Wednesday, November 08, 2006

Something non-midterm related

So... back before I had my mid-term meltdown, I used to write about energy issues occasionally. One of the issues that is particularly interesting is the rapid decreases in the cost of electricity storage. Two new bits of news on that front:

Eestor, a possibly-vaporware company in Texas hawking an ultracapacitor that, if it pans out, could change - oh, everything. I've written about it a whole mess of times. The latest story from Texas actually has an interesting food-based explanation of Eestor's technology:
In fact, he said, the science behind capacitors has been well understood for more than a century. The devices put opposite electrical charges on a pair of conductive plates. The two plates are kept close enough to maintain the electrical field but far enough to keep the charges from cancelling out.

Think of it as a grilled-cheese sandwich: The bread holds opposite charges. The cheese helps maintain the opposing charges, even as it separates the bread and keeps those charges from canceling each other out. Then you stack one layer atop another....

The hard part is making them efficient enough to store more and more power. Most research has focused on ways to increase the surface area of the plates so they can hold a greater charge. To use the grilled-cheese example, the nooks and crannies of a rough piece of bread can hold more butter than a smoother slice of the same size.

Earlier this year, the Massachusetts Institute of Technology said its researchers were developing plates made of super-small nanotubes that would vastly increase surface area on the same size plate.

Weir and Nelson have gone the other direction: They're focusing on the cheese instead of the bread. Different types of cheese — and thinner slices of it — help store more powerful charges. EEStor's patent describes a method that takes a really good cheese and creates an extremely thin layer of it.
So the science is well understood, the technology is plausible, the company is starting to get more serious press, and you can explain it all with one of my favourite type of lunches. Does it get better than that?

It's worth admitting something - I had a pretty poor understanding of EEStor's technology at first (the grilled cheese analogy is so helpful) and didn't realize that the MIT technology mentioned in the quote above dealt with a different component to the capacitor system. It seems - and here I'm out of my element, so grain of salt everybody - that the MIT and EEStor technologies are complementary, not competing. If one company were to integrate both - assuming that's possible - you would have a superior product. The problem, for now, is that carbon nanotubes are still pricey, and it probably won't make sense to use them for some time yet.

Anyway, even if EEStor doesn't pan out, another company (Altairnano) has demonstrated their high-performance, fast-charging batteries designed specifically for electric cars. They come in 35kwh and 70kwh variants, the larger one being enough to power a small car approx. 350 miles. They claim that with the appropriate charger, the battery can be charged in under 10 minutes.

Herein lies the problem for electric cars that want fast charges - capacitor or battery-based: To flow 70kwh in to a battery in 10 minutes requires a massive voltage, amperage, or both. Most homes wouldn't have that capacity at all, so charging your car at home (one major selling point for electric cars) would still be a time-consuming process.

However, purpose-built rapid chargers could be built for gas station-like service. The problem would be trying to serve more than a few people at once. If 2,500 people tried to charge their cars in 10 minutes all at once, you'd need a nuclear reactor to handle the load - or many, many smaller generators to come on as needed.

1 comment:

auntiegrav said...

WHY, exactly, are all these people driving around in 1 to 2 tons of steel when they really need to just accomplish some task on a computer?
The ultracapacitor doesn't address the root of the problem: that most people don't need to go where they are going, nor nearly as often as they do. Inventing more enabling technology looks nice if you work for the gubmint and you want to make someone THINK you are doing something, but in the end, it doesn't change the fundamental principle of wasteful behaviors. Technology just doesn't impress me anymore. Especially nanocrap that has to be produced in supersized cleanrooms or that was developed by MIT or any other grant-sucking 'institution'. Make the idiots stay home and have an electric van deliver food and Nintendo cartridges to their door. It would be more efficient than transporting them to advertising jobs to sell crap we don't need just so they can buy cars.