Neutron radiography measurements of in-situ PEMFC liquid water saturation in 2D & 3D morphology gas diffusion layers

This work uses neutron radiography to examine the through-plane liquid water distribution of an operating polymer electrolyte membrane fuel cell (PEMFC) with a Sigracet SGL 25BC, a 235 gm thick, 2D straight fiber Gas Diffusion Layer (GDL). This work is performed for interdigitated flow fields at several cross flow rates, and a parallel flow field for comparison. The effect on pressure drop, effective permeability and liquid water saturation is determined. These results are compared to the previously studied Sigracet SGL 10BC, a 420 mu m thick, 3D "spaghetti" fiber GDL, for comparable cross flow rates. The SGL 25BC has a higher permeability than the SGL 10BC. The 25BC has a relatively constant saturation within the GDL, from 8% to 10%, which is higher than the 10BC saturation level, between 4 and 8%. This may indicate that 2D GDLs may be better suited to low pumping power situations, while 3D GDLs may be better suited to low liquid water situations. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.