Investigation of Current Density Effect on Water Vapor Concentration Profile along PEMFC Channels by TDLAS

Abstract

In this article, we applied tunable diode laser absorption spectroscopy (TDLAS) technique to measure variation of water vapor concentration in gas flow channels in an operating polymer electrolyte membrane fuel cell (PEMFC). TDLAS measurement offered an optical remote sensing to detect slight change of water vapor concentration, showing that electrochemical reaction in an operating PEMFC is not uniformly observed. We performed TDLAS measurement in gas flow channels in the anode and the cathode with variation of cell current density. We observed increase of water vapor concentration due to electrochemical reaction along the cathode channel as well as along the anode channel from the inlet, suggesting that generated water was exhausted through the both channels. It was also shown that less electrochemical reaction was observed in the upstream of the channel presumably due to less hydration of the membrane because of dry gas supply.

Keywords

• polymer electrolyte membrane fuel cell
• tunable diode laser absorption spectroscopy
• mass transfer
• electrochemical reaction