THE EFFECT OF FIBER ORIENTATION AND MULTIPLE PAPERMAKING ON RECONSTRUCTION AND INTERNAL MASS TRANSPORT OF A CARBON PAPER

Carbon paper is often used as the current collector and gas diffusion layer in lithium-air batteries and fuel cells, and its internal morphology greatly influences the diffusion of materials. Relevant literature shows that carbon paper is an anisotropic porous medium, and the distribution of carbon fiberrs has a regular pattern. The difference in fiber distribution angle leads to a difference in internal morphology, which affects the transport properties and anisotropy of carbon paper. In this paper, a numerical method that considers fiber placement angle range for reconstructing carbon paper is proposed, and some geometric models of carbon paper are reconstructed. The pore size distribution and transport properties of geometric model are calculated and studied by improved thirteen direction average method and lattice Boltzmann method. The effects of carbon fiber distribution angle and multiple papermaking on the transport properties and anisotropy coefficient of carbon paper are studied. Results with an increase in dφ include an increase in the average effective diffusion coefficient in through-plane direction and a decrease in the anisotropy coefficient and average effective diffusion coefficient in in-plane direction. Double papermaking can improve the average anisotropy coefficient of carbon paper and the average effective diffusion coefficient in in-plane direction and reduce the average effective diffusion coefficient in through-plane direction. However, the influence of papermaking times (layer number > 1) on transport properties of carbon paper is insignificant.