Performance Analysis and Structural Improvement of a Thermoelectric Cooling Assembly Under Extreme Thermo-Mechanical Conditions

Thermoelectric cooling assemblies (TECAs) employed in aerospace and vehicle-mounted launch equipment are required to maintain efficient thermal management while withstanding severe thermo-mechanical environments. However, the coupled effects of thermal gradients, assembly preload, and mechanical impact may induce significant stress concentration and compromise the structural reliability of TECAs. In this study, a multiphysics finite element model is established to investigate the cooling performance and impact resistance of a TECA. The thermal performance predicted by the numerical model is validated experimentally, with the predicted temperature difference showing good agreement with the measured results. The effects of bolt preload and ambient temperature on the cooling characteristics are systematically analyzed. Furthermore, the stress responses of critical components under different impact directions and pulse waveforms are investigated. The results indicate that increasing bolt preload can effectively enhance cooling performance, while excessive preload provides diminishing benefits. The ambient temperature significantly affects the optimal operating current and cooling capacity due to the temperature-dependent TE properties. Under mechanical impact, the +Z-direction impact and the half-sine pulse cause the highest predicted stress response, resulting in maximum stresses of 363.1 MPa and 127.4 MPa in the ceramic substrates and the TE legs, respectively. To mitigate impact-induced stress, three structural improvement schemes, including bolt layout modification, limiting frame, and thermal pads, are proposed. Among them, a 0.5 mm thermally conductive silicone pad achieves the largest stress reduction, decreasing the maximum stresses of the ceramic substrate and thermoelectric legs by 37.4% and 16.0%, respectively, with an 11.1% reduction in cooling capacity. The PI limiting frame reduces the maximum stresses of the ceramic substrate and thermoelectric legs by 23.4% and 20.5%, respectively, while limiting the cooling capacity degradation to 6.6%. This work provides quantitative guidance for the stress-oriented structural design of TECAs in complex mechanical environments.