Lithium Ion Capacitor Has Long Way To Go

August 16th, 2011 by Charis Michelsen

Electric cars have giant batteries (useful for a number of things besides driving the actual car, even). Also under consideration as the primary power source for electric cars (and buses, motorcycles, yachts, etc.) is the lithium ion capacitor.

Regular CleanTechnica readers may be familiar with how a capacitor works, and the long-term cost breakdown, with the conclusion being that capacitor’s aren’t quite ready to be stuffed under the hood.

They’re still not quite ready. The Smart Grid Exhibition in Tokyo (and before that, the one in Yokohama), however, included two capacitor-driven electric cars at the booth run by FDK Corporation. The vehicle was the Miluira, built by Takayanagi (which makes tiny little cars and mopeds). The sliced-open model displayed a bank of six lithium ion capacitors instead of a battery, each with a capacity of 90V, 300F.

FDK manufactures lithium ion batteries as well as rechargeable batteries, and first considered using a lithium ion capacitor as a back-up power supply. A full charge of all six capacitors in FDK’s exhibit took just one minute, which makes a capacitor attractive as a primary power source.

However, the capacitor is still probably best used as a back-up — while the car’s top speed was 80 km/h (just shy of 50 mph) and it accelerated from 25mph to 50mph in 5 seconds, a full charge carried it just 14 minutes and 3.5 km (a little over two miles). Not bad for a first try, all things considered.

Source | Gallery: Response.jp

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Tags: capacitor, Japan, lithium ion capacitor, prototype, quick charge, smart grid exhibition, tokyo, ultracapacitor, yokohama

About the Author

Charis Michelsen spent 7 years living in Germany and Japan, studying both languages extensively, doing translation and education with companies like Bosch, Nissan, Fuji Heavy, and others. Charis has a Bachelor of Science degree in biology and currently lives in Chicago, Illinois. She also believes that Janeway was the best Star Trek Captain.

Travis Moore

If you make a car modular and you make the parts such as doors, hood, trunk, roof like large super capacitors as well as other body panels you could put solar panel on the top and use regenerative breaking to have extra range. To power the car use something like rechargable zinc air fuel cells or newer versions of NiZn cells. Also you could use methane fuel cells. Put the motors inside the wheels to save space. Motors could be made more efficient by using rare earth magnets and pulsed direct current. To pulse the dc all you need is a ball bearing swtich. The magnets moving on the rotor pull the metal ball off the switch to break the circuit. This acts like alternating current. Bifillar coils on the motor should also increas efficientcy. Also you can make the coils with a coabalt prayseodymium or rare earth iron core. The motors would act as generators while breaking charging the capacitors. They could also be very high voltage or low voltage by increasing the fillar of the coils. To that I add that you can also lower the voltate in parallel or increase it in searies. Current capacity of coils depends on diameter of the magnet wires which do have to be one piece wire and not braided wires.
Ed

I’m not sure that it makes sense to just evaluate supercap cost based on $/kWhr like lithium batteries. Large energy storage is not the appropriate use for such a device; peak power is the right application, so the cost metric should be which solution is the best in terms of $/kW over some lifetime. They might supplement an EV energy storage system, but their primary use should be boost/regen and/or start/stop. So, I do not agree that they have a long way to go. They were never intended for the application this article supposes.
Breath on the Wind

A car is not a good mode of transportation within a house, because it is not a good match of potential with needs. Similarly Super Capacitors, (aka ultra capacitors and double layer capacitors) have far greater POWER potential than batteries but less ENERGY potential. For a long range we need energy potential. If we were to install charging points at frequent stops then we need power potential for rapid charging.

Bus service can presently take good advantage of the power potential of super capacitors. Regenerative braking and hybrid design could also use super caps to effect. They are becoming extremely popular in larger sizes so that Maxwell has recently increased its production of its largest 3000 F super caps. Some feel that future expansion in energy potential and the development of hybrid batteries will come from an exploration of super caps rather than batteries.
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Omelay

a combination of capacitor and battery would make a great stop-gap solution. the capacitor can take more energy faster and trickle it to batteries making regenerative braking way more efficient.
Anonymous

Regenerative braking. Caps may work better that batteries there so you can try a hybrid approach.