Page 47 - Introduction to Transfer Phenomena in PEM Fuel Cells

36 Introduction to Transfer Phenomena in PEM Fuel Cells
membrane). Hydrogen is introduced at the anode and oxygen is introduced at
the cathode. The protons are transported from the anode to the cathode
through the electrolyte membrane, and the electrons flow through an external
circuit represented by the charge [SPI 07] (see Figure 1.14). These batteries
work at a temperature below 100°C with efficiency of around 50%.

Figure 1.14. Principle of a PEMFC

The low operating temperature gives them an ability to start up relatively
quickly. These fuel cells are developed to power small and medium-sized
vehicles and fixed installations. The power range of PEMFC ranges from a
few tens of watts to around 10 megawatts [BLU 07]. PEMFC technology is
currently one of the largest research and development areas in the world. The
main aim of the research is to increase performance (in terms of efficiency,
lifetime, compactness and mass) and to reduce the cost (by a factor of 5 to
100 depending on the type of application).