The Charge of the Ultra - Capacitors
Last November's IEEE's Spectrum Magazine edition had a very interesting article by Joel Schindall, associate director of the Laboratory for Electromagnetic and Electronic Systems at MIT, about ultracapacitors and their possible applications in the automotive industry. Schindall is involved actively in this field of research and is hopeful that they will provide a key role in automotive electricity.
An ultracapacitor is a "souped-up" version of a capacitor, an electric device which stores a great amount of energy in a remarkably small space. Current Latest development in ultracapacitors can are expreted to store up to 50 times percent as much energy as a battery about the same size and are able to stand more than 300,000 charge/recharge cycles. But can they replace batteries? Schindall states that not really, but they can complement regular batteries to power current electric devices such as A/C, power brakes or window locks.
The truth is that ultracapacitors can't hold discharge electricity for a long time [Edited], while regular batteries can. The moment electricity is released from ultracapacitors, it dissipates fast (about 2 minutes). Applications such as those mentioned above, where an important burst of energy is needed during a certain amount of time, are the most adequate.
The article continues with information about the methods of manufacturing ultracapacitors and very interesting notes about the use of nanotechnology for this purpose. Read it here.
[Source: IEEE (Thanks to Domenick for the tip)]
[Edited: Errors fixed]
Reader Comments (Page 1 of 1)
Snowdog 6:33PM (12/05/2007)
Typical ABG misreading and misquoting of facts.
"We think—and our work so far supports our theory—that by doing so, we can create a device that can hold up to 50 percent as much electrical energy as a comparably sized battery."
ABG translation:"Current ultracapacitors can store up to 50 times as much energy as a battery about the same size"
So in reality there is a theory that someday ultracaps just might make it to 50% of battery capacity, in ABGs land of no editors or fact checking (or even reading) it becomes currently wrong by two orders of magnitude.
Seriously guys. I said it before and I will say it again. Get an editor. ABG is handy only for the occasional link of interest to other sites. I don't blame the individual contributers for their mistakes. We all make mistakes, but we need some checks, so less of them go live.
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Some Guy 6:43PM (12/05/2007)
Worst. Research. Ever.
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TX CHL Instructor 8:54PM (12/05/2007)
Snowdog beat me to it. Innumeracy will be the death of the greenies.
There wasn't anything worthwhile in the entire post. You got so much wrong that it isn't even worth refuting.
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Chris M 11:11PM (12/05/2007)
Yep, thems sum prettty obvious misteaks, all write!
Careful reading and a good understanding of the technology involved would help immensely. Energy density of capacitors, and even ultracapacitors, is well below that of plain old heavy lead acid batteries. It would be an improvement to equal half the capacity of lead acid. Where ultracaps shine is in high power output (for brief intervals), a nearly unlimited charge/discharge cycle count, and no damage from full discharge.
BTW, while ultracaps can slowly self-discharge, they can hold a substantial amount of charge for days or weeks, as many an unwary electronics tech has found.
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Karkus 11:08AM (12/06/2007)
If you don't understand the technology, there's no shame in just reposting the original article instead of trying to paraphrase it. (And this applies to those of you who don't understand hybrid technology too.)
PLEASE institute a policy where you at least have to let one other blogger edit your post before posting anything. And try to focus on quality instead of quantity.
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werepants 1:42PM (12/06/2007)
Sorry ABG, but I think you would do better to have car nuts with green leanings than tree huggers trying to report car news, especially when some of the issues can be moderately technical. I like the content that the site provides, but grossly inaccurate technical reporting on top of overt political bias and unprovoked opining harms the rep of this blog.
That said, the limiting factor of ultracaps is not the storage-period discharge, but the energy density and expense. However, considering how many advances have been made in capacitor tech in recent years, and how much more mature (and less likely for dramatic change) the battery industry is, it wouldn't be surprising to see ultracapacitors take over for a great variety of applications.
Just think about it - charge times measured in minutes rather than hours (allows the fuel station model to continue) and practically infinite charge cycles. Also, I wouldn't be surprised if the technology could wind up much more "green" than batteries in the long run, since you can avoid all that lithium and the reportedly adverse effects of mining it.
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dave 12:19AM (12/07/2007)
As an interested observer of ultracap technology, I like keeping up on the latest advances. However, I am self-taught at best. So I appreciate you guys calling out the editors. I could have easily surmised that ultracap tech had advanced by quite a leap, and was ready to start powering our Jetson-mobiles. A little bit of knowledge is more dangerous than no knowledge at all...
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werepants 7:11PM (12/11/2007)
Thanks for fixing some of the errors - however, my understanding is that while the output curve varies sharply depending on the storage state of a capacitor, it can be managed quite precisely with easily available and well understood (albeit expensive) controllers.
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Gypsy 8:48PM (12/08/2007)
What should have been made clearer in the article is that with the advance of the high density capacitors regen breaking becomes much more efficient. At even 25% of the main battery capacity because caps can be charged rapidly and discharged rapidly they would make an EV capable of using very slow discharge main batteries. That in turn opens up the possibility of designing main batteries that have a higher total storage (KWhr available) even if the instantaneous current (KW output) is low. That is a big deal.
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