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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Structural Optimization of Porous Flow Fields to Improve Water Management Ability of PEFC

Get access (open in a dialog) DOI: 10.1615/IHTC15.pmd.009116
pages 6773-6787

Abstract

Polymer electrolyte membrane fuel cells (PEFCs) with porous flow fields can be stably operated at higher current density conditions compared with the cells with conventional types of flow fields, however the key structural parameters determining water transport has not been identified. This study explores an improved structure of porous flow fields for PEFCs especially focusing on the water transport mechanism. By using porous flow fields with different porosities and fiber diameters, the influences of these structural parameters on the cell performance are investigated. In addition, the influences of these structural parameters on liquid water transport are investigated by observing the water flows passing through the porous flow fields. Further, the performance and stability of the cell with a cathode side porous flow field coated by a hydrophobic micro porous layer (MPL) and without a cathode side diffusion layer (GDL) are investigated to examine the effects of removing GDLs from cells. We found that porous flow fields with the higher porosity and the smaller fiber diameter can improve the cell performance. The higher porosity induces superior transport of water in the inplane direction, and the smaller fiber diameter induces superior transport of water in the through-plane direction. We also found that a cell with an MPL coated porous flow field on the cathode side can be operated with a 0.9 A/cm2 current density condition even without a cathode side GDL.