Daimler Ag

Ford Motor Company Limited

Nissan Motor Company Limited

Cellcentric Gmbh & Co. Kg

Richard Fellows

Michael Procter

Yosuke Fukuyama

Takeshi Shiomi

Laura Iwan

Simon Farrington

Hao Zhang

Herwig Haas

Sven Schmalzriedt

Janusz Blaszczyk

Pere Antoni Pastor Nigorra

Elisabeth Funk Woolliams

Christopher J Richards

Andrew Leow

Mike Davis

Matthew Blair Guenther

Adrian Kent Roett

Shiomi Takeshi

A method for starting a fuel cell in a fuel cell system, at temperatures below the freezing point of water, includes, in a first step, that the hydrogen concentration in the anode is increased; after which, in a second step, an anode pressure is increased for a fixed period of time, and while air is supplied to the cathode, the maximum possible current is drawn from the fuel cell, and after which, in a third step, the fuel cell is switched in a load-free manner and the anode pressure is reduced. After the third step, the second step and the third step are repeated successively until a sufficient performance of the fuel cell for its normal operation is reached.

Fuel cell freeze start method with anode pressure control

Methods are disclosed for detecting and lessening fuel starvation conditions in an operating fuel cell system. The fuel cell systems comprise a solid polymer electrolyte fuel cell with a regulating apparatus for regulating the pressure of fuel supplied to the anode inlet of the fuel cell, in which the outlet pressure from the regulating apparatus oscillates during operation. The methods involve monitoring an electrical output of the fuel cell during operation, determining the amplitude of oscillation in the electrical output, and then, if the determined amplitude of oscillation in the electrical output exceeds a predetermined amount thereby indicating a fuel starvation condition, taking a remedial action to lessen the fuel starvation condition.

Method for detecting and lessening fuel starvation in fuel cell systems

Methods are disclosed for starting up a fuel cell system from starting temperatures below 0&#xb0; C. The methods apply to systems comprising a solid polymer electrolyte fuel cell stack whose cathodes comprise an oxygen reduction reaction (ORR) catalyst and whose anodes comprise both a hydrogen oxidation reaction (HOR) catalyst and an oxidation evolution reaction (OER) catalyst. In the methods, from the beginning of starting up until the fuel cell temperature reaches 0&#xb0; C., the fuel cell stack current is kept sufficiently low such that the current density drawn does not exceed the stack's capability for the oxidation evolution and the oxygen reduction reactions to occur at the anode and cathode respectively (i.e. current density drawn is less than the stack's maximum OER/ORR current density).

Below freezing start-up method for fuel cell system

Improved methods are disclosed for shutting down and storing a fuel cell system, particularly for below freezing temperature conditions. The methods comprise stopping power production from the fuel cell stack, monitoring its temperature, and repeatedly performing a predetermined warming operation if the stack temperature falls to a normal threshold temperature. In the improved methods, either an initial threshold temperature and/or an initial warming operation are used that differ from the respective normal threshold temperature and the predetermined warming operation.

Shutdown and storage method for fuel cell system at below freezing temperatures

Methods and systems are provided for cold-start of fuel cell stack in fuel cell vehicles. In one example, a method may include in response to cold-start of fuel cell vehicle, limiting the load drawn from the fuel cell stack. In addition, a coolant pump may be operated at a higher rate through a bypass loop to get heat quickly to the fuel cell stack to increase the solubility of water in the fuel cell stack to prevent ice formation. The net effect is that the fuel cell stack is then operated within the ice capacity of the membrane, and start-up at lower temperatures is possible without experiencing an intermittent performance drop due to active area freezing. Once the fuel cell stack is sufficiently warmed up, the coolant pump rate and fuel cell stack may be adjusted according to the demand.

Method for cold-start of fuel cell stack

Improved methods are disclosed for shutting down and storing a fuel cell system, particularly for below freezing temperature conditions. The methods comprise stopping power production from the fuel cell stack, monitoring the amount of energy remaining in an energy supply, monitoring the stack temperature, and repeatedly performing a predetermined warming operation if the stack temperature falls to a normal threshold temperature and if the amount of energy remaining exceeds a certain minimum amount. In the improved methods, when the amount of remaining energy is less than or equal to the minimum amount, a final warming operation is performed that differs from the predetermined warming operation.

A method for starting operation of a solid polymer fuel cell from a temperature below 0&#xb0; C. is disclosed that prevents certain problems with ice formation as the fuel cell thaws. During startup, the method involves providing the volumetric oxidant flow at a rate less than two thirds of its maximum when the coolant temperature is near 0&#xb0; C.

Freeze start method for fuel cells

A device for separating a fluid having a water and gas portion in a fuel cell system includes a fluid inlet an a fluid outlet with an outlet valve. The separating device includes a first reservoir region for collecting the water portion of the fluid. The first reservoir region includes a first outlet to feed the water portion in the direction of the fluid outlet. The separating device also includes a second reservoir region having a second outlet that feeds the water portion in the direction of the fluid outlet so that the first reservoir regionis connected in series in terms of flow via the second reservoir region with the fluid outlet. In an installation position of the separating device the first outlet is arranged lower than the second outlet so that deposits of the water portion completely covering the first outlet are prevented from flowing away.

Separating device for a fuel cell system, fuel cell system with the separating device and method for operating the separating device

Bipolar plate assemblies are disclosed in which the transition fuel channels are offset from the transition oxidant channels in the transition regions on the active sides of the plates. This configuration allows for a reduced pressure drop in the coolant flow in the transition regions on the inactive, coolant side of the plates and thereby improves coolant flow sharing. The assemblies are suitable for use in high power density solid polymer electrolyte fuel cell stacks.

Flow field plate for improved coolant flow

A system and method is provided for minimizing the degradation of a fuel cell after shutdown by forcing remaining air out of a fuel cell system. Upon fuel cell shutdown, the flow of air to the cathode of the fuel cell can be kept at a low rate. The flow of cathode exhaust gases along an exhaust conduit is substantially restricted while the pressure of the supply air supplied is increased. As a result, the pressure of the cathode exhaust gases in the exhaust conduit increases. The voltage of the fuel cell can be to deplete the oxygen in the supply air. The pressure of the supply air is decreased to a pressure lower than the pressure of the cathode exhaust gas in the exhaust conduit such that the cathode exhaust gas flows backward through the system to push out any remaining air.

System and method for minimizing fuel cell degradation after shutdown

Ruthenium or a Ruthenium compound is applied to an anode structure according to a predetermined pattern, with only part of the anode active area containing Ru. The parts of the MEA that do not contain Ru are not expected to suffer degradation from Ru cross-over, so that overall degradation of the cell will be diminished. Having less precious metals will also translate into less cost.

Reversal tolerant membrane electrode assembly for a fuel cell

The pressure drop associated with the coolant flow in the coolant transition regions of a typical high power density, solid polymer electrolyte fuel cell stack can be significant. This pressure drop can be reduced by enlarging the height of the coolant ducts in this region of the associated flow field plate so that the ducts extend beyond the plane of the plate. The height change can be accommodated by offsetting the ducts in adjacent cells in the stack and by employing non planar MEAs in this region. By reducing the pressure drop, improved coolant flow sharing is obtained.

Flow field plate for reduced pressure drop in coolant

A fuel cell system comprising a fuel cell stack, a fuel recirculation line provided with a jet pump and a valve controlled by a control unit based on the anode-cathode pressure differential such that the valve is closed to reduce or stop fuel supply when the anode-cathode pressure differential reaches a predetermined value, and opened again to circulate more fuel through the jet pump when the pressure differential is below a predetermined value, to create a pulsed fuel supply that improves the fuel recirculation at low loads and ensures adequate water removal from the anode flow field channels.

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Vancouver, Canada

Richard Fellows