AFCC’s automotive fuel cell stack is a Polymer Electrolyte Membrane (PEM) fuel cell that operates with compressed gaseous hydrogen and air.

PEM fuel cells separate the anode and cathode sides of the fuel cell with a proton-conducting polymer membrane (the electrolyte). Platinum based catalysts are coated on both sides of the polymer membrane to form the anode and cathode.

Gas diffusion layers of carbon fiber paper sandwich the catalyst coated membrane (CCM) which is then combined with a plastic frame to form a membrane electrode assembly (MEA).

Bipolar plates made from metal or carbon then help form a unit cell which can then be stacked in series to form a fuel cell stack (see diagram below).