Improved Extruded Thermoelectric Materials

Abstract

Using improved extrusion technology for bismuth antimony tellurides, RMT has developed new extruded thermoelectric materials (TEM) with increased thermoelectric figure of merit (Z). The p-type materials exhibit maximum Z values of 3.28 × 10⁻³ K⁻¹ to 3.32 × 10⁻³ K⁻¹ in the electrical conductivity range from 900 Ω⁻¹ cm⁻¹ to 1100 Ω⁻¹ cm⁻¹. The corresponding Z values for the n-type materials lie in the similar range of 2.82 × 10⁻³ K⁻¹ to 2.87 × 10⁻³ K⁻¹. The wide variation of the electrical conductivity allows their application in miniature thermoelectric coolers (TEC) for cooling and temperature stabilization in the temperature range from 225 K to 350 K. Using the improved TEM, miniature TECs with pellet height of 0.3 mm were manufactured and tested; the test results showed that the maximum temperature difference was 2 K to 3 K higher while the energy consumption was 10% to 15% lower than for standard RMT miniature TEC.