Panasonic Corporation says it has developed a flexible lithium-ion battery with a thickness of 0.55mm, or about 0.022 inches. Suitable for use in card-type and wearable devices, the rechargeable battery can function even after being repeatedly bent into a radius of 25mm or twisted to an angle of 25 degrees, the company says.

Card devices, which are often carried in wallets or pockets, require internal components that can withstand bending and twisting. Current lithium-ion batteries, such as prismatic or pouch batteries, are neither flexible nor twistable, according to Panasonic. Repeated bending can have a negative impact on the charge/discharge cycle and life of such batteries, resulting in shorter operating time for the devices.

Panasonic says its new flexible battery can withstand a bending radius equivalent to R40mm and a twisting angle ±15°/85.6mm. Image credit: Panasonic. Panasonic says its new flexible battery can withstand bending and twisting beyond Japan's industrial standards for identification cards (a bending radius equivalent to R40mm and a twisting angle ±15°/85.6mm). As a result of its laminated outer layer and internal structure, the company says the battery maintains more than 99% of its initial capacity after 1,000 bends with a radius of 25mm or after twisted 1,000 times with an angle ±25°/100mm.

The laminated body and internal structure also work to prevent leakage and abnormal heating during repeated bending and twisting, making it safe for use in wearable and body attached devices and smart clothing, Panasonic says.

Sample shipments are scheduled to start by the end of October 2016. Product development will continue toward mass production, Panasonic says, with an eye to attaining a slimmer form factor geared to IoT devices.