Microscopic Monitoring of Local Temperature in the High Temperature Proton Exchange Membrane Fuel Cell Stack

The non-uniform distributions of internal temperature in a membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC) stack affect not only the reactions that occur in it, but also its performance and lifetime. In this work, micro-electro-mechanical systems (MEMS) are utilized to develop a new generation flexible micro temperature sensors for use in high-temperature electrochemical environments, and they were applied in high temperature fuel cell stack to measure the temperature. Polyimide foil (50 mu m) is selected as a substrate, and liquid polyimide is used as the protecting layer because of its high temperature resistance. The micro sensors were embedded in the cathode flow plate of HT-PEMFC stack (7 cells). The results demonstrate that they do not influence stack performance, and the calibration curves was measured by micro sensors are linearity and reliability. The curves of local temperature that were measured by micro sensors in the cell stack at the operating temperatures of 160 degrees C and at constant currents of 2, 10 and 20A are fairly consistent each other. The results show that the non-uniform of heat distributions, and its internal chemical reaction is more severe, resulting in a large temperature difference inner HT-PEMFC stack at a constant current of 20A.