h i g h l i g h t sWe have studied the impact of cross-flow on gas-diffusion layer saturation levels. Cell saturation levels correlate strongly with the level of cross-flow rate. GDL saturation is lower at higher permeability. Water removal is more effective at higher channel-to-channel pressure gradients. Liquid-water transport mechanisms similar to breakthrough pressure phenomena exist for under-land area transport.
a b s t r a c tLiquid-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.
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