Modelling membrane hydration and water balance of a pem fuel cell

Polymer electrolyte membrane (PEM) fuel cells requires an appropriate hydration in order to ensure high efficiency and long durability. As water is essential for promoting proton conductivity in the membrane, it is important to control membrane water hydration to avoid flooding.
In this study we propose a novel mathematical zero-dimensional model for water mass balance of a polymer electrolyte membrane. Physical and electrochemical processes occurring in the membrane electrolyte are included; water adsorption/desorption phenomena are also considered. The effect of diffusivity, surface roughness and water content driving force is considered. We validate the model against experimental data.
The water balance calculated by this model shows better fit with experimental data-points compared to other models such as the one by Springer et al.. We conclude that this discrepancy is due a different rate of water transport when membrane absorption/desorption is considered in the model. The model becomes useful when studying fuel cell systems in dynamic conditions.