A new manufacturing method for lithium-ion batteries could lead to smaller, lighter batteries that can be charged in just seconds.
Batteries that discharge just as quickly would be useful for electric and hybrid cars, where a quick jolt of charge is needed for acceleration.
The approach only requires simple changes to the production process of a well-known material.
The new research is reported in the scientific journal Nature.
Because of the electronic punch that they pack, gram for gram, lithium-ion batteries are the most common rechargeable batteries found in consumer electronics, such as laptops.
However, they take a long time to charge; researchers have assumed until now that there was a speed limit on the lithium ions and electrons that pass through the batteries to form an electrochemical circuit.
Gerbrand Ceder, at the Massachusetts Institute of Technology (MIT), US, and his colleagues used a computer simulation to model the movements of ions and electrons in a variant of the standard lithium material known as lithium iron phosphate.
The simulation indicated that ions were moving at great speed.
"If transport of the lithium ions was so fast, something else had to be the problem," Professor Ceder said.
That problem turned out to be the way ions passed through the material.
They pass through minuscule tunnels, whose entrances are present at the surface of the material.
However, the team discovered that to get into these channels, the ions had to be positioned directly in front of the tunnel entrances - if they were not, they could not get through.
The solution, Ceder discovered, was to engineer the material such that it has a so-called "beltway" that guides the ions towards the tunnel entrances.
A prototype battery made using the new technique could be charged in less than 20 seconds - in comparison to six minutes with an untreated sample of the material.
Most commercial batteries use a material made up of lithium and cobalt, but lithium iron phosphate does not suffer from overheating - something that has affected laptop and mp3 player batteries in a number of incidents.
Even though it is cheap, lithium iron phosphate has until now received little attention because lithium cobalt batteries can store slightly more charge for a given weight.
However, the researchers found that their new material does not lose its capacity to charge over time in the way that standard lithium ion batteries do.
That means that the excess material put into standard batteries to compensate for this loss over time is not necessary, leading to smaller, lighter batteries with phenomenal charging rates.
What is more, because there are relatively few changes to the standard manufacturing process, Professor Ceder believes the new battery material could make it to market within two to three years.
So, these batteries charge faster, are less potentialy dangerous, and have a longer useable life than conventional lithium ion batteries, and can be manufactured without having to set up entirely new production lines. I guess people who what viable electric cars will be over the moon.
NPR had a story on this about a month or two ago and I had only heard part of it, never got the chance to run down a source on this development. This promises to be quite a boon in a number of applications beyond viable electric cars.
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This article makes me think of the new Apple batteries I've heard about. Does anybody know about the technology Apple is using in its new laptops? Is it still Lithium Ion technology?
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salm wrote:Please let them have a storage capacity high enough to power projectors in cell phones.
Have you actually used one? The brightness is so low, they're useless outdoors or near windows (in the daytime), plus the resolution, sharpness and contrast are all sucky. They're just about usable for showing people business slides in a room with white walls and no natural light (at an image diagonal of half a metre or so), but I'd still prefer to take a laptop wherever possible. Battery power isn't the problem here, it's the brightness and thermal efficiency of light sources you can fit into a phone.
salm wrote:Please let them have a storage capacity high enough to power projectors in cell phones.
Have you actually used one? The brightness is so low, they're useless outdoors or near windows (in the daytime), plus the resolution, sharpness and contrast are all sucky. They're just about usable for showing people business slides in a room with white walls and no natural light (at an image diagonal of half a metre or so), but I'd still prefer to take a laptop wherever possible. Battery power isn't the problem here, it's the brightness and thermal efficiency of light sources you can fit into a phone.
Ah, ok. I didn´t know that. I thought the only problem left was battery capacity.
salm wrote:
Ah, ok. I didn´t know that. I thought the only problem left was battery capacity.
A good quality projector needs very expensive, very large bulbs as well to get the required brightness. I know from my own work that each bulb is good for about two months of hard use or six months of daily use(There are two conference rooms with the very nice projectors, one is used about 10 hours a day with one meeting ending only to have another start, the other gets used every day anywhere from one to seven hours worth, same projector and the bulbs lasted less than a year)
Each bulb also cost over sixty dollars and were fist sized. Not something to inspire confidence for squeezing into a cell-phone.
"A cult is a religion with no political power." -Tom Wolfe Pardon me for sounding like a dick, but I'm playing the tiniest violin in the world right now-Dalton
Mr Bean wrote:A good quality projector needs very expensive, very large bulbs as well to get the required brightness.
LED arrays and solid state lasers are possible alternatives, though the former are optically complicated and the later are expensive - there are some low end (but full size) projectors that use LED sources and a few really high end projectors based on lasers. The fundamental problem with minaturisation is heat dissipation, regardless of how much you scale down the components and optics. The best (commercially available) LED sources are about three times more power efficient than halogen bulbs, but you'd still melt a mobile phone if you tried to get even low-end desktop projector brightness out of it.
Starglider wrote:
LED arrays and solid state lasers are possible alternatives, though the former are optically complicated and the later are expensive - there are some low end (but full size) projectors that use LED sources and a few really high end projectors based on lasers. The fundamental problem with minaturisation is heat dissipation, regardless of how much you scale down the components and optics. The best (commercially available) LED sources are about three times more power efficient than halogen bulbs, but you'd still melt a mobile phone if you tried to get even low-end desktop projector brightness out of it.
I keep hearing about LED based projectors but it keeps coming back to the fact that bright enough LED's don't exist at affordable prices yet and are still five to ten years down the road. And even then it's either a array of LED's not just one. Which makes it agian harder to fit into a phone sized object.
"A cult is a religion with no political power." -Tom Wolfe Pardon me for sounding like a dick, but I'm playing the tiniest violin in the world right now-Dalton
Mr Bean wrote:I keep hearing about LED based projectors
They exist, at least in the home theatre ~800 lumen segment. Plus there are all the 'pico projectors' of course; the one I got to try was about two thirds the size of a mobile phone and plugged into the phone to source its content.
but it keeps coming back to the fact that bright enough LED's don't exist at affordable prices
It's not just brightness, it's efficiency. You can use really bright LEDs in a large projector because you can put them on a big heatsink with a large fan blowing over it. That isn't possible in a cellphone, which was what I was getting at with my earlier post. Increasing the brightness of LEDs can be done with packaging and manufacturing tweaks, but increasing their efficiency is a tough solid state physics challenge.
Anyway kinda OT, as for the original post, for consumer electronics it's nice but electric cars do seem to be the killer app. You'd be limited by the rating of your house wiring charging in the garage, but it would enable 'electric filling stations' (if you can replace >50% of the charge in the time it takes to have a cup of coffee), and that's a big plus for the feasibility of all-electric vehicles.
