Panasonic Corporation announced that it has developed a flexible lithium-ion battery with a thickness of only 0.55mm, or about 0.022 inches. Suitable for use in card-type and wearable devices, this rechargeable battery can retain its characteristics even after repeatedly bent into a radius of 25mm or twisted to an angle of 25 degrees.   Card devices, which are often carried in wallets or pockets, require internal components that can withstand bending and twisting. Slim lithium-ion batteries ar...