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Hybrid cars are at the intersection of nanotechnology and battery technology research June 1, 2007

Posted by Brian Angliss in Energy & the Environment, Environment, technology.
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Nanotechnology isn’t a technology in and of itself so much as it’s an enabling technology. What this means is that the science and technology of the very, very small (aka nanotechnology) enables radical changes across a massive number of other technologies and fields. For example, nano-scale particles of gold can be combined with a chemical marker to turn from red to blue (or vice-versa) in the presence of toxins.

However, as PBS’ NewsHour program reports, another application of nanotechnology is dramatically improved batteries and electronic components called “ultra-capacitors.” The amount of energy that a battery can store is directly proportional to the surface area of the electrodes, meaning that if you double the surface area of the electrodes, your battery can store twice as much energy and either operate twice as long, run twice as hard, or, if you could figure out a way to fold up or roll all that area into a smaller package, make the batter smaller and lighter.

To give you an example, Tesla Motors put out a white paper on their electric roadster’s battery pack in which they say that they’re using a battery pack composed of approximatley 6800 lithium-ion batteries that are each a little bigger than a AA battery. The pack weighs about 450 kg (993 lbs), stores about 56 kilowatt hours (kwh) of electric energy and delivers up to 200 kilowatts of electric power. According to this interview of AltairNano CEO Alan Gotcher, the electrode area for lithium-ion batteries is about 1 square meter per gram of electrode material. Applying this to the Tesla battery pack (and assuming that only about 50% of the pack’s mass is actual electrode material), we end up with 225,000 square meters. To put this into perspective, this is about 55.6 acres, a little less than 1/4 square kilometer, or about 30 soccer fields.

Using nanotechnology, however, gives us the opportunity to increase this area dramatically. According to Alan Gotcher, his company estimates that they can increase the area of their lithium-ion batteries by a factor of 40-200 using nanotech-based battery electrodes. To continue using the Tesla battery pack as an example, this would mean that their existing battery pack would be more like 9-45 square kilometers of electrode area, or 120 to 600 soccer fields. Tesla Motors estimates that they can get over 200 miles per charge – this could increase to something like 8000-40,000 miles per charge using nanotech. Or, more likely, Tesla Motors could keep the electrode area roughly the same but save vehicle mass instead, conservatively reducing the battery pack mass by 50% and thus cutting around 475 pounds out of the vehicle.

And this is why companies like Nissan (from the NewsHour story) are so interested in using nanotechnology for electric and hybrid vehicles.

[Crossposted: The Daedalnexus, Scholars & Rogues]

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Comments»

1. Thoughts in the Daedalnexus - June 1, 2007

Hybrid cars are at the intersection of nanotechnology and battery technology research

Nanotechnology will transform nearly every field it touches, and it has the potential to touch literally every field.  In this case, it could transform batteries by giving them 40x or more the capacity of current batteries.

2. Sam Smith - June 2, 2007

So – the obvious questions. Time to market penetration and cost?

Also – and tell me if this is a stupid question – but say I can store 100 times more energy. Makes owning an electrical car practical, but it exerts no impact on the ultimate energy cycle – it still takes X amount of coal to produce Y amount of electricity, regardless of how that electricity is stored and spent.

Or is this question better posed within the framework of, say, solar storage?

3. Brian Angliss - June 4, 2007

Time to market and cost are a big question, but when it comes to batteries, if it costs 5x base but gives you 100x the storage, it’s still cheap. And the savings may not include the battery disposal savings either, since you’re disposing of significantly fewer heavy metals.

The power still has to be generated, but grabbing charge overnight is a huge piece of Tesla Motor’s claims to cheap fuel. But ultimately, advanced battery technologies are a prerequisite to wide-spread solar and wind (and especially to massively decentralized solar). Until now batteries for such systems have usually been environmentally nasty (things like lead-acid car batteries, but bigger) because better batteries like lithium-ion didn’t have the nearly unlimited recharge cycles of lead-acid. If Mr. Gotcher is right and his batteries can handle 20,000+ recharge cycles with his new electrodes, then that’s a huge deal.

One recharge cycle per day when you can handle only 500-1000 recharge cycles gives you 1.5-3 years before you replace your batteries. But at 20,000 cycles, you get 55 years, which is WELL past the expected usable life of the solar panels you’re charging the batteries with.

As far as nanotech improving solar panels the same way, there’s actually been some research in this exact area recently. Check out http://www.physorg.com/news7076.html and http://www.technologyreview.com/Energy/17025/


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