Powering wearable devices by human heat with highly efficient, flexible, bio-inspired generators

Introduction

Self-powered wearable electronic devices will be key technologies for future portable electronic systems in the Internet of Everything (IoE). However, their potential is limited because of their need for batteries, which are bulky, heavy, lack the flexibility to be adapted to the human body, and require frequent recharging or replacement. In that context, flexible thermoelectric generators (TEGs) that capture the body’s heat and convert it into electrical energy are a potentially promising and sustainable alternative.

Current Challenges

Nevertheless, commercial TEGs are produced on rigid substrates, so they cannot adapt to the human body. The current solution proposed is to produce them on flexible polymeric substrates, which unfortunately have low thermal conductivity. As a result, the active power-generating layer must be very thick, and it is not efficient enough.

Additional Issues

Additional problems include:

• Poor electrical and thermal contacts
• Non-availability of commercial low input power DC-DC converters

Project Objectives

POWERbyU seeks to merge four scientifically disruptive concepts to achieve the technological breakthrough of getting flexible and efficient enough flexible TEGs:

1. Generate not yet existing bio-inspired, nano-engineered, flexible polymeric substrates with very high thermal conductivities in the out-of-plane direction.
2. Generate a bio-inspired patterning of the polymer surface to drive the thermal flow from perpendicular to parallel to the energy generation layer. This is important because then, the important length to avoid thermalization is not thickness but lateral size.
3. Produce world-record efficient quasi-2D thermoelectric layers generated by a unique deposition tool.
4. Develop new solutions for the commercial DC-DC converter.

By assembling all the previous concepts, I expect a novel high-efficiency, flexible TEG able to generate tens of mW/cm², enough to self-power wearable devices.

Potential Applications

Additional fields of application could include:

• Thermal management in buildings
• Textiles
• Packaging