Fact sheet n°3 : How does a fuel cell work?
Hydrogen can actually be used in fuel cells to generate electricity; for instance, in a vehicle. But…
WHAT IS A FUEL CELL?
A FUEL CELL IS:
a magic box that turns hydrogen and oxygen into electricity!
Well, not exactly. A fuel cell does in fact allow the production of electricity from hydrogen and oxygen. However, no magic tricks are involved in the process. Let’s see then how a PEM fuel cell works!
First, let’s see what they’re made of. A fuel cell is made up of several layers: in the middle we have a membrane or an electrolyte separating the two electrodes, the anode and the cathode. The whole thing is then compressed between two flow plates.
Hydrogen travels through the small channels in one plate, and oxygen through the other. The membrane in the middle has a secret, it acts as a filter that lets protons through but not electrons.
Gaseous hydrogen arrives through small channels in the outer plate. When it reaches the anode, the latter’s catalytic power breaks it in two. Two protons and two electrons are formed. The protons travel across the membrane to the other side, where they attach themselves to the oxygen to form… water!
The electrons can’t get through, remember? They have to take another route to reach the other side. It is this flow of electrons that produces an electricity that can be used to power an electric motor for any other application .
REMEMBER! THERE ARE SEVERAL TYPES OF FUEL CELLS, NAMELY:
PEMFC
Proton Exchange Membrane Fuel Cells
AFC
Alkaline Fuel Cells
SOFC
Solid Oxide Fuel Cell
Operating temperature – maturity – deployment:
However, these are only the main ones, there is also the MCFC (Molten Carbonate Fuel Cells), the PAFC (Phosphoric Acid Fuel Cells) …
THE MAIN DIFFERENCES
To each technique its advantages and disadvantages.
PEM fuel cells are highly adapted for mobility use. They are light, efficient and reactive.
Alkaline fuel cells are the most mature and are even used by NASA in the Space Shuttle!
But they are loosing ground to PEM fuel cells.
The competition is fierce…
SOFCs have excellent efficiency but require high temperatures. They are well suited for high-power applications.
