Optical measurement technique of water contents in polymer membrane for PEFCs

The feasibility of an optical technique is examined for the measurement of the membrane water content in polymer electrolyte fuel cells (PEFCs). Transmission of the infrared light of 1.92 mu m wavelength is used to measure the water content in the polymer electrolyte membrane. A calibration procedure is examined, and the technique is applied for the transient measurement of a Nafion membrane that gives the value of water diffusion coefficient, consistent with previous reports. The technique is then applied to an operating PEFC to show its applicability for in situ measurement.