Thermal and thermal stress analysis of a thin-film thermoelectric cooler under the influence of the Thomson effect

Abstract

This work has two parts. The first part details the thermal analysis of a thin-film thermoelectric cooler under the influence of the Thomson heating, the Joule heating, and the Fourier's heat conduction. A constant Thomson coefficient, instead of traditionally a constant Seebeck coefficient, is assumed. The influence of the Thomson effect on the cooling power, the achievable temperature difference and the optimum operating current density is then explored. It is found that the Joule's heat and the conduction heat flowing to the cold junction can be significantly reduced if thermoelectric materials with properly designed Thomson coefficients are employed. A modified thermal conductance and a modified electric resistance are resulted. The second part of this paper details the analysis of the thermal stresses existing in the layered structure and induced by the temperature difference via a non-coupled thermal elastic theory. The results provide a preliminary knowledge to judge whether the thin-film structure is destroyed by the thermal stresses or not, especially by the shear stresses between adjacent layers.