Wearable Tech
A Girl Wear Looking Into The Smartwatch | Image credit: Freepik

Human Battery: Can wearable tech use the human body as a power supply?

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Even the most innovative, efficient, and sleekest device is only as good as its power source. The ongoing quest for faster computing and more power has recently resulted in dangerous crises like the Samsung Galaxy 7 explosions. The solution has been put forward by a number of scientific teams and enterprises – self-powered devices that generate electricity from body heat and motion.

With no internal battery needed, we’re closer to ditching the chargers than we might think. One newly developed wearable device is making strides towards using the human body as a battery, powered by body heat. It’s a low-cost wearable device to be sported as a bracelet or ring. It uses thermoelectric generators to convert the body’s internal temperature into electricity. Whilst in its early development days, it represents a future where we’ll be able to power wearable electronics without having to include a battery. 

Predicted Wearable Boom
Image credit: Smart Insights | Boom in wearable technology

Smartwatches and wrist wearables have taken off in recent years. The small surface space of which any wrist device consumes calls for incredibly discrete and powerful self-charging capabilities. We could be closer to achieving this than we think.

Why are self-powered electronic devices useful?

Other than the mere convenience of not having to charge a device, the key application most scientists are interested in is health. This is particularly the case for devices like pacemakers which currently require surgery to change the battery. This new technology has the capacity to save lives. Brain surgery is also an eager player in the game – since most implants last up to 5 years.

The human body as a power supply 

Energy is generated from multiple sources, and there are many ways for self-powered devices to work. Piezoelectric energy is generated through pressure applied to certain materials. Think back to school science classes and you’ll remember harvesting energy through movement. However, movement is less practical in the case of human-generated energy since it’s undesirable to have a device powered only when you’re in motion. The main source of energy in the spotlight at the moment is body heat, also known as thermoelectric energy. 

The human body, in most cases, is always a different temperature to the external environment. Thermoelectric generators pick up on this temperature difference to create energy. In 2019, a team of electrical engineers at North Carolina State University built a small device that generated electricity through thermoelectrics. The device can be embedded in clothing or worn as an armband – in a similar fashion to many fitness wearable devices. 

The head is one of the warmest parts of the human body – and one wearable tech device that’s also making some noise this year is smart eyeglasses. These look and act in the same way as regular prescription eyeglasses, yet they have the capacity to track brainwaves, send alerts and even relay digital content via augmented reality. Should such eyeglasses get their hands on this body-powered energy source – it could be a game-changer. 

Powering wearable technology

The number of connected wearable devices globally has more than doubled over the past three years. From 325 million in 2016 to 722 million in 2019 and is forecast to reach well over a billion by next year (Statista). Ultimately, it’s a growing space to invest in and improve the user experience of potentially billions of people. 

Whilst the use of wearable technology is growing at an unprecedented speed – powering the devices through the wearer is likely to take several years to enter the mainstream market. Nevertheless, it hasn’t stopped companies like Xiao from thinking about the possibilities. Their thermoelectric generator could soon be ready for real-life applications.

The device generates one volt of electricity for every centimeter of skin space. This clearly isn’t enough to power a full-blown machine like a laptop but could be the future of powering a small wearable. 

This ultimately means that wearable gadgets wouldn’t ever need to be removed or charged to the wearer’s inconvenience. Using a regular battery incurs a depletion of said battery which will need to be replaced. Thermoelectric devices can be worn at all times, powering themselves, even when the wearer is asleep.

This is clearly a major advantage for wearable technology like smartwatches and smart rings that measure activity during the day and sleep at night. The potential for self-powered wearable tech devices is virtually limitless and we are only beginning to explore the possibilities.