Optimal design for micro-thermoelectric generators using finite element analysis

To fabricate micro-thermoelectric generators (μTEGs), one must design the optimal structure of the μTEGs and achieve thermoelectric thin films with excellent properties. This study investigated the role of the dimensions of μTEGs, including the length of the thermoelements, thickness of the substrates, and cross-sectional area of the thermoelements. To evaluate the power generated by μTEGs and their efficiency, three-dimensional models of μTEGs were subjected to finite element analysis. Three-dimensional models are more accurate than one-dimensional models, since the directions of the heat flux and electrical current are not parallel in μTEGs. The governing equations were derived from the Seebeck effect and Peltier effect, which show thermoelectric energy conversion. In the simulation, the substrate, n-type material, and p-type material were assumed to be silicon, Bi2Te3, and Sb2Te3, respectively. We calculated the thermoelectric power generated by the μTEGs and their thermoelectric energy conversion efficiency. These two evaluation indices represent the performance of μTEGs. The thermoelectric simulation produced design guidelines for high-performance μTEGs.