Joining of Half-Heusler and Bismuth Tellurides for Segmented Thermoelectric Generators

Pham Hoang Ngan*, Li Han, Dennis Valbjørn Christensen

*Corresponding author for this work

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Abstract

Segmented generators where the p- or n-type legs are formed by joining materials in series enables each material to operate in their most efficient temperature range. Here, we have fabricated and characterized segmented thermoelectric p- and n-type legs based on bismuth tellurides and half-Heusler alloys p-type Hf0.5Zr0.5CoSn0.2Sb0.8 and n-type Ti0.6Hf0.4NiSn. A two-step process was introduced to join the half-Heusler to the bismuth tellurides to form a segmented structure which was then characterized for its thermoelectric and structural properties. The output power generation was characterized under various hot side temperatures up to 873 K with the cold side fixed at 323 K. The stability of the joints was also investigated under heat treatment and thermal cycling. Under working temperatures from 323 K to 873 K, the obtained p-type segmented legs could deliver a power density of 0.3 W cm−2 and maximum voltage of 115 mV. With the same condition, the power density and the maximum voltage generated by n-type segmented leg were 0.25 W cm−2 and 102 mV. The area-specific contact resistances of the p- and n-type legs were 50 μΩ cm2 and 35 μΩ cm2, respectively. The output performance of each leg was ∼ 95% after 6 cycles from 323 K to 873 K.
Original languageEnglish
JournalJournal of Electronic Materials
Volume47
Issue number1
Pages (from-to)701-710
ISSN0361-5235
DOIs
Publication statusPublished - 2018

Keywords

  • Segmented thermoelectric generator
  • Thermoelectric joining
  • Bismuth telluride
  • Half-Heusler

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