Numerical Investigation on the Electrical Performance Optimization of a Tubular Thermoelectric Generator for Waste Heat Recovery

In the waste heat utilization of automobile exhaust, the tubular thermoelectric generator (TTEG) has structural advantages compared with the flat-plate thermoelectric generator. A kind of TTEG that is composed of Bi0.5Sb1.5Te3 and Ni conical rings alternately attracts researchers' attention, and it generates electrical power based on the transverse thermoelectric effect. However, the electrical performance of such TTEG still needs to be improved for industrial utilization. In this study, the performance of TTEG was optimized through numerical simulation by changing its related structural parameters, including the tilt angle, the thickness of the conical ring, and the relative content of Ni. It is confirmed that the optimal tilt angle with maximum open-circuit voltage (OCV) is 27.3°; on this basis, it is found that a thinner thickness corresponds to a larger OCV; furthermore, when using a conical rings’ thickness of 0.75 mm and increasing the relative content of Ni in the Bi0.5Sb1.5Te3/Ni layered pair from 10% to 90%, the OCV decreases from 198mV to 105mV while the power density increases from 413W/m2 to 1350W/m2. It is believed that these findings can help to develop TTEGs with better electrical performance.

Fabrication of Skutterudite-Based Tubular Thermoelectric Generator

The conversion efficiency of the thermoelectric generator (TEG) is adversely affected by the quality of thermal contact between the module and the heat source. TEGs with the planar substrate are not suitable for the curved heat sources. Several attempts have been made to tackle this issue by fabricating complex tubular-shaped TEGs; however, all efforts have been limited to low-temperature applications. Furthermore, the electrical contact resistance of the module is critical to achieving a high-power output. In this work, we developed the tubular TEG with significantly low specific contact resistance by optimizing the joining process. We show that the modified resistance welding (MRW) performed by spark plasma sintering (SPS) is an efficient joining method for the fabrication of the TE module, with high feasibility and scalability. This research seeks to suggest important design rules to consider when fabricating TEGs.