Abstract: A fuel cell includes a membrane electrode assembly (MEA) and at least one bipolar plate having an anode-side gas distributor structure for distributing anode reactants, a cathode-side gas distributor structure for distributing cathode reactants, and a guide passage structure for distributing a cooling medium. At least one of the anode-side gas distributor structure and the cathode-side gas distributor structure is divided into at least a first field and a second field, each of the first and second fields having an entry port and an exit port for the reactants. In addition, a method for such a fuel cell includes passing a reactant into an entry port of the first field and out of an exit port of the first field, mixing the reactant with a fresh reactant so as to form a mixture, and passing the mixture into the entry port of the second field.

Abstract: A membrane electrode assembly for a fuel cell having a polymer electrolyte membrane, having a layer sequence comprising an ion-conducting membrane (2), a catalyst layer (3) and a gas diffusion layer (5). A substantially catalyst-free, porous condensation layer (5) is arranged between the catalyst layer (3) and the membrane (2).

Abstract: A fuel cell includes a membrane electrode assembly (MEA) and at least one bipolar plate having an anode-side gas distributor structure for distributing anode reactants, a cathode-side gas distributor structure for distributing cathode reactants, and a guide passage structure for distributing a cooling medium. At least one of the anode-side gas distributor structure and the cathode-side gas distributor structure is divided into at least a first field and a second field, each of the first and second fields having an entry port and an exit port for the reactants. In addition, a method for such a fuel cell includes passing a reactant into an entry port of the first field and out of an exit port of the first field, mixing the reactant with a fresh reactant so as to form a mixture, and passing the mixture into the entry port of the second field.

Abstract: A fuel cell includes a membrane electrode assembly (MEA) and at least one bipolar plate having an anode-side gas distributor structure for distributing anode reactants, a cathode-side gas distributor structure for distributing cathode reactants, and a guide passage structure for distributing a cooling medium. At least one of the anode-side gas distributor structure and the cathode-side gas distributor structure is divided into at least a first field and a second field, each of the first and second fields having an entry port and an exit port for the reactants. In addition, a method for such a fuel cell includes passing a reactant into an entry port of the first field and out of an exit port of the first field, mixing the reactant with a fresh reactant so as to form a mixture, and passing the mixture into the entry port of the second field.

Abstract: A passage structure for PEM fuel cells is configured locally differently in order to adapt the flow of gas on the membrane electrode assembly (MEA). Starting from the cathode entry port, the active gas volumetric flow per unit area on the MEA is locally varied by changing the number and/or cross section of the gas-carrying passages, so that the flow decreases toward the cathode exit port. Suitable configuration of the passage structure according to the invention allows the steam partial pressure to be optimally matched to the local conditions. The mass conversion is improved in these regions as a result without the electrolyte's drying out. At locations in the flowfield with a low gas humidity, the measures according to the invention (increased number of passages or passage width) significantly reduce the flow velocity. As a result, the transfer of water from the MEA to the gas flow is reduced and drying of the MEA is diminished.

Abstract: A fuel cell stack for gaseous fuel includes a membrane electrode unit and a distribution plate including a channel area having gas channels for distributing the anode gas and the cathode gas to the membrane electrode unit and a port area for supplying the anode gas and the cathode gas into the channel area. Additional connecting channels discharge from the port areas along the gas channels so that unused anode gas or cathode gas is locally meterable from the port areas into the gas channels via these connecting channels.

Abstract: A fuel cell includes a membrane electrode assembly (MEA) and at least one bipolar plate having an anode-side gas distributor structure for distributing anode reactants, a cathode-side gas distributor structure for distributing cathode reactants, and a guide passage structure for distributing a cooling medium. At least one of the anode-side gas distributor structure and the cathode-side gas distributor structure is divided into at least a first field and a second field, each of the first and second fields having an entry port and an exit port for the reactants. In addition, a method for such a fuel cell includes passing a reactant into an entry port of the first field and out of an exit port of the first field, mixing the reactant with a fresh reactant so as to form a mixture, and passing the mixture into the entry port of the second field.

Abstract: A membrane electrode assembly for a fuel cell having a polymer electrolyte membrane, having a layer sequence comprising an ion-conducting membrane (2), a catalyst layer (3) and a gas diffusion layer (5). A substantially catalyst-free, porous condensation layer (5) is arranged between the catalyst layer (3) and the membrane (2).

Abstract: A passage structure for PEM fuel cells is configured locally differently in order to adapt the flow of gas on the membrane electrode assembly (MEA). Starting from the cathode entry port, the active gas volumetric flow per unit area on the MEA is locally varied by changing the number and/or cross section of the gas-carrying passages, so that the flow decreases toward the cathode exit port. Suitable configuration of the passage structure according to the invention allows the steam partial pressure to be optimally matched to the local conditions. The mass conversion is improved in these regions as a result without the electrolyte's drying out. At locations in the flowfield with a low gas humidity, the measures according to the invention (increased number of passages or passage width) significantly reduce the flow velocity. As a result, the transfer of water from the MEA to the gas flow is reduced and drying of the MEA is diminished.

Abstract: In a fuel cell the reaction area of the cell (bipolar plate) is divided. For startup, only a partial area of the bipolar plate is supplied with the reactants via separate inlet and outlet ports. This partial area thus heats up relatively rapidly due to its reduced size, and the resulting reaction heat may be transferred to adjacent reaction areas and/or used for heating. After reaching the operating temperature in these areas, the reactants may also flow over the adjacent reaction areas until achieving the full operating power of the fuel cell.

Abstract: A fuel cell stack having gaseous fuel is described, comprising a membrane electrode unit (8) and a distribution plate (1) including a channel area (2) having gas channels (3) for distributing the anode gas and the cathode gas to the membrane electrode unit (8) and a port area (4) for supplying the anode gas and the cathode gas into the channel area (2). Additional connecting channels (6) discharge from the port areas (4) along the gas channels (3) so that unused anode gas or cathode gas is locally meterable from the port areas (4) into the gas channels (3) via these connecting channels (6).

Abstract: The invention relates to an electrochemical fuel cell stack, comprising at least one membrane-electrode unit (MEA) consisting of an anode, a cathode and an electrolyte membrane which is located between them, at least one gas distributor structure on the anode side, comprising an anode gas inlet area, an anode gas outlet area and channels for guiding the anode gas from the anode gas inlet area to the anode gas outlet area, said anode gas containing hydrogen and being un-wet or partially wet; at least one gas distributor structure on the cathode side, comprising a cathode gas inlet area, a cathode gas outlet area and channels for guiding the cathode gas from the cathode gas inlet area to the cathode gas outlet area, the cathode gas containing oxygen and being un-wet or partially wet; and a coolant distributor structure, comprising a coolant inlet area, a coolant outlet area and channels for guiding the coolant from the coolant inlet area to the coolant outlet area.