Abstract: Power plant systems and processes are described that enable recovery of at least a portion of the fuel storage energy associated with a storage system for supplying fuel to the power plant systems. A first embodiment of an energy-recovery power plant system includes at least one fuel storage container and at least one expander that can receive fuel from the fuel storage container at a first pressure and provide the fuel to the power plant at a second pressure that is lower than the first pressure. A second embodiment of an energy-recovery power plant system includes a first conduit fluidly coupling the fuel storage container and the power plant for delivering fuel from the fuel storage container to the power plant and at least one regenerative thermodynamic cycle engine thermally coupled to the first conduit such that heat may be exchanged between the fuel and a working fluid for the regenerative thermodynamic cycle engine.

Abstract: Membrane degradation in PEM fuel cells can be explained as follows. Hydrogen peroxide (H2O2) formed around cathodes and anodes catalytically reacts with Fenton's reagents to produce radicals. Such radicals attack the membrane and initiate oxidative decomposition. Only trace quantities of Fenton's reagent are necessary to lead to the production of radicals in-situ. Simply avoiding direct contact of Fenton's reagent elements with the MEA is therefore not sufficient to improve MEA lifetime. Components of a fuel cell system should also be made of materials that are essentially free of Fenton's reagents pursuant to the invention. One embodiment of the invention provides a fuel cell system, wherein the fuel cell stack and/or the supply apparatus and/or the discharge apparatus are/is made of materials that are essentially free of Iron (Fe).

Abstract: A significant problem in PEM fuel cell durability is in premature failure of the ion-exchange membrane and in particular by the degradation of the ion-exchange membrane by reactive hydrogen peroxide species. Such degradation can be reduced or eliminated by the presence of an additive in the anode, cathode or ion-exchange membrane. The additive may be a radical scavenger, a membrane cross-linker, a hydrogen peroxide decomposition catalyst and/or a hydrogen peroxide stabilizer. The presence of the additive in the membrane electrode assembly (MEA) may however result in reduced performance of the PEM fuel cell. Accordingly, it may be desirable to restrict the location of the additive to locations of increased susceptibility to membrane degradation such as the inlet and/or outlet regions of the MEA.

Abstract: An electrochemical fuel cell stack comprises a plurality of fuel cell assemblies, wherein, each fuel cell assembly comprises a cell compressed between a pair of flow field plates, a perimeter seal circumscribing the cell and interposed between the pair of flow field plates, and a first diode, having an aspect ratio greater than 10:1, positioned adjacent to, and outside of, the perimeter seal along a first edge of the cell and interposed between the pair of flow field plates.

Abstract: The present invention relates to improving the overall efficiency of a fuel cell system by reducing parasitic power consumption. A controller is programmed to decrease oxidant stoichiometry until oxidant starvation is detected or until oxidant stoichiometry is about one. When oxidant starvation is detected, the oxidant stoichiometry is increased until oxidant starvation is no longer detected. The fuel cell system employs a sensor for detecting an operational characteristic such as voltage output, or oxygen or hydrogen concentration in the cathode exhaust stream. The controller uses the operational characteristic to calculate oxidant stoichiometry or to determine when there is oxidant starvation at the cathode.