Mathematical Model of Proton Exchange Membrane Fuel Cell with Consideration of Water Management

Abstract

One‐dimensional model on the membrane electrode assembly (MEA) of proton exchange membrane fuel cell is proposed, where the membrane hydration/dehydration and the possible water flooding of the respective cathode and anode gas diffusion layers are considered. A novel approach of phase‐equilibrium approximation is proposed to trace the water front and the detailed saturation profile once water emerges in either anode or cathode gas diffusion layer. The approach is validated by a semi‐analytical method published earlier. The novel approach is applicable to the polarization regime from open circuit voltage to the limiting current density under practical operation conditions. Oxygen diffusion is limited by water accumulation in the cathode gas diffusion layer as current increases, caused by excessive water generation at the cathode catalyst layer and the electro‐osmotic drag across the membrane. The existence of liquid water in the anode gas diffusion layer is predicted at low current densities if high degrees of humidification in both anode and cathode feeds are employed. The influences of inlet relative humidity, imposed pressure drop, and cell temperature are correlated well with the cell performance. In addition, the overpotentials attributed from individual components of the MEA are delineated against the cell current densities.

PEMFC purging at low operating temperatures: An experimental approach

“…As discussed earlier, water and nitrogen accumulation at the anode side diminishes the cell performance, and hence designing an optimum purge strategy should be performed by considering this crucial impact. 24,25 Different factors affect the water transport [33][34][35][36][37][38][39][40] and nitrogen crossover [41][42][43][44] in a PEMFC. Water generation occurs at cathode side, and the excess water is partly removed from the cathode channels; hence, a desired water removal capacity can be achieved by applying effective flow channel design and GDL modifications.…”

“…Water generation occurs at cathode side, and the excess water is partly removed from the cathode channels; hence, a desired water removal capacity can be achieved by applying effective flow channel design and GDL modifications. [45][46][47][48] Water transport in PEMFC depends strongly on the operating temperature [33][34][35][36][37] and temperature profile inside the PEMFC. [38][39][40]49 Higher temperature means more water evaporation and hence more water removal from the cell in vapour form.…”

“…50 At lower operating temperatures, more liquid water is formed in the cell that increases the chance of flooding, making the role of water management to remove the excess water from the cell more significant. [33][34][35] Kim and Mench 39 have shown that in the presence of temperature gradient across the membrane electrode assembly (MEA), water transport is favoured towards the cold side. The same phenomenon has been experimentally confirmed by Hueang et al 40 and Abbou et al 38 Abbou et al 38 have reported that when the anode side was 5°C colder than the cathode side, water accumulation at the anode side was induced compared with when both sides had a similar temperature.…”

“…Water transport in PEMFC depends strongly on the operating temperature and temperature profile inside the PEMFC . Higher temperature means more water evaporation and hence more water removal from the cell in vapour form .…”

“…Higher temperature means more water evaporation and hence more water removal from the cell in vapour form . At lower operating temperatures, more liquid water is formed in the cell that increases the chance of flooding, making the role of water management to remove the excess water from the cell more significant . Kim and Mench have shown that in the presence of temperature gradient across the membrane electrode assembly (MEA), water transport is favoured towards the cold side.…”