Flexible batteries may not be an entirely new idea, but here's a development with more backbone than most: engineers at Columbia have developed a flexible lithium ion battery shaped much like a human spine. The battery is claimed to offer superior energy density to the flexible prototypes we've seen before.
The battery is also claimed to provide stable voltage no matter how it's twisted or contorted, positioning the technology firmly in the realm of wearable tech, not to mention portable flexible devices and displays.
It's made up of solid energy-storing components which are essentially the vertebrae of the prototype. These are composed of lithium cobaltate cathodes, graphite anodes with a separator between, along with copper and aluminum current collectors and a polyethylene supporting film.
These are separated by so-called "flexibility providers" akin to the disks and ligaments that allow your back to bend. What these are made from isn't immediately clear — apparently they're the secret sauce — so we've asked for more details.
We've seen similar technology from the likes of Panasonic (with its thin and twisty flat and flexible lithium ion batteries), the Korea Advanced Institute of Science and Technology (and its similar thin-film technology) and LG (an altogether stringier affair). But by the sounds of it, Columbia's technology may lend itself to more energy-intensive demands.
According to assistant professor Yuan Yang, who led the team of engineers, the prototype boasts among the highest energy densities of flexible battery prototypes developed at 242 Wh/L, achieving around 85 percent of what you'd expect from a non-bendy lithium ion battery available today.
And though it is just a prototype, Yang suggests it shows promise as a commercially-viable product. Columbia's press release cites "smart phones, tablets, and TV – to smart fabrics, smart glass, transdermal patches, sensors, and more" as potential applications. However, the study admits that the complexity of this technology does increase cost while limiting the possible applications.
Further, the team claims that the battery shows "stable capacity" when
cycled – in other words, its capacity holds up to being charged,
depleted and recharged, even when bent. After 100 charge cycles, the
battery retained over 94 percent of its discharge capacity.
It's also claimed it stands up to load tests, lending credence to its wearable viability. Video of the testing shows what appear to be two "vertebrae" being pulled apart and together, accordion-like, over and over. "The battery also shows almost no decay after bending for 10,000 times or twisting for 1,000 times," Yang tells New Atlas.
Apparently Yang came up with the idea for the battery while doing sit-ups at the gym. Whether the battery is prone to aches, pains, creaking and spams isn't on the public record.
The team's study was published in the journal Advanced Materials on January 31.
The video below, complete with sinister blue gloves, shows the prototype powering a Huawei Android Wear smartwatch.
Source: Columbia University
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