Here's another peak at Apple trying to improve battery life without increasing the size of the battery - remember, the iPad - internally - is mosty battery.
Apple looking to increase battery life with dense lithium cells:
Apple is investigating techniques to increase the energy capacity of rechargeable lithium battery cells without increasing the size of the battery, allowing longer battery life in future devices.
The proposed invention is detailed in a new patent application published by the U.S. Patent and Trademark Office this week and discovered by AppleInsider. The filing, titled "Increasing Energy Density in Rechargeable Lithium Battery Cells," describes charging a battery using a "multi-step constant-current constant-voltage (CC-CV) charging technique."
The CC-CV charging technique would allow the thickness of the anode active material inside a battery cell to be increased in both "volumetric and gravimetric energy density." But while the density of the power capacity would be increased, the size of the battery, as well as its maximum charging time and minimum life cycle, would remain unchanged.