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Modeling the liquid water transport in the gas diffusion layer for polymer electrolyte membrane fuel cells using a water path network

 
: Alink, R.; Gerteisen, D.

:

Energies 6 (2013), No.9, pp.4508-4530
ISSN: 1996-1073
English
Journal Article
Fraunhofer ISE ()
Energietechnik; Wasserstoff- und Brennstoffzellentechnologie; Brennstoffzellensysteme; fuel cell; management; GDL; Percolation; Model

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.

: http://publica.fraunhofer.de/documents/N-266966.html