Numerical modeling and optimization of the segmented PbTe-BiTe-based thermoelectric leg

摘要

The segmentation of thermoelectric materials is an efficient way to improve the overall efficiency of a thermoelectric leg. However, this improvement can be obtained only when the constituent materials are appropriately proportioned. A numerical model is established for optimizing the performance of the segmented leg based on the coupled equations of the thermoelectric with temperature-dependent material properties. The numerical model can be used to determine the optimal length ratio and current density for the segmented leg. On the basis of the numerical model, the performance optimization of the K_(0.02)Pb_(0.98)Te/Bi_(0.3)Sb_(1.7)Te_3 segmented leg is performed, and its maximum conversion efficiency and maximum output power are calculated. Results show that the reasonable length ratio design of the thermoelectric leg can take a full advantage of the characteristics of the thermoelectric materials, and it can effectively improve the conversion efficiency and the electrical output power. In addition, the numerical model is validated by finite-element simulated results and experimental results.