Influence of Leg Geometry on the Performance of Bi2Te3 Thermoelectric Generators

Abstract

This study utilized COMSOL Multiphysics to simulate the performance of a thermoelectric module (TEM) made by alumina (Al2O3), copper (Cu), and bismuth telluride (Bi2Te3) materials, specifically exploring different leg geometries. The TEM design had Al2O3 for insulation, Cu for conducting, and Bi2Te3 for TE legs between the Cu layers. Investigated the influence of square and rectangular TE legs with heights of 2.0 mm, 2.75 mm, and 3.5 mm on critical parameters, including temperature gradient, electric potential, normalized current density, and total internal energy within the TEM. Furthermore, the impact of varying thicknesses in the insulator and conductor layers of the TEM was explored. The results consistently demonstrated that the square leg geometry, particularly when configured with a height of 2.75 mm, outperformed other leg geometries. Consequently, it is recommend the adoption of square-shaped Bi2Te3 TEM, measuring 1 mm × 1 mm × 2.75 mm, with a 0.50 mm Al2O3 thickness and 0.125 mm Cu thickness during the manufacturing process. Study how factors like the Seebeck coefficient (S), thermal conductivity (k), and electrical conductivity (σ) affect temperature differences in the leg design of TE devices. At lower temperatures, modeling reveals lower electrical conductivity and enhanced thermal conductivity, highlighting the significance of S = ± 2.37×10⁻⁴ V/K. This illustrates the high potential of TEM for applications in thermoelectric generator (TEG) manufacturing.