Late last week the US Patent Office released a patent application (PDF) filed by Apple in April of this year. The application deals with “a fuel cell system which is capable of both providing power to and receiving power from a rechargeable battery in a portable computing device.” Such a system “eliminates the need for a bulky and heavy battery within the fuel cell system,” thereby allowing for a significant reduction in size and weight of the device.

Over the last few years, battery technology has emerged as the major limiting factor in the advance of smartphone technology. Apple’s iPhone has been constantly plagued by reports of poor battery life, going all the way back to the iPhone 3G. The iPhone 4S pays for its more advanced technology – namely Siri and its faster processor – with a surprisingly short battery life. Apple is rumored to have a software fix in the works – iOS 5.1 is expected to help with battery issues – but there is only so much a software fix can do. The smartphone industry is in desperate need of a breakthrough in battery technology. Apple’s fuel cell technology may be just such a breakthrough.

The limitations imposed by current battery technology is mostly exclusive to smartphones. Apple’s notebooks – the MacBook Pro and MackBook Air – and the iPad tablet have all been largely immune to the kinds of battery life complaints leveled at the iPhone. The issue is one of size: the smaller a battery gets, the less power it will hold. The more technology Apple and other manufacturers try to cram into the shell of a smartphone, the smaller the battery becomes, and consequently the lower the battery life. Conversely, a battery that satisfied users’ power demands would increase the size and weight of the device, which would in turn lead to user complaints that the phone was too bulky. Fuel cells would go a long way toward solving this dilemma.

It is worth noting, however, that this is only a patent application. Apple has filed countless such applications as it has explored various technologies over the years, and not all of them have panned out. At present, all this means is that Apple is exploring the possibility of using fuel cell technology in their devices. So, don’t expect next year’s iPhone to suddenly be sporting fuel cells in place of traditional batteries. Indeed, we may never see fuel cells in Apple devices. But then again, we know that Apple is at least exploring the technology, so don’t be surprised if in a couple years Apple announces a phone that you only have to charge once a week, instead of once a day.

[Hat Tip: Mashable]