On July 25, 2013, the US Patent & Trademark Office published a patent application from Apple that reveals charging techniques for Solid State batteries. Solid State batteries fall into low-power density and high-energy density categories. On the latter side of the equation, Toyota is working on a Solid State battery for 2020 vehicles that will deliver 3 to 4 times battery life. Obviously Apple is interested in the low-power side of Solid State batteries for iDevices and likely future wearable computers. According to Wikipedia, Solid Sated batteries "are easy to miniaturize and can be constructed in thin film form," which would be great in context with bendable devices and those with flexible displays. They also eliminate the problem of electrolyte leakage found in traditional batteries. This kind of batteries also tends to have very long shelf lives and usually don't have any abrupt changes in performance with temperature, such as might be associated with electrolyte freezing or boiling. At the end of the day, we'd like to see battery life extended for iDevices in the 3 to 4 times range like the goal Toyota is aiming for. Now that would be great news.