Dynamic model of solid polymer fuel cell water management

For system simplicity, it is advantageous to operate the solid polymer fuel cell on dry gases at low overpressures. Under these conditions, water management inside the cell is a critical issue. To determine the effect of operating conditions on performance, a two-dimensional dynamic model is developed. Water balance equations are written for each membrane element taking into account: production, drag and diffusion of water in the membrane, and diffusion of water vapour in the gas diffusion layers. The model can reasonably reproduce the polarisation curves of a cell operated on various oxygen fractions and can qualitatively describe the effect of various operating conditions (dry gases, current density level, co- and counter-flow, anode recirculation).