Optimizing Design for High-Efficiency Fuel Cells

A method and device for distributing the power generated by multiple fuel cell systems in a vehicle. The method involves activating the fuel cell systems with a time delay between each activation. This prevents all the fuel cells from ramping up and down power together, which would cause increased degradation due to voltage cycling. By staggering the fuel cell power activations, it allows some fuel cells to stabilize and dissolve any platinum oxide before the next fuel cells ramp up power. This reduces degradation and allows the fuel cells to operate at different power levels.

Source

A recovery control system for fuel cells that can detect and recover from air supply issues that can occur when restarting the fuel cell after a shutdown. The system senses abnormal cell voltage behavior that indicates insufficient air supply. When this is detected after certain conditions are met, it increases the air flow to avoid cell performance degradation. The recovery system monitors voltage differences between measured and expected values. If the difference changes in a certain way after a power down, it indicates air supply issues and triggers increased airflow.

Source

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.

Source

Pulse hydrogen supply system for a proton exchange membrane fuel cell that can provide a pulsating hydrogen flow to remove water and purging hydrogen from the fuel cell. The system has a high-pressure vessel and low-pressure vessel that can generate pressure waves through opening and closing electromagnetic valves. This pulsing hydrogen flow helps dynamically dislodge and remove water droplets that can accumulate in the fuel cell, improving cell performance and durability.

Source

Fuel cell system that enhances fuel cell lifetime by controlling hydrogen partial pressure in the cell membrane. The system calculates the optimal target hydrogen partial pressure based on the catalyst location in the membrane. A controller adjusts the gas supply to achieve the target. This reduces chemical degradation of the membrane. The catalyst suppresses hydrogen peroxide formation when hydrogen is over-rich. By limiting hydrogen partial pressure, the catalyst location maximizes the suppression effect.

Source

Fuel cell system that can detect poor quality hydrogen fuel and prevent irreversible degradation of the fuel cell performance. The system uses a pressure sensor to monitor the hydrogen gas pressure in the fuel cell. If, after a certain amount of time, the pressure does not reach expected levels based on the amount of hydrogen supplied, it indicates impurities in the gas. The system then disables power generation to avoid damaging the fuel cell.

Source

Dynamic adjustment of fuel cell systems to optimize purge valve actuation and improve efficiency. The adjustment involves analyzing the behavior of the proportional valve during purging operations to infer the hydrogen concentration in the fed gas. This inferred hydrogen concentration is then used to dynamically fine-tune the fuel cell system operation, such as optimizing purge and drain valve actuation, to maximize efficiency.

Source

Fuel cell system that improves thermal efficiency and reforming efficiency for hydrocarbon fuel cells. The system has a modular design with a first module containing a burner to combust unreacted fuel and air from the fuel cell, a heat exchanger to preheat air, and a vaporizer to convert water to steam. A second module mixes fuel from an external source with the steam and reforms it into hydrogen. The reformed fuel is then heated with the exhaust air and supplied to the fuel cell.

Source

Controlling a fuel cell stack to recover performance after sustained high-output operation by thermally managing the fuel cell stack. The cooling system is configured to further cool the stack after power generation stops if the stack temperature is above a preconfigured degradation threshold. This uses the cooling system to recover performance and reduce degradation after long high-power runs.

Source

Hydrogen detection apparatus for fuel cell vehicles that optimizes energy savings versus reliability tradeoff by intermittently operating the hydrogen sensor with an off time that varies based on the operating environment. A microcomputer sets the off time and drives the sensor control circuit. The hydrogen sensor has exposed interfaces for contacting hydrogen gas. This allows environment-specific tuning of the detection frequency to save energy while still ensuring safety.

Source

Reducing the concentration of hydrogen in cathode exhaust from a fuel cell stack. This is done by selectively recirculating cathode air when hydrogen is supplied to the anode, and discharging ambient air when supplied to the cathode. It uses valves and an air compressor to store and release cathode air to lower hydrogen levels. This prevents hydrogen leakage from the fuel cell exhaust.

Source

An anode catalyst for a fuel cell that allows it to operate on hydrogen containing up to 5 ppm of carbon monoxide. The catalyst is a binary alloy of platinum with either rhodium or osmium. The platinum content of the alloy is 45-80 atomic % and the rhodium/osmium content is 20-55 atomic %. This composition provides improved carbon monoxide tolerance compared to pure platinum catalysts.

Source

A fuel cell system that periodically adjusts the offset of hydrogen pressure sensors in the cells to ensure proper hydrogen supply. The system detects cells with low voltage compared to others and modulates the pressure sensor offset for those cells. This allows maintaining consistent hydrogen supply as sensors drift over time.

Source

A thermal management system for a fuel cell vehicle that improves fuel efficiency by continuously supplying heat to a solid-state hydrogen storage container without an additional power supply. The system uses waste heat from the fuel cell stack to heat the hydrogen storage container and maintain it at the temperature needed for hydrogen release. This avoids adding extra components like heaters or combustors. The system has three containers and a circulating heat transfer medium to transfer heat from the fuel cell stack to the hydrogen storage container.

Source

Operating a fuel cell system with a proton-conducting membrane to avoid coking and degradation when the system is not fully warmed up. The system measures the stack temperature and fuel supply then limits the current output to prevent excessive carbon deposition. This prevents performance loss due to coking while still allowing dynamic power output adjustments to match load needs.

Source