An analytical model for alkaline membrane direct methanol fuel cell

Abstract

In this study, a multiphase analytical model is developed for alkaline anion exchange membrane direct methanol fuel cell (AAEM-DMFC). The model prediction agrees with experimental data reasonably. Modeling results show that the methanol feed concentration, operating temperature and membrane thickness are the three factors that most significantly affect the cell performance. The effect of reactant flow rate is insignificant in high flow rate range, and this effect enhances when the flow rates are low. In low current density range, the cell shows better performance with lower methanol feed concentrations, while this trend reverses in high current density range. A similar trend is also found for the operating temperature. A thinner membrane leads to a higher methanol crossover; however, it yields better performance in mid and high current density range. Water is mass transfer limited once membrane thickness is high enough, resulting in the decrease of limiting current density. The carbon dioxide bubbles produced in anode are removed faster at higher operating temperatures. When the anode of the cell faces up, the best performance can be achieved. Inclining the cell leads to lower cell performance, and the performance degradation becomes more significant with larger inclining angles.