Effect of interfacial thermal resistance on the performance of thermoelectric generator systems

Thermal resistance, though a key determinant of heat transfer in thermoelectric generator systems (TEGS), has received far less attention than its electrical counterpart. Here, we systematically uncover the role of interfacial thermal resistance of TEGS and quantify its impact on overall performance. By integrating thermoelectric transport theory with complex-variable methods, we establish a cross-dimensional model that captures the coupled thermal–electric behavior of the full system. Numerical analyses reveal that interfacial cracks critically degrade performance by elevating the thermal resistance at the device–source/sink junctions, whereas the impact of ceramic substrates on the performance of TEGS is limited (<3%) when their thickness is below 1 mm. Furthermore, we demonstrate that optimizing structural parameters, such as the leg height and cross-sectional area, can effectively counteract the detrimental influence of interfacial resistance. These findings highlight thermal resistance as a decisive, yet often overlooked, factor in TEGS design, and provide concrete guidelines for engineering high-efficiency thermoelectric systems.