Effect of gas diffusion layer thickness on liquid water transport characteristics in polymer electrolyte membrane fuel cells

Abstract Researchers worldwide endeavor to develop the thinner gas diffusion layers (GDLs), which are enabling to achieve high power-density polymer electrolyte membrane fuel cells (PEMFCs). A number of experiments have attempted to understand the underlying mechanisms in the GDL that are responsible for water management and performance improvement. Here, we investigate the effect of GDL thickness on the dynamic behavior of liquid water using a multiphase lattice Boltzmann method. Various GDL configurations are simulated aiming on the fundamental understanding of multiphase flow phenomena. We report results of water saturation, water distribution and relative pressure distribution inside the GDL to elucidate the impact of GDL thickness on the water transport behavior. Water breakthrough and water creeping that determine the water behavior are deeply studied. In addition, we investigate the influence of channel-rib (CR) structure on a thin GDL. Optimum CR width is pursued for the effective water removal from a thin GDL. The results and findings here are expected to lead to more reliable water management and related high-power technologies of PEMFCs.