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Ultra capacitors

Discussion in 'Battery Discussion' started by vfx, Apr 20, 2009.

  1. vfx

    vfx Well-Known Member

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  2. johnr

    johnr Member

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    I think ultracapacitors have a huge potential. Their power density and longevity are unmatched - but they're still lacking in energy density compared to lithium batteries. Using nanotechnology, the surface area can be increased significantly - and since the surface area of a capacitor is directly proportional to its energy density, I see no reason why such a "nano-ultracapacitor" couldn't eventually surpass the energy density of the best batteries.
     
  3. WarpedOne

    WarpedOne Supreme Premier

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    Real physical things never scale linearly over orders of magnitude.
    "Surface area is directly proportional to its energy density" actualy means the error in calculating it in this way is insignificant. But this changes dramaticaly as you start to reach ultra high densities comparable with intramolecular bonds. When that happens linear scaling disappears. People that know something about making ultracapacitors don't see how this limit could be overcome buy simply "scaling up" of current principles.
     
  4. johnr

    johnr Member

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    Oh, my mistake then. I know the energy density is related to the surface area and the thickness of the dielectric. But I was incorrectly assuming that at those "nano" scales it would remain fairly linear. Still there's got to be a lot of room for improvement ... theoretically at least.
     
  5. Kevin Sharpe

    Kevin Sharpe Active Member

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  6. Norbert

    Norbert TSLA will win

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    Ultracapacitors to Boost the Range of Electric Cars - Technology Review

     
  7. vfx

    vfx Well-Known Member

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    Small number, big name.
     
  8. dpeilow

    dpeilow Moderator

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    That could be the connection that has Elon excited again.
     
  9. stopcrazypp

    stopcrazypp Well-Known Member

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  10. Norbert

    Norbert TSLA will win

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    Yes, I guess this part: "which have the advantage of delivering fast bursts of power and can be recharged hundreds of thousands of times without losing much capacity" makes them good candidates for use in hybrids. The article doesn't really indicate whether doubling the capacity, which they hope to achieve by the end of the year, would already make them competitive also on a price basis, but it seems they may be able to achieve 40 watt-hours per kilogram using the not-so-expensive conventional electrolyte.

    If it is true that they could "eventually" achieve "500 watt-hours per kilogram", then that would certainly put them in the range that Li-Ion may have in several years (hopefully), or even above. Same for the cost, if they are able to achieve "$150 per kilowatt-hour". Though that sounds very very optimistic.
     
  11. stopcrazypp

    stopcrazypp Well-Known Member

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    They say "$2,400 and $6,000 per kilowatt-hour." Given a hybrid usually uses 1-2kWh, it's a bit high. I know the Honda replacement battery costs $2k and it's ~0.9 kWh. Prius replacement battery is $2,588 and ~1.3kWh. That's price to consumer too (not bulk price). And the cost is only coming down in recent years.

    Interesting they don't mention power density or cost per kW as that is more important for hybrids. Volumetric density matters too (the brake backup supercaps in the Prius and the Leaf actually take up a lot of space; for the Leaf it takes up a big chunk of the "hump" in the trunk). Anyways as a whole, I feel they have a decent chance in the hybrid market, but still a long way to go before being adequate for EVs.
     
  12. Bud

    Bud Member

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  13. Norbert

    Norbert TSLA will win

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    Rice University | News & Media

     
  14. TEG

    TEG TMC Moderator

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    Another day, another university breakthrough.
    Lets see the game changing products hit the market already!
     
  15. Norbert

    Norbert TSLA will win

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    ...continued...

    This seems to avoid some difficulties associated with some other super-caps, however here:

    ScienceDirect - Carbon : Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array templates

    they merely talk about "the ability to achieve energy densities above 10 W h/kg", which doesn't seem interesting for EV energy storage, but there seem to be other areas of application. And interesting in so far as they seem to develop more and more ways to use nanotech.
     
  16. Norbert

    Norbert TSLA will win

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    This seems to be an early research result, unlike the use of nanotubes as an alternative to copper for wires (currently same conductivity at a sixth of the weight) which I just posted in the Off-Topic section, for which they are now working on a manufacturing process (i.e. ready to leave the lab).
     
  17. vfx

    vfx Well-Known Member

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    #20 vfx, Sep 20, 2011
    Last edited by a moderator: Mar 13, 2016


    "nano"​
     

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