# Tests confirm Envia Systems’ lithium-ion battery breakthrough



## Ziggythewiz (May 16, 2010)

Let it begin! Let it begin!!


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## ElectriCar (Jun 15, 2008)

Wow, my Calb 200 are only 90wh/kg.


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## rochesterricer (Jan 5, 2011)

Wow, with these kind of verified results and the possibilities of the PolyPlus batteries, I may not need to pin all of my hopes on the DBM Kolibri batteries materializing soon. These are exciting times folks


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## Nathan219 (May 18, 2010)

Now can they build them en mass? If this battery is safe and has useful life cycle it will change the world electric vehicles.
Gasoline 2520.7875 watts/kg 25% useable energy =630 watts/kg
Battery _______400 watts/kg 90% useable energy =360 watts/kg 
Let us hope this isn't vapor ware!


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## tomofreno (Mar 3, 2009)

What is their life cycle, power density, and range of operating temperature?


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## PhantomPholly (Aug 20, 2008)

This other report claims that this is not in a lab, but in an actual market-ready product. If the improvements are simply to the cathode and anode materials, not to the battery assembly process, then they should be able to make good their claim to be in production within 18 months.

This new energy-density falls in right at 7 times heavier than an average of gasoline and diesel fuel, using 8Kwh as our benchmark for "a gallon." That compares with around 30 times heavier for Tesla batteries.

This gives me an estimate of how long (about 2-3 more years) I need to make my current car last - a "15 gallon tank" of these new batteries would be under 650 lbs (reasonable for a car), and that would give even a 20mpg car a 300 mile range.

And, let it be recalled into prosperity that PhantomPholly predicted that the gas problem would be moot within 10 years' time...


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## rochesterricer (Jan 5, 2011)

PhantomPholly said:


> This other report claims that this is not in a lab, but in an actual market-ready product.


Read the comments section of that article. Someone from Envia chimes in and its pretty interesting.


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## frodus (Apr 12, 2008)

So the energy density is high.... what about power density? How many C can they do? And how many cycles can they do before they start to degrade significantly?


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## palmer_md (Jul 22, 2011)

45aH for only a few cycles...and at c/20. All tests except the first two cycles done at c/3. No data shown for c or a multiple of c.

Seems they have some work to do to maintain capacity. They have 400wH/kg at the c/20 rate, but much less (2/3) that at c/3 and it seems to be dropping fairly rapidly.

http://enviasystems.com/announcement/


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## PhantomPholly (Aug 20, 2008)

I'm generally the slow one on the battery side - but if the total Kwh of the pack is tripled, doesn't that mean that you can reduce the C rate on discharge for the same amount of current?

Everything in the real world has operating limits. It seems like this particular operating limit can be easily managed by a) use of a larger pack and b) tuning the controller to prevent excessive C levels.

Not everyone needs, or even wants, a Maserati. A 300 mile Leaf at a more reasonable cost would open the door to mass adoption.


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## palmer_md (Jul 22, 2011)

PhantomPholly said:


> I'm generally the slow one on the battery side - but if the total Kwh of the pack is tripled, doesn't that mean that you can reduce the C rate on discharge for the same amount of current?


I agree that tripling the size and running c/3 would make everything the same except that we are talking about 300 cycles to lose 30% capacity and dropping rapidly, and with the Calb/TS we have 3000 cycles to lose 20% and the curve is fairly flat at that point. Cycle life seems to be the issue. I think this shows great progress, but it is still a work in progress at this point.


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## PhantomPholly (Aug 20, 2008)

palmer_md said:


> I agree that tripling the size and running c/3 would make everything the same except that we are talking about 300 cycles to lose 30% capacity and dropping rapidly, and with the Calb/TS we have 3000 cycles to lose 20% and the curve is fairly flat at that point. Cycle life seems to be the issue. I think this shows great progress, but it is still a work in progress at this point.


The biggest part of the capacity loss seems to be limited to the early part of the test where they ran the battery down to 0% DOD. Again, that seems like it could be controlled with a smarter power controller.


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## palmer_md (Jul 22, 2011)

PhantomPholly said:


> The biggest part of the capacity loss seems to be limited to the early part of the test where they ran the battery down to 0% DOD. Again, that seems like it could be controlled with a smarter power controller.


I think you meant 0%SOC. But yes, it appears you are correct. It could also be that the reason for the rapid loss of capacity on the 80%dod cycles is that they are overcharging to 0%dod and perhaps they should leave 5% at the top and it would increase cycle life.

Anyhow, interesting stuff.


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## Ziggythewiz (May 16, 2010)

It does seem strange that they say the first discharges were to 100% DOD, and later ones were to 80. Are they just testing 1 of these?

I wouldn't consider publishing any results unless it was done on dozens (or enough that the statistical variance between cells would indicate that that sample size was large enough to be relevant) of cells. And if testing more than 1, why would you not have groups of cells doing things like as many cycles as possible to 20% DOD, 50%, 80%, and 100%.

Your 80% DOD cycle life shouldn't be based on a cell that has gone to 100%


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## PhantomPholly (Aug 20, 2008)

Yep, clearly strange. And also sounds like they didn't make a bunch of them for testing as they ought. Maybe this is meant as a "worst case" test?

In any event, all above are correct that they need to test a larger number over a larger number of cycles before we get too excited. If decline remains linear as the chart indicates, it won't take but a thousand cycles before that "price advantage" doesn't seem quite so advantageous - especially when you are still stuck at C/3 with half your original capacity...


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## gor (Nov 25, 2009)

palmer_md said:


> I agree that tripling the size and running c/3 would make everything the same except that we are talking about 300 cycles to lose 30% capacity and dropping rapidly, and with the Calb/TS we have 3000 cycles to lose 20% and the curve is fairly flat at that point. Cycle life seems to be the issue. I think this shows great progress, but it is still a work in progress at this point.


at present it's 450 cycles and counting

they sure cycle-wise it should be same or similar to regular li-ion

and 450 cycles already represents 135 000 miles...

so, 400 wh/kg vs 75-150 wh/kg now
and at lest x2 times for (100miles range leaf or 200 mi byd e6)x2=
= 200-400 mi range --- same range as gas vehicle
how often we fill-in gas in our cars?
once a week?
...30 min charge on interstate - not a problem...

so, if it goes the same (0-60- better), cost about the same, and gas prices climbing, - who will argue against EVs? 
yes, future is here : ))

to once a week


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## litholas (Mar 2, 2012)

The cycle test graph suggests that these batteries, at this point of the development, are better operated at 80% DOD, which implicates a capacity of rather 300Wh/kg at a cost of 170$ per kWh; and after 500 cycles the capacity drops to 75%.

This still makes pretty good EV-batteries. We now have to wait for data about charge-efficiency, safety and durability/life span.

P.S.:The picture shows the cells being wrapped in some foil only, so the batteries will certainly not work for more than 400 cycles at 200 downto 160Wh per kg - before further development.


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## redorblack (Feb 14, 2011)

It seems to have slipped past all of you and almost got past me...

Simple math... 450 cycles x 300 miles a cycle = 135000 miles. Only problem... 45ah isn't getting anyone 30 miles, much less 300. Sure, if you build a pack big enough due to go 300 miles (probably 10-20p?) then you can cycle them low enough to only go 450 cycles in 135000 miles. How is it going to do in a pack that has the intent of cutting the cost/weight/packaging size rather than increasing range? I'm fine with 100 mile range (or less), but under the higher draw how will they do?


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## Coulomb (Apr 22, 2009)

palmer_md said:


> I agree that tripling the size and running c/3 would make everything the same except ...


But we need 3-4C peak for average EV performance. 6C+ peak for spirited performance. [ Edit: not for a very long range pack; I was still thinking 1 hour of driving. So divide my figures by about 3-5. ]

So if these really are limited to C/3, then we'd need 10x, not 3x.

But they may have other applications in mind, e.g. solar storage. In that application, C/3 (burning your capacity in just 3 hours) is close to worst case. You prefer to run at C/10 or C/20, so you get more hours of light and power.

Maybe they're quite capable of 3C for minutes like other lithium chemistries, just that they haven't measured that or even designed fo that because the target market is solar or other storage. It would sure be nice to see some more data.

[ Edit: redorblack, I've just realised that we are saying more or less the same thing. Sorry for the effective double-post. ]

[ Edit2: though I see that on their web site, they are claiming that these 45 Ah cells are "automotive grade". By the co-founder, president, and CTO. I'm afraid they lost a lot of credibility right there for me. ]


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## PhantomPholly (Aug 20, 2008)

I should probably go read up on "C" again before making a dumb post, but I'm at work and want to know...

300 miles of driving is approximately a 5 hour discharge. If you only discharge to 80%, then actual range is about 375 which is about 6 hours of highway driving.

What is the actual C rate of total discharge in 6 hours?


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## Ziggythewiz (May 16, 2010)

C/6 ... ...


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## somanywelps (Jan 25, 2012)

PhantomPholly said:


> I should probably go read up on "C" again before making a dumb post, but I'm at work and want to know...
> 
> 300 miles of driving is approximately a 5 hour discharge. If you only discharge to 80%, then actual range is about 375 which is about 6 hours of highway driving.
> 
> What is the actual C rate of total discharge in 6 hours?


discharge rate C == rate for total discharge in 1 hour.

(So total discharge rate to discharge in 6 hours is one sixth of C so C/6)


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## Coulomb (Apr 22, 2009)

*Re: Tests confirm Envia Systems lithium-ion battery breakthrough*



PhantomPholly said:


> 300 miles of driving is approximately a 5 hour discharge. If you only discharge to 80%, then actual range is about 375 which is about 6 hours of highway driving.


Right. But the 300 miles is surely a "marketing range", so it will presumably be for 100% discharge. (A marketing range doesn't have to be a practical one that you can use every day, usually and sadly.)

So that means a C/5 *average* draw. But there will still be plenty of peaks in there, to say 3x that (so 0.6C), which is almost twice C/3 (0.333C), which is where most of the data is. If peaks of 0.6C don't cost much cycle life, then that could be fine.

You raise a good point, that with very long range packs, the average draw has to be much less than 1C. I for one am not used to thinking that way.


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## PhantomPholly (Aug 20, 2008)

Thanks Coulomb. I was sure it was more complicated than that...

Ok, so there are transients but usually they are more or less "momentary." Speed Racer, certainly, would change the formula but it sounds like largely if it really is a 300 mile pack then the normal driver won't seriously hurt the pack most days.

I don't think that they mentioned anything about a specific pack size - only that they would pack 3 times the energy in the same weight (so that a 100 mile A123 pack would weigh the same as an Envia 300 mile pack, etc.). Based on what we're seeing, I think I would want a 350 mile pack to be on the safe side of the notable drop associated with high-C use in their tests. 

It may be more telling that they only did high-C discharge testing in the first few cycles. I have to think that repeatedly treating the pack that way would severely curtail the life.


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## Coulomb (Apr 22, 2009)

*Re: Tests confirm Envia Systems lithium-ion battery breakthrough*



PhantomPholly said:


> It may be more telling that they only did high-C discharge testing in the first few cycles.


Um, weren't they doing C/20 and C/10 cycles at the start? (Can't readily see on this phone).

Those are *low* discharge rates, possibly necessary as part of the manufacturing process, to form some interface (someone posted about that recently somewhere, re 0.01 V cell voltage). [ Edit: in fact, here: Can Lithium be brought back to life? ]

That I think is still telling, as none of the data has discharges higher than C/3.


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## PhantomPholly (Aug 20, 2008)

Got it. Interpreting the graph:

The first test at C/20 to 100% DoD resulted in a 1% decrease in capacity. 
The second test at C/10 to 100% DOD likewise resulted in a 1% decrease. 
The third test at C/3 to 100% DOD, however, resulted in a *10% decrease in capacity*. 

I don't know if the dots represent a single cycle, or several (10?) The remaining tests were at C/3 to 80% DOD, with each cycle reducing capacity by well under 1%.

One would presume if you never ran over 80% DOD that that large drop would never have occurred.


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## IamIan (Mar 29, 2009)

Link
(March 6 2012 )



> he doesn't expect to see the technology in mass production vehicles until 2015


Looks like 3+ Years.



> Several companies have licensed the same technologies as did Envia from the Argonne National Laboratory.


Doesn't look like they own the tech ... nor are they exclusive in their license from Argonne... who looks to be currently retaining the ownership.



> Envia won't build its own large factories, Kapadia said





> The start-up's aim is to sign a few major customers,


Reads to me like ... they only plan to resell the tech they are leasing from Argonne ... to other OEMs ... and let those other OEMs do all the factory work... but they aren't exclusive in the license from Argonne.

So if you're a large OEM ... why bother with the non-exclusive Envia middle man? ... license the Argonne tech from Argonne yourself.


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