Automotive exhaust thermoelectric generators: Current status, challenges and future prospects

The automobile has become an integral part of the modern life. It, however, also triggers off a string of problems such as energy shortage and environmental pollution. As a static power generation technology, thermoelectricity has been widely used to recover the redundant exhaust heat, forming automotive exhaust thermoelectric generators (AETEGs). In this paper, a comprehensive review on AETEGs was firstly carried out from the perspective of nationality where research objects, conditions, main features and important outcomes for each study were highlighted. The feasibility of AETEGs has been demonstrated and a considerable progress has been made. However, no commercial automobile has equipped with AETEGs. Following that, the bottlenecks and challenges associated with various aspects such as material, geometry, heat transfer, space and weight, were pointed out by comparing research status and objects, and the strategies to cope with were reviewed. Finally, a research roadmap from material level, to component level and to whole device level was proposed and eleven promising research directions were refined to accelerate the application progress. In summary, there is still a long road before commercial applications of AETEGs and considerable effort should be poured into sustainedly. This review intends to guide the future study to a large extent.