Condensation Mitigation Techniques for Fuel Cells

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.

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An anode subsystem for preventing water accumulation in fuel cell systems. The subsystem includes a hydrogen supply path, a recirculation path, a water separator in the recirculation path, and a jet pump connecting the supply and recirculation paths downstream of the separator. The supply path also connects to the separator at its lowest point. This configuration eliminates water accumulation by using the jet pump to continuously purge any water from the recirculation path and by draining any water from the supply path via the separator.

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A vehicle power system that uses onboard hydrogen generation to power electric vehicles without relying on hydrogen refueling infrastructure. The system has an electrolyzer to separate hydrogen and oxygen from water, a fuel cell to generate electricity using the hydrogen and oxygen, and a power conditioning unit to output the electricity to charge the vehicle's battery. The onboard power source can be a battery or renewable sources like solar/wind.

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Designing gas diffusion layers (GDLs) for fuel cells that improve efficiency and stability by providing custom porosity gradients. The GDLs have non-uniform porosity along the oxygen flow direction to distribute oxygen evenly over the catalyst layer. This reduces hotspots and water accumulation that can decrease fuel cell efficiency.

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A method to remove water from hydrogen fuel cell exhaust gases. The method uses a rotating sorbent wheel, heat exchanger, and evaporator in the exhaust flow path. The wheel absorbs water vapor from the exhaust in one section and releases the water into a different section as it rotates. The heat exchanger recovers waste heat from the exhaust. This integrated system aims to capture over 99% of the water content from fuel cell exhaust gases.

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A system and method for purging condensate water and hydrogen from a fuel cell stack in a way that improves operation stability and efficiency by accurately and adaptively managing the purging process. The system includes a purge valve that selectively directs the purged water/hydrogen to either the atmosphere or back into the fuel cell humidifier based on stack pressure and conditions.

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High efficiency, low emission integrated system that produces hydrogen and electricity using a fuel cell with an integrated steam methane reformer (SMR) to convert natural gas to hydrogen. The system includes a water-gas shift reactor, absorber column, PSA purification system, and other components to increase the hydrogen concentration from the SMR and remove impurities. The system also recycles CO2-rich flashed gas and anode exhaust to the SMR to increase heat production.

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Fuel cell system that effectively removes impurities like nitrogen and water vapor from the anode exhaust gas of a fuel cell stack. The system has separate discharge valves for gas and water purification stages. The valves are opened and closed at different times to prevent pressure drops that can reduce purging effectiveness. This optimized timing allows sufficient discharge of both impurities without lowering the internal pressure.

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A method to control the hydrogen pressure for the anode (hydrogen electrode) of a fuel cell stack. The method estimates the amount of gas being discharged when water and impurities are purged from the anode, by monitoring the amount of hydrogen supplied and consumed. When the discharged gas exceeds a reference value, it compensates the supply to prevent undershoot or overshoot.

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Fuel cell system that recycles and separates the fuel exhaust to recover hydrogen, CO2, and water. The system includes an anode tail gas oxidizer (ATO) to burn any remaining fuel exhaust. A gas separator separates the ATO exhaust into CO2 and water. Some of the fuel cell exhaust is recycled back into the fuel inlet to humidify it, and the rest is sent to the separator to recover hydrogen. The separated hydrogen is then added to the fuel inlet.

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Fuel cell device with optimized unit cell structure for high performance and water drainage. The unit cell has a hydrogen electrode side separator and air electrode side separator with grooves for gas channels. The grooves on the air side separator are evenly spaced. The hydrogen side separator has grooves in the same positions as the air side, but with fewer grooves overall. This increases contact area between the separators, reduces resistance, and improves current collection while maintaining good water drainage.

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Method and apparatus for detecting and preventing water flooding in fuel cell stacks. It uses pressure drop monitoring and flow regulation in dual-stack fuel cell systems to provide early warning and mitigation of water flooding. The method involves monitoring hydrogen pressure drop which increases with water flooding. If pressure drop exceeds a normal value, indicating potential flooding, flow valves on the fault stack are adjusted to reduce cooling flow and increase flow on the other stack. This rebalances gas distribution to prevent flooding.

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Fuel cell system and method where rotating the hydrogen pump in both directions during idle periods prevents water clogging the fuel cell's hydrogen channels.

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A regenerative fuel cell system that produces hydrogen and oxygen fuel by electrolyzing water. The system has separate valves to return any crossover gases back to their storage tanks. When oxygen accompanies the hydrogen produced, the hydrogen and oxygen react to remove the oxygen before returning the pure hydrogen to storage. Likewise, if hydrogen accompanies the oxygen, they react to remove the hydrogen before returning the pure oxygen to storage. This prevents crossover gases from reaching the wrong tanks and potentially causing fires or explosions.

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Fuel cell system that reduces backflow of water from the circulation system and blocking of the hydrogen flow path. It does this by positioning the circulation system components like the hydrogen pump and vapor-liquid separator so that the hydrogen outlet is below the fuel cell stack's hydrogen supply port, and the hydrogen inlet is below the stack's hydrogen discharge port.

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