Abstract: A method for determining the starting state of a fuel-cell system is provided having cathode and anode chambers separated by a membrane-electrode assembly, comprising the steps of initially introducing hydrogen into the anode chamber, measuring the voltage and evaluating whether at least a threshold value has been reached immediately after the start of the introduction of hydrogen into the anode chamber, and determining the starting state as a function of whether the threshold value has been reached.

Abstract: The invention relates to a fuel cell system comprising a shut-off element arranged in each case in a supply path and exhaust path of the anode and/or cathode supply, and comprising a gas connection arranged in each case between a shut-off element and a fuel cell stack for connecting to an external test gas supply. The gas connections allow diagnosis and/or maintenance of the fuel cell stack in the installed state.

Abstract: The invention relates to a fuel cell system comprising a shut-off element arranged in each case in a supply path and exhaust path of the anode and/or cathode supply, and comprising a gas connection arranged in each case between a shut-off element and a fuel cell stack for connecting to an external test gas supply. The gas connections allow diagnosis and/or maintenance of the fuel cell stack in the installed state.

Abstract: A method for determining the starting state of a fuel-cell system is provided having cathode and anode chambers separated by a membrane-electrode assembly, comprising the steps of initially introducing hydrogen into the anode chamber, measuring the voltage and evaluating whether at least a threshold value has been reached immediately after the start of the introduction of hydrogen into the anode chamber, and determining the starting state as a function of whether the threshold value has been reached.

Abstract: The invention relates to an arrangement for a cathode recirculation of a fuel cell (10) of a fuel cell system (1) with a cathode supply (30) for the fuel cell (10), having a cathode supply path (31) and a cathode waste gas path (32), and a flushing loop (50) of a stack housing (16) of the fuel cell (10) is mechanically connected in terms of fluid to the cathode supply (30), wherein a recirculation fluid (7) can be circulated in the cathode supply (30) and in the flushing loop (50) by means of a recirculation fluid pressure generator (33, 53) in the cathode supply (30) and/or in the flushing loop (50).

Abstract: The invention relates to a starting method for a fuel cell system (100), particularly for an air/air start of the fuel cell system (100). The method enables the reduction of damaging half-cell voltages in the fuel cell stack (10) through voltage limitation by means of a DC voltage converter. The homogeneous flushing of the fuel cell stack (10) required for this takes place by means of introduction of an anode operating medium into an anode inlet channel (17) of the otherwise sealed fuel cell stack (10) until a predetermined pressure is reached and flushing of the active areas of the fuel cells (11) of the stack (10) after said pressure is reached through opening of an anode discharge adjusting aid (26), preferably arranged in an exhaust coupling (29) connecting the anode exhaust line (22) and the cathode exhaust line (31).

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: The invention relates to an arrangement for a cathode recirculation of a fuel cell (10) of a fuel cell system (1) with a cathode supply (30) for the fuel cell (10), having a cathode supply path (31) and a cathode waste gas path (32), and a flushing loop (50) of a stack housing (16) of the fuel cell (10) is mechanically connected in terms of fluid to the cathode supply (30), wherein a recirculation fluid (7) can be circulated in the cathode supply (30) and in the flushing loop (50) by means of a recirculation fluid pressure generator (33, 53) in the cathode supply (30) and/or in the flushing loop (50).

Abstract: The invention relates to a starting method for a fuel cell system (100), particularly for an air/air start of the fuel cell system (100). The method enables the reduction of damaging half-cell voltages in the fuel cell stack (10) through voltage limitation by means of a DC voltage converter. The homogeneous flushing of the fuel cell stack (10) required for this takes place by means of introduction of an anode operating medium into an anode inlet channel (17) of the otherwise sealed fuel cell stack (10) until a predetermined pressure is reached and flushing of the active areas of the fuel cells (11) of the stack (10) after said pressure is reached through opening of an anode discharge adjusting aid (26), preferably arranged in an exhaust coupling (29) connecting the anode exhaust line (22) and the cathode exhaust line (31).

Abstract: A fuel cell system (100) having a fuel cell stack (10) and a fuel cell cooling system (40) to cool the fuel cell stack (10), including a coolant path (4) into which the fuel cell stack (10) is integrated so as to transfer heat and in which at least one cooler (43) or heat exchanger is arranged. It is provided that the at least one cooler (43) or heat exchanger that does not have shock-hazard protection is interconnected so as to establish equipotential bonding (47), whereby at least one control element is arranged in the connection of the at least one cooler (43) or heat exchanger to equipotential bonding (47). Moreover, a vehicle having such a fuel cell system (100) is disclosed.

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).