LG Chem says it has a cable-type lithium-ion battery that is so flexible it can be tied in knots and worn as a bracelet or woven into textiles. For mobile device designers, the eventual commercial production of such a battery would be a very big deal in reducing design constraints. Flexible batteries have been created before but made in flat sheets and have not stored much energy. The LG Chem flexible battery is thin and very flexible, able to be placed anywhere in any shape. Thin strands of copper wire are coated with nickel-tin. The strands are made into a metal yarn and wrapped around a rod. Once the rod is removed, a strong spring results.
Read more at: http://phys.org/news/2012-09-lg-chem-cable-batteries-reshape.html#jCp