Numerical investigation of water flow mechanism at the micro-porous layer and gas diffusion layer interface of proton electrolyte membrane fuel cells

In the proton electrolyte membrane fuel cell, the effect of realistic gas diffusion layers (GDLs) and microporous layers (MPLs) interface structures on the liquid water flow is investigated via a multiphase lattice Boltzmann (LB) method simulation with a multiple-relaxation time. The simulation results show that the water saturation inside the MPL and GDL is reduced, but the porosity inside the MPL and GDL is substantially decreased when the polytetrafluoroethylene (PTFE) content inside the GDL and MPL is increased. In the GDL, the water saturation is first increased and then decreased by increasing the MPL invaded depth, such that the water removal ability is enhanced at the proper MPL invaded depth. When the MPL invaded depth is replaced by the MPL crack, the liquid water tends to flow into the MPL crack so that the liquid water drainage is improved by the MPL crack, and the MPL and GDL porosity being increased by the MPL crack. Overall, a comprehensive understanding regarding the GDL and MPL interface-structure effect on two phase transport within PEMFCs is provided by this paper, which guides the design of high-performance proton electrolyte membrane fuel cells.