New Kirigami-Inspired Battery Can Stretch and Contract

Manufacturers have plenty of reasons to challenge conventional battery formats. Mobile devices are getting smaller, so a rectangle of lithium may not be the best option. A team of engineers from Arizona State University and Jinan University in China have jointly developed a lithium-ion battery based on the kirigami technique, which allows it to stretch up to 150 percent of its original size.

Current market demands are pushing engineers to the limit to fit a little more capacity into the devices they design. The average user shows no mercy when asking for more battery, especially if the model doesn't allow manual replacement. Lithium-ion batteries are the number one choice among manufacturers, however, we know very well the temperament they can develop when conditions aren't right. We first talked about a flexible lithium-ion battery back in January 2013. Efforts to commercialize similar designs are still a work in progress, but we're always open to exploring other alternatives.

One such alternative was created by engineers from Arizona State University and Jinan University in China. Their battery, which relies on the same manufacturing methods known for current batteries, is inspired by the art of kirigami, which unlike origami, prioritizes cutting the paper in addition to folding it. This gives the battery several linked modules, with an appearance similar to a stick of gum wrapped in aluminum. The user can gather all those modules together, or spread them out as needed, without immediate restrictions. In their proof of concept, the engineers used a Samsung Gear 2 smartwatch connected to the kirigami battery, which in turn was installed in an elastic band. The user was able to move the band and adapt its shape to the arm without the battery interrupting its operation.

Obviously, there are important limits to the design, and one of them is capacity. The more complex the shape of the kirigami battery, the less energy it can store. By comparison, a standard rectangular lithium-ion battery intended for a quadcopter stores seven times more energy than this design. Even so, there are times when an engineer might be willing to sacrifice capacity to avoid altering the physical shape of the product, and that's when the kirigami battery can shine.

Source: Popular Mechanics