A Review of Models for Water Droplet Detachment From the Gas Diffusion Layer-Gas Flow Channel Interface in PEMFCs

Understanding the fundamental mechanisms of water transport in proton exchange membrane fuel cells (PEMFCs) is necessary for effective management of product water. Among the transport mechanisms affecting the performance of PEMFCs are droplet formation, growth, and detachment at the gas diffusion layer (GDL)-gas flow channel interface. The presence of water droplets on the GDL blocks the access of gases to the reaction sites, increases channel pressure drop, and creates inconsistencies in the gas velocity fields down the channel length, all resulting in performance deterioration. In order to gain an insight into controlling droplets, an in-depth review of PEMFC water droplet detachment models published in the literature is presented here. Summaries of supporting data, modeling techniques, and conclusions are also presented.