Geometric structural design for lead tellurium thermoelectric power generation application

High thermoelectric figure of merits have been achieved in lead telluride (PbTe) alloys recently, which are beneficial for future thermoelectric applications. In this study, a PbTe-based thermoelectric module is constructed by eight pairs of p-type PbTe–8%SrTe and n-type PbTe0.998I0.002–3%Sb legs with initial sizes of 3 × 3 × 3 mm3. The relationship between multiple geometric parameters and performance of module has been studied by finite-element simulation. The maximum output power (Pmax) of 7.6 W and efficiency (ηmax) of 15.3% have been achieved at ΔT = 500 K for ideal contacted PbTe-based thermoelectric module. Contact resistance must exist in experimental thermoelectric module, so it has been considered in simulation about geometry optimization. The cross-sectional area ratio (Ap/An) and height (H) show strong dependent relationship to optimize module performance. The larger Ap/An and relatively lower H are propitious to enhance the output power. Moreover, the efficiency is improved at an optimum Ap/An and relatively higher H. In this PbTe-based module, the Pmax = 4 W is achieved at Ap/An = 1.78 and H = 0.65 mm, while ηmax = 14% is achieved at Ap/An = 1.64 and H = 13 mm under ΔT = 500 K. The Pmax and ηmax are 20% and 65% larger than those of initial design sizes. Thus, geometric structure modification is a good way to improve the performance of thermoelectric applications.