Abstract: A cooling system for an aircraft fuel cell system includes a coolant pump to circulate coolant through the cooling system and a radiator to reject heat to ambient air. A cooler zone is provided downstream of the radiator, comprising a plurality of parallel cooling branches. A warmer zone is provided downstream of the cooler zone, the warmer zone including a fuel cell stack. A bypass valve is arranged to provide coolant to the warmer zone from upstream of the radiator. A restrictor may be arranged to provide coolant to the warmer zone from downstream of the radiator.

Abstract: An aircraft fuel cell system includes a pressure vessel, a fuel cell stack located in the pressure vessel, a source of compressed air, and a valve to supply compressed air from the source of compressed air into the pressure vessel. Also included in the pressure vessel may be a coolant reservoir for a coolant loop for the fuel cell stack, as well as power electronics for the aircraft. A control system may purge the pressure vessel via a vent coupled to an external environment if an unacceptable level of hydrogen in the pressure vessel is reported by the hydrogen level sensor.

Abstract: A system for use with a fuel cell stack supplied by a tank of hydrogen includes a combustor coupled to the fuel cell exhaust line to receive and combust residual hydrogen gas in the exhaust, a turbine coupled to the combustor to receive combusted exhaust from the combustor; and a mechanical device coupled to the turbine to extract work from rotation of the turbine. The combustor may further be coupled to receive and combust hydrogen in fuel cell circulation-loop purge gas, and the combustor may further combust hydrogen received from the fuel tank via a fuel tank purge line or on demand. Supplementary oxygen may be supplied to the combustor based on an oxygen level detected by the oxygen sensor in the combustor exhaust line.

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.

Abstract: An aircraft includes a battery pack, an internal support structure to support the battery pack in the aircraft, a first bracket rigidly coupling the battery pack to the support structure, and a second bracket rotationally coupling the battery pack to the support structure. The first and second brackets may be located on opposite sides of the battery pack. The internal support structure may be located in a wing of the aircraft and the first and second brackets may be aligned in a fore-aft direction of the aircraft. The internal support structure may be located in a nacelle of the aircraft and the first and second brackets may be aligned along a transverse direction of the aircraft. The second bracket may include two hangers to support a mass of the battery pack in tension.

Abstract: An aircraft includes a battery pack, an internal support structure to support the battery pack in the aircraft, a first bracket rigidly coupling the battery pack to the support structure, and a second bracket rotationally coupling the battery pack to the support structure. The first and second brackets may be located on opposite sides of the battery pack. The internal support structure may be located in a wing of the aircraft and the first and second brackets may be aligned in a fore-aft direction of the aircraft. The internal support structure may be located in a nacelle of the aircraft and the first and second brackets may be aligned along a transverse direction of the aircraft. The second bracket may include two hangers to support a mass of the battery pack in tension.