Batteries that stretch are perfect for smart watches and clothes

Used to be that the only time your lithium-ion batteries changed their shape was when they were about to explode in an airliner cargo hold. But thanks to the ingenuity of an Arizona State University research team, future power packs could not only bend but stretch up to 150 percent of their original size while providing an uninterrupted stream of power. Their secret: the ancient Japanese art form of Kirigami. It's an offshoot of the more well-known Origami form that involves both folding and cutting the working material.

Such a battery "could potentially be used to replace the bulky and rigid batteries that are limiting the development of compact wearable electronic devices," Hanqing Jiang, an associate professor in the School for Engineering of Matter, Transport and Energy, said in a statement. The technology could eventually even be woven directly into fabrics. For now, however, the team has embedded the battery prototype into a stretchy smartwatch band as a proof of concept, which you can see in action in the video above.