The structure of
the gas diffusion layer (GDL) of a proton exchange
membrane fuel cell (PEMFC) affects the transfer of the reaction gas
and the water flooding phenomenon. First, the three-dimensional numerical
model of the GDL was reconstructed by the stochastic reconstruction
method, and the kinetic behaviors of liquid water in the conventional
GDL, circular groove GDL, and elliptical groove GDL were compared
and analyzed, based on which the liquid water penetration time, the
effective diffusion rate of oxygen, and relative permeability of water
in the three GDLs were analyzed, and the results of the study found
that the circular groove GDL had the best drainage effect. Second,
based on the PEMFC with serpentine channels, an electrochemical model
of the GDL with circular grooves was arranged in the flow field, and
the effects of the groove depth distribution and center spacing of
circular grooves on its performance were numerically investigated.
It was found that the presence of circular grooves enhanced the transfer
rate of reactants from the GDL to the catalytic layer and increased
the current density. Oxygen concentration uniformity and under-rib
convection were enhanced when the groove depth was designed to have
a power function distribution with an exponent close to 1, effectively
reducing flooding. The best drainage effect was achieved when the
groove spacing was 2 mm, and also the cell performance was more stable.