# MIT Researchers Reveal Way to Create Battery That 'Charges in Seconds'



## EVDL Archive (Jul 26, 2007)

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...


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## JRP3 (Mar 7, 2008)

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.


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## JRP3 (Mar 7, 2008)

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...ough-could-charge-batteries-in-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.


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## PhantomPholly (Aug 20, 2008)

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!!!


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## JRP3 (Mar 7, 2008)

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


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## david85 (Nov 12, 2007)

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.


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## Sunking (Aug 10, 2009)

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


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## Stunt Driver (May 14, 2009)

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.


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## JRP3 (Mar 7, 2008)

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.


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## samborambo (Aug 27, 2008)

News Bot said:


> 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.


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## david85 (Nov 12, 2007)

In theory, these could be used to slowly charge off the grid, then dump the energy rapidly into the mobile traction pack for recharge times that are less than ICE refueling times. Although I agree fast charging isn't as big a concern as things like temperature operating range, cycle life, cost, and energy density.

Still encouraging though.


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## PHAT_pudding (Oct 8, 2009)

samborambo said:


> 20 minutes is as good as it's ever going to get.
> 
> Sam.


i wouldn't say that. 

things like super conductivity and induction docking stations etc could seriously change things in the future. massive infrastructure! but could still happen. 

don't hold your breath though, cos it'll be longer than we'd like


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## JRP3 (Mar 7, 2008)

samborambo said:


> 20 minutes is as good as it's ever going to get.


http://www.thefreelibrary.com/AeroV...ic+Vehicle+Fast+Charge+Milestone.-a0164211582


> The *35kWh* (kilowatt-hour) battery pack, developed by Altair Nanotechnologies (NASDAQ:ALTI), is designed for use in the Phoenix Motorcar Sport Utility Truck. This battery pack is designed to allow the truck to travel more than 100 miles on a single charge. The test, conducted by engineers at AV's Monrovia, California *Monrovia* is a city located in the foothills of the San Gabriel Mountains in the San Gabriel Valley of Los Angeles County, California, United States. The population was 36,929 at the 2000 census. Energy Technology Center, was a milestone in battery fast charging, demonstrating the capability of fully charging the pack in *less than ten minutes*.


Also the other side of fast charging is fast discharge/higher C rates, which is a good thing.


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## PhantomPholly (Aug 20, 2008)

samborambo said:


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


Not pointless. As prices go down, "Accumulators" will become common.

People WANT to recharge quickly - it is what they are accustomed to with gasoline. The market will demand it, the vendors will supply it.

If 20 seconds is not feasible, the market will find a compromise which works.


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## tomofreno (Mar 3, 2009)

> Charging a 30kWh pack in 20 seconds would require at least 325MW of power.


 30,000Wh*60min/hr = 1,800,000Wmin, 1,800,000Wmin/1/3min = 5,400,000W = 5.4MW. Your points are well taken, but I don't see how you got 325MW Sam. If one were to charge at a very high pack voltage of 600V, this would be 9000A.  
Better have a good bms.


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## Guest (Oct 16, 2009)

Yes, a 30 kw pack in 20 seconds is pretty extreme - as well as pointless. I can't fill my gasoline tank in 20 seconds either. 

At a charge voltage of 375 volts, a 30 kw charge in 20 seconds takes 14,400 amps of current. There aren't 14,400 amps in the world.

But at 10 minutes, which it often DOES take to fill my tank, we are talking about 500 amps. 

In 20 minutes, we are talking 250 amps. ANd actually, my 100 ah cells will actually charge at that rate now. The limitation isn't the cells, its the charger.

We're actually going to set up a set of batteries and a Manzanita 75 to do this to see if it actually does harm batteries. The manufacturer claims you can charge at 3C.

It will be a kind of expensive solution with a $20K battery pack and a $4600 charger, along with some pretty hefty 1/0 cables and contactors. This pretty quickly becomes a smooth $25,000 "quick charge" home station. How badly do you need to charge that quickly?

The electric car thing is a hot topic right now. There is a lot of public interest in it. But to a large degree, they are asking the wrong questions, and unfortunately, there is no shortage of experts out there willing to speak to this, that have no idea what they are talking about.

I was bemused to read a very recent "study" of electric car adoption/market penetration out to 2020. Since it's very difficult for me to tell what I'll be doing 5 years from now, these are always fun. They did note that their entire study was based on the cost of Lithium Ion cells dropping from the current $720 per kWh capacity to around $440 per kWh. 

As I just had 100 Blue Sky 180 Ah cells delivered, I put the 4 function to it and came up with about $339 kWh delivered and sitting in my driveway.

If you don't know the CURRENT price of the central component to electric cars, how can you publish a "professional peer reviewed study" examining electric car market penetration out to 2020?

As you all know, we sleep, the car charges. If you're driving more than 50 or 75 miles a day, you're working too hard at it anyway. Move closer to work. 

And if you want to drive across the country, I recommend the Cadillac Escalade. It has air conditioned seats that blow cool refreshing air up your ass all the way to Denver and back. You sit up high, on a foot and a half of upholstery, with great visibility, and it is much safer than in a small car.

And if we would all do our local driving in fun little electric cars, the gasoline would be $0.75 cents per gallon, they'd deliver it to your house, and we'd get steak knife sets and S&H green stamps again.

When you are the only guy in your town with an electric car you built, it is easy to think of yourself as "little, ugly, and your mother dresses you funny." Particularly if you simply eat the crap put out by the national media. But actually YOU are the solution. You guys have electric cars, and most of you built them. Stay calm, and devote a little bit of time to demonstrating the cars to others, explaining why range and charge time aren't quite the issues they think, and describe the issues that ARE real.

After a full CENTURY of waiting, the basic science and even engineering of the much needed better battery has happened. WE SHOULD HAVE A PARTY. All that's left is the standard, one each, chicken/egg scenario EVERY technology seems to face. If there were more cars, more people would produce batteries. IF there were more batteries, more people could afford electric cars.

But the nice thing about the chicken and egg scenario, which always LOOKS impossible, is that there really aren't any instances of failure. It comes out the same way every time, LOTS of chickens and LOTS of eggs. The truth is over half the chickens lay eggs, and ALL the eggs come from a chicken somewhere, and if they didn't, they'll produce one themselves soon enough. Ultimately, the price of chickens and the price of eggs are all in all pretty reasonable.

We need SMALLER batteries with more power most of all. Fitting them into cars is hard.

Second in importance, we need lighter batteries, producing more power. Less weight and more power do equal more range and better performance.

Third in importance is we need them to be less expensive.

Charging more quickly actually doesn't even make my list. I'm old. I sleep 8 hours every night. Truth to tell, my car sits 22 hours out of the day. It's even lazier than I am.

Public charging stations?

I don't really care. They're kind of like public toilets. If you gotta have one, it's good they are there. I'd rather use my own toilet in my own home. And the same with my charging station. And for pretty much the same reason. Do you know where that charging plug has been?

Jack Rickard
http://evtv.me


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## Sunking (Aug 10, 2009)

The key is not fast charging of under one minute, 10 to 20 minutes is adequate and doable today. The key is density and price of something like 300 wh/kg at less than $100 per Kwh.


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## david85 (Nov 12, 2007)

Well said, jrickard. I can't really add much to that other than to say there hasn't been a single "study" or other media report that I felt was fair, balanced, up to date and accurate.


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## samborambo (Aug 27, 2008)

tomofreno said:


> 30,000Wh*60min/hr = 1,800,000Wmin, 1,800,000Wmin/1/3min = 5,400,000W = 5.4MW. Your points are well taken, but I don't see how you got 325MW Sam. If one were to charge at a very high pack voltage of 600V, this would be 9000A.
> Better have a good bms.


Yeah, brain fart. Multiplied by 60 twice! 

You're spot on with your figures.

Still, 5.4MW is enough to power a small suburb.

Sam.


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## samborambo (Aug 27, 2008)

jrickard said:


> Public charging stations?
> 
> I don't really care. They're kind of like public toilets. If you gotta have one, it's good they are there. I'd rather use my own toilet in my own home. And the same with my charging station. And for pretty much the same reason. Do you know where that charging plug has been?
> 
> ...


Haha! Excellent Jack. Do you mind if I use that line? I'm presenting a paper on EV charging infrastructure at an engineering conference in a few weeks.

You've got some great points on "peer reviewed" reports and the current state of lithium batteries. The real important advances need to be in energy density, cycle life and price. If power density relative to energy density (the "C" rate) remains as it is, LiFePO4s are already powerful enough for any application I can think of.

Batteries will never be "good enough". As cell chemistry improves we will find more applications for the batteries like long range vehicles, electric flight, alternative to unfeasible electricity reticulation and possibly electric sea freight.

Sam.


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## IamIan (Mar 29, 2009)

how is this any different from this old thread:

Li-Ion/Phosphate batteries with 20 second charge you say!!!

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If it is just re-reporting this same old news... it is still being mis-interrupted ... in the old thread the references all lead back to a report showing a rapid discharge time... and no rapid charge times at all had been tested.


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## JRP3 (Mar 7, 2008)

Actually if you listen to the audio on that page Prof Gerbrand Cedar talks about the charge rate, probably where the reporters got their information.
From the very beginning of the audio: "we can do full charge and discharge in 10 to 20 seconds....we've shown it is scientifically technically feasible to make batteries that charge in that time scale..."
Pretty clear.


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## JRP3 (Mar 7, 2008)

jrickard said:


> As you all know, we sleep, the car charges. If you're driving more than 50 or 75 miles a day, you're working too hard at it anyway. Move closer to work.


Agree.



> *You sit up high*, on a foot and a half of upholstery, with great visibility, and it is much safer than in a small car.


Not in a potential rollover situation.



> We need SMALLER batteries with more power most of all. Fitting them into cars is hard.


That's only true because cars have not been designed for batteries. It would be so simple to design a vehicle where the entire underbody would hold plenty of cells, *if *they were cheap enough. Similar to GM's "skateboard" concept.


> Second in importance, we need lighter batteries, producing more power. Less weight and more power do equal more range and better performance.


 This would be nice, but not strictly necessary. 200 mile packs are more than plenty as you've stated, and quite possible with current technology.


> Third in importance is we need them to be less expensive.


I must strongly disagree. This should be number one, as I've previously stated why your numbers 1 and 2 are not a big issue and can be addressed with vehicle design. Build a vehicle with good underfloor pack area and weight saving techniques and todays best batteries at a lower price point will be more than enough for most applications.


> Charging more quickly actually doesn't even make my list. I'm old. I sleep 8 hours every night. Truth to tell, my car sits 22 hours out of the day. It's even lazier than I am.
> 
> Public charging stations?
> 
> ...


Agree again, with the caveat that fast charging and public charging stations will help with public perception and acceptance.


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## IamIan (Mar 29, 2009)

JRP3 said:


> Actually if you listen to the audio on that page Prof Gerbrand Cedar talks about the charge rate, probably where the reporters got their information.
> From the very beginning of the audio: "we can do full charge and discharge in 10 to 20 seconds....we've shown it is scientifically technically feasible to make batteries that charge in that time scale..."
> Pretty clear.


Not quiet... as clear or easy as that... and yes this is the same old story being re-reported more than 6 months later... will it keep coming back every ~6 months or so still with no actual product progress?

The audio you reference does not change what the actual work they did was actually testing.

You can also read another report on this here:

Super Fast Charging Batteries

And so far their treatment reduced the usable capacity of the battery to 1/3 of what it was before they treated it... that takes the ~100Wh/kg of LiFePO4 down to Lead Acid range of ~33Wh/kg.

The actual charge rate used in the MIT work that Prof Gerbrand Cedar references has been published 6+ months ago in Nature:



> a, Discharge rate capability after charging at C/5 and holding at 4.3 V until the current reaches C/60. C/n denotes the rate at which a full charge or discharge takes n hours. The loading density of the electrode is 3.86 mg cm-2. At 2C, the capacity is close to the theoretical value. b, Capacity retentions when performing full charge–discharge cycles at constant 20C and 60C current rates for 50 cycles. The loading density of the electrode is 3.60 mg cm-2 for the 20C rate and 2.71 mg cm-2 for the 60C rate. The voltage window is approximately 2.5–4.3 V. The electrode formulation is active material (80 wt%), carbon (15 wt%) and binder (5 wt%).


Catch that? They used a charge rate of c/5 until 4.3V then holding 4.3V until current dropped bellow c/60.... yeah... that isn't a revolutionary charge rate at all. 

The assumptions / guesses even by Prof Gerbrand Cedar that this process might work for charging rates like the tests showed it working for discharging rates is still untested, and unproven... He thinks it will work but has not actually done so... and without knowing the rest of that out of context audio it is difficult to actually know what specifically he was replying to.

Saying it will work without having verified results to back it up just puts those assumptions and claims in the same realm as Esstor.

So far in 6+ months ... all references to this work all have ended up point back to the same original MIT work that only tested fast discharge rates... and did not do any such 10 second fast charging.


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