The effect of micro-channels in the MPL on the predicted membrane water content in a PEMFC – a modeling study

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

The micro-porous layer (MPL) in a proton exchange membrane fuel cell is frequently believed to constitute a barrier for the liquid water owing to its low hydraulic permeability compared to the porous substrate. When micro-channels are carved into the MPL on the side facing the catalyst layer, liquid water may be diverted from wet regions of the fuel cell to the drier inlet and outlet sections where it can evaporate and assist in hydrating the membrane as well as provide a pressure relieve at the interface between the catalyst layer and the MPL where delamination can occur under freezing conditions. This modeling study investigates the effect of such micro-channels on the predicted membrane hydration level for a predetermined set of operating conditions with a three-dimensional computational fluid dynamics model that utilizes the multi-fluid approach.