Flexible 'yarn' battery

LG is a company that is associated with consumer products. Now the chemicals division of the company has come up with a revolutionary battery -- a flexible, rope/cable-type Lithium-ion battery, that is so flexible that it could be tied in knots, or even woven into textiles. This, naturally, opens up new possibilties in design.

The LG battery's technology is nothing revolutionary -- it is the same as any conventional Li-ion battery in a smart phone or tablet or camera. But they have adopted a novel fabrication technique that makes the battery truly flexible. The conventional batteries are built up in layers, while the 'yarn' battery is, well, twisted like a rope into a hollow, spring like helix.

LG flexi battery powering a display
(courtesy: www.phys.org)

Thin strands of copper wire are coated with a nickel-tin (Ni-Sn) alloy to create the anode. These strands are twisted into a yarn, and then wrapped tightly around a 1.5mm-diameter rod. The rod is removed, leaving a strong spring. Next, aluminium wire is wrapped around the spring, and then the whole assembly is dragged through a slurry of lithium cobalt oxide, which coats the aluminium wire and becomes the cathode. Finally, the anode-cathode spring is wrapped in a protective outer coating, and then an electrolyte is poured down the middle of the hollow spring. Voila! the battery is ready!

Dont think of running to the market to get a replacement 'rope battery' for your smart phone. The technology is quite a few years away so far as commercial production is concerned.

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