Electric vehicles run on batteries – but they can also run on capacitors. The technology isn’t quite at the practical stage yet, but FDK Corporation’s refined capacitor is one step closer to a marketable product. Their latest effort was fitted to Takayanagi’s Miluira cart model and exhibited at Tokyo’s Eco Products 2011 this month. The new capacitor is called the EneCapTen, and it reaches a full charge in just sixty seconds.
FDK, a subsidiary of Fujitsu, has been producing batteries and electric components for the past 6 decades, and they’ve been developing capacitors since 2007. Most of their capacitors are stationary – while a capacitor charges and discharges very quickly, the size required for them to hold a significant amount of power makes them very difficult to haul around.
Since capacitors charge much more quickly than either lead acid or lithium ion batteries – even with rapid charging technology – they seem like an attractive solution to the problem of quickly charging electric cars. With a capacitor in the car and charging stations outside of say, convenience stores or supermarkets, the car could be fully recharged while you run in to pick up a gallon of milk.
Quick charging isn’t the only advantage to a capacitor; since there’s no chemical reaction (as in a battery), they’re easier to maintain. FDK claims that their capacitor should run for 500,000 charging cycles without a problem, while a lithium ion battery starts to degrade after only 6000 cycles. A capacitor even works reliably at higher temperatures than either lead acid or lithium ion batteries.
The problem comes with the power to volume ratio – only about 30% of that of a lead acid battery. A capacitor discharges as quickly as it charges, and the full charge will only take a small EV 3 miles down the road. While the capacitor can be recharged incredibly rapidly, the short range makes it still impractical as a mobile power source.
FDK’s solution is to work on integrating capacitors with standard lithium ion batteries (which would extend battery life), and also to work on fitting capacitors into the cars. The EneCapTen package currently integrated into the Miluira has a total of 12 cells and 45V, and it’s about the size of a car battery. It still won’t take the Miluira very far, but it’s taking it in the right direction.
Source | Image: Response.jp.