Transport properties evaluation of pore-scale GDLs for PEMFC using orthogonal design method

Abstract

Gas diffusion layer (GDL) is an essential component of proton exchange membrane fuel cells, serving the functions of gas-water transport, thermal-electrical conduction and mechanical support. The various microstructural characteristics of the GDL have coupled and complex impact on transport properties, which is not comprehensively considered in previous studies. This study combines stochastically reconstruction techniques, pore-scale modeling and orthogonal design method to evaluate the coupling effect of multiple microstructural characteristics on transport properties, and determine the impact degree of each microstructural characteristics, including fiber diameter, porosity, GDL thickness, fiber orientation coefficient, binder and PTFE content. Finally, new mathematical models are developed and validated to predict and optimize the anisotropic transport properties accurately and rapidly by considering the coupling effect of multiple microstructural characteristics. The results showed that porosity has higher impact degree on gas diffusion and heat conduction than other microstructural characteristics. The combinations of microstructural parameters are optimized to achieve higher performance, with thermal conductivity and gas diffusivity increased by ≥139% and 62%, respectively. The prediction mathematical models are validated with the error ranging from 1% to 8%, which can predict transport properties and optimize the GDL microstructure accurately and rapidly.