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MIT's Nano Storage Could Replace Hybrid Batteries
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.'"
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.
Engineering is the art of compromise.
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.
"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.You can't take the sky from me...
A battery stores energy in chemical form (sulfuric acid eventually reacts with lead, for instance), while a capacitor uses physical effects, storing energy in an electrostatic field using an insulator between two conducting plates.
Dog is my co-pilot.
As far as I can see, they have 2 big plus points:
.25in of plastic, it could easily be .24in of ultracapacitor with .01in of plastic coating. The same goes for every cosmetic part of the car that doesn't need to be transparent or comfy, as well as any structural members that the stuff turns out to have the right properties to replace. There's a hell of a lot of weight in a car that has the potential to be made out of ultracapacitor instead of whatever it's made of now.
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 dashboard being
A pizza of radius z and thickness a has a volume of pi z z a
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
"THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
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 doesn't pull off a miracle).
If Assange fell off a cliff, his ghost would declare it a victory.
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.
And it's easy to insult environmentalists when you don't know what you're talking about. We already have tons of spare generating capacity for EVs and PHEVs -- everywhere except the pacific northwest. And even if we had to build more, as if electricity infrastructure was somehow more expensive to build and operate than oil infrastructure (it's far cheaper -- that's part of why a joule of electricity costs so much less than a joule of gasoline).
Why electric cars? Here's a primer.
If Assange fell off a cliff, his ghost would declare it a victory.
Providing electricity to parking areas in apartment buildings is not much more difficult or costly than providing lighting. In cold climates, parking slots with 120V plug ins are routinely provided for apartment dwellers to power block heaters (for example, check the specs on Minot University student housing apartments in North Dakota). Hell, I have heard that sometimes even movie theaters have them for public use in non-assigned parking spaces (any Alaska dwellers with first-person support?). The only reason that there is a 'last 10 feet' problem is that there is absolutely bone-zero real demand for a solution. The electrical infrastructure is really a non-issue, it's the rolling storage that's the hold-up.