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Power Technology

Improved High-Performance Energy Storage 129

Posted by ScuttleMonkey from the electrons-in-a-volkswagon dept.
Physicists at the University of North Carolina have developed new improvements for high-energy-density capacitors that can store up to seven times as much energy per unity volume as common capacitors. "The amount of energy that a capacitor can store depends on the insulating material in between the metal surfaces, called a dielectric. A polymer called PVDF has interested physicists as a possible high-performance dielectric. It exists in two forms, polarized or unpolarized. In either case, its structure is mostly frozen-in and changes only slightly when a capacitor is charged up. Mixing a second polymer called CTFE with PVDF results in a material with regions that can change their structure, enabling it to store and release unprecedented amounts of energy."
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Improved High-Performance Energy Storage More

Improved High-Performance Energy Storage

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  • Wrong University (Score:5, Informative)

    by jmcharry ( 608079 ) on Monday July 02, 2007 @05:41PM (#19722499)
    From TFA, it is North Carolina State University. You are about to be set upon by wolves!
    • Yeah, this is a travesty, as UNC!=NCSU in any form or way. Not surprised that this has come about, but it would be a lot nicer if NCSU actually developed the process, I mean they are not lacking in the facilities, they have their own clean room!

  • Quite a Result (Score:3, Insightful)

    by JamesRose ( 1062530 ) on Monday July 02, 2007 @05:41PM (#19722503)
    I was wandering about this for some time, you look at any electronics board, the biggest things on them are chips, which are actually many many small components, and capacitors, which are disproportionately big in comparison to everything else which has been turned into miniscule gizmos integrated into everything else.

    • I was wandering about this for some time, you look at any electronics board, the biggest things on them are chips, which are actually many many small components, and capacitors, which are disproportionately big in comparison to everything else which has been turned into miniscule gizmos integrated into everything else.

      It could change the size of certain capacitors whose values and tolerances it matches. However, a more space-efficient capacitor would not necessarily lower the number of capacitors required u

  • polymers (Score:5, Informative)

    by wizardforce ( 1005805 ) on Monday July 02, 2007 @05:42PM (#19722513) Journal
    CTFE Chlorotrifluoroethylene PVDF Polyvinylidene fluoride http://en.wikipedia.org/wiki/Polyvinylidene_fluori de [wikipedia.org]
    • "CTFE Chlorotrifluoroethylene PVDF Polyvinylidene fluoride"

      Hmm... I should write that down. Does anybody have an extremely loooong piece of paper?

  • Vaporware... (Score:5, Informative)

    by Rhys ( 96510 ) on Monday July 02, 2007 @05:43PM (#19722519)
    Key phrase from TFA:

    "Their predictions of higher energy density capacitors are encouraging, but have yet to be experimentally tested."

    Call me when they're being produced in something resembling quantity. Yeesh.

  • major faux pas in /. description of article (Score:5, Informative)

    by Yonder Way ( 603108 ) on Monday July 02, 2007 @05:48PM (#19722565)
    The editors are asleep again. The summary says the discovery was made at University of North Carolina [unc.edu], which really surprised me because all of the good engineering is happening at North Carolina State University [ncsu.edu].

    It might seem like a trivial slip but to those around here there is a pretty huge difference.

    Oh yeah, and DUKE SUCKS.

    • Re: (Score:2, Funny)

      by gregoryb ( 306233 )
      Seriously! When I read the summary, I was really confused. My first thought was "UNC has electricity!?"

  • We already have "ultracapacitors".... (Score:3, Interesting)

    by Joce640k ( 829181 ) on Monday July 02, 2007 @05:50PM (#19722591) Homepage
    Is this really newsworthy?

    http://www.google.com/search?q=ultracapacitors [google.com]

  • but what's the internal impedance of these things? What's the maximum charge/discharge rate? And no I didn't RTFA.

    • Re: (Score:1, Funny)

      by Anonymous Coward
      FTA: 14 ohms at 1KHz, 500mA/Hr, 750mA/Hr

      Let me know if you need information on other topics too, politics, sex, etc.
    • those are properties of the plates and the conductors rather than the dielectric, as the conductors electrical resistance approached zero, the max charge rate would approach infinity. The amount of charge on the other hand depends on the surface area of the capacitor's plate, and the dielectric constant of the insulator between the plates; the new material has a very high dielectric constant as well as a high puncture voltage.
  • Combine this with plates coated in carbon nanotubes and the storage would go way up. Hopefully the Sony versions won't explode though.

  • Coppertops? (Score:4, Funny)

    by Alyred ( 667815 ) on Monday July 02, 2007 @05:54PM (#19722631)
    Well, guess all those AIs in the matrix won't need us any longer. Goodbye, reality!

  • Great... (Score:5, Funny)

    by Valdez ( 125966 ) on Monday July 02, 2007 @05:58PM (#19722675)
    Now first year EE students are going to actually *die* when they forget their cap is still charged.

    It was bad enough to just get your shiny new needlenose pliers welded together. =/

    • Comment removed based on user account deletion
      • Even in my "Intro to EE for mech E students" class, on the first day we were told to march ourselves down to the bookstore and buy a breadboard and various other materials. We covered circuit analysis, filters, all kinds of fun stuff - and built/examined everything we studied.
    • "Back in the day", in high school electronics, there were a few folks in the class who took it just because they thought it would be easy. They would do no work, and a day before projects were due, would pester those of us who were already finished to do their work for them. I got tired of "Come on. Come on. Come on. Come on.", so I grabbed some high-voltage caps out of the back room, and (thanks to a diode and resistor) would charge it from the AC socket. Since you're dealing with rectified AC, peak-
      • Heh, I built a taser in high school.

        9 Volt battery, wired into a relay and a button. Connect the Battery to the coil, the coil return to the switch side of the relay, and the "normally true" side of the switch to the button, and the button back to the battery. Connect a couple of metal pins to either side of the coil. Press the button, and you have a complete ciruit. It charges the coil, and breaks the switch, breaking the circuit. The coil then discharges through whatever's touching the pins (the air if th

  • From the sounds of TFA, these things will be able to power my Flying Car(tm).

  • Shipstones (Score:4, Interesting)

    by Anonymous Coward on Monday July 02, 2007 @06:12PM (#19722801)
    In his novel Friday Robert Heinlein described a fictional device called a "Shipstone". This was an ultra-super electricity storage device.

    Supposedly, the shipstone had a dramatic positive effect on the world. It was no longer a problem to get electricity from where it's made to where you need it. Big solar power systems were put in areas that get lots of sun, for example. Cars would run on Shipstones, and instead of gas stations, they had stations where you could swap the discharged Shipstone from your car for a fresh, fully-charged one.

    I have been wondering if these new ultracapacitors might someday become practical "Shipstones". How close are ultracapacitors to, say, powering a car?

    Can you drain the power slowly from an ultracapactor, to run a car for a few hours, or do you have to drain it quickly? Does charge leak out slowly over time from an ultracapacitor, or can you make it fairly inert?

    • Re: (Score:3, Interesting)

      by guruevi ( 827432 )
      Using gold capacitors (very expensive though) you would get a far bit already. I had a power amp with 2 1F (not micro-farad, plain farad) gold capacitors and 2 years standing in dry storage and the thing still had a charge (painful). Capacitors are already used as a power source instead of a battery in certain applications and the requirements in cars (high output in short time periods) make capacitors a great candidate. The problem of course is the power density and of course the leaks which is many times

    • Re:Shipstones (Score:4, Interesting)

      by cartman ( 18204 ) on Monday July 02, 2007 @08:26PM (#19724097)

      I have been wondering if these new ultracapacitors might someday become practical "Shipstones". How close are ultracapacitors to, say, powering a car?

      I should start by saying that I'm not an EE, however I've done some reading on this topic.

      Ultracaps are still far from being practical for powering a car. Right now the best Ultracaps store 5-10 Wh/kg, which means they could only store enough energy to power a car for a few miles. Furthermore, the price of the ultracaps is about 10x too expensive for the car to be within the price range of what most consumers expect.

      HOWEVER, Ultracaps have seen dramatic and encouraging improvements during the past 10 years. Ultracaps have decreased in cost/kjoule by a factor of about 3 over the last 5 years, and have seen dramatic improvements in energy density. At the current rate of improvement, in about 10 more years Ultracaps will be usable for plug-in hybrids that cost about the same as conventional vehicles and can run for 10-20 miles on electricity alone. Unlike batteries, ultracaps can be recharged extremely quickly and will not require replacement after repeated recharging.

      Can you drain the power slowly from an ultracapactor, to run a car for a few hours, or do you have to drain it quickly? Does charge leak out slowly over time from an ultracapacitor, or can you make it fairly inert?

      You can drain the ultracap slowly. However ultracaps can be more dangerous than batteries since they can discharge all their energy instantaneously.

      • Re: (Score:2, Interesting)

        by tkw954 ( 709413 )

        Right now the best Ultracaps store 5-10 Wh/kg, which means they could only store enough energy to power a car for a few miles.

        This may be an impediment if you're thinking about plug-ins, but if you're talking about hybrids the story changes. The major improvements from hybrid powerplants are load balancing by allowing the engine to run at the optimum operating point and by regenerative braking. Neither of these have large storage requirements: all you need to get the regenerative braking benefits is to

      • Re: (Score:2)

        by RingDev ( 879105 )
        The nice thing about ultra capacitors in full-electric, and even hybrid-electric cars is the speed at which they can charge/discharge. With a traditional chemical cell battery, you can only pull energy out so fast, and you can only put it in at a much slower rate. That means that heavy breaking with a regenerative breaking system will not be able to put all of that energy back into the batteries as they will generate energy faster than the batteries can accept the charge. Adding capacitors to the mix howeve

  • Wrong measure (Score:1, Interesting)

    by Anonymous Coward
    It's great that they have "seven times the energy per unity [sic] volume", but what is the energy density improvment per unit mass??? Seems like that would be a lot more important for mobile applications.

  • *yawn* only seven times? (Score:5, Informative)

    by syukton ( 256348 ) on Monday July 02, 2007 @06:25PM (#19722907)
    Call me when they're competing with MIT's carbon nanotube based ultracapacitors. Conventional ultracapacitors can achieve an energy density of 6Wh/kg, but the CNT ultracapacitors being researched and developed by MIT are claimed to achieve an energy density of 60Wh/kg (or, let's say, ten times more than this "new" capacitory developed by North Carolina State University).

    Overview: http://lees-web.mit.edu/lees/projects/cnt_ultracap _project.htm [mit.edu]
    More-detailed Poster (PDF): http://lees-web.mit.edu/lees/posters/RU13_signorel li.pdf [mit.edu]
    • Yup, that's what I went to go get numbers for to compare this against.
      http://www.greencarcongress.com/2006/02/mit_carbon _nano.html [greencarcongress.com]
      Now, if they can even get anywhere near their potential 60 kW/kg that's
      damn good and comparable to NiMH with much better economics of use.
    • Neither group has a working prototype, so there's plenty of reason for both approaches to be investigated. Honestly, are you some sort of MIT-fanboy that you have to put down another university's research?

    • Re: (Score:2)

      by GWBasic ( 900357 )

      Call me when they're competing with MIT's carbon nanotube based ultracapacitors. Conventional ultracapacitors can achieve an energy density of 6Wh/kg, but the CNT ultracapacitors being researched and developed by MIT are claimed to achieve an energy density of 60Wh/kg (or, let's say, ten times more than this "new" capacitory developed by North Carolina State University). Overview: http://lees-web.mit.edu/lees/projects/cnt_ultracap [mit.edu] _project.htm More-detailed Poster (PDF): http://lees-web.mit.edu/lees/posters/RU13_signorel [mit.edu] li.pdf

      It's also important to take into consideration how the capacitors behave in differing operating conditions. Assuming the capacitor will be used in a car, will it work at -20 degrees? What aobut 130 degrees? Can it handle road vibrations? Will it still work after 10 years of abuse?

  • Ultracapacitors? Finally, it's time for (Score:3, Funny)

    by Dachannien ( 617929 ) on Monday July 02, 2007 @06:26PM (#19722915)
    Break out the railguns, baby, it's time for some head shots!

  • why compare to "common capacitors"? (Score:5, Interesting)

    by Eric Smith ( 4379 ) * on Monday July 02, 2007 @06:32PM (#19722967) Homepage Journal

    seven times as much energy per unity volume as common capacitors
    It may well be a breakthrough, but I'm not impressed with that particular claim. Aerogel capacitors (e.g., Cooper Bussman PowerStor series) and Electric Double Layered Capacitors (e.g., Panasonic SG series "gold capacitors") already have at least 2000 times higher energy storage density than common capacitors.
  • I'm not interested until it can store as much energy as my common alkaline battery does now -- or at least a NiMH rechargable. Seems someone else awhile ago felt they could build a capacitor with nanotubes that might approach this value, while still having the advantages of speeed and near limitless charge/discharge cycles. THAT's what interests me at the moment.

  • Finally solving battery problems? (Score:3, Interesting)

    by MtViewGuy ( 197597 ) on Monday July 02, 2007 @06:52PM (#19723155)
    While I do agree that this research is still preliminary, the technology has the huge potential to finally overcome two major hassles in terms of electric power storage, namely charge times (after all, capacitors charge way quicker than any NiMH or Li-On battery pack) and density of storage.

    This could open the way for two things:

    1) A decent means to storage power generated by solar panels and wind turbines so it can be used when the Sun is not up and wind velocity is low. That could make it possible for true distributed power generation, where every home generates its own electricity and shares the excess with other people in the neighborhood.

    2) A true, practical electric car. With supercapacitor batteries, we could dramatically increase the range of the electric car, reduce the size of the battery pack so it rarely inteferes with interior space, and charge the battery pack in about the same time you fill up a 20-gallon fuel tank! :-)

    That's why I think people are still underestimating MIT's announcement of nanotube-based supercapacitor development. It could potentially make the whole idea of fuel cell power superfluous.

  • Intruiging (Score:1, Interesting)

    by martin_henry ( 1032656 )
    As an EE student in Virginia, I'm very interested in the subject of this article: unfortunately, it doesn't really say much more than the post above....
  • Where are the cheap, highly efficient photonic crystals for storing optical energy without transduction to electrons or chemical potential?

  • What I want to know... (Score:1, Funny)

    by Anonymous Coward
    Can this store 1.21 Gigawatts?

  • Unity volume? (Score:3, Informative)

    by jpellino ( 202698 ) on Monday July 02, 2007 @08:12PM (#19723917)
    Surely you mean "unit volume"

  • Practicality? (Score:2, Insightful)

    by AugustZephyr ( 989775 )
    This is another example of a super-material that is great at just one thing. How does it stand up to heat (or cold for that matter). Is it to brittle to put in a portable device? Is it able to be produced efficiently (read: cost effectively)? Unless some of these other questions are answered this is just another material to be used as some kind of benchmark in a laboratory.

  • The trouble with ultracapacitors (Score:3, Interesting)

    by Animats ( 122034 ) on Tuesday July 03, 2007 @12:15AM (#19726457) Homepage

    Ultracapacitors are really impressive. They exceed the limits of what was considered physically possible twenty years ago. The newer ones can be charged fast and discharged fast; it's not like the older ones that could only deliver tiny currents. People have used ultracapacitors to start auto engines.

    The problem, though, is that all the energy can come out at once if they're shorted or damaged. Lithium-ion battery thermal runaway is a problem, and laptop fires have resulted. Ultracapacitor failures will be worse. You don't really want to have a fuel tank's worth of energy stored in a capacitor. But saving the energy from braking a car is probably OK.

    • That's why you'd use multiple independent ultracaps, each with its own failure prevention / short detection circuits. That way you only lose one cap, not the entire lot, which is a lot less dangerous.

    • You don't really want to have a fuel tank's worth of energy stored in a capacitor.
      You also don't really want it in 20 gallons of gas, either. Whether it's an idiot with a paper clip, or an idiot with a match, bad things can always happen.
  • Advances in capacitors??? How shocking!
  • Wake me when they invent energon cubes.

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