Application of Secondary Channels for Improved Water Removal and Oxygen Concentration in Proton Exchange Membrane Fuel Cell

Liquid water hinders the performance of proton exchange membrane fuel cells at high power densities due to non-uniform heat and mass transfer and potential starvation caused by the accumulation of liquid water inside the porous layers and reactant channels. The addition of secondary flow channels is a recent novelty that shows potential for improving the existing flow fields with minor modifications. The secondary channels serve as additional pathways to remove liquid water from critical areas of the cell, such as lands in areas where serpentines change direction. In this work, secondary channels had been utilized on a more complex, triple serpentine, flow field than before, and implement the methodology of auxiliary channels, arrayed holes, and pairs of conjunction holes to improve water removal but at the same time ensure high oxygen concentration inside the cathode catalyst layer. A three-dimensional computation fluid dynamics model was developed for a single fuel cell with an active area of 50 cm(2), calibrated using existing experimental data, and secondary channels were added to investigate liquid water transport inside the cell. The influence of different geometrical parameters on water and reactant concentrations, current uniformity, and cell performance are outlined and an optimal solution is resolved which results in superior performance of the fuel cell as well as the methodology on how to further improve the flow field in a future study.