High-Resolution Neutron Radiography Analysis of Proton Exchange Membrane Fuel Cells
Neutron radiography enables direct visualization and quantification of many water transport phenomena in proton exchange membrane fuel cells (PEMFCs). The advantage of the technique is that neutrons have a long penetration length through most common PEMFC materials of construction (with a 1/e length of about 11 cm for aluminum), while having a relatively short 1/e length for water (of order 3 mm). This sensitivity to water enables precise measurements via neutron radiography of the water content in an operating PEMFC that are primarily limited by systematic measurement uncertainties. Recent advances in the spatial resolution of neutron detector technology enable direct measurement of the through-plane water content. This new data provides gas diffusion layer water profiles that can serve as input or comparison data for a large class of one-dimensional PEMFC models. In this article, the technique of neutron radiography is discussed, with an emphasis on the quantitative image analysis of the through-plane water content.
KeywordsPoint Spread Function Proton Exchange Membrane Fuel Cell Fluence Rate Membrane Electrode Assembly Total Water Content
This work was supported by the US Department of Commerce, the NIST Ionizing Radiation Division, the Director’s office of NIST, the NIST Center for Neutron Research, and the Department of Energy interagency agreement No. DEAI01-01EE50660. The authors wish to acknowledge R. Mukundan, J. Spendelow, R. Borup, and J. Davey from Los Alamos National Laboratory for assistance with the water sorption measurements, and E. Baltic at the National Institute of Standards and Technology for technical support.
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