A general design framework of flexible thermoelectric devices bridging power requirements for wearable electronics

Abstract

Wearable thermoelectric generators (WTEGs) promise sustainable power for wearable electronics with various strategies proposed for on-body applications. However, there is still a lack of power-demand-oriented system design that directly provides WTEG configurations tailored to targeted end electronics, resulting in sufficient power only under extreme ambience. To address this, we propose a straightforward, power-demand-oriented design framework for WTEGs that bridges the power requirements of end electronics. As we input the properties of thermoelectric materials, specific operational conditions (temperature and heat transfer coefficient), expected power output and required flexibility, the design framework can directly determine the geometric features of thermoelectric pillars and fill factor. The effectiveness has been widely verified using data from the literature, showing a mean absolute deviation of 7.1 %. This framework shows high working efficiency and significantly shortens the design process, which is the very first ever-reported design tool for WTEGs. As a case, we use the framework and design a skin-conformable thermoelectric textile (TET) with optimal structure configurations and enhanced heat transfer capabilities, achieving a high normalized power density of 4.48 μW cm⁻² K⁻². As expected, the TET, with a maximum power density of 231 μW cm⁻² successfully powered a series of on-body electronics when attached to the forearm at a breezy ambient temperature of ∼283 K. On the other hand, the TET exhibits a cooling effect of 5.73 K. Our work provides a thermal design guide for WTEGs, shedding light on the direct connection between WTEG configurations and end electronics.