Determination of Silicide-Based Thermoelectric Modules Efficiency

In this work, thermoelectric module (TEM) prototypes based on magnesium silicide and higher manganese silicide were developed (Fig. 1). Different designs of modules and different brazing materials were tested, with a focus on device feasibility and reliability. Contact resistivity measurement of the silicide/metal brazed electrode and finite element analysis of thermal induced stress were also performed, to guide the design of TE modules. The electrical power and the efficiency were evaluated with a specially developed testing system. [1] Furthermore, infrared thermography was used as a diagnostic tool to investigate internal thermal and electrical interfaces. The testing apparatus (Fig. 1) is based on the heat flow meter method at the cold side of the module and it is conceived to test TE modules (single or in cascade) with a footprint up to 60x60 mm2. The system works from room temperature up to about 900 K, under vacuum or inert atmosphere. Electrical characterizations were performed both in a steady state condition, and with fast pulsed current-voltage (I-V) measurements, thus without disturbing the measurement, providing high reliability on the efficiency determination. Measurements of commercial modules and of silicide-based module prototypes are presented.