The technology inside this rechargeable battery is nothing new—it's lithium-ion setup could be used to power your smartphone, digital camera, or quadcopter. But make no mistake, this is no ordinary battery. Thanks to its clever, art-inspired shape, it can extend and retract like a car antenna, even when being used. Stretchable batteries allow engineers and roboticists to custom-fit batteries into moveable, flexible devices like a robot's legs or a springy wristwatch band—places where an ordinary battery could not go.

A team of engineers at Arizona State University and Jinan University in China have just developed a fascinating new way to redesign the lithium-ion battery by borrowing techniques from traditional Japanese origami. (It's actually kirigami, where you fold and cut paper, if you want to get technical about it.) As they report in the journal Scientific Reports, the researchers made foldable batteries that can stretch and expand to more than 150 percent of their compacted size.

"What's great is that these batteries are not produced in any particularly fancy way. [The research team] is basically using tried-and-true methods to develop good and cheap batteries, and then cutting and folding them in clever ways," says Daniel Steingart, a leading energy storage engineer at Princeton University, who was not involved in the research. The final battery looks much like several square battery packs strung together with flexible connectors.

"What's great is that these batteries are not produced in any particularly fancy way."

According Hanqing Jiang, a mechanical engineer at Arizona State University behind the new battery design, says engineers have been trying to build foldable batteries for years. The reason is that scientists have long realized that even simple cuts and folds could create fascinating shapes with useful properties—for example, turning flat batteries into forms that mimic everything from old-school telephone cords to stacked taco shells. However, Jiang's new design uses an extremely common battery and overcomes a longstanding issue—a tendency for the material to break and tear where it's been folded and creased. That's because Jiang's battery designs use carefully calculated soft creases, limiting the chance of damage.

Jiang looks toward today's burgeoning market for smartwatches and sees an interesting opportunity for his new battery design. For example, he says, the flexible batteries could be integrated into the wristband an Apple Watch or a Samsung Gear 2, "providing about double the current energy capacity. . . and [shaving off] material to create a thinner face," he says.

To test this out, Jiang and his colleagues even hooked up one of their batteries to a Gear 2, which worked as well as they could have hoped:

This content is imported from YouTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

Steingart says that with further research, such origami-inspired batteries could even hold bigger promises. "The motion of the expanding battery also mimics some movements you see in soft robotics," he says. That means this kind to technology could bring researchers closer to a long-standing goal in robotics: Using the basic material of moving parts to store energy.

There is one crucial caveat to know about flex batteries, Steingart says: Any foldable, origami-like battery designs come with a tradeoff. The more complicated the shape, the less energy you can fit into a given volume of battery.

"If you're a designer trying to make the thinnest watch face possible, who knows?"

It's a pretty simple concept: a square battery has a lot more volume and a lot less packaging than Jiang's design—multiple chunks of batteries stacked on top of each other. In practice, this means that a standard square quadcopter battery could hold roughly 7 times more energy than Jiang's tightly folded origami one, even if it were squished into a square-like shape.

Yet even with those limitations, foldable batteries could change the game of engineers who need power in odd shapes. "When you ask a battery to be flexible like this, you give up some of the energy you can store in a given volume. But if you're a designer trying to make the thinnest watch face possible, who knows? The aesthetics might make that tradeoff worth it," Steingart says.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io