The Tokyo Auto Show included a neat electric concept vehicle - the Compo. It is an electric scooter that is also a large lithium battery pack. It can used as a standalone scooter - but also can be inserted into the Honda Mico electric car. It also can used as the a power supply for camping or powering your home during an emergency.
The battery can be charged at home - inserted into the scooter and/or the auto. No details were available about the amp hours or the range. Lithium batteries hold twice the power in half the size of a normal lead-acid battery.