A new Apple patent filing published by the USPTO on Thursday could lead to significantly longer battery life in iPads, iPhones, MacBooks and other hardware with lithium-ion or lithium-ion packs. The use of a multi-step, constant-current, constant-voltage (CC-CV) would increase the capacity of the battery without physically increasing its size. Present-day batteries need to use longer anodes and cathodes to draw in more current and make the battery bigger.
The technique would counteract newly introduced problems with being at a higher state of charge and being overly sensitive to temperature. New batteries using the patent would lower the current for the device when either the higher state or a cooler temperature is in effect. Apple's approach would not only prevent excess wear on the battery that shortened its lifespan but could be overall more efficient by reducing the harm that might happen to a normal battery.
Apple hasn't named which specific devices would get the improved batteries, but the implementation could bring improvements in two different ways, it said. Devices could either extend their battery life without having to change the design or could use a smaller battery to make room for other features.
The balance between battery size and design has been an increasingly important debate for Apple. It filed the patent in September 2009, just months after battery life became a primary focus of the MacBook line. To significantly extend the useful runtime of its portables without increasing their overall size, it had to remove the traditional battery door and seal the lithium-polymer pack in to afford more room. Denser lithium cells could either bring the door back without necessarily lowering battery life or else could lead to even longer-lasting sealed-in batteries.
iPads, iPhones and iPods could also benefit, both for obvious battery gains but also for the much greater sensitivity to space limitations. Apple has had to gradually add more features to stay competitive over the past four years, ranging from simple additions like GPS to a front camera, even as the design has slimmed down. On the iPad, higher density could also lead to smaller, lighter batteries that reduce the weight and improve the usability for e-reading.
As with most patents, Apple isn't obligated to use the multi-step CC-CV technology and may not necessarily use it, although most of its more practical patents often have bearing on real products coming in the following few years.