A quick and efficient measurement technique for performance evaluation of thermoelectric materials

Evaluating the performance of thermoelectric (TE) materials is critical for developing an efficient long lasting thermoelectric generator. Various parameters like resistance, TE power, TE efficiency as a function of temperature and time play an important role in developing and optimizing TE materials and legs. If one needs to evaluate the TE legs for performance or contact metallization optimization, study of a brazed or packaged device everytime could prove to be an expensive, time consuming process especially as a quick intermediate qualification. In this work, a simple approach that uses eutectic Gallium Indium (Ga-In) paste as a metallizing substitute with good electrical/thermal contact is employed which also avoids the need for brazing/welding (or any permanent joining) and provides a reliable platform for a quick leg qualification. Using open circuit voltage (V_oc) and device voltage (V_d), one can evaluate important TE quantities like peak power, material resistance changes, peak current and power versus current characteristics to understand the leg performance. The proposed approach is successfully demonstrated with three different TE material systems namely Bismuth Telluride, Skutterudite and Half Heusler systems.