Design and performance of compact thermoelectric generators based on the extended three-dimensional thermal contact interface

Highlights: • Three-dimensional heat extensional structures are designed and simulated. • Heat extensional structures are integrated into compact thermoelectric generators. • The heat extensional structure makes heat flow transferred directionally. • Requirement of heat contact area is weakened by using heat extensional structures. • By using phase change material, output remains stable even if removing heat source. - Abstract: The thermal contact can influence the output performance of thermoelectric generators. However, in some applications, the heat source cannot afford an enough heating area for thermal contact. Therefore, compact thermoelectric generators based on optimized thermal contact interface should be designed and developed. In this paper, three-dimensional thermal extensional structures are designed, simulated, implemented and tested to optimize the thermal contact interface of compact thermoelectric generators. The result indicates that the compact thermoelectric generators based on three-dimensional thermal extensional structures can reduce the requirement of thermal contact area and make the heat flow directionally transferred to thermoelectric modules along the three-dimensional structure. In only 3600 mm² thermal contact area, the compact thermoelectric generators based on the three-dimensional structure can generate 5.58 V and 829 mW within 900 s.