Influence of different substrate materials on thermoelectric module with bulk legs

The thermoelectric effect is a promising source of renewable energy that can be used to interconvert thermal and electrical energy based on the Seebeck effect and Peltier effect. Conventional thermoelectric modules (CTEMs) cannot be bent to cover irregular surfaces such as the human body. Further, they are fragile and have expensive ceramic substrates. Hence, it is difficult to apply them, particularly in wearable devices. We demonstrate low-cost flexible thermoelectric modules (FTEMs) using flexible copper clad lamination as a substrate. The weight of an FTEM is only 0.43 g/cm2, which is approximately 2.5 times lower than that of a CTEM (1.06 g/cm2), even though the two devices use the same thermoelectric materials (n-type Bi2Se0.3Te2.7 and p-type Bi0.5Sb1.5Te3) fabricated using the same process. In addition, the output density of the FTEM is several tens of times higher than that of the CTEM with a temperature difference of 15 K. The FTEM also exhibits a cooler performance of 13.76%. This is particularly important for cases where the power density per unit area and weight are important, such as the applications of a thermoelectric module on human skin, automobiles, and spaceships. These results can be applied to improve the applications of thermoelectric modules. [Display omitted] •A high performance FTEM is developed.•FTEM achieved an output power per unit weight 11 times that of CTEM.•FTEM achieved the highest output power per pair of n-type and p-type legs of 0.7 mW.•FTEM can serve as guidance for developing novel wearable thermoelectric devices.