These days, just about every Apple product is defined by a non-removable battery. It's with no small hint of irony, then, that Apple just received a US patent for a universal removable battery system. As proposed, the technique would let Apple cut batteries from lithium-polymer or similar materials into commonly sized packs that could then be swapped between devices, providing all the benefits of removable, rechargeable batteries with a longer lifespan than an old set of AAs. Batteries could have serviceable cores for when they finally give up the ghost, and computers could even alternate between charging the batteries (when plugged in) or using them to extend the runtime of MacBooks. We'd recommend against basing any purchasing strategy around Apple's filing, though. The Cupertino team originally applied for the patent in 2010, and in turn broke out the technology from a patent it had filed in 2007 -- there's no guarantees Apple is still interested in replacing those disposables, let alone any sealed-in batteries. That won't stop us from yearning for the day when a Magic Mouse lasts for more than a week of heavy use.