Thermal Effect on Water Transport in Proton Exchange Membrane Fuel Cell

Adequate water management is critical in proton exchange membrane fuel cells for improving performance and durability. In this paper, we present results of experiments allowing to quantify the effect of a temperature difference between anode and cathode flow field plates on the transport of water. The results confirm the existence of a temperature-gradient driven flux between the anode and cathode compartments. They show the strong interplay between water management and heat management and they confirm that water flows mostly in vapor form through the porous media of the MEA. Apart from the current density and the difference between the temperature of the electrodes and of the flow field plates, the water flux in the direction perpendicular to the membrane is also (weakly) dependent on the humidification of the gases. No significant effect has been measured as a function of the GDL thickness as well as of the presence or absence of a MPL. However, using a MPL improves significantly the performance of the fuel cell.