Thermoelectric performance and stress analysis on wearable thermoelectric generator under bending load

With the growing popularity of flexible micro-electronics and health-monitoring sensors, wearable flexible thermoelectric generators (TEGs) are receiving attention due to their ability to convert body heat into electricity. In this study, a three-dimensional model of wearable TEGs encapsulated in the PDMS material is established based on the nonlinearly coupled thermoelectric transport constitutive law, large deformation of materials, and the 3-parameter Mooney-Rivlin nonlinear hyperelastic constitutive law of polydimethylsiloxane (PDMS) material. The thermoelectric performance and mechanical reliability of the wearable TEG are investigated under the bending load by employing finite element method. A comparison between numerical results and experimental data is conducted for validation of the model. Effects of the leg shape, filling factor and height of the legs are examined on the thermoelectric performance and mechanical reliability of the wearable TEGs. The optimized dimensions of wearable thermoelectric generators are obtained and analyzed. The results show that, thermoelectric performance and flexibility of the wearable TEG can be enhanced by increasing the number of thermocouples in the TEG. The results of this paper provide useful suggestions for the structural design and practical application of wearable TEGs encapsulated in PDMS materials.