A123 systems cell failure

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jasonck08

jasonck08

Flashlight Enthusiast
Joined
Sep 16, 2007
Messages
1,516
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Redding, CA
So a while ago I bought about 6x A123 18650's off eBay. I only cycled them about 5 times tops then I left them in my battery drawer at about 3.2v. They worked great, I probably did a few tests at 15A or so and also ran them in a hotwire light for a few minutes. They sat in there for probably 6 months or so. I just checked 5 cells and 2 of them read an extremely low voltage .05v, .06. The 3rd one ~1.5v, and the 4th and 5th, pretty normal around 3.2-3.3v. I threw one cell away previously because it managed to discharge itself down to 0 by itself too. I've only seen this happen maybe to one other regular LiCo cell.

Just curious to see if anyone else has had this type of problem with A123 Systems cells. The only thing I know of that would cause a cell to read that low of a voltage is if the CID broke. But that should not happen when its just sitting in a drawer. Anyone have any clues as to what went wrong? :confused:
 
Hello Jasonck08,

I have killed a bunch of A123 cells by subjecting them to higher charge voltages. Other than that they have been very robust.

The seem to handle charging to 4.20 + 0.00 - 0.35 volts. A little higher voltage results in cells with voltages in the range that you are seeing. Is there a chance you charged them on a charger that is capable of higher voltages?

Tom
 
jasonck08 said:
Well the seller claims they are original, and even shows pictures of other fake cells etc. And I doubt non-real A123 cells can stand up to 30C discharge currents...
Click to expand...
After calling a battery distributor while representing a .mil agency trying to get some bare 18650s and getting flat out told no, unless I wanted them to build packs for us or if we were a certified pack builder we were out of luck. That leaves me pretty leery about the legitimacy of anyone doing bulk business selling tons of cells being anything but factory seconds or recycled forgeries.

Did your voltages hold up to what they should have for the 15A test you mentioned? Do you have a charger that gives internal resistance readings? I have zero faith in anything lithium battery related on ebay unless someone is pulling them from packs. (I.e. dewalt packs for 26650 A123's or laptop packs for various li-ion 18650's) The low voltage youre reading wouldnt indicate the CID opening, as thats a mechanical interrupter from internal pressure, and would be 0.00. I dont know if A123 cells even have a PTC which could crack or be damaged and go high resistance. I would expect a normal voltage range until load was applied, not the .05-.06 youre seeing



SilverFox said:
Hello Jasonck08,

I have killed a bunch of A123 cells by subjecting them to higher charge voltages. Other than that they have been very robust.

The seem to handle charging to 4.20 + 0.00 - 0.35 volts. A little higher voltage results in cells with voltages in the range that you are seeing. Is there a chance you charged them on a charger that is capable of higher voltages?

Tom
Click to expand...

4.20? Typo, or being a naughty boy and sticking batteries into chargers not meant for it?
 
SilverFox said:
Hello Jasonck08,

I have killed a bunch of A123 cells by subjecting them to higher charge voltages. Other than that they have been very robust.

The seem to handle charging to 4.20 + 0.00 - 0.35 volts. A little higher voltage results in cells with voltages in the range that you are seeing. Is there a chance you charged them on a charger that is capable of higher voltages?

Tom
Click to expand...

I always charged them with the Lifepo4 setting with 3.6v cutoff on my hobby charger. I believe I did charge them a few times at the 5A setting (max charge spec for these cells).


CKOD said:
After calling a battery distributor while representing a .mil agency trying to get some bare 18650s and getting flat out told no, unless I wanted them to build packs for us or if we were a certified pack builder we were out of luck. That leaves me pretty leery about the legitimacy of anyone doing bulk business selling tons of cells being anything but factory seconds or recycled forgeries.

Did your voltages hold up to what they should have for the 15A test you mentioned? Do you have a charger that gives internal resistance readings? I have zero faith in anything lithium battery related on ebay unless someone is pulling them from packs. (I.e. dewalt packs for 26650 A123's or laptop packs for various li-ion 18650's) The low voltage youre reading wouldnt indicate the CID opening, as thats a mechanical interrupter from internal pressure, and would be 0.00. I dont know if A123 cells even have a PTC which could crack or be damaged and go high resistance. I would expect a normal voltage range until load was applied, not the .05-.06 youre seeing
Click to expand...

It's not at all surprising that a normal US battery supplier would not sell you bare 18650's. The majority of the worlds battery packs are assembled in China and Taiwan. These companies are supposed to use the cells for battery packs, but will often times agree to sell bare cells as well. Like I said I got these from ebay from a Chinese seller. Item #:
200598284760. They claim they are 100% real. Could they be fake? Yes, its possible, but if they are fake they held up to some pretty high currents reasonable well when i first tested them. It's also possible that they are reject cells, or lower grade cells. I guess the only way to know for sure would be to pull a cell or two from a power tool pack, and compare it against these cells.​



 
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