Replacement batteries for your cell phone might not be the cheapest things around, but a Chinese designer has come up with a rather interesting cell phone design, dubbed the rollphone,that is shaped like a cylinder and is powered by your standard AA battery, ensuring that if it ever does run out of juice when you’re on the road, replacements should be easy to source for. The display of this device is a flexible one, rolled into the device itself, very much like how film for cameras used to look like. Seems like a pretty useful concept design, though you probably won’t see phone manufacturers adopt such a design anytime soon.