A123 prismatic cells - THE solution?

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Mar 29, 2016
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Hi,
5.5 years ago I bought four A123 packs of 39.6V 2.3Ah each.
I thought they were pricey then, but now after 5.5 years of abuse with motor that draws 2800W and regens 1200W, I feel stupid for not buying more. They are still perfect! Even they don't have BMS - individual checking shows that all cells are balanced.
What happened to this company and why everybody recommends LG/Samsung cells that although have an initial higher specific energy at the beginning of their service, they lose the advantage to the A123 after 1.5-2 years and keep declining while the A123 stays intact. (The A123 with their LiFePo4+nano technology have a negligible aging effect)

Because I need a longer range (I only have 360Wh but the cells are perfect as new), I need to change...
What do you think about the 20Ah prismatic cells A123 makes? The specs claim the same power performance and abuse, and a much higher energy density of 137Wh/Kg instead of 100Wh/kg in the 26650 cells that I have.
Looking at the spec I really don't understand how anyone can think of other Li-Ion chemistry...

Also - since I have no experience in soldering cells together (especially prismatic cells which I never saw before besides pictures), what would you suggest?
Are there shelf-ready battery packs for sale, somewhere? I need 16S, but so far found none at any configuration.
If not - can you direct me to the tools/guides/parts of how creating such a pack by myself, along with the protection circuit?

Thanks for any info,
Roy
 
A123 cells are very good, I have been using 24s 20Ah pouches on my bike for two years now, though it seems like the pouch cells aren't as tough as cylindrical cells, regardless they take a fair amount of abuse.
I'm pushing over 100a battery current, though my cells have degraded somewhat, and I want more range, hence why I'm making a 18c20s 18650 pack out of 2.9ah cells.

li-ion have gotten very cheap compared to lifepo4, and when taking in the consideration that if you pull the same out of both packs the depth of discharge is much lower on li-ion due to the higher capacity, therefor the "500" cycle rating isn't such a big deal. Since said cycle rating goes up to 1000-1500 if you do this, even more if you don't fully charge to 4.2v

A123 cells still have their place though, they make absolutely beast car batteries and other areas where wh/kg isn't a huge concern.
 
li-ion have gotten very cheap compared to lifepo4, and when taking in the consideration that if you pull the same out of both packs the depth of discharge is much lower on li-ion due to the higher capacity, therefor the "500" cycle rating isn't such a big deal. Since said cycle rating goes up to 1000-1500 if you do this, even more if you don't fully charge to 4.2v

Which website would you recommend for buying battery cells/pack?
And which chemistry would you recommend for high power usage (discharge and regen)
I get lost around Aliexpress/Hobbyking/etc...
What do you think about a123rc.com for buying A123 products? Do they seem authentic? (It's just looks too good to be true...)
And what is your opinion about AllCells (seems quite expensive), and what about EM3EV ?

I tend to stay within LiFePo4 because I demand rapid charge rates, especially during regen.
I live in a very hilly city, and slopes of 10%+ are very common here. My 9C+ 2706 motor pumps back easily currents in excess of 20A back into the battery, which would kill a regular Li-Ion chemistry quite shorty. Am I right?
I also just love the fact I can "refuel" my E-Bike within 15min, if I want to. (The A123 support up to 4C charge rate). It's the closest you can get to the little-time you use to fuel your car.
 
Try a forum search on "A123 xxx".. There is a LOT of info on both pouch pack builds, suppliers (be very careful) , and issues that some have had in use.
A123 can cells , such as yours, are highly regarded for many power applications, where quality, reliability and safetty are primary requirements, but as you now realise, they are not ideal for E bikes due to their seriously limited energy density, and cost.
Lico, NMC, ICR, etc 18650s are, cheaper, practically double the energy density, and now have suitable power capability for bikes. They are also readily available in suitably configured packs...unlike the A 123 pouches which can be challenging to assemble.
Search out those threads, and spend a while catching up with others experience.
..Here is a start for you.. https://endless-sphere.com/forums/viewtopic.php?f=14&t=38761&hilit=A123
 
Hillhater said:
Try a forum search on "A123 xxx".. There is a LOT of info on both pouch pack builds, suppliers (be very careful) , and issues that some have had in use.
A123 can cells , such as yours, are highly regarded for many power applications, where quality, reliability and safetty are primary requirements, but as you now realise, they are not ideal for E bikes due to their seriously limited energy density, and cost.
Lico, NMC, ICR, etc 18650s are, cheaper, practically double the energy density, and now have suitable power capability for bikes. They are also readily available in suitably configured packs...unlike the A 123 pouches which can be challenging to assemble.
Search out those threads, and spend a while catching up with others experience.
..Here is a start for you.. https://endless-sphere.com/forums/viewtopic.php?f=14&t=38761&hilit=A123

I did some research and most li-ion packs are sitting at 190Wh/Kg, but after deducing 20% so they achieve 1000-1500 cycles instead of just 500 - You get a modest 150-160Wh. (and with the A123 you get at least 2000 with 100% DOD and brutal discharge rates)
The A123 26650 cells are expensive, giving you only 0.75Wh/$, but the A123 15Ah prismatic cells give you about 1.65Wh/$ (but without BMS and pack).
While Samsung cells (30Q - for high power) fare at around 1.15Wh/$ with already a BMS and pack, I assume they quite match up eventually when assembled in a pack, so the claim that Li-Ion is cheaper is not correct, unless you use really, really, cheap cells.
Also, remember the Samsung cells will lose their capacity benefit after 2 years, and from that point - the A123 will be favorable. (Mine is 5.5 years old and I already saw several Li-Ion generations pass by, among my friends)
That's why I don't see why bother for high-energy cell, if it will be limited at it's discharge rate, limited by it's SOC (to increase it's life), and still it would match up an A123 eventually. Sure, you get a weight benefit, but only for 1.5-2 years, and no one wants to spend so much money to get such a short time of "edge".
I remember a post here where someone showed a Li-Ion cell with 270Wh/Kg density, but the performance spec was very, very bad. Even by the manufacturer, It looked like the cell will kick the bucket after 500 cycles.
 
eTrike said:
A123s are great for power and longevity, and in some situations are still highly desireable. Not as great for volume and weight but you can't win them all. I've got some nearing 9 years old with lots of abuse... recently tested over 95% of original capacity. A ~5kWh prismatic pack I've got weighs 105lbs. For that weight I could have ~9kWh with alternate chemistry. They are/were a great battery choice though :)

Exactly! Imagine how much money you would have spent on Li-Ion chemistry over 9 years.
If weight is a problem, I can just take 2 of my A123 packs (instead of 4), and let them run all the power: 39.6V 2.3Ah*2 => 4.6Ah.
That's "just" 9C for a 40A controller, which is nothing for a cell which is rated for 30C continuous.
Range will be shorter of course, but for quick city commute it's more than enough.
 
thunderstorm80 said:
Exactly! Imagine how much money you would have spent on Li-Ion chemistry over 9 years.
If weight is a problem, I can just take 2 of my A123 packs (instead of 4), and let them run all the power: 39.6V 2.3Ah*2 => 4.6Ah.
That's "just" 9C for a 40A controller, which is nothing for a cell which is rated for 30C continuous.
Range will be shorter of course, but for quick city commute it's more than enough.

Get some actual , fully built, 15-20Ahr pack costs to do a real comparison.
And whilst you are doing it compare the size and weight, and how it fits your bike.
If you slill like the result, if you have the cash, and are happy with the fit and weight on the bike, then go for it.
Everyones requirements and priorities are different......
.....apparently you have a VERY short commute :roll:
 
Hillhater said:
thunderstorm80 said:
Exactly! Imagine how much money you would have spent on Li-Ion chemistry over 9 years.
If weight is a problem, I can just take 2 of my A123 packs (instead of 4), and let them run all the power: 39.6V 2.3Ah*2 => 4.6Ah.
That's "just" 9C for a 40A controller, which is nothing for a cell which is rated for 30C continuous.
Range will be shorter of course, but for quick city commute it's more than enough.

Get some actual , fully built, 15-20Ahr pack costs to do a real comparison.
And whilst you are doing it compare the size and weight, and how it fits your bike.
If you slill like the result, if you have the cash, and are happy with the fit and weight on the bike, then go for it.
Everyones requirements and priorities are different......
.....apparently you have a VERY short commute :roll:

I agree 20Ah would be too heavy with the number of S members required, I am more into the 15Ah version.
I use 39.6V*9.2Ah for my daily commute (or set them to 79.2V 4.6Ah). It's enough for what I do daily. It's heavy with 3.8Kg, but if I would have taken a Li-Ion chemistry, I would have needed a much bigger Wh pack to deal with the same powers (discharge and regen so the pack will not die out quickly), so I would eventually stay with the same weight, or even more.
(Also because I will not use 20% of the battery capacity, to begin with).

My only problem is when I want to go out of town. That's when 360Wh of range are not enough.
And still - I am not convinced who will buy a regular Li-Ion chemistry for a powerful EV unless you don't mind buying your whole pack again after 2-3years. (Assuming a daily heavy use with powerful regen)

I would be happy if you can recommend which Li-Ion cells to buy, according to what you say. Cells that will last for 1000 cycles at least (with deducing 20% of the capacity for that), so I will still have a significant weight advantage over the A123. Cells that can accept rapid charge rates during regen without shortening their life considerably.
My goal is not only efficiency and weight, but also long term economy.
Also, I looked around the famous Samsung/LG cells, and couldn't find info if the cycle-life can be improved further by using low C rates (both ways), which requires more parallel members.

And here is another different approach:
What if I used the A123 cells to handle most of the power demands, while the rest of battery capacity will be composed of Li-Ion - which will deliver modest, supportive currents to the powerful but smaller A123 packs. In that way we can enjoy both worlds:
Poor Wh/Kg for power&abuse, supported by high Wh/Kg for energy storage.
I guess it's easily achievable by mating the Li-Ion pack with a low discharge/charge current BMS which will act as a current-limiter, right?
 
I don't believe in such a marriage because of there discharge curves. Hybrid batteries are for somebody with many meters and time on their hands. This would be an experiment to be monitored to the extent it would be a headache.
 
thunderstorm80 said:
And still - I am not convinced who will buy a regular Li-Ion chemistry for a powerful EV unless you don't mind buying your whole pack again after 2-3years. (Assuming a daily heavy use with powerful regen)

First off, your A123 cells are Li-Ion, they just use a LiFePO4 cathode material.
Modern NMC/NCA cathode material cells designed for endurance (like grid-tie) can handle many 10's of thousands of cycles and still be ~190Wh/kg.

Likewise, from a safety perspective thermal run-away almost always start from the SEI layer over the anode, which is the same no matter the cathode material.
 
liveforphysics said:
thunderstorm80 said:
And still - I am not convinced who will buy a regular Li-Ion chemistry for a powerful EV unless you don't mind buying your whole pack again after 2-3years. (Assuming a daily heavy use with powerful regen)

First off, your A123 cells are Li-Ion, they just use a LiFePO4 cathode material.
Modern NMC/NCA cathode material cells designed for endurance (like grid-tie) can handle many 10's of thousands of cycles and still be ~190Wh/kg.

Likewise, from a safety perspective thermal run-away almost always start from the SEI layer over the anode, which is the same no matter the cathode material.

NMC/NCA with 10000 of cycles and 190Wh/Kg? Can you show me where to buy such cells?
I see NMC/NCA cells which are rated to 500-700 cycles only. (with 100% DOD)

Can you explain the safety thermal run-away issue? I didn't understand what you meant with regarding to mixing hybrid chemistries.
 
eTrike said:
Yes that is a great idea-- no current limiter needed and is pretty straightforward. Many 48V packs (14S li-ion or 16S LiFe) work nearly perfectly together.

More info: https://endless-sphere.com/forums/viewtopic.php?f=14&t=78434&p=1157862

I know I can put them in parallel with the correct ratio of serial members, but do they work TOGETHER (half the current for similar capacity members) or will the A123 do most of the hard work? That's what I want to achieve, otherwise hybrid configuration is useless.
 
Methinks where ur going wrong is u r fixated on the brand A123, and hard cased prismatic as a format..

My understanding is that making pouch cells using the same lifepo4 chemical brew is easy, and even no-name mainstream chinese paks are fine. Thats where u should be looking.

i recently ordered a 5.5kg,15ah 36v 12S lifepo4 pouch cell pak from china, $270US w/ charger & shipped to oz. off ebay. 6-8weeks delivery, surface only from china to oz.

http://www.ebay.com/itm/36v-15ah-LiFePO4-Battery-3A-Charger-BMS-Electric-Bicycles-Rechargeable-USE-500w-/131699945629?autorefresh=true&autorefresh=true

It should be comfortable with 1.5c constant discharge.

a trick ping and others use, is to use e.g 5ah pouches in parallel groups for higher c-rates, as above e.g., 12s 3p paks yield 3c no problem. So u can get lipo like dis/charge rates from lifepo4.

A trick i learned, given the hopeless ambiguity in chinese descriptions (understandable really), is to focus on the cell voltage. 3.2/.3v is lifepo4, ~3.7v is lipo and ~4.2 v is limn (most 18650 cells). so e.g, if a 36v pak is made of lipo pouches, it will have 10 cells (& hi c-rates & ~short life), & lifepo4 paks will contain 12 cells due to lower voltage cells. (12x3.3v=39.6v, a nice boost over 36v and 540wh).
 
cycleops612 said:
Methinks where ur going wrong is u r fixated on the brand A123, and hard cased prismatic as a format..

My understanding is that making pouch cells using the same lifepo4 chemical brew is easy, and even no-name mainstream chinese paks are fine. Thats where u should be looking.

i recently ordered a 5.5kg,15ah 36v 12S lifepo4 pouch cell pak from china, $270US w/ charger & shipped to oz. off ebay. 6-8weeks delivery, surface only from china to oz.

http://www.ebay.com/itm/36v-15ah-LiFePO4-Battery-3A-Charger-BMS-Electric-Bicycles-Rechargeable-USE-500w-/131699945629?autorefresh=true&autorefresh=true

It should be comfortable with 1.5c constant discharge.

a trick ping and others use, is to use e.g 5ah pouches in parallel groups for higher c-rates, as above e.g., 12s 3p paks yield 3c no problem. So u can get lipo like dis/charge rates from lifepo4.

A trick i learned, given the hopeless ambiguity in chinese descriptions (understandable really), is to focus on the cell voltage. 3.2/.3v is lifepo4, ~3.7v is lipo and ~4.2 v is limn (most 18650 cells). so e.g, if a 36v pak is made of lipo pouches, it will have 10 cells (& hi c-rates & ~short life), & lifepo4 paks will contain 12 cells due to lower voltage cells. (12x3.3v=39.6v, a nice boost over 36v and 540wh).

I am not locked on A123, or on the LFP chemistry.
That's why I started this thread, but so far no one has actually gave me a link where to buy non-LFP cells that has 10000 cycles with 190Wh/Kg (as one member said that exists). And I am only interested in quality cells and willing to pay the premium for them. Not cheap chinese material.
And as the other member said - If you don't buy A123 LFP, don't bother with LFP at all - it's not worth it. They are of inferior quality, and that's why they are so cheap.
 
To thunderstorm80
You are about to chose between elephant and horse(lot of). If you take same weight on A123 and any modern NCA (corresponding to your application), you will probably find out that NCA will still have more (much more) capacity after 9 years of everyday use. But advantage of NCA will be:
1) 2-3x the capacity (which gives you more freedom if you have to go further one day)
2) It will still cost less being 2-3x the capacity (see seller Tumich with LG GA(edit: Sanyo GA) at~0.32USD/Wh)

P.S.My everyday use vehicle, which was moped then bicycle (battery migrated and still migrating) uses simplest and cheapest hobbyking Lipos (4s hard cases), they still have about 80% capacity after 5 years, just because I use them in modest range , under 4.1V/cell and mostly under 50% capacity cycle.(and it will happen to you with 2-3x capacity)
 
We just haven't had the time 4 to 6 years to road test the new 18650 battery packs. Hell I'm still testing my A123 pack 830 cycles 4 years old. Works great no bms and very high regen.
 
parabellum said:
To thunderstorm80
You are about to chose between elephant and horse(lot of). If you take same weight on A123 and any modern NCA (corresponding to your application), you will probably find out that NCA will still have more (much more) capacity after 9 years of everyday use. But advantage of NCA will be:
1) 2-3x the capacity (which gives you more freedom if you have to go further one day)
2) It will still cost less being 2-3x the capacity (see seller Tumich with LG GA at~0.32USD/Wh)

P.S.My everyday use vehicle, which was moped then bicycle (battery migrated and still migrating) uses simplest and cheapest hobbyking Lipos (4s hard cases), they still have about 80% capacity after 5 years, just because I use them in modest range , under 4.1V/cell and mostly under 50% capacity cycle.(and it will happen to you with 2-3x capacity)

Well, putting aside for the moment 18650 limn has less than 1/3 the lifespan, fast degradation and my demonstrable assertions that their rating specs are a lie, can we have an example please (using my lifepo4 purchase for comparison), of a ~5.5kg 18650 pak that produces ~1200-1500wh, 900w peak & costs ~$288US w/ charger & freight?

I showed you mine, so it seems fair.
 
?

The pack you linked to earlier: http://www.ebay.com/itm/36v-15ah-LiFePO4-Battery-3A-Charger-BMS-Electric-Bicycles-Rechargeable-USE-500w-/131699945629?autorefresh=true&autorefresh=true

*if* it delivers the claimed ratings, is 540Wh, 540W continuous discharge and 1080W peak.

It's longevity/cycle life has also yet to be established. I hope it's good and does what you need, but not a lot can be claimed for an unknown, inexpensive battery from ebay that you don't even yet have in hand...
 
parabellum said:
To thunderstorm80
You are about to chose between elephant and horse(lot of). If you take same weight on A123 and any modern NCA (corresponding to your application), you will probably find out that NCA will still have more (much more) capacity after 9 years of everyday use. But advantage of NCA will be:
1) 2-3x the capacity (which gives you more freedom if you have to go further one day)
2) It will still cost less being 2-3x the capacity (see seller Tumich with LG GA at~0.32USD/Wh)

P.S.My everyday use vehicle, which was moped then bicycle (battery migrated and still migrating) uses simplest and cheapest hobbyking Lipos (4s hard cases), they still have about 80% capacity after 5 years, just because I use them in modest range , under 4.1V/cell and mostly under 50% capacity cycle.(and it will happen to you with 2-3x capacity)

I loved the metaphor of the elephant and the horse.
Can you please give me a link where I can buy such cells. Ebay is full of fake/poor quality cells...
Aliexpress can't be trusted as well in that manner.
I would like two or three online shops where you would recommend to buy such cells or a built pack.
For example:
http://em3ev.com/store/
but they don't come anywhere near the specs you claim modern Li-Ion has...
I also know http://www.a123rc.com, but that's mostly for A123 merchandise.

I would have bought from Justin, but their AllCells are too expensive. (and there is an expensive shipment as well, outside America)
So far everyone is just throwing numbers, figures, articles, but not about a single reputable shop where you can buy the spoken equipment!
(I didn't find the seller "Tumich" you talk about - can you please be more specific?)
 
thunderstorm80 said:
Can you please give me a link where I can buy such cells. Ebay is full of fake/poor quality cells...
Yes, that why we have endless sphere community and sell/buy stuff from reputable users inside, that are kind enough to share their access possibilities providing stuff at small mark-up.
https://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
P.S. If you just make an effort to copy/paste Tumich in google search bar, it is the 4th search result and 1st if you add 18650
 
cycleops612 said:
I showed you mine, so it seems fair.
I do not really understand your question, is it?
Weight (5.5kg) and capacyty(1.2KWh) you are giving could be archived with LG GA (edit: Sanyo GA), which is NCA + Si chemistry if I am not mistaken (about chemistry). But price will be higher (double at least) and you could discharge with >3KW continuous and peak even higher.
cycleops612 said:
Well, putting aside for the moment 18650 limn has less than 1/3 the lifespan, fast degradation and my demonstrable assertions that their rating specs are a lie
BTW Sony Konions (from Makita packs VTC1 and VTC 2 I believe), which are Magnesium (edit: Manganese as noticed by amberwolf) based, did delivered all they claims. Only issue I see is their calender life, but there is no claim about that in their specs. sheet. Still have ~1KWh on stationary duty, for over 5 years now.
 
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