Abstract: An aircraft includes a battery pack mounted inside the aircraft, a vent coupled between the battery pack and a surface of the aircraft to at least partly define a vent path between the battery pack and the surface of the aircraft, and a burst membrane located in the vent path. The vent may be coupled to a rear upper portion of a wing or to an outboard side of a nacelle. The aircraft may also include a flexible coupling between the vent and the surface of the aircraft. The aircraft may also include a fairing over a vent outlet to provide a smooth surface for the vent outlet. The battery pack may include battery modules and an enclosure, the battery modules and the enclosure defining paths along which discharge from a thermal event can flow towards the vent.