Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

P. Scharfer
University of Karlsruhe (TH), Karlsruhe, Germany

J. Krenn
University of Karlsruhe (TH), Karlsruhe, Germany

W. Schabel
University of Karlsruhe (TH), Karlsruhe, Germany

M. Kind
University of Karlsruhe (TH), Karlsruhe, Germany

Direct methanol fuel cells (DMFCs) are capable of utilising a liquid fuel directly into electric energy. They are therefore an interesting alternative for battery systems in mobile applications. The electric efficiency of DMFCs is currently around 40 % and therewith clearly below the efficiency of hydrogen fuel cells (60 %). This lack of efficiency is mainly caused by the so-called Methanol Crossover, an undesired methanol permeation through the proton conducting polymer membrane within the cell. In this contribution, the Inverse-Micro-Raman-Spectroscopy (IMRS) was applied to investigate the mass transport of methanol within Nafion^® 115-membranes for DMFCs. The membranes were spanned across a reservoir filled with a mixture of methanol and water and were in contact with conditioned air on top. By means of IMRS, the solvent concentration profiles at different experimental conditions were measured and compared to simulation results. The measured methanol concentration profiles changed with air velocity across the membrane and were dependent on the composition of the methanol-water-mixture underneath. These influences could be described by a simulation, based on literature data, with only small deviations.

EXP-12 pages DOI: 10.1615/IHTC13.p21.120 Download article

Article price - $35.00

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