The sun may be in your iPhone battery's future. Yesterday, Apple received Patent No. 7,868,582 from the U.S. Patent and Trademark Office for powering electronics partially with solar power. The patent, which was originally filed in 2009, describes a system of using a solar panel for charging different portable devices, including a notebook computer, tablet, phone, or other handheld gadget. It specifically deals with converting the power from a solar panel to meet the power requirements of electronics. The system includes a voltage converter that ensures the available solar power can be converted and used to recharge batteries. The solar panel could either be embedded in the device or be removable, according to the patent. Although Apple has not yet released any solar-powered gadgets, it's clear that the company is interested in letting people use sunlight to charge when they can't get to an AC outlet. It's the fourth patent that Apple has received related to solar power, according to Patently Apple.