How does a fuel cell work?

Answer 1

A fuel cell is a electrochemical device that converts the chemical energy of fuels such as hydrogen and natural gas, and oxidants like air and oxygen into electricity.

Fuel Cell Functionality

Fuel cells generate electricity from a simple electrochemical reaction in which an oxidizer, typically oxygen from air, and a fuel, typically hydrogen, combine to form a product, which is water for the typical fuel cell. Oxygen (air) continuously passes over the cathode and hydrogen passes over the anode to generate electricity, by-product heat and water. The fuel cell itself has no moving parts - making it a quiet and reliable source of power.

The electrolyte that separates the anode and cathode is an ion-conducting material. At the anode, hydrogen and its electrons are separated so that the hydrogen ions (protons) pass through the electrolyte while the electrons pass through an external electrical circuit as a Direct Current (DC) that can power useful devices. The hydrogen ions combine with the oxygen at the cathode and are recombined with the electrons to form water. The reactions are shown below.

Anode Reaction: 2H2 => 4H+ + 4e-

Cathode Reaction: O2 + 4H+ + 4e- => 2H2O

Overall Cell Reaction: 2H2 + O2 => 2H2O

Individual fuel cells can then be combined into a fuel cell "stack." The number of fuel cells in the stack determines the total voltage, and the surface area of each cell determines the total current. Multiplying the voltage by the current will yield the total electrical power generated.

Power (Watts) = Voltage (Volts) X Current (Amps)