Multiscale LBM–FVM simulation of cracked gas diffusion layers in proton exchange membrane fuel cells

A coupled three-dimensional lattice Boltzmann method–finite volume method (LBM–FVM) framework is developed to bridge pore-scale transport phenomena with full-cell performance in proton exchange membrane fuel cells (PEMFCs). Microstructural transport properties of pristine and cracked gas diffusion layers (GDLs), obtained from pore-scale LBM simulations, are imported into a continuum PEMFC model implemented in OpenFOAM. The effects of anode-cracked, cathode-cracked, and both-sides-cracked GDL configurations on cell performance are investigated. The results show that cracks appearing in cathode-side GDL induce the most severe performance degradation, highlighting the dominant role of the cathode in PEMFC operation. The influences of operating pressure ( 1.0 , 1.5 , and 2.0 atm ) and inlet gas velocities are further examined, with cathode inlet velocities varied from 1.0 to 9.0 m / s while fixing the anode inlet velocity, and vice versa. Higher operating pressures and cathode inlet velocities significantly enhance cell voltage and power density, whereas variations in anode inlet velocity have a negligible impact on overall PEMFC performance. This work provides a multiscale simulation framework for explaining the role of GDL microstructure, particularly crack-induced heterogeneity, in governing transport behavior and performance degradation in PEMFCs.