Imagine never having to charge your smart watch again.
Researchers at North Carolina State University have created a wearable device that produces electricity from body heat using a flexible thermoelectric generator. This breakthrough technology could not only make wearable devices more convenient, but save on the energy required to charge them.
If you don’t already own a piece of wearable technology, you’ve probably shaken hands with someone who does. Smart watches and fitness trackers are catching up to smart phones as a must-have technology. But these nifty devices aren’t without disadvantages, like the need to charge them at least a few times a week.
With thermoelectric generator technology, your Fitbit or Apple Watch could run continuously without needing to be plugged in. Such convenience has the potential to further integrate this technology into our daily lives.
But it’s not all about fun toys like smart watches and fitness trackers. The team at North Carolina University has its eyes on the market for medical devices, like heart monitors and environmental sensors. Thermoelectric generators would eliminate the need to remove these devices to charge them, making the technology safer and more reliable for patients.
Last year, North Carolina University produced its first experimental prototype for a wearable thermoelectric generator. It was a small, body-conforming patch that generated the most heat when worn on the upper arm.
Though it was lightweight, the patch was rigid and uncomfortable to wear. That’s why researchers began working on a flexible device instead.
“We wanted to design a flexible thermoelectric harvester that does not compromise on the material quality of rigid devices yet provides similar or better efficiency,” said Mehmet Ozturk, a professor of electrical and computer engineering at the university. “Using rigid devices is not the best option when you consider a number of different factors.”
The new design uses a non-toxic metal alloy called EGaln to connect the thermoelectric elements in the device. The allow has lower resistance and allows for greater power generation. It also makes the device “self-healing”, as Professor Ozturk explains.
“Using liquid metal also adds a self-healing function: If a connection is broken, the liquid metal will reconnect to make the device work efficiently again. Rigid devices are not able to heal themselves.”
As wearable devices grow in popularity, we will continue to consume more and more energy charging them. Having a built-in body heat generator could substantially reduce the carbon footprint of these devices.