Performance analysis and optimization of a double X-type thermoelectric generator with a lateral hollow structure

This study proposes a novel lateral double X-type thermoelectric generator (TEG) structure, in which the geometry of the thermoelectric semiconductor is optimized to simultaneously regulate electrical and thermal transport properties. Based on a coupled multiphysics numerical simulation, the influence mechanism of lateral hollowing on TEG performance is systematically investigated. The results indicate that, compared to traditional TEGs with the same thermoelectric material volume, increasing the hollowing degree significantly enhances both output power and efficiency when the load resistance exceeds 20 mΩ. A moderate draft angle enhances the temperature gradient, whereas an excessively large angle leads to performance degradation under low load conditions. Specifically, in Case 1 at θ = 30°, the maximum efficiency improvement reaches 52.27 %, but a 24.85 % reduction is observed under low load. In addition, the thermoelectric semiconductor height has a distinct impact on performance: a lower height (H = 1.2 mm) favors power output (improvement of 10.68 %), while a higher structure (H = 2.0 mm) enhances efficiency (up to 25.80 %). It is noteworthy that geometric variations significantly influence thermal stress distribution. This work provides a new design strategy for developing TEGs with both high performance and mechanical reliability.