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Nanotech Anode Promises 10X Battery Life
UNIMurph sends word out of Stanford University that researchers have discovered a way to increase battery life tenfold by using silicon nanowires. Quoting News.com: 'It's not a small improvement,' [lead researcher Yi] Cui said. 'It's a revolutionary development.' Citing a research paper they wrote, published in Nature Nanotechnology, Cui said the increased battery capacity was made possible though a new type of anode that utilizes silicon nanowires. Traditional lithium ion batteries use graphite as the anode. This limits the amount of lithium — which holds the charge — that can be held in the anode, and it therefore limits battery life... 'We are working on scaling up and evaluating the cost of our technology,' Cui said. 'There are no roadblocks for either of these.'"
Now, if we can see the same kind of improvements in electricity transmission, solar power electricity generation, and larger scale electricity storage, we might be able to really reduce fossil based fuels and CO2 emissions.
I reserve the right to think for myself. Others' opinions are optional. Puppy on lap = typos...not illiteracy.
This is Sony's way of making a military-grade exploding battery.
Damn I thought we were going to get a factor of 100 improvement in battery capacity.
http://michaelsmith.id.au
It's not even 10fold -- at least not currently. It's only "several" times improvement without an equivalent cathode improvement. Now, that may well happen, but it hasn't happened yet. However, they think they may be able to commercialize it in five years.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
Very briefly put, no. The explosive nature of lithium batteries has very little to do with the electric energy stored in them. If the electric energy stored in a battery was even remotely close to the amount of energy released by burning the chemicals they are composed of, then we would all be driving electric cars by now. In fact, more modern lithium batteries are less prone to explode because they have lower internal resistance, so they don't heat up as much when discharged. I keep seeing this fallacy about energy content vs explosive danger when people discuss batteries, but it is frankly nonsense. Many high-power explosives don't produce a whole lot of heat when they detonate, it is the rapid shock-wave that gives them their destructive power. Conversely, regular butter contains enough energy to drive your car on it, but it is quite tricky to ignite and hence fairly safe.
Anyway, poorly manufactured Lithium batteries are dangerous because they ignite easily. It has very little to do with their energy content.
"...There are no roadblocks for either of these."
So quit with the jibber-jabber and make with the 50 hour laptop battery.
And, let me add, I don't say this to diminish the importance of this news. A severalfold improvement is major, major news. Not in the least because this anode likely lends itself to very rapid charging at the same time. What we're looking at is, as it stands, giving it the sort of charge time and range as a gasoline vehicle, meaning that there's no reason to stick with gasoline (when you can get lower maintenance (assuming long lifespan batteries), higher torque, quieter, more thermodynamically efficient vehicles that only require gas station visits on long trips, require hardly any new infrastructure (versus oil, which needs a lot of infrastructure construction) due to mostly off-peak charging (timer-based to get you a low rate and use our huge amount of unused off-peak capacity), lets us use domestic energy supplies instead of funding our enemies with oil imports, and even if all of the electricity came from burning fossil fuels, would still emit almost half the greenhouse gasses. An equivalent cathode improvement for electric vehicles simply means that you could then drive cross-country on a single charge.
As for lifespan, Yi Cui's team expects to be able to get at least 1,000 cycles out of this. That may not sound like much, but when you can go ~350 miles on a charge, that's 350,000 miles. And not like the battery just disintegrates up at the end of its lifespan; it simply doesn't hold as much charge.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
This technology sounds wonderful. I'd absolutely adore batteries to last ten times longer than they do at present. It would be amazing... imagine 20 or 30 hours of 'real life' battery life on a laptop instead of 2-3 hours. However, I'm really getting tired of stories on Slashdot that basically can be summarised as "Scientists promise [amazing product] using [amazing technology]". Nanotech, nuclear fusion, genetic engineering, micro-scale fission power plants, exotic materials... whatever. You know what? I'm sick of reading stories about theoretically possible things that might (but probably won't) make it into an actual product some time in the near future.
Slashdot ought to have a section for "navel-gazing scientific speculation". Seriously, this sort of "we can make [x] perform [10, 100, 1000...] times better!" bullshit belongs right alongside the "in [10, 20, 50] years, everyone will be in flying cars!" type of crap which has filled Scientific American for, well, forever.
It's 2008. We still don't have flying cars, practical nuclear fusion, fission-powered cars, or multi-petabyte holographic storage devices. In the real world, advances in technology are usually incremental and evolutionary in nature, or a serious tradeoff at best (As an example, the move underway from platter-based hard drives to solid-state hard drives, while revolutionary in nature, involves massive tradeoffs in price-per-gigabyte which are only slowly lessening). It took CD technology a decade or two to give way to a successor with 10 times the storage capacity (dual-layer DVD-R), and making bits smaller is (arguably) a lot easier than increasing energy density (barring the use of nuclear technology or other exotic things which-- again-- isn't realistically going to happen any time soon).
So where's the "NotGonnaHappen" tag?
With spending like this, exactly what are "conservatives" conserving?
Nanowires Boost Laptop Battery Life to 20 Hours
http://hardware.slashdot.org/article.pl?sid=07/12/19/169259
The world belongs to those who get up early. - I'm far from being the king of Earth then
Nano-technology . . . last I heard, not the easiest stuff to engineer in. Nope - can't find too many qualified workers on street-corners. 'quipment ain't at the local machine shop.
Erm, even if this isn't just another load of vapor, just how much will these things cost? and how do you mass-produce 'em?
Oh, and we've heard this whole "new technology discovered which promises blah." We didn't need to hear it twice.
http://www.solarnetwork.net/ is an app that hopes for this - but bigger and cheaper storage would help with the intermittent nature of these 2 power sources. does anyone think that affordable battery capacity could increases the way hard drive capacity did over the last 10 years? 1997 I think I was installing 8GB drives in a machine maybe? maybe even 4GB drives for laptops? Today it's easily 10 times that size on average.
The Wikipedia article on Energy Density lists the energy density of lithium batteries with nanowires at about 6MJ/kg and the energy density of TNT at about 4MJ/kg. And unlike butter or gasoline or some other things, I think the lithium battery has the oxidizer in the package (though maybe not right in the molecule like TNT). I don't think they're going to let you take many of these on the plane with you.
One swallow does not a fellatrix make
After the event, there were several studies of what to do about it. One suggestion was to make available lithium batteries as an alternative. The cells proposed were really quite big. After a few interesting incidents in testing, one of which had an engineer cowering behind a filing cabinet screaming "get that wire away from that thing", one REME officer suggested that with a simple piece of spring loaded steel, the cells could find an alternative use as emergency grenade substitutes. (Disappointingly, the actual solution proposed was to fit an internal fuse.)
Given the energy density of this proposal, a simple micro-Sterling generator driven by sticks of dynamite might be safer in the briefcase.
*The Ministry of Defence is kind of like the Pentagon, but without the competence.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
giving it the sort of charge time and range as a gasoline vehicle
Stop and think for a second, or do some math, because electric cars will *never* 'fill up' as fast as a chemically powered car. Instead of pouring in gasoline, imagine that gasoline powering a flamethrower which you point into your gas tank, and you'll have a better grasp of what it means to transfer energy directly (as in electricity) versus high density potential (like gas).
Assume your electric car needs only 20 horsepower to maintain 60 mph.
One horsepower is about 750 watts, assuming perfect efficiency.
That's 15 kilowatts to keep the car going 60 mph.
To make the numbers easy, figure 300 mile range. That means you need to drive for 5 hours.
5 hours times 15 kilowatts is 75 kilowatt-hours.
Now let's assume the 'electric station' supplies electricity to charge your car at 500 volts.
75000 watt-hours divided by 500 volts equals 150 amps.
For an hour. Assuming perfect charging.
To get to a 3 minute charge time (one twentieth of an hour) you need 20x the amperage, or 3000 amps.
To carry 3000 amps of current for 3 minutes without melting insulation, my numbers show you'd need copper wire about 2.5 inches in diameter (and you'd still get a temperature rise of 90 degrees farenheit over ambient). And note to electricians who may think the numbers are off, don't forget you're charging with DC voltage, not AC, so you're gonna need about 5000 circular mils worth of wire.
I cannot imagine Joe Average plugging TWO wires, each of which is thicker than his wrist, into his car for a 3 minute recharge.
And yeah, you could drop it to 300 amps, but then you're talking 5000 volts.
So basically... you're never, ever going to see a 'gas station' for electric cars. They'll always be charged for long periods at home, or at 'charging garages'.
Maybe you take the wrong approach to "charge" a car.
What about standard, pre-charged batteries that you simply swap at the "gas" station instead of really charging the car? This way the whole process can be done in the same amount of time than filling up gasoline.
This is not even to complicated. You more or less rent the battery from the respective company and return it when it's empty (just to exchange it for a fully charged one).
The "gas" station has all the time in the world to charge the empty batteries, replace/repair faulty ones, etc.
Isn't that a more logical (and much safer) solution to the problem?
The whole principle of operation of storage batteries is to separate charge by oxidising at one pole and reducing at the other, thus the larger the electrical storage per unit volume, the greater the available chemical energy. When the poles are connected, the oxidiser is reduced and the reducer is oxidised back again, in such a way that the exchanged electrons pass along a wire outside the battery rather than directly between the reagents internally. Replying to the GP, the lower the internal resistance, the closer the reagents must be together and the more rapid their reaction, since this is how the battery discharges. Any internal short will allow a potentially more catastrophic reaction, since more current will be generated. It is true as per the GP that butter has a high energy density but is quite safe. Now mix that butter with the correct quantity of powdered oxidiser - say powdered potassium chlorate - and you have, basically, home made blasting explosive. You are not comparing like with like. I wonder who the GP works for?(It's probably illegal to write this posting from the UK, but, Gordon, are you going to lock up everybody who knows a bit of basic chemistry?)
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
Your numbers are a bit off. The Tesla roadster quotes a range of 356km on 54kWh.
If you use 1000 V , 4 parallel plugs, a 100A charging current, that gives you 66kWh in 10 minutes. 100A is doable with AWG 1 ( 7.35mm ), and most of the time you wouldn't be charging from empty anyway, so something like 6 minutes is more reasonable. Of course, this is only necessary if you need to take a pit stop during a long journey, most people would probably just charge it at home over night.
Interview with Dr. Cui, here.
Why OpalCalc is the best Windows calc
Who cares if things get reported more than once. It's something that enough people thought was interesting that they thought it should be posted. Obviously some people want to discuss it. If you've already read the story, and don't want to discuss it any more, then that's fine, but there's lots of people who miss the story the first time around, and would like to discuss it.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
That might be a pretty good idea, for several reasons. But it's not a slam dunk; there are problems that would have to be resolved.
What is the total weight of the car batteries? How much energy will be spent physically swapping them? This isn't just a starter battery... If nothing else, this would probably be the end of the self-service gas station (at least until our car-refueling robot overlords sweep in to save the day)... And remember, it's the driver that's going to end up paying for any labor, or any energy expense in general from swapping batteries.
Another poster's concern about some batteries being in better condition than others doesn't seem like a huge deal in and of itself. The battery station is going to have to monitor the condition of the batteries in its inventory to dispose of them when they're no longer usable; so there's going to be some standard minimum: "you will get at least X out of this battery swap." Maybe you get more sometimes -- nice bonus. The station might set tiered pricing -- for an extra $x.xx you get a better guarantee about the condition of your new battery...
However, unless the station can penalize you for degradation of the battery you turn in (relative to the condition in which you got it), there will be no incentive not to mistreat batteries. What exactly that means will depend on the battery technology, but generally some usage patterns are better for overall battery life than others. If the average battery is abused, average overall life goes down, and then cradle-to-grave energy efficiency goes down (as you have to manufacture / recycle more batteries).
There would be overhead on the station's end to keep a sufficient inventory of charged batteries. To keep that to a minimum, there should be pretty tight standards to make all cars' batteries interchangeable. Is that currently the case in electric cars? How practical is it to have one (or at least a small number of) standard battery? (Again, we're no longer talking about the market for starter batteries here...)
Suppose I swap out my batteries and the replacements fail catestrophically; who all has liability exposure? The station? The previous owner? The manufacturer? How do you keep track of a battery's lineage of ownership?
Ooh, crazy Bad Hollywood Plot theory time -- a terrorist quietly assumes control of a battery station. Over the course of a few days, he swaps out the batteries from as many cars as possible, replacing them with packages that are half battery, half explosive. Once his devices are distributed, across the city vehicles start exploding at random. Film at 11.
Car batteries are not ~$40, 20lb propane tanks. Car batteries are $8k, several hundred pound devices bolted to the base of your car. Not going to happen.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
The Slashdot summary correctly draws from the news.com article, but the news.com article is mis-reporting this news. It is not battery life that is being discussed but rather energy density. Capacity has never referred to battery life. The Nature Nanotechnology journal article in question (abstract, fulltext, pdf - for some reason they are all freely downloadable) reports that their Si nanowire anode has a little more than 10 times the capacity of common graphite anodes, and they have achieved that in charging and 75% of that in discharging.
In terms of cycles, they have data in their supporting info document that shows they have only tested a cell with this electrode up to 30 cycles! So no discussion of battery life can even be made.
Energy density can be found by knowing the capacity of each electrode, the electrolyte properties and volume, and the cell voltage (which is usually about 4 V for Li-ion batteries). They claim to have reached their theoretical maximum 4200 mAh/g capacity for a Si electrode. This is indeed ~10x the capacity of graphite anodes, which are the lowest capacity anodes used in Li-ion batteries (300-400 mAh/g). More common carbon (C6) anodes are about twice that. And, in fact, Li metal anodes have about the same capacity, 3800 to 4000 mAh/g, as these Si nanowires. So the capacity is hardly a breakthrough. However, they may be more safe than Li metal: "Li metal" batteries are Li-ion batteries with Li metal electrodes, which have had safety issues due to Li dendrites (trees) growing between electrodes and shorting out the cell. This article (needs subscription) from years back explains the details of electrode choices and other challenges regarding Li-ion and Li metal batteries. It seems these Si nanowire electrodes may yield similar energy density to Li metal, or several times that of the Li-ion batteries that are in common use.