A comprehensive two-dimensional mathematic model was developed for PEMFC with conventional single parallel flow field.In this model

the transport of the two charged species

electrons and ions

as well as that of the chemical species was considered.The model also described the phenomena of liquid water flooding and water transport through membrane.The influence of pressure and liquid water flooding on the fuel cell performance was investigated respectively.The distribution of liquid water in the cathode and water content of membrane were compared under different cell voltage and relative humidity of anode gas.The polarization curves predicted by the model agreed well with the published experimental data.The result indicated that liquid water flooding was more serious with a smaller output voltage.Liquid water condensation was good for keeping high conductivity of membrane near the cathode

but it would flood the electrode and decrease the performance of the cell.