Apple, a company that produces millions of gadgets with non-removable batteries, has been granted a patent for a universal battery charging system.
Filed in March 2010 and described as a "method and system for recharging batteries for wireless electronic devices," the patent details a system that could have standard, rechargeable batteries able to power a multitude of devices.
If that sounds a bit abstract, imagine a standard-sized battery and various gadgets with an appropriately-sized battery slot. You could use the same battery to power your iPhone, iPod, wireless mouse and so forth. In case your iPhone battery goes low, you could switch it with a battery from another device.
Of course, various gadgets have various power requirements, but Apple has thought of that too. From the patent application: "a rechargeable battery may be adapted to negotiate with the coupled electronic device for an agreed range of power parameters at which power will be transferred to the device and to configure the rechargeable battery to provide power at the agreed range of power parameters."