Panasonic – Flexible li-ion batteries withstand bending and twisting with no loss of function


Panasonic has announced the development of innovative, highly flexible rechargeable lithium-ion batteries which can safely withstand repeated bending with a radius of 25mm or twisting with a maximum angle of 25°.

The extremely thin batteries, just 0.55mm high, are ideal for use in smartcards and space-constrained wearable devices.

The flexibility of the new battery is an extremely useful feature in batteries for smart cards, which must be able to withstand bending without becoming defective. In smart watches, a flexible battery allows for the strap and body’s design to be adjustable to different wrist shapes and sizes.

In conventional lithium-ion batteries, repeated bending not only reduces the charge capacity and the life of the battery, but also compromises the battery’s safety. Panasonic’s new flexible battery is designed for safe and long-lasting operation. In stress tests it retains 99% of its original capacity even after 1,000 bends and twists.

The flexible lithium-ion battery is in development by Panasonic’s research and development engineers; mass production is scheduled to start in 2018. The three models planned so far feature charge capacities between 17.5mAh and 60mAh. The smallest weighs 0.7g and the largest 1.9g.


  • Stacked electrode structure
  • Laminated outer layer prevents leakage and overheating


  • Smart cards
  • Smart watches
  • Wearable devices