A fuel cell system , comprising: - a plurality of fuel cell modules (11 - 1n) connected so as to form a fuel cell group having first and second electrical supply terminals configured to be terminated to an electrical load , - a measuring device (21 - 2n) connected to the fuel cell modules (11 - 1n) and configured to measure a load current of the respective fuel cell modules (11 - 1n), - a controller for detecting a respective operating state of the fuel cell modules (11 - 1n) by way of the load current of the respective fuel cell module measured by the measuring device (21 - 2n), said controller being connected to the fuel cell modules (11 - 1n) for controlling the operation of the fuel cell modules (11 - 1n), - wherein the controller is configured to provide a load current (L) demanded by the load in a full-load operating mode by operating all fuel cell modules (11 - 1n), and to provide a load current (L) demanded by the load in a partial-load operating mode of the load by operating all or part of the fuel cell modules (11 - 1n), - wherein the controller is configured to detect whether the operating state of the fuel cell modules (11 - 1n) is in a respective partial load range of the respective fuel cell module, said partial load range being defined by a lower limit above a load current of zero and an upper limit below a full load current, - wherein the controller is configured to provide a load current (L) demanded by the load in a first partial-load operating mode of the load by operating all fuel cell modules (11 - 1n) of the fuel cell group such that all fuel cell modules (11 - 1n) of the fuel cell group are within the respective partial load range of the respective fuel cell module (11 - 1n). - a plurality of fuel cell modules (11 - 1n) connected so as to form a fuel cell group having first and second electrical supply terminals configured to be terminated to an electrical load , - a measuring device (21 - 2n) connected to the fuel cell modules (11 - 1n) and configured to measure a load current of the respective fuel cell modules (11 - 1n), - a controller for detecting a respective operating state of the fuel cell modules (11 - 1n) by way of the load current of the respective fuel cell module measured by the measuring device (21 - 2n), said controller being connected to the fuel cell modules (11 - 1n) for controlling the operation of the fuel cell modules (11 - 1n), - wherein the controller is configured to provide a load current (L) demanded by the load in a full-load operating mode by operating all fuel cell modules (11 - 1n), and to provide a load current (L) demanded by the load in a partial-load operating mode of the load by operating all or part of the fuel cell modules (11 - 1n), - wherein the controller is configured to detect whether the operating state of the fuel cell modules (11 - 1n) is in a respective partial load range of the respective fuel cell module, said partial load range being defined by a lower limit above a load current of zero and an upper limit below a full load current, - wherein the controller is configured to provide a load current (L) demanded by the load in a first partial-load operating mode of the load by operating all fuel cell modules (11 - 1n) of the fuel cell group such that all fuel cell modules (11 - 1n) of the fuel cell group are within the respective partial load range of the respective fuel cell module (11 - 1n). <EOS>