Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Abstract

In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

Liquid water in cathode gas diffusion layers of PEM fuel cells: Identification of various pore filling regimes from pore network simulations

“…No detailed comparisons with experimental results were presented. Although somewhat different and not exactly a PNM, the model presented in [33] can be also mentioned here since it seems that it combines both injection in liquid phase and condensation.…”

A Review on Cold Start of Proton Exchange Membrane Fuel Cells

“…The phase change between ice and vapor arises when T local is lower than T f , then vapor will desublimate into ice when the vapor pressure is higher than P sat , but the reverse won't happen under the operating conditions in PEMFCs [7]. Alink et al [33] developed a numerical model to study the liquid water transport in the GDL for PEMFCs with water path networks. Pasaogullari et al [34,35] studied the transport of liquid water in both hydrophilic and hydrophobic diffusion media in GDL with a one-dimensional analytical model and drew the conclusion that capillary transport is the dominant transport process to remove water from flooded GDLs.…”

Coupled continuum and condensation–evaporation pore network model of the cathode in polymer-electrolyte fuel cell

“…A condensation algorithm is also presented in Refs. [20,21] and the conclusion is that condensation has a significant influence of the liquid distribution. However, the model is different from the one proposed in Ref.…”