Fuel Cells for Aviation

A hydrogen fueled high altitude aircraft using a thermodynamic fuel cell system that maximizes efficiency and minimizes environmental impacts. The system compresses inlet air using multiple compressors and cools it using liquid hydrogen to maintain low temperature for the fuel cell. The hydrogen is also compressed and expanded before the fuel cell. The exhaust is cooled to condense water that is collected and expelled as ice. The high efficiency hydrogen conversion enables long range flight with lower fuel volumes. The VTOL aircraft can fly at high altitude with reduced environmental impact.

A fault-tolerant fuel cell module for a vertical takeoff and landing aircraft. The module comprises multiple hydrogen fuel cells in a stack, with flow field plates to distribute hydrogen and oxygen. The fuel cells are combined in a modular unit with reduced part count, enabling high power density. Compressed air is supplied by turbochargers. Heat exchangers warm hydrogen extracted from liquid hydrogen fuel.

System for refueling hydrogen fuel cell-powered aircraft with minimum boil-off and leakage of cryogenic hydrogen fuel. The system uses a compressor to pressurize ambient temperature hydrogen from a storage source, and a heat exchanger to absorb excess compression heat. This heat is converted to usable energy to power the aircraft. The compressed hydrogen at ambient temperature is then transferred to the aircraft's onboard cryogenic hydrogen storage. This reduces boil-off and leakage compared to directly transferring cryogenic hydrogen.

A system for jump-starting a hydrogen fuel cell in a hydrogen fuel cell-powered aircraft using the aircraft's electrical power system and energy storage devices, such as batteries or ultracapacitors. The system uses the electrical power stored in the energy storage devices to provide the initial high voltage required to start the fuel cell. A controller monitors the fuel cell's voltage and starts the fuel cell when it drops below a threshold. The controller then connects the energy storage devices to the fuel cell to provide the high voltage required for starting.

Managing excess hydrogen fuel in fuel cell aircraft to prevent losses and reduce costs. The method involves offloading unused fuel from the aircraft's fuel tank to prevent boil-off or leaks. This is done when there is leftover fuel after a flight or if the flight is cancelled. The aircraft can be flown to a location needing power, like an airport during a natural disaster, and used to generate and provide electricity.

Predictive fuel cell management for integrated hydrogen-electric systems like aircraft. It optimizes the number of fuel cells online at any given time to avoid wasting energy or damaging cells. The system uses a controller to monitor aircraft flight conditions and predict the power requirements for each phase of flight. Based on this data, it activates or deactivates fuel cells to match the power needs without overloading the fuel cell stack.

A modular fuel cell system for aircraft propulsion that reduces size and complexity while improving efficiency. The system uses a compressor to supply air to multiple fuel cells through separate circuits instead of individual balance of plant systems for each cell. This allows a single compressor and cooling circuit to serve multiple cells, reducing weight and complexity compared to dedicated BOP systems for each cell. The system also has a controller that converts power from the first subset of cells into electrical current for an electric motor.

A fuel cell powered UAV with a convertible cathode. The fuel cell can switch between using ambient air and using onboard stored oxygen. This allows the UAV to fly at higher altitudes where oxygen concentration is too low for normal fuel cells. The switchable cathode enables the fuel cell to adapt to changing oxygen availability during flight.

Fuel cell system for aircraft that consumes hydrogen and oxidizer to eliminate venting flammable gases. The system uses a fuel cell along with a catalytic hydrogen burner to consume residual hydrogen and oxidizer gases. This prevents release into the aircraft cabin. The burner conditions the oxidizer before supplying it to the fuel cell. The reactions are exothermic and can be used to heat the fuel cell during startup or provide heat to other aircraft systems.

A fuel cell powered aircraft that converts between using ambient air and stored oxygen to power the fuel cell, allowing operation above 15,000 feet where air oxygen is too low for normal fuel cells. The aircraft has a fuel cell cathode that can switch between air and oxygen, allowing it to use ambient air at lower altitudes, then switch to using stored oxygen at higher altitudes where air oxygen is insufficient. The switching can be automated based on flight parameters, atmospheric conditions, power demands, etc. This allows the aircraft to efficiently use ambient air when possible, while having the oxygen option for high altitude flight.

A modular fuel cell system for electric aircraft. The system uses hydrogen fuel cells to provide power for on-board electric motors. The fuel cells are housed in modular units that can be combined to scale up power as needed. The fuel cells receive compressed air and hydrogen, and produce electricity and water as byproducts. The cells are cooled using heat exchangers. The modular design allows fault tolerance and lightweight power generation for vertical takeoff and landing electric aircraft.

Low-pressure drop water exchanger for fuel cell power systems in unmanned air vehicles (e.g. drones) that allows longer flight times through efficient use of hydrogen fuel cells. The exchanger uses hollow tubes with water-permeable membranes to selectively transfer water vapor from the fuel cell exhaust to the intake. The membranes are made of materials like perfluorosulfonic acid or other polymers. The hollow tube design provides lightweight and low-pressure drop compared to existing water exchangers, making it suitable for airborne applications.

Aircraft fuel cell system that is simpler, safer and more autonomous. It uses separate hydrogen zones, a hybrid pressure regulator, and allows independent power delivery without a converter.

A hybrid fuel cell power generator for unmanned aerial vehicles (UAVs) that enables long endurance flights. It combines a proton exchange membrane fuel cell with a hydrogen generator and recirculating hydrogen path. The generator has an ambient air path across the fuel cell cathode and a recirculating hydrogen path across the anode. Water is transferred from the cathode air to the hydrogen stream. A separate hydrogen generator adds hydrogen to the recirculating path. This closed loop system sustains fuel cell operation without external hydrogen tanks. Temperature control of components improves efficiency and longevity.

An aircraft emergency power system using a fuel cell instead of a ram air turbine to generate electrical power during emergency operations. It does this by supplying hydrogen gas and warmed air to a fuel cell system to generate power proportional to the demand. A solid hydrogen storage system releases hydrogen at a controlled rate matched to the fuel cell load.