UC San Diego

Wearable devices have seen tremendous growth in the recent decade in the consumer electronics space, which promotes research on their next-generation technologies and form factors for comprehensive physical, physiological and biochemical sensing, as well as high flexibility, conformity, and stretchability form factors toward more intimate human-machine interactions. However, the current development of wearable sensors and electronics has been hindered by the lack of efficient, autonomous economical, and practical energy systems. In particular, the power of wearable energy harvesters and the energy density of flexible energy storage devices cannot satisfy the demand of common wearable applications, which fundamentally challenges the concept of self-sustainable wearable devices. Aiming to address this challenge, in this dissertation, the concept of designing a microgrid-like wearable system was proposed, describing a new design concept for wearables that features reliable, practical, sustainable, and autonomous operation. The scenario-specific design considerations for eliminating the performance mismatch between components, minimizing individual disadvantaged characteristics, and maximizing the system’s energy reliability are discussed. Towards establishing high-performance microgrids on wearable platforms, advances in wearable bioenergy harvesters and batteries, along with implementations of the wearable microgrid concept into electronic textile and electronic skins platforms are presented. Such implementations include systematic integrations of energy harvesting, storage, and regulation modules into self-sustainable biosensing platforms, which operate independently on the human body without requiring external energy input. Separately, structural innovations to enable flexibility and stretchability in wearable electronics are introduced. Lastly, this dissertation summarizes existing challenges, theoretical limitations, and prospects of wearable microgrids for commercializing next-generation wearable electronics.