How New Tech Could Turn You Into a Human Battery

A new wearable device could one day transform your body into a human battery.

Researchers have invented a gadget stretchy enough that you can wear it like a ring, a bracelet, or any other accessory that touches your skin. It works by tapping into a person’s natural heat—employing thermoelectric generators to convert the body’s internal temperature into electricity. The device is part of a growing number of new battery technologies that could jump-start personal technology. 

"Chips are becoming more efficient, but making it through the day without charging your phone is unlikely," Andrew Fox, founder of electric scooter charging company Charge, said in an email interview.

"It will take a significant amount of time before we can get two or three days life out of our phones, but there are signs of promise." 

Convenient but Low Power

The new battery device, developed by researchers at the University of Colorado Boulder, can generate about 1 volt of energy for every square centimeter of skin space—less voltage per area than what most existing batteries provide, but still enough to power electronics like watches or fitness trackers. 

Previous designs have flirted with thermoelectric wearable devices, but the new gizmo is stretchy, can heal itself when damaged, and is fully recyclable, according to a recent paper published by the researchers. 

"In the future, we want to be able to power your wearable electronics without having to include a battery," Jianliang Xiao, senior author of the new paper and an associate professor in the Department of Mechanical Engineering at CU Boulder, said in a news release. 

Xiao and others in his group designed the device with a base made out of a stretchy material called polyimine. A series of thin thermoelectric chips are then stuck into the base, connecting them with liquid metal wires. The final product looks like a cross between a plastic bracelet and a miniature computer motherboard.

"Our design makes the whole system stretchable without introducing much strain to the thermoelectric material, which can be really brittle," Xiao said.

The new device could capture the heat from your body when you are exercising and turn it into electricity. "The thermoelectric generators are in close contact with the human body, and they can use the heat that would normally be dissipated into the environment," Xiao said in the news release. 

Many New Battery Technologies on the Horizon

A wide range of other innovations in battery technology also could transform personal electronics.

Current lithium-ion batteries are expensive, flammable, and can harm the environment due to the use of toxic materials, Nikhil Koratkar, a professor of mechanical engineering at Rensselaer Polytechnic Institute, said in an email interview. Koratkar is researching new battery technologies with water-based and ceramic electrolytes and solid-state (ceramic) electrolytes. 

"These new batteries would be highly safe, non-flammable, and potentially cheaper. In the case of batteries with solid electrolytes, they may also be more compact, flexible and perhaps even foldable," he said.

"For batteries with aqueous electrolytes, it may be possible to achieve very fast-charging capability, which is critically important for personal electronics." 

Kevin Jones, CEO of Next-Ion Energy, said in an email interview that his company is developing a battery that can charge a car in 6 minutes and that doesn’t explode. 

"When batteries are charged and used, then they get hot, so the battery must be able to operate at high temperatures; we operate at 200 C," Jones said.

"To charge quickly, the batteries need to be able to get really hot. However, if batteries get too hot, then they explode (vapes, skateboards, cars explode, too), but with our technology, our batteries don't explode. We can charge quickly because we can operate at high temperatures."

Javier Nadal, the UK director of product innovation consultancy BlueThink, said in an email interview that he expects new battery technologies to change daily routines.

"As energy storage technology improves," he said, "we'll see electric planes, home batteries, smart clothing, and increasingly more IoT devices that monitor and automate different aspects of our life."