A fuel cell device has a mounting plate on which a fuel cell unit having a predefined number of fuel cells is arranged, the mounting plate and the fuel cell unit comprising media connections for guiding media, in particular for guiding a coolant and for guiding reactants, and electrical contact points for electrically connecting the fuel cell unit to the mounting plate. Further media connections and further electrical contact points are designed or arranged on the fuel cell unit in such a way that the fuel cell unit can be connected or is connected to a second fuel cell unit with a mechanical fluid connection for further guidance of the media and electrical connection for power uptake.