tabless A123 ?

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tabless A123 ?

Post by HeadsUp » Wed, 16 Nov 2011, 15:05

this link was posted in Ebay finds

http://www.ebay.com.au/itm/16-A123-20ah ... 783wt_1344

the method of attaching screwed lugs looks a bit dodgy . why do these come without proper tabs , is that a manufacturing defect or are we not seeing part of the picture here ?

my thinking is they should have a wider connection media that covers a wider contact area

what do these cells normally use ?

and has anyone here played with them as an alternative to TS ?

thanks

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tabless A123 ?

Post by Johny » Wed, 16 Nov 2011, 15:28

Yes, considering they are rated at 10C peak and are 20AH cells, I wouldn't be pulling 200A through those connections (fastened by what looks like an M4 bolt/nut). The opening for the tab is also a bit tight. A slipping lug would short the cell.
I agree, we must be missing something but the multi-cell picture tends to indicate that we are not.

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Post by Johny » Wed, 16 Nov 2011, 15:30

I think I get it. The entire top "flap" area is rigid. Maybe composed of two strips of copper with plastic film between them and then the plastic film over it.

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Post by coulomb » Wed, 16 Nov 2011, 16:52

Johny wrote: The entire top "flap" area is rigid. Maybe composed of two strips of copper with plastic film between them and then the plastic film over it.

I don't think there is metal over the whole width of the cell; in the top picture it looks like there are standard tabs (maybe one of aluminium, the other obviously copper) but they've shrunk plastic over most of the tab area. I guess this helps prevent shorts, and stiffens the tab area a little.

I agree it certainly looks flimsy.
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tabless A123 ?

Post by HeadsUp » Wed, 16 Nov 2011, 16:55

only way to evaluate if these can be utilised would be to use a razor to separate the flaps on one to see how thick the tabs are and what their full surface area is .

i wondered if there is supposed to be an adhesive laminated strip that fits between the flaps at top , making contact with the +ve and -ve sheets and giving a heavier terminal to bolt to.

otherwise i would have to tie a bullsh1t flag to the end of my barge pole.

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Post by weber » Wed, 16 Nov 2011, 18:00

For more info on "castrated" A123 cells and a more realistic connection method see
http://www.diyelectriccar.com/forums/sh ... 64067.html
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

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Post by coulomb » Wed, 16 Nov 2011, 18:42

Ah, well spotted Weber.

I guess that clarifies the "Condition" statement on the Ebay listing:
Condition:
     
New: Never Used: A new, unused item with absolutely no signs of wear. The item may be missing the original packaging, or in the original packaging but not sealed. The item may be a factory second or a new, unused item with defects.
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tabless A123 ?

Post by HeadsUp » Wed, 16 Nov 2011, 23:51

weber wrote: For more info on "castrated" A123 cells and a more realistic connection method see
http://www.diyelectriccar.com/forums/sh ... 64067.html


yeah agree as per coulomb .

these are factory rejects that were either diverted after being sent to a recycling yard or sneaked out the back door after being taken off-book

assuming the tabs can be reconstituted , and what kind of BMS is required for A123's ?
big expense for no warranty , but then is warranty worth anything on TS ?

2 cells in parrallel then 150 sets in series ( 300 cells total )
0.5 kg each = 150 kg plus weight of cabling and links.
450 VDC
20 kwhr

or 3 in parallel x 150 = 225 kg
30 kwhr

pretty lightweight power pack

30 kwhr of Ts are 340 kg

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Post by coulomb » Thu, 17 Nov 2011, 16:47

HeadsUp wrote: these are factory rejects that were either diverted after being sent to a recycling yard or sneaked out the back door after being taken off-book
...
2 cells in parallel then 150 sets in series ( 300 cells total )
0.5 kg each = 150 kg plus weight of cabling and links.
450 VDC
20 kwhr

If this is assuming 20 Ah cell capacity, you might be caught short. The DIY guy found his cells were at about 18.5 Ah each, so you might end up with about 18.5 kWH instead of 20 kWh.

Remember that if they had capacity of 20 Ah or more, they probably would not have had their tabs cut off, and you wouldn't be getting them cheap off Ebay.

So that makes them less energy dense than real cells.

I wonder if you might end up with the occasional clunker at say 13 Ah, which would reduce the effective capacity of the pack to 13 kWh. That's the trouble with "seconds". The vendor may or may not have weeded out low capacity or even faulty cells, possibly relying on the buyer to test them and return any duds within 24 hours or less of receiving them.
Last edited by coulomb on Thu, 17 Nov 2011, 05:50, edited 1 time in total.
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tabless A123 ?

Post by HeadsUp » Fri, 18 Nov 2011, 03:23

thanks coulomb

i got a reply from the guy , pricing these at $USD 18.50 each plus $ 1380 for freight to Oz ( for 450 of them )

he claims they are perfectly good but had the tabs removed to avoid paying import tariffs into china

i would call that about 150 cm of bullshirts
( based on my guestimate of his height)


reality is A123 would be a good product coming from the factory , great power for weight but my enquiries show the factory is not interested in dealing with home builders , and maybe even builders like Blade would be too small for them

battery options are still a sticking point for EV builders .

i wanna go to Uni and learn how to make the ****** myself


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tabless A123 ?

Post by juk » Mon, 21 Nov 2011, 16:20

" the factory is not interested in dealing with home builders"

That's a shame. SEC filings show that the company is not interested in making a profit either.

http://www.google.com/finance?q=a123

How hard is it to setup an online store and service the hobbyist, which could be their largest market at present.

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tabless A123 ?

Post by Richo » Mon, 21 Nov 2011, 21:16

HeadsUp wrote:i wanna go to Uni and learn how to make the ****** myself


Chemist and nano technology sounds tuff.
Plus some fat cat has already patented about every battery chemistry under the sun just in case it prooves worth while later.
So the short answer is NO but the long answer is YES.
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tabless A123 ?

Post by coulomb » Mon, 21 Nov 2011, 22:20

Richo wrote: Chemistry and nano technology sounds tuff.

True, but you can buy the nano phosphate magic sauce off the shelf in Brisbane, from the Very Small Particle Company. That is, if they can be bothered selling to a small user. There was a talk from the company at the recent AEVA Convention in Brisbane; very interesting.
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tabless A123 ?

Post by HeadsUp » Mon, 21 Nov 2011, 22:21

Richo wrote:
HeadsUp wrote:i wanna go to Uni and learn how to make the ****** myself


Chemist and nano technology sounds tuff.
Plus some fat cat has already patented about every battery chemistry under the sun just in case it prooves worth while later.


i take that as a form of encouragement

I am known in my industry for never giving up in finding elegant solutions to engineering problems.

Resistance is fertile just as salmon swim upstream , i too shall never tire of looking for a solution.

Image

especially to the problems that people say cant be done

red flag to a bull mate

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Post by Johny » Mon, 21 Nov 2011, 22:27

I DARE you to make well-priced high-energy and power density geniune 3000 cycle LiFePO4 cells for the DIY EV market - go-on - dare ya! Image
(I feel like I'm wording up one of those 3 wishes - I'm bound to have left out a crucial parameter...)

Edit: I KNEW it - I spelt genuine incorrectly. Now what'll happen?
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Post by HeadsUp » Mon, 21 Nov 2011, 23:03

Richo wrote:
HeadsUp wrote:i wanna go to Uni and learn how to make the ****** myself


Chemist and nano technology sounds tuff.
Plus some fat cat has already patented about every battery chemistry under the sun just in case it prooves worth while later.


red flag to a bull

tell me it cant be done and i will give it more thought in moments of navel gazing

who is to say that existing materials when combined wont be found to create or hold potential ?

or better supercaps even.

Image

sorry about the double post from me   , an AEVA forum message popped up saying my first post was forbidden coz i was too handsome or something , or was it too many posts in a given timeframe , either of those two.
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Post by Johny » Wed, 23 Nov 2011, 17:48

A warning from another forum about these cells.
http://endless-sphere.com/forums/viewto ... 14&t=33939

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Post by juk » Thu, 01 Dec 2011, 05:55

Thanksgiving didn’t have much to offer by way of thanks for about 125 employees of A123 who were laid off from the lithium-ion battery maker’s Livonia and Romulus, Michigan factories last week.

The layoff announcements came just weeks after A123 reported rising third-quarter losses and lowered its annual revenue forecast, a sad state of affairs it blamed on reduced orders from big customer Fisker Automotive.

A123 has said it hopes to hire back the workers after six months or less, and still employs about 700 workers at the two plants and at A123’s engineering center in Ann Arbor, Michigan. “The part we really want to stress is we expect it to be temporary: hopefully, a blip we all get past,” A123 spokesman Dan Borgasano told local reporters.

Still, for a company that built its Michigan plants with the help of a $125 million state grant and a $249 million Department of Energy stimulus grant, it’s a bad way to enter the holiday season. Given the troubles that bankruptcies at DOE loan guarantee winners Solyndra and Beacon Power have foisted on the Obama administration, A123’s layoffs aren’t going to be welcome political news in the White House, either.

A123 has laid blame for the layoffs squarely on Fisker’s decision to reduce its orders for battery packs. The two companies inked a partnership last year which came along with a $23 million investment by A123 into Fisker.

But Fisker has struggled to deliver its first car, the high-end hybrid Karma sports car, with only about 40 cars delivered to date. Earth2Tech reported that A123 said Fisker is now looking to delay full-scale Karma production until mid-2012 -- despite the fact that it’s raised close to $700 million, most recently with a $58 million tranche of a $150 million “pre-IPO” round.

A123, for its part, has been posting losses since it went public in September 2009. What's more, the company’s third-quarter earnings call didn’t inspire confidence. The company reported a loss of $63.7 million, or 51 cents per share, compared with a loss of $43.7 million, or 42 cents per share, for the same quarter last year. That came despite revenues of $64.3 million, more than double the $26.2 million reported in the same quarter last year.

A123 has also reduced its 2011 annual revenue forecast to a range of $165 million to $180 million, down from its previous forecast of $210 million to $225 million, largely due to the slowdown in orders from Fisker, the company said. With key consumer electronics battery customer Black & Decker shrinking its orders, and grid energy storage systems a growing but small part of its business, A123 really wants the automotive battery segment to pick up.

That’s also the reason it landed a combined $374 million in state and federal loans to build its Michigan plants, of course. (To be fair, Livonia Mayor Jack Kirksey told local reporters that A123 has hired several hundred more people than the 500 it pledged to hire, giving the local economy a bigger-than-expected boost.)

Whether A123 can compete against Asian battery giants in the long game of supplying batteries for electric cars remains quite unclear, particularly if it keeps manufacturing onshore. Fellow U.S. lithium-ion battery maker Boston Power, which raised $125 million in September, has focused on manufacturing in China to compete. Noted greentech investor Vinod Khosla has predicted that A123 would “not be around” in 10 years.

A123 shares were trading at around $2.30 as of mid-afternoon Tuesday -- quite a fall from the $20-and-up it enjoyed in its post-IPO heyday. It hasn’t traded above $10 per share since early 2011.

Read more…

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tabless A123 ?

Post by HeadsUp » Thu, 01 Dec 2011, 06:05


Great product

but apparently poor utilisation or management of the market opportunity ?


despite the economy , they should be going gangbusters.


wonder what a problem solver would find if they put a magnifying glass over the company...

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tabless A123 ?

Post by PlanB » Thu, 01 Dec 2011, 14:53

These guys have got 'em with tabs for $24

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Post by drgrieve » Thu, 01 Dec 2011, 22:46

Yeah that is where Jack Rickard got some recent test cells from. He regards the cells as most likely genuine.

Much better deal than the tab less ones I spotted on ebay.

Now for someone to come up with cheap, easy and effective way to modualize them.

Some assembly required!

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Post by HeadsUp » Thu, 01 Dec 2011, 23:38

drgrieve wrote: Yeah that is where Jack Rickard got some recent test cells from. He regards the cells as most likely genuine.

Much better deal than the tab less ones I spotted on ebay.

Now for someone to come up with cheap, easy and effective way to modualize them.

Some assembly required!


does anyone know the name of the heavy duty paperclips that are made from a spring steel clip about 18 mm wide , and have a tool thats used to spread them , and then snap them down over a pile of documents ?

i was thinking the heavy duty version could be used with two of them per tab , with copper mini bus bars between the clip and the tab

i believe the clip is cad plated .

anyone got a name or source ?

i didnt see them around for about 15 years.

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tabless A123 ?

Post by Wellsey » Fri, 02 Dec 2011, 02:30


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Post by HeadsUp » Fri, 02 Dec 2011, 02:42



beautiful . thanks wellsey

will have to grab a couple of the heavy duty ones and see if they have enough clamping force for the surface area in question.

i dont think battery heat would get high enough to reduce the tensile strength of the spring steel used in their construction but they need to be tested to see if vibration or resonance could cause them to vibrate loose.

two per tab at least

cheers

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Post by EClubman » Fri, 02 Dec 2011, 13:02

Can I suggest that these staples are great quick and dirty way to connect tabbed cells for testing on the workbench, but definitely NOT what you want in a pack for an electric vehicle.

These jobbies were designed to hold a wad of paper together in an office environment, not conduct up to 600A of current in a dirty, vibrating EV pack.

Conductivity, corrosion, area of contact patch, what happens if one should come loose inside the battery box.

I think that something like a braided cell interconnect folded over the two connecting tabs and then a bolt through the middle to hold it all toegether would be much more robust. (Though then you have the issue of how fat this connection is compared to the width of the cells to deal with)

Mark

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