Development of high efficiency segmented thermoelectric unicouples

Highly efficient, segmented thermoelectric unicouples incorporating advanced thermoelectric materials with superior thermoelectric figures of merit are currently being developed at the Jet Propulsion Laboratory (JPL). These segmented unicouples include a combination of state-of-the-art thermoelectric materials based on Bi₂Te₃ and novel p-type Zn₄Sb₃, p-type CeFe₄Sb₁₂-based alloys and n-type CoSb₃-based alloys developed at JPL. The maximum predicted thermal to electrical efficiency is about 15% for a hot-side temperature of 975K and a cold-side temperature of about 300K. Various segmentations have been explored and several unicouples have been fabricated and tested. The set-up for testing these unicouples is described in this paper and some of the tests results reported. I-V curves have been generated for selected unicouples. The results show that experimental thermal to electrical efficiency values close to theoretical predicted values have been measured.