by Simon Handby on 11.09.07 
Loading ...There’s an interesting story today that Maxwell has won a contract to make ultracapacitors for the Mercedes group’s hybrid cars. Though they might sound cryptically space age, they aren’t quite as exciting as a flux capacitor: the devices simply store energy a bit like a battery.
In rechargable batteries, incoming electricity fuels a reaction that causes changes to a chemical substance, trapping energy. When the cells discharge, the chemical reverts to its original state, releasing the stored energy as electricity. Various types of battery have been around for ages, but even modern batteries wear out eventually, and lithium ion cells can occasionally self-destruct.
Capacitors store electricity without any chemical changes, a bit like the way a balloon stores a static charge when you rub it on your jumper. They tend to be a lot lighter, and can store and release lots of power much more quickly than a battery.
Supporters of ultracapacitors say that this makes them ideal for use in hybrids, and as a reservoir for the energy regained by regenerative braking systems in particular. There’s even talk that they may be used in future Formula 1 cars with hybrid power trains, unless we’re very much mistaken.
IMAGE by Flickr user oskay
