Practical evaluation of electrical contact resistance of thermoelectric legs at high operation temperature

Abstract

The evaluation of the electrical contact resistances of thermoelectric legs is important to predict the performance of thermoelectric modules. Thermoelectric modules can be divided into devices operating at high and low temperatures. In the former, the electrical contact resistance can change with temperature. However, many research groups have only analyzed the electrical contact resistance at mainly room temperature. In this study, an electrical contact resistance measurement system for thermoelectric legs of thermoelectric devices at high operating temperature (400 to 600 °C) is proposed, which provides a more accurate performance prediction. The measurement conditions are determined according to the amplitude and frequency of the current to minimize the measurement errors caused by the Peltier effect. Skutterudite thermoelectric legs with a Ti metallization layer are used to understand the specific contact resistance at high temperatures. Based on the obtained results, the thermoelectric module is analyzed through a simulation to investigate the power outputs with the specific contact resistances at both room and high operation temperatures.