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Power Technology

The Replacement For the Battery? 318

Posted by kdawson
from the charge-it dept.
jackd writes "Great article in Technology Review, bordering on 'too good to be true,' about a small company in Texas that is developing the replacement for the electrochemical battery. The device is a kind of hybrid battery-ultracapacitor based on barium-titanate powders. Quoting: 'The company boldly claims that its system... will dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety... The implications are enormous and, for many, unbelievable. Such a breakthrough has the potential to radically transform a transportation sector already flirting with an electric renaissance.'"
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The Replacement For the Battery?

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  • by mcg1969 (237263) on Tuesday January 23, 2007 @08:36PM (#17731138)
    I see the claim about charging in 10 minutes---but I've never seen them claim that will happen at home. It is indeed quite clear, as you've figured out yourself, that a residential hookup just doesn't have the capacity for a fast charge. But frankly, that's not that big of a deal, because in practice it will not be impractical to recharge a car at home over the course of hours.

    It's when you're on a long trip and you need to refill and go that you'll be wishing for a filling station with an ultracap-compatible, high-power electrical supply---for which you'd likely be willing to pay a premium kWh rate.
  • Dupe (Score:5, Informative)

    by ed_g2s (598342) on Tuesday January 23, 2007 @08:40PM (#17731180)
    As likely as it was in September: http://hardware.slashdot.org/article.pl?sid=06/09/ 25/1837254 [slashdot.org]
  • by mcg1969 (237263) on Tuesday January 23, 2007 @08:42PM (#17731208)
    The 10x comment must be pretty rough. From the article, the EEStor ultracaps will come in at 280Wh/kg, with Li-ion at 120Wh/kg and 32Wh/kh. So really, it's more like 2.3x the density of Li-ion. I dunno, that doesn't seem that far to me.
  • by ArcherB (796902) * on Tuesday January 23, 2007 @08:42PM (#17731212) Journal
    But I'll never buy a chemical battery based electric or hybrid. Why? I'm in Alaska. Capacitors can work at low temps much better than the chemical batteries.

    From TFA:
    Finally, EEStor claims that its system works to specification in temperatures as low as -20 C, revised from a previous claim of -40 C.

    "Temperature of -20 degrees C is not good enough for automotive," says Miller. "You need -40 degrees." By comparison, Altair and A123Systems claim that their lithium-ion cells can operate at -30 C.
  • Redox flow batteries (Score:4, Informative)

    by EmbeddedJanitor (597831) on Tuesday January 23, 2007 @08:44PM (#17731228)
    This is what I was talking about... http://en.wikipedia.org/wiki/Flow_Battery [wikipedia.org] http://www.refueltec.com/ [refueltec.com]
  • Re:Better hybrids (Score:3, Informative)

    by Brickwall (985910) on Tuesday January 23, 2007 @08:48PM (#17731276)
    If they can make a reasonable electric battery for a car that provide power for trips up to 60 km or so without needing a recharge, transportation could change dramatically. Couple in a gasoline engine to recharge the battery for longer trips (like a hybrid vehicle) and you could probably cut oil use by the general population by half or more.

    Um, you mean like the recently announced Chevy Volt (made by GM, the "company that killed the electric car"), which has a 40 km capacity on battery, and a small electric engine that kicks in as a generator when the battery runs out? They expect to be producing it in two or three years.

  • by sonoronos (610381) on Tuesday January 23, 2007 @09:20PM (#17731558)
    Taken from the Technology Review article:

    "We're skeptical, number one, because of leakage," says Miller, explaining that high-voltage ultracaps have a tendency to self-discharge quickly. "Meaning, if you leave it parked overnight it will discharge, and you'll have to charge it back up in the morning."

    The Jim Miller quote above confuses me, as Maxwell Technologies advertises a 125V output power module which is spec'd to only lose 70% of its charge after 30 days. So why is he contradicting his own company's products?

    For those who are unfamiliar, while ultracaps sound fantastic, they are ultimately bound by the physical laws of capacitors, one law being that their output voltage drops (linearly) as they discharge. Maxwell Technologies knows about this, so they develop ultracapacitor arrays with extremely high internal voltages (4000+ V) and regulate the power output using efficient step-down converters. Battery cells, of course, do this naturally, because the electrochemical reactions generating the current do so at a voltage determined by the electric potential of the galvanic reaction inside the cell.

    This is one reason why you don't hear much about using ultracaps in portable electronic equipment. While ultracaps may be relatively compact, they are still bulky, and though they may be able to provide the necessary voltage, you have to factor in doubling or even tripling the required voltage to use efficient step-down converters. The story gets even worse for charging. Let's say you want to charge using 12 volts DC. Do you run through dedicated charging circuitry which takes in "safe" voltage, but can only charge the ultracap at battery-style rates (low current), or do you try and charge the ultracap in its theoretical minimum charge time (high current), which means that the wall-warts you are used to seeing will look more like big, boxy IGBT/Invert-based welders (and you thought your xbox 360 power supply was big...)

    In short, while it sounds good in theory, the practical challenges of discharging and charging ultracaps are fairly sizable.

  • by Fordiman (689627) <fordiman@gma[ ]com ['il.' in gap]> on Tuesday January 23, 2007 @09:21PM (#17731560) Homepage Journal
    Why would it?

    For example, your television steps your house current up to a couple thousand volts. At, say, 120kv, your house circuit need only handle 20A (ie: 120kv by 0.02A is 20A at 120v. Given the specs of 280Wh/kg and 100lb [45.5kg] for a vehicle power system, that means we have 12kWh to fill. That means 5 hours for a complete fill-up, or just leaving your car plugged in overnight.)
  • Be careful. Slashdot has been running lots of stories that are "investment opportunities". Read this, the first comment to the story linked from the Slashdot story. I didn't write it, it was written by someone with the nick Emosson, but it sounds correct. (Also, read the other comments showing skepticism of the idea.):

    "Unfortunately EEStor never made and will never make the supercapacitor described in the patent [google.com] because they ignore a well known physical effect, called "dielectric saturation".

    "Barium titanate has been used in capacitors for decades, due to its high dielectric constant: (PDF file) [avxcorp.com].

    "However, the dielectric constant drops as the electric field strength increases: http://www.nap.edu/books/NI000488/html/49.html [nap.edu]
    http://prola.aps.org/abstract/PR/v71/i12/p890_1 [aps.org]

    "At a hypothetical field of 3500 Volts over a thickness of 12.76 micrometers, as proposed in the patent, the dielectric constant of barium titanate would be orders of magnitude lower than the claimed 18500, reducing capacity and energy density by the same factor...

    "This has been discussed in more detail by Prof. Anatoly Moskalev on December 24th and 26th, 2006 in
    http://www.teslamotors.com/blog1/index.php?p=43 [teslamotors.com]

    "with an update on January 20th, 2007:
    http://www.teslamotors.com/blog1/?p=46 [teslamotors.com]."


    Also read this comment considerably below:

    "Further evidences of EEstor's hype! by Roger Pham 1/22/2007 10:41 PM

    "In his patent #7033406, Richard Weir, EEstor CEO, cited data published WAY BACK in 1985 from the Japan's Journal of Applied Physics, as basis for the high dielectric property of Barium Titanate (BaTiO3)powder, when coated with aluminum oxide and calcium magnesium aluminosilicated glass. If BaTiO3 capacitor was so good way back in the 1985, the likes of the GM EV1 would be around evey street corners since 1996, or the Prius would have been a PHEV way back in 1997!

    "What held back coated BaTiO3 powder from becoming a SuperCapacitor was the fact that BaTiO3 has dielectric property that varies by nearly ten folds with just typical seasonal swing in ambient temperature, and the fact that its dielectric property drops by as much with high electrical field strength, as Emosson has brought up!"
  • by viking80 (697716) on Tuesday January 23, 2007 @09:48PM (#17731834) Journal
    barium titanate has an extremely high dielectric constant of around 5000 at room temperature. see http://www.sjsu.edu/faculty/selvaduray/page/papers /mate115/hsiaolin.pdf [sjsu.edu]

    This is hundres of times more than polystyrene, but the challeng is still formidable:

    A cap with 320Wh/kg or 1GJ/m^3 or 1kJ/cm^3 at 3kV would require:

    C/cm^3=0.7Farad

    Since C=k*e0*A/d, e0=8.8E-12, k=5000
    we get C(BaTiO3)/cm^3=4.4E-8*A/d
    and with A*d=1cm^3 (not all of the cap can be dielectric so this is a ceiling)we get:
    A=4m^2 and d=250nm

    So with d=250nm, and U=3kV, the voltage across the dielectric is 12GV/m. Breakdown voltage for most ceramics are less than 300MV/m.

    This would imply less than 1% the capacity claimed. Still an incredible feat, but the car would only go a few km.

  • by Colin Smith (2679) on Tuesday January 23, 2007 @10:02PM (#17731966)
    You don't have "pumps", you have parking spaces with chargers instead.
  • by jmorris42 (1458) * <jmorris.beau@org> on Tuesday January 23, 2007 @10:39PM (#17732330)
    You are almost there, just put the parts together correctly. You said:

    > Maxwell Technologies advertises a 125V output power module which is spec'd to only lose 70% of its charge after 30 days.

    and

    > they are ultimately bound by the physical laws of capacitors, one law being that their output voltage drops (linearly) as they discharge.

    Now do the math. Or you could if enough numbers were available, so lets do it back of the envelope style. It's all about the discharge CURVE. Remember caps won't self discharge like a battery. That voltage is going to be slip sliding away from the small unavoidable losses and the that first 10% of the voltage drop will be seeping out what percentage of the watt-hours? 19% Ouch!

    It will be like a car with a leak in the gas tank, the question is will be be a slow leak that can be ignored in most cases or will it feel like losing gallons per day. They are promising a car with a 500 mile range. Get the losses down where those Maxwell caps are and you lose 15 miles per day to losses. If the losses creep up to 5% terminal voltage per day to losses and recharge nightly and that will be paying for a 50 mile drive whether it sits in the driveway or runs all day. Large losses mean splitting it into banks and only charging what you plan on needing plus a reserve. Big lot of bother. Lets hope for low losses, but at the extreme voltages they are talking about I doubt it.
  • by J05H (5625) on Tuesday January 23, 2007 @10:50PM (#17732450) Homepage
    Heard about this on the radio and looked it up a couple months ago:

    http://www.brown.edu/Administration/News_Bureau/20 06-07/06-022.html [brown.edu]

    It's a battery-capacitor hybrid that has interesting properties. It's not at the same production level, but doesn't provide quite the same strong claims as the EESTOR system. Any opinions on the Brown effort?

    Josh
  • by Jeffrey Baker (6191) on Tuesday January 23, 2007 @11:07PM (#17732644)
    That's just the thing. These supercapacitors have wild performance swings over standard Earth temperature ranges. And the problem of freezing lead-acid car batteries has already been solved. It's called the Absorbed Glass Mat battery and it has been on the market since at least 1989 (has always been the OEM battery in the Miata, for example).
  • Googol = 10^100 (Score:4, Informative)

    by MCRocker (461060) * on Wednesday January 24, 2007 @01:25AM (#17734010) Homepage
    googlecapacitors!
    Argh! The success of google [google.com] has overshadowed the very word that was the inspiration for the name in the first place... googol [wikipedia.org]. May I suggest... googolcapacitors?
  • by lhaeh (463179) on Wednesday January 24, 2007 @01:40AM (#17734150)
    Well I wouldn't want 120KV lines in my house, kinda dangerous since they arc 5 feet or so. You would also have to have a transformer to upconvert from street voltage to 120KV, those are expensive. Just because you increase the voltage to offset the current flow, it will not negate the fact that you are sending 12KW through, you need big wires for that.
  • by Anonymous Coward on Wednesday January 24, 2007 @02:14AM (#17734416)
    A lot of problems here.

    You'd want high voltage to the house, not a high voltage transformer in the house anyway.

    Regardless, transformers for high voltages aren't particularly expensive, you've probably been around more high voltage equipment then you realise:
    - CRT flyback transformers can be had for tens of dollars, they typically do around 30kV
    - Microwave ovens typically power the magnetron with 2kV

    "Just because you increase the voltage to offset the current flow, it will not negate the fact that you are sending 12KW through, you need big wires for that."

    True, but not for the reason I suspect you think this. The wires do not need to be very thick as the current will be small, however the insulation will have to be quite thick because of the high voltage. Primarily you look at the current for conductor thickness, and
  • by anagama (611277) <obamaisaneocon@nothingchanged.org> on Wednesday January 24, 2007 @02:25AM (#17734482) Homepage
    Around here, it is $25 to swap a tank a 5 gallon tank (20# tank, usual size for grill). Propane costs about $2.50 per gallon. In other words, you pay double to swap tanks, or half has much to refill (depending on your perspective).
  • by Fordiman (689627) <fordiman@gma[ ]com ['il.' in gap]> on Wednesday January 24, 2007 @04:43AM (#17735224) Homepage Journal
    Meanwhile, if you don't have time to wait 8 hours (I imagine most people would have it plugged in as they sleep), you pull up to the juice station and plug into their 12kV@30A (360kW) line and be out of there in two minutes flat. It would best be supplied off their own ultracaps that feed off a continous flow of converted 480V 3-phase at 100A apiece (48kW, meaning a 15 minute recovery time per customer. As a station, you'd want lots of extra capacity). I give this setup because there's already infrastructure to install that sort of line.

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