A battery wristband powering a watch, via NanoLetters
Wearable electronics remain the holy grail for a whole lot of engineers and tech companies, who know that building our electronics into our clothes could solve an essential conundrum facing consumers today: We want to be more tightly integrated with our devices, but not all of us are ready for e-tattoos.
But building a computer into a t-shirt is a pretty far-fetched idea, and it’d likely be awkward to use anyway. But what if your shirt could charge your phone? New research published in NanoLetters might make that happen: A Korean team of engineers developed a fabric woven with a flexible battery material and flexible solar panels, which combine to make cloth that could power electronics without bulky traditional batteries.
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The researchers from the Korea Advanced Institute of Science and Technology specifically call out traditional batteries, which work best as cells. And while those cells can be rather thin—look at smartphone batteries, for instance—they don’t flex well.
“Although considerable progresses have been seen for wearable electronics, lithium rechargeable batteries, the power sources of the devices, do not keep pace with such progresses due to tenuous mechanical stabilities, causing them to remain as the limiting elements in the entire technology,” write the authors.
To build a more flexible battery, the team created a battery out of yarn. Seriously. A nickel-coated polyester yarn serves as the current collector, which is then wrapped in a polyurethane binder along with an outer polyurethane separator layer to act as insulation.
This image from the paper shows the textile battery as used on a t-shirt, as well as a watchband battery with solar cells.
The resulting battery thread is extremely durable, which the team demonstrated by weaving it into cloth used for a t-shirt and a watch strap. They also added “flexible and lightweight solar cells based on plastic substrates” to the outer surface of the battery, which the team says can recharge “the textile battery without physical connection to power outlet.”
Of course, the same questions asked of any new battery tech apply to this: How much charge can it hold, and how much power can it deliver? Voltages are currently low, and the researchers are focusing on how to make sure the batteries deliver consistent power levels when stretched and moved. While the solar panels were demonstrated to be able to charge, they’re not going to be enough to charge your phone.
Still, that engineers developed a battery yarn is mind-blowing. If it ever makes it to commercial market—I’d bet that something like it will eventually—the possibilities are pretty endless. Even if a shirt can’t act as a battery for your devices, battery fabric could be used to power a huge array of low-voltage devices. A heart-monitoring undershirt or other health-related concepts come to mind. Or perhaps something more frivolous, like Hammer pants that change colors based on your mood. (Yes, I want these.) In any case, it looks like wearables are getting closer to infiltrating all parts of our wardrobe.
