Abstract: A device and method for determining the purity of hydrogen, includes a measurement fuel cell cascade having at least one measurement fuel cell, a hydrogen inlet and a hydrogen outlet, a cell voltage monitoring unit that is electrically connected to the measurement fuel cell stack and monitors a voltage output of the measurement fuel cell stack, and a valve located downstream of the measurement fuel cell cascade in the direction of flow of the hydrogen for allowing dead-end operation of the measurement fuel cell cascade. The device for determining the purity of hydrogen further includes an evaluation unit that is connected to the cell voltage monitoring unit and receives a signal corresponding to a voltage output of the measurement fuel cell cascade from the cell voltage monitoring unit as a function of time, wherein the evaluation unit is designed to determine the purity of the hydrogen from the received signal.

Abstract: A method for treating hydrogen-containing and oxygen-containing residual gases of fuel cells, wherein the residual gases are fed to a gas circuit, and a residual gas mixture resulting therefrom is circulated in the gas circuit by a device for converting hydrogen and oxygen to water. In order to reduce the amount of hydrogen and oxygen in the residual gas mixture, at least part of the residual gas mixture is discharged from the gas circuit.

Abstract: A bipolar plate for an electrochemical cell, includes a flow space arranged between a first and a second plate element and has a flow inlet and a flow outlet for a coolant flowing through the flow space. Each plate element has a contact plane for contacting the other plate element and, between the flow inlet and the flow outlet, a plurality of elevations protrude from the contact plane and face away from the other plate element. The elevations have openings facing the contact plane. First flow channels are formed through the openings in the elevations by the elevations of the two plate elements being offset from one another. Each elevation at least partially overlaps at least one elevation of the other plate element. A direction-dependent flow resistance is set in the first flow channels of the bipolar plate.

Abstract: A method for treating hydrogen-containing and oxygen-containing residual gases of fuel cells, wherein the residual gases are fed to a gas circuit, and a residual gas mixture resulting therefrom is circulated in the gas circuit by a device for converting hydrogen and oxygen to water. In order to reduce the amount of hydrogen and oxygen in the residual gas mixture, at least part of the residual gas mixture is discharged from the gas circuit.

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 module includes a fuel cell and an operating medium supplier for supplying operating media to the fuel cell, wherein the fuel cell has at least one stack of fuel cells, and the operating medium supplier has current terminals and has operating medium terminals, where availability of the fuel cell is further improved because the fuel cell and the operating medium supplier are separable from each other, and the fuel cell includes a module controller/regulator arranged on or in the fuel cell and is configured to bring the fuel cell to a secure state via a deactivation procedure before the fuel cell is separated from the operating medium supplier and/or to start up the fuel cell via an activation procedure after connection of the fuel cell to the operating medium supplier.

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 bipolar plate for an electrochemical cell contains two plate elements between which a flow field has a flow inlet and a flow outlet. The flow field has coolant flowing through it. Each plate element has a contact plane for making contact with the respective other plate element and a plurality of first embossments project from the contact plane and face away from the other plate element. One of the plate elements has second embossments. Both the first and the second embossments have an aperture to the contact plane of the plate element. Flow channels are formed by the apertures by having the embossments of the two plate elements offset against one another such that each embossment only partially overlaps one embossment of the other plate element. The second embossments are smaller than the first embossments such that the flow channels are restricted in the second embossments.

Abstract: A method for operating a fuel cell stack which includes a number of fuel cells and at least one gas circuit, where the fuel cells are supplied on the gas inlet side with oxygen and hydrogen as reaction gases, and where at least oxygen is circulated in the fuel cells via the gas circuit, so as to provide a fuel cell stack with a simple structure and reliable intergas removal.

Abstract: A bipolar plate for an electrochemical cell contains two plate elements between which a flow field has a flow inlet and a flow outlet. The flow field has coolant flowing through it. Each plate element has a contact plane for making contact with the respective other plate element and a plurality of first embossments project from the contact plane and face away from the other plate element. One of the plate elements has second embossments. Both the first and the second embossments have an aperture to the contact plane of the plate element. Flow channels are formed by the apertures by having the embossments of the two plate elements offset against one another such that each embossment only partially overlaps one embossment of the other plate element. The second embossments are smaller than the first embossments such that the flow channels are restricted in the second embossments.

Abstract: An electrochemical cell includes a flow chamber disposed between two plate elements and having a flow inlet and a flow outlet for a flow medium permeating the flow chamber and defining a main flow direction of the flow medium between the flow inlet and the flow outlet. One of the plate elements has protrusions for supporting the plate element on the other plate element in a regular grid structure, between which a network of flow channels passing through the flow chamber runs in at least one flow channel direction. The regular grid structure is configured in such a way that the grid of the flow channels has two or more flow channel directions each enclosing an angle differing from zero degrees relative to the main flow direction of the flow medium.

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: An electrochemical cell includes a flow chamber disposed between two plate elements and having a flow inlet and a flow outlet for a flow medium permeating the flow chamber and defining a main flow direction of the flow medium between the flow inlet and the flow outlet. One of the plate elements has protrusions for supporting the plate element on the other plate element in a regular grid structure, between which a network of flow channels passing through the flow chamber runs in at least one flow channel direction. The regular grid structure is configured in such a way that the grid of the flow channels has two or more flow channel directions each enclosing an angle differing from zero degrees relative to the main flow direction of the flow medium.

Abstract: A method for operating a controller includes receiving a first accumulated thermal value of an electrical machine and an associated first time stamp from a memory, initializing a processor of the controller with the first accumulated thermal value and the associated first time stamp, determining whether a second time stamp has been received, calculating a difference between the second time stamp and the first time stamp responsive to determining that the second time stamp has been received, calculating a second accumulated thermal value as a function of the first accumulated thermal value, the first time stamp, and the second time stamp, and updating the first accumulated thermal value with the second accumulated thermal value.

Abstract: A method for operating a controller includes receiving a first accumulated thermal value of an electrical machine and an associated first time stamp from a memory, initializing a processor of the controller with the first accumulated thermal value and the associated first time stamp, determining whether a second time stamp has been received, calculating a difference between the second time stamp and the first time stamp responsive to determining that the second time stamp has been received, calculating a second accumulated thermal value as a function of the first accumulated thermal value, the first time stamp, and the second time stamp, and updating the first accumulated thermal value with the second accumulated thermal value.