Effects of Humidification on the Membrane Electrode Assembly of Proton Exchange Membrane Fuel Cells at Relatively High Cell Temperatures

✍ Scribed by K.-M. Yin; C.-P. Chang

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 760 KB
• Volume: 11
• Category: Article
• ISSN: 1615-6846
• DOI: 10.1002/fuce.201100041

✦ Synopsis

Abstract

This study focuses on the performances of proton exchange membrane fuel cells (PEMFCs) at 80 and 90 °C with feeds of varying degrees of humidification. The results show that ohmic resistance of the solid electrolyte decreases as the current density is raised because of the back diffusion of liquid water, that is, generated in the cathode active layer. On the other hand, severe liquid water accumulation occurs at high current densities, which hinders the oxygen transport in the cathode gas diffusion layer (GDL) resulting in the Nernst diffusion limitation. The polarization measurement correlates well with the electrochemical impedance spectroscopy (EIS) analysis. The effects of humidification on membrane hydration, activity in the catalyst layer, and oxygen diffusion over‐potential in the cathode GDL are elucidated with the proposed equivalent circuit model at varying operating current densities.