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Breakthrough on capacitor technology

6.5K views 23 replies 20 participants last post by  blkwrxsti  
#1 ·
Super Battery

Image

Nanotube filaments on the battery's electrodes
image: MIT/Riccardo Signorelli


But capacitors contain energy as an electric field of charged particles created by two metal electrodes. Capacitors charge faster and last longer than normal batteries. The problem is that storage capacity is proportional to the surface area of the battery's electrodes, so even today's most powerful capacitors hold 25 times less energy than similarly sized standard chemical batteries.

The researchers solved this by covering the electrodes with millions of tiny filaments called nanotubes. Each nanotube is 30,000 times thinner than a human hair. Similar to how a thick, fuzzy bath towel soaks up more water than a thin, flat bed sheet, the nanotube filaments increase the surface area of the electrodes and allow the capacitor to store more energy. Schindall says this combines the strength of today's batteries with the longevity and speed of capacitors.

"It could be recharged many, many times perhaps hundreds of thousands of times, and ... it could be recharged very quickly, just in a matter of seconds rather than a matter of hours," he says.
...
Schindall thinks hybrid cars would be a particularly popular application for these batteries, especially because current hybrid batteries are expensive to replace.
Hat tip to silvachris1.
 
#3 ·
Very cool, but don't get too excited about charging in "a matter of seconds". The problem is you can't supply the electricity that fast without having a huge current or a huge voltage (or both). A standard household outlet will still take a few hours to charge the car no matter what the battery pack looks like.
 
#4 ·
I think in the short to mid term there will be a real market for "super-duper" capacitors for use as short term charge reservoirs to be used in parallel with batteries. Their purpose will be to reduce charge-discharge cycling on the batteries (improve battery life) and to provide quick bursts of power (these types of capacitors have much lower internal impedance than batteries). I think they will work especially well with regenerative braking.
 
#15 ·
The problem with capacitors is that they don't store energy well over a period of hours - you can charge them up, but the charge will start bleeding away. Chemical batteries hold their charge for much much much longer.

Chemical batteries do have a limit to how fast you can charge them, so a capacitor may help absorb and reclaim excess energy from regenerative braking, which is a good thing.
 
#17 ·
One way to use a super capacitor array would be to charge it up quickly - say over several minutes - and then continue your long range trip on the highway by powering the motor and charging the battery from the capacitor. That way you minimize the time that the capacitor has to actually hold the charge.
 
#16 · (Edited)
Super-Caps hmmm interesting. Super Capacitors are really good for short term power surges such as an electric motor during start-up. There exellent for fast charges and discharges. Great for power savings or help in battery charge for the main storage batteries such as the lithiun ion batteries. With super caps along with the lithium ion batts, they in synergy should help in extending mileage in between charges for an electric vehicle such as volt. Thus, the 40 miles on pure electric power may be increased by a few miles given that GM is not utilizing these type of super-caps in their Volt.

It's tough to gauge based on the information how much charge those super-caps will save without seeing the specifications of the super cap and the loads (electric motors) for the Volt type applications. There are other parameters that need to be looked at but I could bore you on those details.
 
#22 ·
This technology is quite promising, the fact that a Lithium Ion Battery can be re-charged hundreds of thousands of times gives an electric car, a 10-15 year life. As far as infrastructure regular gas stations can have Electric charge plugs, available at each bay/or selected bays (until greater demand is required), and a charge price can be calculated and added to a debit/credit card conveniently. If the re-charge process even took 5 minutes this would be quick enough to make Hybrid Cars just as easy to live with as gasoline ones.

This is an investment I want to get in on.:yup:

:drive:
 
#23 ·
It will be interesting to see how they copyright the technology. Is the process to create the material through nanotech, a patentable piece of intellectual property or will it be the actual material itself?

Obviously, changing your material in old capacitors led to variances in capacitance as well as other characteristics, so I'm assuming they would be trying for maximum capacitance with this product. If you changed the material you can vary discharge properties etc. and market it through its benefits.

I'm a bit rusty when it comes to component level specifics. Can anyone tell me if material used in traditional capacitors, was selected primarily for its surface area (thereby governing capacitance)?
 
#24 ·
I'm a bit rusty when it comes to component level specifics. Can anyone tell me if material used in traditional capacitors, was selected primarily for its surface area (thereby governing capacitance)?
I found some links:

Barium Titanate (ceramic) or Tantalum - surface area is important, but the material used is also selected for cost and manufacturability. Ultracapacitors are a whole new ballgame - I think everyone is trying different materials to see if they work, cost be damned. I like kemet's explanation for the layman, written by people who make and sell billions:

http://www.sofia.usra.edu/Edu/materials/activeAstronomy/sec5_capacitor.pdf

Of course, Wikipedia has a lot of information too:

http://en.wikipedia.org/wiki/Capacitors

http://en.wikipedia.org/wiki/Ultracapacitor