Abstract: A fuel cell assembly with at least one PEM fuel cell for generating electrical energy from reactant gases includes at least one membrane/electrode having a membrane coated with platinum electrodes and, respectively positioned on each side, a porous gas diffusion layer, or having a membrane and, respectively positioned on each side, a porous gas diffusion layer coated with a platinum electrode, and also includes bipolar plates that lie against the gas diffusion layers and through which, during operation, a coolant flows, wherein at least one of the platinum electrodes has a smaller area than the gas diffusion layer, where the gas diffusion layer protrudes beyond the platinum electrode for a part of an edge region of the membrane/electrode unit, so that the formation of an electrochemical potential in this part of the edge region of the membrane/electrode unit is prevented in order to prevent damage to the membrane.

Abstract: A fuel cell assembly with at least one proton exchange membrane (PEM) fuel cell for generating electrical energy from the reactant gases hydrogen and oxygen, which includes at least one membrane/electrode unit having a membrane that is coated with platinum electrodes and, respectively positioned on each side thereof, a porous gas diffusion layer, or which has a membrane and, respectively positioned on each side thereof, a porous gas diffusion layer that is coated with a platinum electrode, and which includes bipolar plates that lie against the gas diffusion layers and through which, during operation, a coolant flows, where access by at least one of the reactant gases to the membrane is blocked by a mechanical block for a part of an edge region of the membrane/electrode unit In order to prevent damage to the membrane.

Abstract: A fuel cell assembly with at least one PEM fuel cell for generating electrical energy from reactant gases includes at least one membrane/electrode having a membrane coated with platinum electrodes and, respectively positioned on each side, a porous gas diffusion layer, or having a membrane and, respectively positioned on each side, a porous gas diffusion layer coated with a platinum electrode, and also includes bipolar plates that lie against the gas diffusion layers and through which, during operation, a coolant flows, wherein at least one of the platinum electrodes has a smaller area than the gas diffusion layer, where the gas diffusion layer protrudes beyond the platinum electrode for a part of an edge region of the membrane/electrode unit, so that the formation of an electrochemical potential in this part of the edge region of the membrane/electrode unit is prevented in order to prevent damage to the membrane.

Abstract: A fuel cell assembly with at least one proton exchange membrane (PEM) fuel cell for generating electrical energy from the reactant gases hydrogen and oxygen, which includes at least one membrane/electrode unit having a membrane that is coated with platinum electrodes and, respectively positioned on each side thereof, a porous gas diffusion layer, or which has a membrane and, respectively positioned on each side thereof, a porous gas diffusion layer that is coated with a platinum electrode, and which includes bipolar plates that lie against the gas diffusion layers and through which, during operation, a coolant flows, where access by at least one of the reactant gases to the membrane is blocked by a mechanical block for a part of an edge region of the membrane/electrode unit In order to prevent damage to the membrane.

Abstract: A humidification cell of a fuel cell apparatus includes a first outer plate and a second outer plate. A gas chamber, a humidification chamber and a water-permeable membrane separating the two chambers, are disposed between the first outer plate and the second outer plate, starting from the first outer plate. A first water-permeable support element that prevents fibers from detaching and also prevents medium flows from blocking narrow gas outlets, is disposed between the first outer plate and the membrane in such a way that the first support element is made of a filter material.

Abstract: A humidification cell of a fuel cell apparatus includes a first outer plate and a second outer plate. A gas chamber, a humidification water chamber, and a water-permeable membrane that separates the two chambers are disposed between the first outer plate and the second outer plate starting from the first outer plate. A first water-permeable support element is disposed between the first outer plate and the membrane. The first support element is made of a woven fabric formed of a plastic. A discharge and an entrainment of liquid water can be prevented during load changes or other non-stationary fuel cell operating states accompanied by a sudden change of gas volume flow in that the plastic is a fluoropolymer or a fluoroplastic. Advantageously, the fluoropolymer or fluoroplastic is formed at least partly, preferably entirely, of an alternating copolymer of ethylene and chlorotrifluorethylene (E-CTFE).

Abstract: A humidification cell of a fuel cell apparatus includes a first outer plate and a second outer plate. A gas chamber, a humidification chamber and a water-permeable membrane separating the two chambers, are disposed between the first outer plate and the second outer plate, starting from the first outer plate. A first water-permeable support element that prevents fibers from detaching and also prevents medium flows from blocking narrow gas outlets, is disposed between the first outer plate and the membrane in such a way that the first support element is made of a filter material.

Abstract: The invention relates to a method for producing a tight crystalline mullite layer on a metallic and/or ceramic substrate by using the plasma spraying technique. To this end, a sol containing mullite precursors with a proportion of 2 to 25% by weight with regard to the oxides (3 Al2O3/2 SiO2) is used as a spraying additive. This method is carried out under atmospheric conditions, and the sol is injected with a focussed jet and with an overpressure of at least one I bar into the plasma flame. An additional compacting of the layer can be advantageously effected by repeatedly passing over the layer with the plasma flame. The method is particularly suited for applying a gas-tight crystalline mullite layer to a steel substrate.