In situ optical diagnostics for measurements of water vapor partial pressure in a PEM fuel cell

Saptarshi Basu, Hang Xu, Michael W. Renfro, Baki M. Cetegen

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


A fiber optic coupled diode laser sensor has been constructed for in situ measurements of water vapor partial pressure in active proton-exchange membrane (PEM) fuel cell systems. The bipolar plate of a prototypical PEM fuel cell was modified to allow for transmission of a near infrared laser beam through the flow channels on either the fuel or oxidizer side of its membrane-electrode assembly. The laser wavelength was scanned over several water rotational and vibrational transitions and the light absorption was detected by measuring the transmitted laser power through the device. The intensity and line shape of the measured transition was used to extract path-averaged values for the water vapor partial pressure. Measurements were initially taken in a non-operating cell with known temperature and humidity input gas streams to calibrate and test the optical device. A technique for rapid determination of the water partial pressure was developed. The optical technique is applicable over a significant temperature and humidity operating range of a PEM fuel cell. The measurement technique was applied to an operating PEM fuel cell system to examine the effects of incoming gas humidity and load on the water vapor partial pressure variation in one of the flow channels.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalJournal of Fuel Cell Science and Technology
Issue number1
StatePublished - Feb 2006


  • Absorption spectroscopy
  • In situ measurements
  • Laser diagnostics
  • PEM fuel cells

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Mechanics of Materials
  • Mechanical Engineering


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