Todays capacitors are almost the ideal energy back-up system for hybrid-electric vehicles. They are capable of enormous power outputs (and inputs) making them ideal for capturing large amounts of regenerative energy. They are also very safe, but most significantly in terms of car lifespan, economics and consumer confidence, they can be charged and discharged from 0 to 100% and back again for millions of cycles without appreciable degradation.
In fact, to date the only problem has been that capacitors do not store nearly as much total energy as chemical batteries. By way of example, the NiMH pack in the Prius can contain about 46Wh per kilogram of battery mass, while the best ultracapacitors, until recently, were only about 6Wh/kg.
But a company in Japan has just announced that they may have finally cracked this last stumbling block in ultracapacitor technology. They claim that their new capacitors have energy densities from 30 to 75 Wh/kg! :shock:
http://www.jeol.co.jp/english/newsroom/2003/031003.htm
http://www.okamura-lab.com/ultracapacitor/ecsnews2Eng.htm
What could this mean for future hybrids?
The pack in the '03 Prius contains about 1.8kWh of energy, but as the computer limits the available state of charge from between ~60% minimum and 80% maximum (to extend battery life), this means that only 360Wh of energy is actually available.
This much energy (360Wh) could be stored in only 6kg of JEOL's new ultracapcitors! That could be easily placed under the front bonnet, freeing up room from where the larger NiMH battery pack was. As they claim to make these ultracapacitors from "aluminium and coal", there is even the possibility that these capacitors may end up relatively inexpensive.
The 30Wh/kg version has a power output of 8kW per kg! :shock: You could get an extra 200bhp of shove with just an 18kg capacitor!
Fingers crossed everyone....
In fact, to date the only problem has been that capacitors do not store nearly as much total energy as chemical batteries. By way of example, the NiMH pack in the Prius can contain about 46Wh per kilogram of battery mass, while the best ultracapacitors, until recently, were only about 6Wh/kg.
But a company in Japan has just announced that they may have finally cracked this last stumbling block in ultracapacitor technology. They claim that their new capacitors have energy densities from 30 to 75 Wh/kg! :shock:
http://www.jeol.co.jp/english/newsroom/2003/031003.htm
http://www.okamura-lab.com/ultracapacitor/ecsnews2Eng.htm
What could this mean for future hybrids?
The pack in the '03 Prius contains about 1.8kWh of energy, but as the computer limits the available state of charge from between ~60% minimum and 80% maximum (to extend battery life), this means that only 360Wh of energy is actually available.
This much energy (360Wh) could be stored in only 6kg of JEOL's new ultracapcitors! That could be easily placed under the front bonnet, freeing up room from where the larger NiMH battery pack was. As they claim to make these ultracapacitors from "aluminium and coal", there is even the possibility that these capacitors may end up relatively inexpensive.

The 30Wh/kg version has a power output of 8kW per kg! :shock: You could get an extra 200bhp of shove with just an 18kg capacitor!
Fingers crossed everyone....