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Comments: 191 +-   MIT's Nano Storage Could Replace Hybrid Batteries on Monday March 03 2008, @05:12PM

Posted by Zonk on Monday March 03 2008, @05:12PM
from the replace-the-darn-bunny dept.
power
transportation
science
mattnyc99 writes "Last week we discussed Popular Mechanics' reporting from MIT, but missed one of the coolest breakthrough of all, something scientists have been working on quietly as Detroit spends money elsewhere. The Lab for Electromagnetic and Electronic Systems has been doing some mega-efficient work with ultracapacitors, which store drastically less energy than a battery but have essentially none of the drawbacks — especially via carbon nanotube arrays. Automotive experts say the new research is enough to start replacing batteries in hybrid cars, and plug-in vehicles might not be far behind. From the scientist who thinks ultracapacitors are potential competitors for the pack in his Toyota Prius: 'I try to contain myself, because it hasn't been proven yet, but it could be a real paradigm change.'"
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Submission: MIT's Nano Storage Could Replace Hybrid Batteries by mattnyc99 (1008511)
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  • Better capacitors (Score:4, Interesting)

    by QuantumG (50515) * <qg@biodome.org> on Monday March 03 2008, @05:13PM (#22628644) Homepage Journal
    Implications for Focus Fusion? [lawrencevi...hysics.com]

    • Capacitors have drawbacks too (Score:5, Informative)

      by EmbeddedJanitor (597831) on Monday March 03 2008, @05:23PM (#22628778)
      Even discounting the problems getting very high capacity with low ESR, capacitors still have a drawbacks. The charge is proportional to the voltage which means that the voltage keeps going up with more charge. On the discharge side it means that the voltage keeps reducing as you discharge the capacitor. Thus, the power supplies that are powered by capacitors need to work with a wider range of voltages. This tends to make them less efficient and more complex.
      • On the plus side, it's easier to measure charge.

      • Re: (Score:3, Interesting)

        by Ixlr8 (63315)
        Although your point is valid to a certain extent, I think you're exagarating the 'problem' of charge and voltage being proportional. Modern switched mode power converters can do a good job.

        Additionally I could see a solution in which not all capacitors are use at the same time. By activating them in a proper order/way, one could make a more constant source that can then be the input for a SMPS.
        • Modern switchers do a pretty good job, but as with everything else there are compromises. As you tune for stability you tend to give away performance. Dealing with wider voltage ranges makes the whole trade-off even harder.

        • Re:Capacitors have drawbacks too (Score:4, Funny)

          by thisissilly (676875) on Monday March 03 2008, @08:26PM (#22630644)
          Modern switched mode power converters can do a good job.

          Y'know, I was thinking about going into Tosche Station to pick up some of those...

    • The implications are that it still won't work.

  • Did anybody elses Science Teacher (Score:3, Interesting)

    by JohnnyGTO (102952) on Monday March 03 2008, @05:16PM (#22628684) Homepage
    leave charged capacitors on the parts shelf to reinforce the "Don't Touch" rule? I bet one of these would reallllly hurt :-)
  • These hold less energy than batteries and yet they're going to be economically feasible? Can someone please explain to me how this is going to work, because it's not making sense to me right now. It sounds like they'll either have to add so many capacitors that it becomes counter productive, or else they'll have a short range and useless for road trips. Either way it won't work.

    • Re:less than batteries? (Score:4, Informative)

      by BlueParrot (965239) on Monday March 03 2008, @05:33PM (#22628890)
      The main issue with battery technology is not amount of charge held ( there are already electric cars that can get a similar range as petrol ones ), but the batteries that have a good enough performance are very expensive and wear out after a number of years. It also takes quite a while to recharge. If super capacitors can obtain a longer lifetime then the economics may look more attractive and they also have the advantage that the recharge time is more or less limited by the rate at which you can deliver energy, rather than the performance of the storage system.
      • What about capacitor/chemical battery hybrid storage systems? The big chemical portion for power density, and the ultra capacitor for bursting.

      • Re:less than batteries? (Score:4, Insightful)

        by peragrin (659227) on Monday March 03 2008, @05:54PM (#22629148)
        you forgot two other important differences. Weight, and toxic chemicals. Super capacitors are far cleaner and easier to dispose of later. Also the Chemical that make up large battery banks are very heavy. If you can shave 500 pounds off of a car just by removing the batteries and replacing them with equal sized super capacitors then your electric car will be a lot more efficient over the long haul.

        • Re:less than batteries? (Score:5, Informative)

          by Rei (128717) on Monday March 03 2008, @07:16PM (#22630040) Homepage
          1) Li-ion batteries use no toxic components in manufacture, and while conventional li-ions have some chemicals that are poisonous in the end products, A) the latest generations of them designed for automotive use lose those (such as using nicer electrolytes and replacing the LiCoO2 cathode), and B) they break down harmlessly once disposed (no heavy metals or the like).

          2) For a given amount of charge, an ultracapacitor is a lot *heavier* than a battery bank. They're lower energy density (assuming EEStor [wikipedia.org] doesn't pull off a miracle).
      • This is one that has been in the back of my mind since I heard about an supercapacitor based bus they have going in Beijing. It charges at every bus stop from an inductive charger. I found that so conceptually attractive. And it also fits so well with the Chinese attitude towards life. I live in China and people are really into keeping it light and just getting by with what you need. My in-laws can't stand my love for clutter and collecting stuff like old PCs.

        Anyhow, after seeing that,

          • Re: (Score:3, Insightful)

            by Rei (128717)
            No ripping up of massive stretches of road needed. It can be done as an incremental process. Step one, vehicles are increasingly electrified (already increasingly underway). Step two, the vehicles are designed to have inductive chargers and any new or repaved roads have chargers/meters installed. The vehicles still need to have sufficient battery or gasoline power to keep going a relevant distance when there are no suitable roads around. Step three, enough roads in some places are converted that cars c

          • Re: (Score:3, Interesting)

            by TheRaven64 (641858)
            All the systems of this nature I've seen only work while the vehicle is resting and contain an RF tag that handshakes with the vehicle and turns off the coil while it's not in use. In China, they're used at bus stops, so the bus can charge while people are getting on and off. They could also be embedded at traffic lights, so if you stop when the lights are red you can recharge your car a bit. If they can get the switching to happen fast enough then it might be feasible to use them while in motion, but I
    • From the article:
      '"In order to prolong the life of the battery in my car, they only use it over the middle 10 to 15 percent of its range he says. "So actually I'm only using perhaps 15 percent of the capacity. With an ultracapacitor you can use it all, or almost all."'

      So, if you're only using 10%-15% of the battery, then 5% for current ultracapacitor isn't too far off. With the ultracapacitor you don't have to worry about battery memory or the explosiveness of LiIon. So, in the researcher's eyes, thi

    • rtfa (Score:5, Informative)

      by Scrameustache (459504) on Monday March 03 2008, @05:36PM (#22628938) Homepage Journal

      These hold less energy than batteries and yet they're going to be economically feasible? Can someone please explain to me how this is going to work, because it's not making sense to me right now.
      there's no battery memory caused by partial discharging and no reduction in capacity with each recharge. "They never wear out, they have no electrolyte, they don't have any chemistry taking place in them," Schindall says. "It's just an electric field that stores the energy. So you can recharge a capacitor a gazillion times. It's very efficient--just the internal resistance of the wires." The ions cling electrostatically to materials in a capacitor, which also allows for much quicker charge times. And by avoiding the chemical reaction that drives traditional batteries, there's no real danger of a capacitor suddenly overloading--or exploding like a laptop's lithium-ion battery pack.
      • just dont plug them in the wrong way...

      • Re: (Score:3, Informative)

        by Rei (128717)
        1) Li-ions have no memory effect.
        2) Modern automotive li-ions are rated for a decade or two of service.
        3) Modern automotive li-ions are non-explosive. Compare, for example, this A123 battery with a traditional li-ion [youtube.com].
        4) Many modern automotive li-ions have very fast recharge times -- 5-15 minutes, depending on the type.

        Don't get me wrong -- ultracapacitors are great. But until they can increase their energy density by an order of magnitude, they're only competing against the batteries in hybrids (and not p
    • You can use them more than traditional batteries. It's kind of like how an NiMH AA rechargeable battery holds roughly half as much charge as an alkaline would, but you can recharge it 4-600 times or so and thus get 2-300 times more use out of it.

    • Re: (Score:3, Informative)

      by Andy_R (114137)
      As far as I can see, they have 2 big plus points:

      That they can be cycled as many times as you like without degrading, and they don't get damaged by being totally discharged. This opens up possibilities like contunially topping them back up with recovered braking energy, as well as getting rid of the buffer needed to prevent total discharge with conventional batteries.

      Secondly, they are not volatile, so they could be built into a lot of places where you couldn't put a lead/acid battery - instead of your dash
    • Don't you think a question as basic as yours would have been considered by the folks putting forth this research? /Obviously/, the article is lacking in sufficient detail to prevent such idle speculations as yours.

      But give the freaking MIT scientists a break, eh?

    • Re:less than batteries? (Score:5, Informative)

      by misleb (129952) on Monday March 03 2008, @06:12PM (#22629348)

      These hold less energy than batteries and yet they're going to be economically feasible? Can someone please explain to me how this is going to work, because it's not making sense to me right now. It sounds like they'll either have to add so many capacitors that it becomes counter productive, or else they'll have a short range and useless for road trips. Either way it won't work.


      Probably already addressed adequately by other responders, but I'll chime in.

      At the moment, ultra-capacitors may be best suited for systems such as hybrids where you have a constant, low power source such as a small generator in a hybrid. The idea being that you could get good power/acceleration out of a capacitor when needed and the rest of the time is spent recharging from the motor. All without the disadvantages of batteries. Think of it as a sort of electrical flywheel.

      -matthew

  • The reality is that it will take quite a few years to test such systems for pollution, crash resistance, flexibility, and so on if used on the quantity levels required to power plug-in hybrid 100 plus mpg vehicles.

    During this time, it would be logical to buy one of the 2009 or 2010 model year plug-in hybrids that will be on the market - and then ten years down the road see if a battery pack replacement using this capacitor technology is on the market and cheap enough due to large scale production to implement.

    Do now. Not ten years in the future.

    (p.s. a cure for half of all cancers is being tested in the UK right now, but it takes almost a decade to do the trials before it comes to market)
  • I've been planning the initial works to convert my car ('91 Chrysler Daytona) to an Electric Plug-in.
    My (tentative) plan is to use a hybrid Battery/UltraCapacitor design for "burstable" speed where batteries are lacking.
    Perhaps if this new design works its way out into the wild, I will opt for a pure ultra-capacitor design? I doubt it, but it certainly would be cool. Recharge times would be very, very fast.

    • My (tentative) plan is to use a hybrid Battery/UltraCapacitor design for "burstable" speed where batteries are lacking.

      I suggested this on the EAA-PHEV mailing list, as a way to buffer the battery storage system from heavy draws (i.e. hard acceleration) although I don't think anything ever came of it. The trick is going to be to isolate the capacitor(s) from the battery storage system during the heavy draw, so the motor pulls the power from the capacitor. I suggest doing this by determining the accelerator position/rate of travel (off to floor in under X milliseconds = ultra capacitor bursting).

      If you do decide to go wit

  • Ka Booooooom!!! (Score:5, Informative)

    by Powerbear (1227122) * on Monday March 03 2008, @05:34PM (#22628914)

    "And by avoiding the chemical reaction that drives traditional batteries, there's no real danger of a capacitor suddenly overloading--or exploding like a laptop's lithium-ion battery pack."

    They won't explode like a lithium-ion battery pack, it will be a 100X worse.

    If anything pierces the dielectric, all the energy stored in the capacitor will discharge violently in milliseconds.

    • Re:Ka Booooooom!!! (Score:5, Funny)

      by fahrbot-bot (874524) on Monday March 03 2008, @05:37PM (#22628960)
      If anything pierces the dielectric, all the energy stored in the capacitor will discharge violently in milliseconds.

      I hear something like this happens with condoms too.

        • Re: (Score:3, Interesting)

          by clonan (64380)
          Unless of course you created a bank of super capacitors...This picture in the article suggested they were only maybe 1 cm across.

          Lets take your 400 miles of charge (100 kw/h) and break it into 1000+ watch battery sized devices.

          Sure if one gets pierced it is bad, but a well grounded system will prevent the others from melting while the one goes Ka BOOOOOOM.

          Not only that, but I bet it will be cheaper to manufacture them in mass when they are small.

        • Re:Ka Booooooom!!! (Score:4, Informative)

          by SEAL (88488) on Monday March 03 2008, @07:27PM (#22630150)

          Gas tanks don't explode. It takes 3 things to get something to burn. Oxygen, Heat, Fuel. To get something to explode, the fuel needs to be dispersed in the oxgen and there needs to be enough oxygen to support the explosion.
          Gas *vapor* is what's most dangerous. Dat to day you don't deal with that, except when you fill up or when your car has mechanical problems. But in a crash, if a gas tank were to leak, you suddenly have a high risk situation.

          Also, boats -- particularly inboards, are more dangerous. Gas vapor is heavier than air so it tends to collect in the bilge area, whereas a car has open air beneath it. That's why you're supposed to run the blower for a bit before attempting to start a boat engine.

          Capacitors on the other hand, have extremely high discharge rates and require no fuel, oxygen or heat to explode. Enough energy to power a vehicle for more than 100 miles would cause serious damage if the capacitor were to fail from an accident or manufacturing defect.

          Everyone may think putting capacitors in a car is a good thing, but you're essentially mounting bombs in the car.
          A properly designed ultracapacitor would ground out to the car's body in the event of a failure. It should be safer than gas simply because there is nothing that can be dispersed in an accident.

          • Re: (Score:3, Interesting)

            by Agripa (139780)
            Sealed electrolytic capacitors fail through bursting when the pressure inside becomes too great which is usually caused by too high a voltage. That does not have the characteristics of a dialectic failure in a high energy capacitor which happens much more quickly and is limited only by inductance. I have seen 1 x 1/2 inch aluminum bus bars used for connecting capacitor banks in high energy physics experiments with holes punched through them from when the capacitor bank shorted out. I have had my own glas
  • This is a question I've wondered about since a friend of mine was talking about the best chemical-battery replacement.

    What is the theoretical limit of a capacitor? That is, if you could somehow place all the atoms exactly where you wanted, what's the energy/weight ratio you could obtain?

    • Re:Theoretical limit of capacitors? (Score:5, Interesting)

      by mikeee (137160) on Monday March 03 2008, @05:49PM (#22629096)
      A capacitor has to hold the positively and negative charged portions of itself nearby, but electrically isolated; to keep the insulation from being crushed (opposite charges attract, remember) requires a certain physical strength proportinal the the charge stored that will put at least a top-end limit on capacitor capacity.

      Interestingly, this is dependent (duh) on the strength (energy) of chemical bonds, so IIRC, the theoretical limit for capacitors is actually pretty much the same as for chemical fuels or batteries. (Now, small electric motors are more efficient than small engines, so electric systems can be a huge win, although the fuel system don't have to carry their own oxidizer...blah blah blah.)

      Pretty much anything non-nuclear (you can throw flywheels, nanotech windup springs, and what have you in, too), should in a perfect world max out at roughly the same magnitude because they're all fundamenentally dependent on that chemical bond strength.
  • Can someone please remind me how they differ?

    • Re: (Score:3, Informative)

      by Scareduck (177470)
      A battery [wikipedia.org] stores energy in chemical form (sulfuric acid eventually reacts with lead, for instance), while a capacitor [wikipedia.org] uses physical effects, storing energy in an electrostatic field using an insulator between two conducting plates.
  • No story about ultracapacitors would be complete without a reference to EEstor. As usual, they've shifted their delivery goal to late 2008 [forbes.com].

  • I dunno guys (Score:4, Funny)

    by JudgeFurious (455868) on Monday March 03 2008, @05:48PM (#22629086)
    I'm sticking with my 2006 GTO with the 6.0 V8 engine. Yeah it gets lousy mileage but I figure that if I go places really, really fast then I'm not polluting for as long as all those other people. Plus I'm helping to get rid of all that messy oil. As soon as that stuff is all used up we'll see real progress towards an alternative.

    I'm doing it FOR the planet.

  • Electricity (Score:4, Interesting)

    by Archangel Michael (180766) on Monday March 03 2008, @06:23PM (#22629472) Journal
    So, how is all the new demands for electricity going to be satisfied.

    I know everyone likes Electricity and such, but current demands are taxing the existing power grid / infrastructure.

    And with all the NIMBYs out there, nobody is willing to build new and needed Hydro Electric, Nuclear, Coal powered plants anytime soon. So, the result is "cool, electric cars, but I can't use them because of the blackouts". And I don't assume that somehow people will give up the NIMBY attitudes for an electric car.

    Its easy to be an environmentalist, you don't have to think of the requirements to achieve whatever goals you might have. It just has to sound good.

  • They've come a long way (Score:3, Interesting)

    by blanchae (965013) on Monday March 03 2008, @06:59PM (#22629868) Homepage
    In the early 2000s, I researched the design of a capacitor that would be able to power a 2000 lb car (CRX) at 70 mph for 180 miles then recharge and drive back. The best capacitor technology at the time required an electrolytic cap the size of one of those old wooden oak office desks with each layer being in the order of 0.001" thick. It would of required some major thin film technology. On top of that it would weigh more than the car it was supposed to power!

    An alternative was to purchase existing 1 farad supercaps and build the required capacitance through series and parallel circuits to get the voltage and capacitance up. The cost was over $250,000 at the time. The last issue was building a charging circuit that could quickly charge the cap up within 30 minutes.

    I also explored the design of making a 200 mph electric dragster. The issue was the megawatts of electrical energy that needs to be transferred within 6 seconds to the electric motors. It was the equivalent of a large electrical explosion. Here's the latest world record electric dragster at 160 mph: Dennis "Kilowatt" Berube [teva2.com]

  • Detroit spending money elsewhere? (Score:3, Insightful)

    by MaWeiTao (908546) on Monday March 03 2008, @07:14PM (#22630010)

    Last week we discussed Popular Mechanics' reporting from MIT, but missed one of the coolest breakthrough of all, something scientists have been working on quietly as Detroit spends money elsewhere.


    I find it amusing that the summary takes a jab at American automakers in light of the fact that Ford has an on-going partnership with MIT. Whether Ford's funding is supporting this specific project I can't confirm, but clearly they are funding these types of projects. A press release describing the partnership can be found here [mit.edu].

    And just because they aren't investing specifically at MIT doesn't mean they aren't investing in this sort of research.
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