In-Plane Temperature Measurement and Water Droplet Detection of a Proton Exchange Membrane Fuel Cell Using Phosphor Thermometry: Initial Development

Thermal behavior inside fuel cells plays a significant role in fuel cell performance and durability. Internal temperatures of a proton exchange membrane (PEM) fuel cell govern the ionic conductivities of the polymer electrolyte, influence the reaction rate at the electrodes, and control the water vapor pressure inside the cell. Temperature gradients also influence mass transport due to phase-change-induced flow and thermo-osmosis. Many techniques developed for studying in situ temperatures such as thermocouples sensors either disrupt fuel cell performance or carry unknown accuracy. The objectives of this research are to design and construct thermal sensors based on the principles of the lifetime-decay method of phosphor thermometry to measure temperatures of cathode gas diffusion layer inside a PEM fuel cell with minimal invasion. The sensors also demonstrate the possibility of detecting water droplet formation in the flow channels qualitatively making it possible to experimentally relate local temperature distribution with liquid water formation. Further development is required in order to increase the accuracy and utility of the sensors before conclusive testing can be performed.