Water Transport in Membrane of PEM Fuel Cell Under Transient Operation

In this study, the primary focus is investigating the transient behaviors of water transport in the membrane when the cell voltage reaches its lowest values during acceleration. To cope with the objective, this study involved the installation of multiple micro relative humidity and temperature sensors in the bipolar plate channels to measure the temperature and water distribution in the flow fields both on the cathode and anode of a single cell PEMFC. Experiments have been conducted to acquire temperature and water distribution change data under varying load conditions with different time intervals. The current density was systematically adjusted from 0.1A/cm2 to 0.4A/cm2. Time intervals of 0 seconds and 5 seconds have been introduced to control the rapidity of acceleration process. This approach allowed for examining water transport characteristics in the membrane during transient operation. Specifically, an ANN (Artificial Neural Network)-based model has been developed to predict membrane water content. The net water mole flux transported in the membrane as the sum of electro-osmotic force and back-diffusion force is calculated based on the measured temperature and relative humidity by combining the ANN-based model with other empirical correlations. The research provides visual information about the water transport in the membrane during the transient state. The data corresponding to different acceleration time intervals are compared to assess the time-dependent effects of load changes. It is evident that the time intervals of acceleration significantly influence the water characteristics in the membrane and output voltage of operating PEMFC. This study contributes significantly to enhancing the knowledge of water transport transient behaviors in the membrane of PEMFC, providing the foundation for further research to improve the performance and durability of PEMFC for transportation applications.