Speaker
Description
Thermoelectric generators (TEG’s) are devices able of converting waste heat into usable electricity through the Seebeck effect, which makes them very attractive to fight against global warming. To develop novel TEG’s, made of more sustainable, cheap, and less toxic materials, many crucial aspects need to be considered. The nature and quality of the interface between the TE materials and the solders/electric connectors used on the device are some of them. High electrical and thermal interfacial resistivity ruin the devices performance, even if materials with good thermoelectric properties are used.
In this work, several jointing fabrication techniques are explored to evaluate the optimal method to connect manganese doped tetrahedrite legs to copper contacts. To build the thermoelectric legs, Cu11Mn1Sb4S13 tetrahedrites were synthesized by solid state reaction and hot-pressing techniques. The materials where shaped into cubes and connected to copper electrodes manually and using cold and hot-pressing techniques. Nickel paint, water-based Ag paint, and a Zn-Al5wt% solder, were used for materials jointing, being also explored the possibility of contact fabrication without the use of any paints or solders.
The contact resistance of the legs/contacts joining was measured on a custom-made system based on a three-contact pulsed current method and computer simulations using the COMSOL Multiphysics program were made. The simulations consisted of a thermoelectric couple made by a tetrahedrite leg (p-type semiconductor), and a magnesium silicide leg (n-type semiconductor). A 603 K thermal gradient and electrical insulation conditions were applied to an optimized model [1]. For the simulations, some of the measured contact resistance values were used and the impact on the performance of the thermoelectric couple was evaluated by obtaining the respective I-V and I-P curves.
