Available online at https://doi.org/10.1016/j.jpowsour.2015.05.016
Santamaria, Anthony, Maxwell K. Becton, Nathanial J. Cooper, Adam Z. Weber, Jae Wan Park (2015) Effect of Cross-Flow on PEFC Liquid-Water Distribution: An In-Situ High-Resolution Neutron Radiography Study. Journal of Power Sources 293, 162 - 169
Liquid-water management in polymer-electrolyte fuel cells (PEFCs) remains an area of ongoing research. To enhance water removal, certain flow-fields induce cross-flow, or flow through the gas-diffusion layer (GDL) via channel-to-channel pressure differences. While beneficial to water removal, cross-flow comes at the cost of higher pumping pressures and may lead to membrane dehydration and other deleterious issues. This paper examines the impact of cross-flow on component saturation levels as determined through in-plane high-resolution neutron radiography. Various humidities and operating conditions are examined, and the results demonstrate that cell saturation levels correlate strongly with the level of cross-flow rate, and lower GDL saturation levels are found to correlate with an increase in permeability at higher flow rates. Effective water removal is found to occur at channel-to-channel pressure gradients greater than the measured breakthrough pressure of the GDL, evidence that similar liquid-water transport mechanisms exist for under-land area transport as in transverse GDL flow.
Keywords: Fuel cells; Neutron radiography; Permeability; Liquid-water saturation; Gas-diffusion layer; Cross-flow; Breakthrough pressure