Ballard Power Systems Corporation

Other

Ford Motor Company Limited

Daimler Ag

Nucellsys Gmbh

University of North Florida

Brian W Wells

Russell H Barton

Henry H Voss

Joel A Ronne

Harald Anton Nigsch

Richard Joseph Hampo

Lizhi Zhu

Richard Allan Sederquist

Alexander Douglas Mossman

Gregory A James

George Alexander Skinner

Rob Baumert

Craig Greenhill

Kenneth W Strang

Benno Giesecke

Craig R Louie

Tan Duc Uong

Charles Joseph Schembri

Alex Mossman

Robert Kenneth Parr

A fuel cell system is provided that is capable of operating at high temperatures and near-ambient pressure with partial humidification of air supplied to the fuel cell stack. The fuel cells of the stack incorporate gas diffusion barrier layers at the cathode side thereof. The system includes a cooling loop for circulating a liquid coolant through the stack. In some embodiments, an incoming air stream is partially humidified with water vapor transferred from a cathode exhaust stream in a gas-exchange humidifier or enthalpy wheel. In other embodiments, a cathode recycle is employed to partially humidify the incoming air. The humidity of the air and cathode exhaust streams is maintained below a stack saturation point. Methods of operating the fuel cell system are also provided.

Ambient pressure fuel cell system employing partial air humidification

Passive recovery of liquid water from the cathode side of a polymer electrolyte membrane through the design of layers on the cathode side of an MEA and through the design of the PEM, may be used to supply water to support chemical or electrochemical reactions, either internal or external to the fuel cell, to support the humidification or hydration of the anode reactants, or to support the hydration of the polymer electrolyte membrane over its major surface or some combination thereof. Such passive recovery of liquid water can simplify fuel cell power generators through the reduction or elimination of cathode liquid water recovery devices.

Passive recovery of liquid water produced by fuel cells

A fuel cell based power supply comprises a main power converter and control that allows the fuel cell stack to be electrically shorted from time-to-time to improve performance. Additionally, the power converter may temporarily disconnect the fuel cell stack from the load after shorting, allowing the fuel cell stack to return to an open circuit voltage, and/or provide current limiting during a period after shorting to provide stable operation while the fuel cell stack powers the load and recharges a power storage device.

Power converter architecture and method for integrated fuel cell based power supplies

A respective bipolar junction transistor is coupled across pairs of fuel cells in a fuel cell stack to monitor the voltage across each fuel cell pairs for a drop in voltage below a threshold voltage. A respective optoisolator coupled to each of the transistors produces a digital signal corresponding to the status of the respective pair of fuel cells. An 'AND' circuit produces a single digital signal corresponding to the status of one or more pairs of fuel cells.

Fuel cell anomaly detection method and apparatus

An electric power generating system is provided that comprises a fuel cell stack having at least one solid polymer fuel cell, a cooling system having a coolant flow path that directs coolant to and from the stack, a fuel regulating system having a fuel flow path and for regulating the supply of fuel from a fuel supply to the stack via the fuel flow path, and a hydrogen concentration sensor. The sensor is located in the vicinity of the fuel regulating system and in the coolant flow path at a location downstream of the stack to detect hydrogen that may have been discharged by components of the power generating system in the coolant flow path upstream of the sensor, or by the fuel regulating system. In the event the measured hydrogen concentration exceeds a threshold level, steps are taken to reduce or stop the discharge of hydrogen from the power generating system.

Fuel cell system having a hydrogen sensor

A controller in a fuel cell system performs various operating parameter checks at a predefined schedule, including one or more of a stack current check; a stack voltage check; a cell voltage check; a purge cell check; an oxygen concentration check; a hydrogen concentration check; a stack temperature check; an ambient air temperature check; a fuel pressure check; and an airflow rate check; a hydrogen sensor heater check; a battery voltage check; a microcontroller self-check; and/or toggling a watchdog. The frequency of the checks are set relative to achieve an efficient control of the fuel cell system by selectively distributing the load on the microcontroller.

Fuel cell system method and apparatus employing oxygen sensor

A fuel cell system includes fuel cells forming a fuel cell stack, having a fuel passage and an oxidant passage. A purge valve is coupled to the fuel passage to exhaust contaminants, and a controller is coupled to temporarily increase the oxidant stream flow rate through the oxidant passage, and to temporarily open the fuel purge valve, if a voltage across a pair of fuel cells is less than a defined threshold voltage. In this resuscitation step, the oxidant flow rate can be temporarily increased by increasing a duty cycle of an air compressor by approximately 50% for a duration of between approximately 5 to 10 seconds. The controller can further shut down fuel cell operation if a voltage across a pair of fuel cells is less than a defined threshold voltage in an inter-resuscitation period immediately following the resuscitation step.

Fuel cell resuscitation method and apparatus

Reactant gas supply streams for solid polymer fuel cells may be heated and humidified using heat generated by the fuel cell and water vapor from the fuel cell exhaust. The heat and water vapor in the oxidant exhaust stream are sufficient to heat and humidify a reactant gas supply stream, preferably the oxidant supply stream. The heating and humidifying can be accomplished by flowing a reactant gas supply stream and a fuel cell exhaust gas stream on opposite sides of a water permeable membrane in a combined heat and humidity exchange apparatus. The method and apparatus are particularly suitable for use with air-cooled fuel cell systems and systems which employ near ambient pressure air as the oxidant gas supply.

Solid polymer fuel cell system and method for humidifying and adjusting the temperature of a reactant stream

A vehicle includes a traction unit capable of delivering mechanical power for driving the vehicle; electric loads; and a fuel cell system for supplying the electric loads with electric power. The fuel cell system includes a fuel cell stack with an anode input line, an anode exhaust line, a cathode input line, and an cathode exhaust line. A compression/expansion loop is employed in the cathode exhaust line. The expansion side of the compression/expansion loop is in thermal contact with the cathode exhaust to cool the cathode exhaust and to transfer the heat of the exhaust to the compression side of the compression/expansion loop at a higher temperature level. A water separator is arranged in the cathode exhaust line for collecting water vapor of product water that is carried in the cathode exhaust and is recycled to the fuel cell system.

Vehicle with a fuel cell system and method for operating the same

An improved plate-and-frame assembly selectively transfers a fluid component from one fluid stream to another fluid stream. In a preferred embodiment, a plate-and-frame humidity exchanger with unitary plates and seals transfers water vapor and heat between two fluid streams.

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Vancouver, Canada

Brian W Wells