Daimler Ag

Ballard Power Systems Corporation

Rainer W Schmidt

Janusz Blaszczyk

Wolfram Fleck

Paul L Paterson

Methods and systems for operating a fuel cell stack having a fuel exhaust stream and a vessel downstream of the fuel cell stack fluidly connected to the fuel exhaust stream are provided. In one embodiment, the method comprises displacing substantially all residual gas in the vessel by providing at least a portion of the fuel exhaust stream to the vessel, and isolating the vessel from the fuel cell stack after the fuel exhaust stream displaces substantially all residual gas in the vessel. At least one bleed down characteristic is determined as fuel exhaust within the vessel is released through an orifice, and an operating condition of the fuel cell stack is set or determined based on the at least one bleed down characteristic. In a specific embodiment, the hydrogen concentration in the fuel exhaust is determined based on the at least one bleed down characteristic.

Methods of operating fuel cell stacks and systems related thereto

An apparatus for recirculating a reactant fluid stream of a fuel cell system, and electric power generation systems comprising the apparatus, are disclosed. The apparatus comprises (1) a common suction chamber fluidly connected to a suction inlet configured to receive a recirculated flow from the exhaust stream of the fuel cell stack, (2) a low-flow nozzle positioned in the common suction chamber and fluidly connected to a low-flow motive inlet configured to receive a first motive flow from a reactant source of the fuel cell stack, (3) a low-flow diffuser fluidly connected to a discharge outlet configured to provide the inlet stream to the fuel cell stack, (4) a high-flow nozzle positioned in the common suction chamber and fluidly connected to a high-flow motive inlet configured to receive the first motive flow from the reactant source, and (5) a high-flow diffuser fluidly connected to the discharge outlet.

Growing community of inventors

Burnaby, Canada

Rainer W Schmidt