The PEM fuel cell is structured like a sandwich. In the centre is a thin plastic film, the Proton Exchange Membrane (or PEM). This membrane is coated on both sides with a thin catalyst layer and a gas permeable electrode made of graphite paper. The membrane is surrounded by two so call ed bipolar plates into which gas ducts have been milled. Through these gas ducts flows hydrogen on the one side, and oxygen on the other. Several of these individual fuel cells can be stacked one behind the other to create a so-called fuel cell stack, thus forming a powerful energy source to drive the vehicle.

D595362 Behind the scenes of fuel cell mobility