Fuel Cell Device

An embodiment fuel cell device includes a fuel cell, a power controller configured to convert a magnitude of a stack voltage output from the fuel cell and to output the stack voltage having the converted magnitude to a load, and a junction box including a bypass diode that includes an anode coupled to the stack voltage and to a voltage input terminal of the power controller and a cathode coupled to a voltage output terminal of the power controller and to the load, wherein the voltage output terminal of the power controller is configured to carry a voltage having the converted magnitude.