Porous-Media Flow Fields for Polymer Electrolyte Fuel Cells I. Low Humidity Operation

This paper proposes an approach of channel development for polymer electrolyte fuel cells (PEFCs), i.e., to fill porous media in the channel region, allowing a simultaneous transport of gaseous reactant, liquid, heat, and electron through the porous-media channel. The added functions of heat/electron conductivity enhance the PEFC operation and the channel design flexibility. The porous media provide support over the diffusion media, thereby diminishing the concern of contact resistance under the channel. This paper, as the first part Of Our work on this channel configuration, focuses on heat and electron transport, excluding liquid water impact. A theoretical analysis of the characteristics of heat transfer and electronic conduction in fuel Cells and of the required pumping power for reactant flows is performed. Factors affecting the temperature variation, electronic ohmic loss, and pumping power consumption are explored. A three-dimensional model is developed, and numerical simulations are carried out to investigate the low humidity operation of fuel cells with both hollow and porous-media channel configurations. Simulation results demonstrate the enhanced characteristics of the heat and electronic current transport and the design flexibility for the proposed approach of porous-media channels. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3183781] All rights reserved.