[News Bot]

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.

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[JRP3]

This could be huge.

The approach only requires simple changes to the production process of a well-known material.....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.

Hopefully this will pan out in the real world.

[JRP3]

Another article with some other details. Apparently they can tweak the chemistry for greater capacity or higher C rates, not surprisingly they are inversely proportionate. http://arstechnica.com/science/news/...10-seconds.ars

The results are pretty astonishing. At low discharge rates, a cell prepared from this material discharges completely to its theoretical limit (~166mAh/g). As the authors put it, "Capacity retention of the material is superior." Running it through 50 charge/discharge cycles revealed no significant change in the total capacity of the battery.
But the truly surprising features of the cell came when the authors tweaked the cathode to allow higher currents to be run into the cell. Increasing the rate by a factor of 100 dropped the total capacity down to about 110mAh/g, but increased the power rate by two orders of magnitude (that's a hundred-fold increase) compared to traditional lithium batteries. Amazingly, under these conditions, the charge capacity of the battery actually increased as it underwent more charge/discharge cycles.

[PhantomPholly]

So, if you discharged it rapidly a few thousand times the total capacity would like triple???

Sign me up - requires lead-foot driving for best battery life!!!

[JRP3]

I don't think so, probably just similar to how regular LiFePO4 capacity increases during the initial cycling, then levels out.

[david85]

Hope something comes of it soon. Although in the video interview, the guest "expert" says that the energy density is not yet at a very good level. I hope their optimism is well placed because eliminating internal resistance is one of the final frontiers of battery design.

We will probably start seeing more of this becuase lithium is still in its infancy.

[Sunking]

Personally I hope there is some truth to this, but experience has taught me MIT publishes a lot of BS.

[Stunt Driver]

I may be wrong, but it's the price that kills EVs still, not the charge speed. If 20KWh of LiFePo would cost reasonable money, like 2-5 thousands - you wouldn't have to worry about speed of charge, just plan trip better.

Even if fast charging batteries will come out soon - it will take ages to standartize on charging possibility, and availability of 30kw+ power sockets.

[JRP3]

Though the title references fast charging the improvements also talk about the ability to have a battery that uses less material yet have the same or better capacity. If the process is not too expensive this could lead to cheaper smaller cells. I agree that fast charging is not really the end all be all that many try to make it, but it is one of the big arguments detractors try to use against EV's.

[samborambo]

Originally Posted by News Bot

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.

More...

Completely pointless. Charging a 30kWh pack in 20 seconds would require at least 325MW of power. That's enough to power a large city.

Then there's the problem of getting the power the last few yards into the vehicle. If the battery was a more realistic 800VDC, the charging cable would need to sustain 405kA for 20 secs. You'd need a forklift to lift that cable. Also, how do you switch 405kA DC? To put that in perspective, lightning strikes are often around 25kA.

Charging above 100kVA becomes problematic and expensive for the on-board charger, connection system and, most severely, utility network infrastructure. Charging a 30kWh pack at 100kVA is aproximately a 20 minute charge to 90% capacity. That's a charge rate of 3C which many LiFePO4's are capable of sustaining. It's obvious now that batteries are not the limiting factor. 20 minutes is as good as it's ever going to get.

Sam.