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: An electrochemical cell has at least one plate element which can be cooled by a liquid coolant, such as water. The plate element has a surface that can be wetted for the purpose of cooling with the coolant. The surface of the plate element in the electrochemical cell is configured such that a contact angle between the surface and the liquid coolant is less than 90°. In the method for producing the electrochemical cell an additional method step is carried out which influences the wettable surfaces of plate elements for cooling with coolant and by which a contact angle between the surface and the coolant is decreased.

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 method for the dry production of a membrane-electrode unit includes assembling a layered configuration including a centrally positioned membrane produced by extrusion and pre-dried at a temperature between 80° C. and 100° C. for 15 min to 30 min, a substrate-electrode unit on each side of the membrane having an electrode layer applied to a substrate, an optional frame around each substrate-electrode unit for fixing the substrate-electrode unit, and two separating films on outer sides. The configuration is pressed together between two laminating rollers so that a pressure connection is produced at least between the membrane and the electrode layers. A short production time is achieved because it is not necessary to keep the membrane moist at high temperatures under pressure. A membrane electrode unit and a roller configuration are also provided.

Abstract: A method for the dry production of a membrane-electrode unit includes assembling a layered configuration including a centrally positioned membrane produced by extrusion and pre-dried at a temperature between 80° C. and 100° C. for 15 min to 30 min, a substrate-electrode unit on each side of the membrane having an electrode layer applied to a substrate, an optional frame around each substrate-electrode unit for fixing the substrate-electrode unit, and two separating films on outer sides. The configuration is pressed together between two laminating rollers so that a pressure connection is produced at least between the membrane and the electrode layers. A short production time is achieved because it is not necessary to keep the membrane moist at high temperatures under pressure. A membrane electrode unit and a roller configuration are also provided.

Abstract: An electrochemical cell has at least one plate element which can be cooled by a liquid coolant, such as water. The plate element has a surface that can be wetted for the purpose of cooling with the coolant. The surface of the plate element in the electrochemical cell is configured such that a contact angle between the surface and the liquid coolant is less than 90°. In the method for producing the electrochemical cell an additional method step is carried out which influences the wettable surfaces of plate elements for cooling with coolant and by which a contact angle between the surface and the coolant is decreased.

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: A gas diffusion electrode for a PEM fuel cell includes a metallic catalyst, and an electrocatalyst layer having a polymer A for hydrophobicizing the electrocatalyst layer and a uniform thickness of between 3 to 40 ?m, especially 25 ?m. The polymer A content is less than 10% by weight based on the metallic catalyst content. Methods of producing and of hydrophobicizing the electrode include screen printing a paste onto a carrier and removing the screen-printing medium by heating. The paste includes at least one metallic catalyst with a content of polymer A up to at most 10% by weight, and a screen-printing medium. The electrocatalyst layer of the electrode has a significantly lower content of the catalyst inhibitor TEFLON® because it is not added only to the screen-printing paste but is subsequently applied, with the same surface-specific effect, by dipping the finished electrocatalyst layer in a solution containing TEFLON®.

Abstract: A gas diffusion electrode for a PEM fuel cell includes a metallic catalyst, and an electrocatalyst layer having a polymer A for hydrophobicizing the electrocatalyst layer and a uniform thickness of between 3 to 40 ?m, especially 25 ?m. The polymer A content is less than 10% by weight based on the metallic catalyst content. Methods of producing and of hydrophobicizing the electrode include screen printing a paste onto a carrier and removing the screen-printing medium by heating. The paste includes at least one metallic catalyst with a content of polymer A up to at most 10% by weight, and a screen-printing medium. The electrocatalyst layer of the electrode has a significantly lower content of the catalyst inhibitor TEFLON® because it is not added only to the screen-printing paste but is subsequently applied, with the same surface-specific effect, by dipping the finished electrocatalyst layer in a solution containing TEFLON®.

Abstract: A screen-printing paste as a starting material for fabricating a gas diffusion electrode through screen-printing includes at least one polymer, at least one metallic catalyst, and a high-boiling solvent. The polymer is a binder including poly(butyl acrylate)-polymethacrylate copolymer, a poly(vinyl alcohol), and a poly(ethylene oxide). The polymer can be two polymers, a first being used for hydrophobicization and present in an amount of between 0 to 10% by weight based on a content of the metallic-catalyst, and a second being a binder. A screen-printing method of fabricating the electrode for a fuel cell includes forming a screen-printing layer having a thickness between 3 and 40 &mgr;m by applying the screen-printing paste to a base. The solvent and the polymer serve as a screen-printing medium. The screen-printing layer is baked to allow only residues of the solvent and the polymer to remain, which do not interfere with using the electrode in a fuel cell.

Abstract: When operating known polymer electrolyte membrane fuel cells it has to be made sure that the phosphoric acid does not directly contact the metal bipolar plate of the fuel cell at high temperatures. In order to avoid such a contact, a sufficiently electroconducting intermediate layer is interposed between the membrane electrode unit and the bipolar plate of the fuel cell, which prevents the phosphoric acid or a mixture of phosphoric acid and water that may escape from the membrane-electrode unit from reaching the bipolar plate. For producing the fuel cell, at least a two-layer stratified structure is introduced which becomes more hydrophobic and more finely pored with increasing proximity to the bipolar plate.

Abstract: The PEM fuel cell has a membrane-electrode assembly with an anode and a cathode and associated bipolar plates. The anode, which forms a hydrogen electrode of the PEM fuel cell, is formed with a substrate of a metal and/or an alloy that is corrosion-resistant within the operational potential range of the hydrogen electrode. That is, the substrate is a good electrical conductor, instead of the poorly conducting carbon powder, and the flow of current within the cell is improved. A catalyst, which is active for the oxidation, is provided at least on the surface of the anode substrate.

Abstract: A fuel cell installation and a method for operating a fuel cell installation with a dynamic power control are provided. The dynamic power control is achieved by additionally connecting at least one subsystem which is kept ready for operation, a starter system and/or a low-voltage unit for nighttime operation and/or an on-board power supply.

Abstract: High-temperature polymer electrolyte membrane (HTM) fuel cells, installations including HTM fuel cells, methods for operating an HTM fuel cell, and an HTM fuel cell installation apply the principle of the known PEM fuel cell and overcomes the major drawback of this fuel cell. By selecting a new electrolyte and changing the operating conditions, in particular the temperature and the pressure, the fuel cells do not depend on water content.

Abstract: A method for operating an HTM fuel cell and to a fuel cell battery. An electrolyte of the fuel cell contains phosphoric acid, a normal freezing point of which is 42° C. The freezing point is reduced by adding at least water as an additive to such an extent that the start/stop operation of the fuel cell, as is required, for example, in mobile fuel cell applications, can be achieved.

Abstract: A membrane electrode assembly for a self-humidifying fuel cell, a method of its production, and a self-humidifying fuel cell battery include a membrane electrode assembly with a membrane electrolyte, into which at least one catalyst layer is laminated, so that water can be generated in a controlled manner within the membrane by recombination of the reaction gases H2 and O2.