Design and Fabrication of a Highly Integrated Flexible Thermoelectric Generator for Wearable Energy Harvesting

Flexible thermoelectric generators (F-TEGs) can harvest human body waste heat to provide continuous power for wearable electronic systems. However, under high integration density, manufacturing reliability and electrical interconnection stability remain challenging. To address these issues, a flexible thermoelectric generator integrating 100 thermoelectric p-type and n-type (TE PN) pairs is designed and fabricated in this work. A PET-based insulation and reinforcement structure is introduced into the PDMS substrate to mechanically constrain the thermoelectric legs, thereby improving structural stability under bending and wearable conditions. In addition, a two-stage gradient soldering process is proposed, in which solders with different melting points are sequentially used for bottom and top electrode connections, effectively preventing interconnection failure caused by solder remelting during large-scale integration. Experimental results show that the fabricated F-TEG achieves a maximum open-circuit voltage of 63.75mV and a peak output power of 163.92μW under simulated wearable conditions. Furthermore, by integrating an LTC3108-based energy management circuit, a complete self-powered sensing system is realized, enabling stable operation of an NTC thermistor sensor. These results demonstrate the feasibility of the proposed structural design and fabrication approach for wearable thermoelectric energy harvesting applications.