New A123 Prismatic 20Ah cells 480g and 30C

[lynchy]

I'm trying to find some of the 15Ah cells. They're expensive but the spec looks really nice. I've been told 30C, 400g for the 15Ah and 480g for the 20Ah cells, so a 48V 20Ah pack that weighs about 6kgs and will deliver a constant 600A, and over 25KW They also claim to have a better life cycle than the A123 26650s. Anyone know of a good source for these and what sort of price they are going for?

 

[liveforphysics]

That would be 166whrs/Kg. This would indicate an enormous increase in specific energy for this chemistry, as if I'm not mistaken, the theoretical maximum for an ideal LiFePO4 cell is something like 140whrs/Kg

 

[lynchy]

They're good but not quite that good Assuming 3.3V, 15Ah - 400g and 20Ah - 480g, I make it 123.75whrs/kg and 137.5whrs/kg respectively. Still pretty impressive though.

I'm waiting on some more info but should have some of these very soon along with a BMS that can deliver a reasonable current, but not quite what these can manage. Maybe see if I can get a special BMS manufactured as I can get a 48V 50A continuous rated BMS but would need a special above that sort of figure.

 

[liveforphysics]

They're good but not quite that good Assuming 3.3V, 15Ah - 400g and 20Ah - 480g, I make it 123.75whrs/kg and 137.5whrs/kg respectively. Still pretty impressive though.

I'm waiting on some more info but should have some of these very soon along with a BMS that can deliver a reasonable current, but not quite what these can manage. Maybe see if I can get a special BMS manufactured as I can get a 48V 50A continuous rated BMS but would need a special above that sort of figure.

Ooops! I think I did a mental calculation off the 48V 20Ah and 6Kg spec or something... lol I shouldn't post when I've been up all night. lol Thank you for correcting my mistake. I am definitely excited to see these cells become available. I'm a little worried for A123 though, as I remember reading something about Chrysler's EV battery production being the focus of the company, then, a month later I read Chrysler entirely dropped it's EV build program. If A123 has all ready produced a bunch of pouch cells, this could be great for us though When Chev dropped them from the Volt project, they sold off a huge amount of cells to recover cash, and a bunch of them ended up in China where folks were willing to sell them to us.

 

[lynchy]

Yeah they're selling them but they're not cheap Figure on about 70% additional cost per Ah when compared with Headway 38120. Do you think that is a worthwhile additional cost over the Headway cells, all things considered?

What sort of cost can high discharge rate Li Po be obtained for?

I'll have the dimensions soon and maybe even have a pic of them in my hands

 

[liveforphysics]

What sort of cost can high discharge rate Li Po be obtained for?

I picked a 4s pack because it works out to just be a little more energy than a 20Ah cell.

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10307&Product_Name=Turnigy_5000mAh_4S_40C_Lipo_Pack

These are listed at $50-60 (depending on membership level), but can be purchased for around $40/pack in quanity.

 

[lynchy]

I can't get onto Hobbycity. It must be blocked in China, Taiwan company?

What are the specs for the packs that you suggested 14.8V 4.5Ah? So if the A123 20Ah cells worked out a little more expensive than a highly dangerous :lol: Li Pol pack that wouldn't be so bad I reckon, all things considered.

 

[liveforphysics]

I can't get onto Hobbycity. It must be blocked in China, Taiwan company?

What are the specs for the packs that you suggested 14.8V 4.5Ah? So if the A123 20Ah cells worked out a little more expensive than a highly dangerous :lol: Li Pol pack that wouldn't be so bad I reckon, all things considered.

It was a 40C discharge 4S 5Ah pack.

You can't use a portal to bypass the China firewall and view the link?

 

[lynchy]

You can't use a portal to bypass the China firewall and view the link?

I'll have to sort that out, but I'm not so clued up on such things

There's loads of stuff blocked in China, like Facebook for example.....

 

[heathyoung]

Download firefox and TOR anonimity.

 

[MitchJi]

Hi,

Yeah they're selling them but they're not cheap Figure on about 70% additional cost per Ah when compared with Headway 38120.

I'll have the dimensions soon and maybe even have a pic of them in my hands

Would you mind posting an actual price?

 

[liveforphysics]

There's loads of stuff blocked in China, like Facebook for example.....

Well, if it blocks FaceBook, it's not all bad then. Be glad for what it keeps out of your country. I'm sure there are hundreds or thousands of portals you can use to bypass the China firewall, or if you like, I can setup a private one for you to use as you please.

Hi,

Yeah they're selling them but they're not cheap Figure on about 70% additional cost per Ah when compared with Headway 38120.

I'll have the dimensions soon and maybe even have a pic of them in my hands

Would you mind posting an actual price?

The man's gotta get supply source deals worked out, and get a cell in his hand before we get the price talk. Don't hassle the guy. lol

He is going to get at least 4 of the 20Ah pouches into my hands, and I will test them for you guys, and then make a battery for my racecar with them, and see how they hold up. When he gets a cell to me, I will explicitly photograph, weigh, test, tweak, etc and post the results for you guys. Maybe get an extra couple cells to perform a dead-short test, and a puncture test, and an over voltage test, and then perform a dissection with lots of photos like I did for you guys with a LiPo cell.

 

[lynchy]

Thanks Liveforphysics

I'm sorry, I don't want to be really cagey but as LFP said it's still early days and I need to fix a few things first before committing to anything. If people are genuinly interested I'll happily make a substantial committment to these cells and will be able to pass them on with a small margin so even if you could source them direct you'd be hard pushed to get them much cheaper at small quantities. I need to start making some sort of living soon as I've ploughed a lot of time, money and commitment into my business and all I've done so far is spend spend spend....

If you read between the lines on what I said already you should be able to get a ball park figure for what these could be sold for. I would say a little more per Whr than say high rate discharge Li Pol. The weight is not quite as low as li po but still signicantly better than the best available LiFePO4 AFAIK, plus the lifecycle and C ratings are supposedly better than A123 26650s and they will not go in flames if your charger has a shit fit. I've got a reasonably priced 48V 80A BMS on it's way to me soon also and can get custom V or A ratings as required. Obviously I need to confirm that these high power BMS do what they claim, that's why all I see to do is spend. However everything I've received so far from this source has met or exceeded it's claims, has been well put together and been 100% reliable. I'm not happy just shifting boxes, it needs to be right first and if it's not right I wouldn't sell it.

I'll see what I can do about getting a few of these ASAP and onto LFP so hopefully we can confirm that they live up to the hype.

Thanks for the heads up on the VPN. I've since heard of another way to do it as well, so I'll be back onto Faceback soon.... Yipee

I'll try to get these A123 cells rushed out ASAP before the rest of the order. "Strike while the irons hot" as they say :wink:

 

[lynchy]

Good news!

I've got some samples on the way. Should hopefully be with me by Monday. Not enough to make a pack but enough to keep LFP happy and a few for my tests also. Got a few 15Ah as well.

 

[liveforphysics]

Good news!

I've got some samples on the way. Should hopefully be with me by Monday. Not enough to make a pack but enough to keep LFP happy and a few for my tests also. Got a few 15Ah as well.

Outstanding news! This is fantastic!

 

[liveforphysics]

Depending on how the testing of these cells go, this could be the cell that makes A123 26650 cells a mere past memory in EV battery pack history.

This could be the LiFePO4 option that finally compares to RC lipo level performance, and cures the cycle life and safety that was LiPo's only drawback.

Simple packs mean reliable packs. A 20Ah pack means a stack of cells 1P, all connections on the top in a simple series configuration of alternating which side the tabs get connected together. Pouches are flat, and stack with no wasted space between them, and fit in a box without loads of deadspace. Makes round cell based packs kinda seem absurd. Zero heat concerns with a cell that do 30C continuous, as the Ri will be low enough it's never going to make any waste heat in itself at E-bike discharge levels, even crazy bastard E-bike discharge levels.

If the tests of these cells live up to the claims, this is going to be a viable replacement for LiPo for the nutjobs like myself out there.

I was kinda worried about using LiPo for the E-bikes I'm making for my parents, but I couldn't let them settle for some heavy weak low-C crap, and I didn't want to dedicate a month of my life towards sticking together A123 26650 cells, so this seems like a Godsend of a battery for people who want all the performance, but don't want to have their mom's making some silly charging mistake and causing the pack to burst into flames. lol

I can't believe that I'm actually excited about an LiFePO4 cell, but I am! lol

Who else out there is pumped for this?

 

[lynchy]

I was excited before but after reading that I'm almost bouncing off the walls

I just did some calcs of how I can check this with some big resistive loads that I have. They are 2ohm, 750W, they're big and I generally have to run a fan on them as they get really hot and the resistance increases. If I connect 1 across a 36V pack it will pull 18A. So I reckon I need 25 of these resistive loads to pull the required current out of a single 36V 15A pack. Thats 16.2KW continuous out of a pack that weighs less than 5kgs without all the negatives associated with Li Po. That's assuming 3V per cell rather than the nominal 3.3V quoted. In reality it will probably sag a bit, but still if it's anything like it's claimed spec it is really interesting.

The payments cleared and they've just told me they will send them today so should have these leaving China with a bit of luck on Monday

 

[arlberg]

Hi!
This is very intersting for my small production batch project as well. Looking forward to hear more about that.

A

 

[vanilla ice]

I'll take three. No, four even.

 

[gestalt]

I personaly have watched the boys at the MIT lab doing fast charge and discharge test on a 20 ah prismatic cell from the ones a123 donated. So far so good and when I go to the ev shop on sunday I will get more technical information for you guys.

 

[myzter]

How are these Prismatic cells rated in comparison to the M1's in Internal impedance: (1kHz AC) 8 mΩ typical
If they are in the 1's & 2's & 3's or in the ultra low territory ???

 

[webfootguy]

Are we talking about the cells available from http://www.alibaba.com/product-gs/274086947/A123_Cell_Prismatic_3_3V_20AH.html ? If so, if you look at the picture carefully, it is stamped A123 but it also says "Made in Korea" I believe.

 

[Malcolm]

Just a heads up: http://www.diyelectriccar.com/forums/showthread.php?t=39504

Not sure if Jeff is a member of ES, but it's odd that he didn't post his info here.

 

[MitchJi]

Hi,

This pdf provides information on the newer A123 Cells:
View attachment es_04_fulop.pdf

 

[gestalt]

Thanks for that great PDF Mitch. Who knows if the hobbycity prismatics are the real thing or not, but even if they arn't possibly they will still have comparable performance. If so, who here would be down for a group buy? On the other hand, I'm really hoping that my involvment at MIT can garer me some access to the a123 prismatics. At the last meeting I was at the team leader told us that a123 said they are just laying around all over at the Michigan plant. One can always hope right? Stacking about twelve of those into my bike would be a dream come true.