Hydrogen fuel cells are, in fact, not as new as you might think. Invented in 1838, first used commercially in 1932 and used in NASA space programmes since 1965. Today there are 10,000’s of hydrogen powered vehicles in use across the world.
Origins
What is a fuel cell?
A hydrogen fuel cell is an electro-chemical power generator that combines hydrogen and oxygen to produce electricity, water and heat.
The technology provides a clean and reliable alternative source of power in a growing number of applications.
How they work
A fuel cell converts the energy stored in hydrogen into useable power.
The fuel cell uses three main components: two electrodes called an anode and a cathode, and an ion conducting electrolyte. Ions are atoms with negative or positive charge.
There is also a fuel, usually hydrogen, and an oxidant, usually air. The anode is responsible for converting the hydrogen, the cathode for converting the air. The role of the ion conducting electrolyte is very important, as it allows ions to pass between the electrodes but not electrons. The electrons are instead forced to flow outside of the fuel cell – this movement of electrons is electricity.
Video: How fuel cells work at Extreme E
Fuel cell types
The ion conducting electrolyte can be solid or liquid and its chemistry usually defines the type of fuel cell.
The most common types of fuel cells are Proton Exchange Membrane (PEM) fuel cells, Solid Oxide Fuel Cells (SOFC), Alkaline Fuel Cells (AFC), and Phosphoric Acid Fuel Cells (PAFC).
In a PEM fuel cell, the anode splits hydrogen into electrons and protons. The protons pass through the electrolyte membrane, while the electrons are forced through an external electric circuit. The cathode recombines the protons, electrons, and oxygen from air to produce water. Alkaline Fuel Cells use the same process as PEM fuel cells except that the ion is a hydroxyl (OH) and water is instead consumed at the cathode and produced at the anode.