For example, it recently won an order to provide a 2.2 megawatt-hour battery, the size of a shipping container, for use in tests to back up a Chinese coal-fired power station.

The removable battery isn't all its cracked up to be. The back of the Nexus One is hard to slide off without a bit of force.

The battery is used for data back-up in the event of a power failure as mentioned above, and continuous operation of a real time clock.