In-Situ Temperature Measurement on Cathode GDL in a PEMFC Using an Optical Fiber Temperature Sensor

Thermal management has been known to play a key role in all aspects of proton exchange membrane fuel cell (PEMFC) performance including transport of gaseous and liquid species. However, it remains a difficult topic to study due to a lack of experimental techniques as they are limited by the PEMFC internal environment and geometry. In this work a non-invasive optical temperature sensor, based on the principles of phosphor thermometry, is presented to measure the in situ temperature on the surface of a gas diffusion layer (GDL) in a PEMFC. Unlike most common experimental temperature measurement methods, the sensor was shown to have no detectable influence on PEMFC performance or local mass transport. The sensor was found to have a relatively high degree of accuracy with a mean temperature difference of 0.110°C with a high accuracy RTD and response time of 0.5 seconds. Temperature data from an experimental fuel cell is presented showing the utility of the sensor during static and transient operation. Results also suggest a strong coupling between local temperature and liquid water saturation.