The present disclosure relates to a battery module including: a battery cell stack in which a plurality of battery cells are stacked; and a pressure drop sheet on one side of the battery cell stack, in which the pressure drop sheet includes: a ventilation layer including ceramic fiber; and a sacrificial layer on at least one face of the ventilation layer, the sacrificial layer is disposed in a direction facing the battery cell stack, and the pressure drop sheet exhibits gas permeability at a critical temperature.