Abstract: A fuel cell system includes a fuel cell stack formed from a plurality of cell units, which have gas diffusion layers, wherein the gas diffusion layer of at least one of the edge cell units has a heat transfer mechanism of reduced efficiency in comparison with the gas diffusion layer of a cell unit from the middle of the fuel cell stack. A motor vehicle may include such a fuel cell system.

Abstract: A diagnostic system for determining the cathode gas quality of a fuel cell system has a fuel cell stack, with a diagnostic fuel cell which can be connected at the cathode side to a cathode supply line and at the anode side to an anode supply line of the fuel cell system. The diagnostic system furthermore comprises a detection unit which is configured to detect a measured value or the measured value time curve of the diagnostic fuel cell operating with the cathode gas provided via the cathode supply line and with the anode gas provided via the anode supply line. The present disclosure moreover relates to a fuel cell system having a diagnostic system, and to a corresponding method.

Abstract: A manufacturing process includes: depositing a catalyst support on a gas diffusion layer to form a catalyst support-coated gas diffusion layer; depositing a catalyst on the catalyst support-coated gas diffusion layer to form a catalyst-coated gas diffusion layer; and depositing an ionomer on the catalyst-coated gas diffusion layer to form an ionomer-coated gas diffusion layer. A membrane electrode assembly for a fuel cell includes: a gas diffusion layer; a polymer electrolyte membrane; and a catalyst layer disposed between the gas diffusion layer and the polymer electrolyte membrane, wherein the catalyst layer includes an ionomer, and a concentration of the ionomer varies within the catalyst layer according to a concentration profile.

Abstract: A bipolar plate for a fuel cell has flow channels for the reactants formed between webs in a plate body, and lines for a coolant, and has hydrophilic structures associated with the plate body formed in a gradient. The gradient of hydrophilic structures is associated with the web with hydrophilicity increasing towards the bottom of the flow channels, wherein microchannels to the flow channels, opening into the flow channels and generating capillary force, are formed in the boundary surface of the webs.

Abstract: A method for starting a fuel cell and to a fuel cell system which is configured to carry out the method. The fuel cell includes electrically conductive bipolar plates, arranged between which there is in each case a cathode, including a fluid-conducting cathode space, a membrane and an anode, including a fluid-conducting anode space. There is provision that the method includes the following steps in the specified order: purging the anode space with a fluid in order to expel fuel, —impressing electricity on a unit composed of the cathode (2k)/membrane (1)/anode (2a) by applying a current and/or a voltage, wherein the fluid is applied to the anode space or continues to be so, —switching off the electricity, and —introducing a fuel into the anode space.

Abstract: A fuel cell system includes a fuel cell stack formed from a plurality of cell units, which have gas diffusion layers, wherein the gas diffusion layer of at least one of the edge cell units has a heat transfer mechanism of reduced efficiency in comparison with the gas diffusion layer of a cell unit from the middle of the fuel cell stack. A motor vehicle may include such a fuel cell system.

Abstract: A diagnostic system for determining the cathode gas quality of a fuel cell system has a fuel cell stack, with a diagnostic fuel cell which can be connected at the cathode side to a cathode supply line and at the anode side to an anode supply line of the fuel cell system. The diagnostic system furthermore comprises a detection unit which is configured to detect a measured value or the measured value time curve of the diagnostic fuel cell operating with the cathode gas provided via the cathode supply line and with the anode gas provided via the anode supply line. The present disclosure moreover relates to a fuel cell system having a diagnostic system, and to a corresponding method.

Abstract: A method for controlling an operating point change of a fuel cell stack (10) operated with an anode operating medium and with a cathode operating medium, in which the fuel cell stack (10) is controlled in such a way that, starting from an initial electric power (L1), the fuel cell stack generates a target power (L2) requested by an electrical consumer (51), which is greater than the initial power (L1) is provided. It is provided that the electric power generated by the fuel cell stack (10) is controlled in accordance with a predetermined current-voltage profile (S1, S2, S3), so that a voltage present at the fuel cell stack (10), starting from an initial voltage (U1) corresponding to the initial power (L1), passes through a local voltage minimum (Umin) and then increases to an end voltage corresponding to the target power (L2).

Abstract: A method for starting a fuel cell and to a fuel cell system which is configured to carry out the method. The fuel cell includes electrically conductive bipolar plates, arranged between which there is in each case a cathode, including a fluid-conducting cathode space, a membrane and an anode, including a fluid-conducting anode space. There is provision that the method includes the following steps in the specified order: purging the anode space with a fluid in order to expel fuel, impressing electricity on a unit composed of the cathode (2k)/membrane (1)/anode (2a) by applying a current and/or a voltage, wherein the fluid is applied to the anode space or continues to be so, switching off the electricity, and introducing a fuel into the anode space.

Abstract: A method for controlling an operating point change of a fuel cell stack (10) operated with an anode operating medium and with a cathode operating medium, in which the fuel cell stack (10) is controlled in such a way that, starting from an initial electric power (L1), the fuel cell stack generates a target power (L2) requested by an electrical consumer (51), which is greater than the initial power (L1) is provided. It is provided that the electric power generated by the fuel cell stack (10) is controlled in accordance with a predetermined current-voltage profile (S1, S2, S3), so that a voltage present at the fuel cell stack (10), starting from an initial voltage (U1) corresponding to the initial power (L1), passes through a local voltage minimum (Umin) and then increases to an end voltage corresponding to the target power (L2).