Nokia has secured a patent for malleable batteries that roll in on themselves, sparking rumors that the firm is planning to develop a flexible smartphone, Digital Spy said.

The batteries, which are capable of taking on a swiss roll-like shape, are designed for use with "multi-function portable electronic devices".

The patent filing reads: "Various embodiments of the invention could be used in any suitable type of portable electronic device such as a mobile phone, a gaming device, a music player, a notebook computer, or a personal digital assistant, for example."

Nokia patented a similar power cell last year for use with wearable devices, but the new technology is said to be more flexible and versatile.

Several curved smartphones have already hit the market, such as the Samsung Galaxy Round and the LG G Flex, but fully malleable hardware is expected to emerge over the next year.

Nokia has not officially confirmed that it plans to develop the flexible batteries described in the patent.