Water transport in the proton exchange-membrane fuel cell: Comparison of model computation and measurements of effective drag

Water transport through the membrane of a PEMFC was investigated by measurement of the net drag under various feed gas humidity. Measured data were compared with computed results obtained using a two-dimensional cell model. Considering the change in the gas content related to the flow configuration, the humidity of the supply gas, reaction rates, and the mass balance of each gas species were derived at five sections along the flow channels. By solving these mass balance equations, the water transport rates and current density distribution were obtained along the flow channels for various feed gas humidity. The results for net drag computed from the model show a similar tendency, but are slightly higher than the measured values. This suggests that there is a certain resistance related to water transport at the cathode membrane interface in association with water production. The cause of this water transport resistance is discussed.