Converting body heat into useable electricity

Imagine if your exercise clothes could generate enough electricity to power your workout gadgets. This could be a reality in a few years with the development of a flexible, self-charging, non-leaky battery (or thermocell) that could convert body heat into power for devices such as fitness trackers.

Traditional batteries are unsuitable for this use as they are inflexible, can leak, and need to be regularly recharged. Now researchers from Deakin University’s Institute for Frontier Materials have created a more sustainable option that works by harvesting moderate temperatures using a thermocell containing materials including cellulose—the key ingredient of paper.

Most thermocells contain liquid electrolytes, but the gel-like cellulose version prevents leakage and has the potential to contour to the body within the fabric of a garment.

“Working on the assumption wearable electronics have quite a low power demand, if we can connect lots of thermocells together—for example to cover a chest area—then we could conceivably power these devices,” says Deakin’s Associate Professor Jenny Pringle, Chief Investigator at the Australian Research Council Centre for Excellence for Electromaterials Science (ACES).

Thermocells make power from heat using two electrodes in contact with an electrolyte. As long as one electrode remains hot and the other cold, energy conversion is continuous. A valuable renewable energy option, they can recycle heat that would normally be wasted from sources like power stations and car exhausts.

Their continuous power production makes them ideal for use in remote locations like oil rigs or the outback, where replacing dead batteries is challenging. The next step is to link multiple cells together, using 3-D printing technologies at ACES, to achieve increased power using body heat.

This flexible thermocell developed by Deakin researchers has the potential to convert body heat into power for wearables. Credit: Dr Liyu Jin

For more information:

Institute for Frontier Materials, Deakin University
Robin Taylor
+61 3 5247 9255