1. Fuel cell system

A fuel cell can be thought of as a black box, with a fuel inlet (a connection to the natural gas network, for example, or a hydrogen tank), an exhaust gas outlet, a connection to the heat network (in the case of a stack operating in cogeneration) and a connection to the electrical network (figure 1 ). Between these connections and the stack of electrochemical cells lies the system that supplies the stack with gas, cools it and shapes the electrical energy produced (by modifying the levels and shapes of voltages and currents where necessary