Research of Factors Impacting Contact Resistance in Thermoelements

Thermoelectric generators are used as alternate power sources, among others purposes, for converting waste heat into electrical energy. In the design of thermoelectric generators, the problem arises of creating effective contacts for commutation legs in a thermoelement and sections made of various thermoelectric materials (TEMs) in a multisection thermoelement. In this study, the impact of contacts’ resistivity on the efficiency of thermoelements is shown in the modeling process using the developed technique. It is established that for the effective operation of thermoelements, the contact resistance should not exceed 10–8 Ω m2. Contact systems based on Ni–P and Co–P alloys are formed by the chemical deposition of metals from a solution of sodium hypophosphite on the branches of thermoelements. The surface of TEMs with a roughness of 300, 500, and 700 nm, which changes the true contact area of the formed contact systems, is studied. As a result of the measurements, it is established that with a surface roughness of 700 nm, thermoelement resistance decreases by 7.8% compared to contacts formed on a surface with a roughness of 300 nm, which increases the efficiency of thermoelements.