Abstract: In the proceeding of the calculation on the diffusion overvoltage, the membrane water porosity is revised based on the fiducially air stoichiometric ratio and actual air stoichiometric ratio. The diffusion overvoltage is 0.06 V more than the result unrevised; It distinctly affects the model result. Membrane ionic conductivity is revised by using air stoichiometric ratio, the effect of water management on ohmic overvoltage is feeble correspondingly. A semi-empirical model of fuel cell is established based on the calculation of the thermodynamic potential and diversified overvoltages. Based on the model, the scale of active overvoltage, ohmic overvolt-age and diffusion overvoltage are calculated under different current density; The simulation results show that ohmic overvoltage and diffusion overvoltage increase following the current density. Polarization experiment is carried on utilizing a fuel cell testbed and the simulation results are in good agreement with the experiment results.

Key words: Fuel cell, Proton exchange membrane, Water management