Effect of geometric dimensions on thermoelectric and mechanical performance for Mg2Si-based thermoelectric unicouple

The generating efficiency of thermoelectric generation (TEG) depends not only on the thermoelectric (TE) performance of TE device, but also on its mechanical performance. And choosing suitable TE materials and geometric dimension can improve the working performance of TE device. Mg2Si is one of the most promising TE materials in the medium temperature range, and Mg2Si-based TE devices have broad application prospects. In this paper, a three-dimensional finite model of the Mg2Si-based TE unicouple used for recovering vehicle exhaust waste heat is constructed for the performance analysis. The TE performance and mechanical performance of the Mg2Si-based TE unicouple under the influence of different geometric dimensions are investigated, respectively. The curves of the output power, the power conversion efficiency and the thermal stress distribution varying with different geometric dimensions are discussed in detail. The calculated result would be helpful for further understanding of the TE and mechanical properties of the Mg2Si-based TE unicouple, and it can also provide guidance for further strength check and optimum geometric design of TE unicouples in general.