iPhone overheating problems could see aid from new patent

As reports of battery problems causing discoloration on the white model iPhone 3GS continue to grow, a patent from Apple published for the first this week looks to address both internal and external elements that could have adverse effects on a device's power source.

Apple continues to adopt non-user-replaceable batteries across its entire line of mobile electronics. As it does, the longevity and performance of those power sources becomes an even more crucial element of the technology in iPhones, iPods and unibody MacBooks.

The new patent aims to address the physical problems inherent in the batteries in electronic devices: namely, the fact that pressures and overheating can inflict damage on battery cells.

The patent, if approved Thursday, would grant the Cupertino, Calif., company "systems and methods for monitoring and responding to forces influencing batteries of electronic devices are provided."

"Pressure can build up within a battery as the battery operates, for example, due to heat," the application reads. "Pressure can also be applied to an external portion of a battery, such as by a physically adjacent object. These pressures generate forces that influence effects of the battery, such as the size and shape of the battery. Although some magnitudes of such forces can be normal, more intense forces may be indicative of an impending battery failure. Accordingly, what is needed are systems and methods for monitoring and responding to forces influencing a battery."

The patent describes a "battery force sensor" that would be able to detect battery problems. If triggered, the sensor could produce an "alarm and a graphical user interface," the patent reads. Similar elements of such a sensor may already be implemented in the iPhone, which can inform the user that the phone "needs to cool down before you can use it."

The approval comes as reports and photos of the white iPhone 3GS overheating and discoloring continue to grow on the Web. The first-hand accounts show the back of white iPhone 3GS models turning brown or pink in certain areas, usually toward the edges.

iPhone 3GS with discoloration on the left; iPhone 3G on the right.

While Apple has declined to comment on the latest issue and even took to closing a large discussion thread on its forum centering on the subject, it's long maintained on its support page a document on "acceptable operating temperatures," for its iPhone models, which was updated last week to take into account the 3GS model.

Triggers for the issue can vary, but usually follow sometime after intensive activity that generates significant heat, such as using 3G data extensively, playing games or navigating with GPS. It's also suspected that engaging in regular tasks for a long time, such as playing music or browsing the web on Wi-Fi, can also cause the symptoms.