assembly is received in an internal space, the module housing having an opening through which the internal space is in communication with an external space, and an adjustment cover configured to cover at least a part of the opening to fill a fire extinguishing agent supplied into the battery module to a predetermined height or above.