Water equilibria and management using a two-volume model of a polymer electrolyte fuel cell

In this paper, we introduce a modified interpretation of the water activity presented in Springer et al. [T.E. Springer, T.A. Zawodzinski, S. ottesfeld, Polymer electrolyte fuel cell model, J. Electrochem. Soc. 138 (8) (1991) 2334–2342]. The modification directly affects the membrane ater transport between the anode and the cathode (two electrodes) of the polymer electrolyte membrane (PEM) fuel cell in the presence of iquid water inside the stack. The modification permits calibration of a zero-dimensional isothermal model to predict the flooding and drying onditions in the two electrodes observed at various current levels [D. Spernjak, S. Advani, A.K. Prasad, Experimental investigation of liquid ater formation and transport in a transparent single-serpentine PEM fuel cell, in: Proceedings of the Fourth International Conference on Fuel ell Science, Engineering and Technology (FUELCELL2006-97271), June 2006]. Using this model the equilibria of the lumped water mass in he two electrodes are analyzed at various flow conditions of the stack to determine stable and unstable (liquid water growth) operating conditions. wo case studies of water management through modification of cathode inlet humidification and anode water removal are then evaluated using this odel. The desired anode water removal and the desired cathode inlet humidification are specified based upon (i) the water balance requirements, ii) the desired conditions in the electrodes, and (iii) the maximum membrane transport at those conditions.