Optimization of the Mechanical and Electrical Performance of a Thermoelectric Module

Finite element (FE) simulation of a thermoelectric (TE) module was conducted to optimize its geometrical dimensions in terms of mechanical reliability and performance. The TE module consisted of bismuth telluride, nand p-type legs. The geometrical dimensions of the module, i.e. leg length and leg cross-sectional area, were varied and the corresponding maximum thermal stress, output power and efficiency of the module was obtained. The optimal design of the module was then suggested based on minimizing the thermal stresses and maximizing the performance, i.e. power and efficiency. The optimal dimensions at a maximum von Mises stress of 75 MPa was a leg length of 2-2.5 mm, a leg width of 1.5-2 mm, which resulted in an efficiency of 7.2. Finally, the influence of solders, i.e. solder material between the leg, the interconnector and the top ceramic layer, on the induced thermal stresses and the module performance was investigated. The results revealed that transition from elastic to plastic deformation in the solder decreases the induced thermal stresses significantly. Moreover, beyond the elastic limit the stress magnitude is very much dependent on the magnitude and mechanism of the plastic deformation in the module. The present study provides a basis for unique and new optimization scheme of the TE modules in terms of endurance and performance.