Wearable Thermoelectric Generator for Sustainable Wearable Electronics

Wearable electronics are getting popular in daily life use in the forms of smartwatch, health care sensors, and more. The most noteworthy feature of these healthcare solutions is the measurement of biosignals of the user and the capability of simultaneously notifying the user with his or her current health state. However, the running time is limited by the energy capacity of the power storage device and hinders the sustainability of the device. In this work, a delicately designed wearable thermoelectric generator (WTEG) using the thermal resistance model collects its energy from a flexible, clean energy power source- the waste heat from a human being [1]. The mechanical flexibility was acquired from the folded flexible printed circuit board, and the device achieved 1 cm of diameter in curvature. An average power of 142 μW was produced from the WTEG and delivered into a voltage step-up converter; subsequently, the output voltage was converted from 34 mV to 2.1V (83 μW). The WTEG was integrated with a lithium-sulfur battery and was capable of charging the battery from the stepped-up power. Consuming balanced power consumption from both the battery and the generator, a commercial continuous glucose monitor (CGM) sensor was operated.<br/>[1] J. Kim, S. Khan, P. Wu, S. Park, H. Park, C. Yu and W. Kim, <i>Nano Energy</i> <b>79,</b> 105419 (2021)