A Study of Water and Oxygen Distributions in the Cathode Flow Channels of a PEM Fuel Cell

Abstract

Water management is a critical operation issue for achieving the highest possible performance of proton exchange membrane (PEM) fuel cells. Quantitative determination of water and species distribution is needed to understand the water management and reactant distribution effects. In this study, the measurement of water and oxygen distributions along cathode flow channels was carried out using gas chromatography (GC). Generally, it is difficult to measure water distribution where water concentration is too high. Here, the measurement of high levels of water saturation in cathode channels was performed according to fuel cell operating conditions. GC measurement was also carried out for flooding and non-flooding conditions. To compare the experimental results with computational results, the three-dimensional CFD simulation of a unit fuel cell was performed using es-pemfc, which is the PEM fuel cell module of commercial CFD code STAR-CD. For the entrance of flow channel that has relatively lower level of water content, the calculated results showed good agreement with measured results. However, some discrepancy between calculated and experimental results was still found for the flow channels near the cathode outlet. The study provides the necessity of the development and adoption of a comprehensive multidimensional PEM fuel cell models including two-phase flow and cathode flooding phenomena for the optimization of fuel cell performance.