A comprehensive single-phase, non-isothermal mathematical MEA model and analysis of non-isothermal effects

A comprehensive single-phase non-isothermal MEA model, accounting for all applicable heat sources, viz., entropic and irreversible heating associated with electrochemical reactions, ohmic heating, phase change, and heat release/absorption due to sorption/desorption of water in electrolyte is presented. The model accounts for water management in two phases, viz., vapour and sorbed phase, and temperature driven vapour diffusion, and thermal osmosis. It is integrated into openFCST, an open-source fuel cell simulation framework, available for download online at http://www.openfcst.org/. Maximum temperatures inside the cell rise by up to 12 degrees C. A detailed breakdown of various heat sources inside the cell is studied. The heat of sorption, ignored in the literature, is more significant than protonic ohmic heating at medium currents and causes a shift in temperature distribution in the in-plane direction. Reversible heat distribution based on Ref. (1) resulted in temperature shifts with anode catalyst layer being the hottest.