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Mystery large format pouch cells
#1
I've come upon some interesting cells locally, and I'm trying to find more information about them. 

Some information I've gathered thus far:
  • Manufactured by LG Chem. Tagged as "Ebike" cells so maybe they are NMC chemistry.
  • I'm guessing they are about 5+ years old, but are still in their factory packaging. Cell voltages are 3.7V to 3.8V which seems right for storage.
  • The first few discharges have been around 8.5Ah. I was expecting capacity to be higher based on size/weight, like 10+. Will they get better with more cycles?
  • 240g, 7x93x185 mm (about 30% larger than a dollar) tabs are 20x15x0.25mm
  • Positive tab is aluminum so spot welding or special solder/flux is required.
  • internal resistance when charged is about 15mOhms.
  • Based on my limited testings, the Energy Density is 130W-hr/kg. That would put these at the lower end of the spectrum for their chemistry.
The good news is these are cheap, less than $40/kW-hr. I picked up a case of 30 cells to experiment with and they have over 100 more cases. I'm trying to figure out if they're worth messing with.

Any input would be helpful.

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#2
If they capacity test OK, and don't self discharge. Definitely. You will need to spot weld the aluminum. Solder is just too difficult, and flux will be too corrosive, especially for large numbers.

You will have to custom design some kind of mount. But I can't otherwise consider not using them for a large project. Given that they have all been stored the same way, they should have degraded in a similar fashion (and therefore have similar capacities), and be easy to capacity match
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#3
Any luck on what these are. Are they 3.2v or 3.7v batteries. What did they fully charge to. Look like a good deal either way.
Thanks
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#4
Definitely 3.7v nominal cells.  
Still no luck tracking down manufacturer's data. I've cycled 3 different cells several times now and capacity is consistently at 8.5Ah (well, +/- 100mAh.)

It looks like they are on craigslist now, at $1 per cell. Assuming a capacity of 8.5Ah, that would be just $32/kWh. I don't know if the seller will ship as I'm not the seller.
https://denver.craigslist.org/pts/d/arva...28325.html
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#5
I bought a some of these a few days ago and have been doing research on them also. From what I can find or assume they where Imported in early 2010. Every cell I tested is at 3.7 volts un charged and stored for years and the charger stops at 4.10 volts. These are the same style the Chevy volt used in 2010-2011 time but thinking its a smaller capacity. I’m going for the long shot and trying to get ahold of the importer. This is the link that the batteries may have came from. Thanks.

https://panjiva.com/Compact-Power-Inc/2678451
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#6
Yes, they seem to very similar to the Chevy Volt cells of that time from.

Please be sure to post any of your testing results.
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#7
Yes you to please.
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#8
I have seen loads of Chevrolet Volt cells in my hands. Also, others from those manufacturers. This does not look like an LG cell to me. Maybe a very very old one... Lg have bar codes... I do see the LGC on it. and other info, like the cell serial... and the pos and neg are switched. I am looking for some sub-10Ah cells... it would be nice to know what these are.

They look a little puffed, like a slight loss of cap. Around the tabs... I would bet they were originally 10Ah.
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#9
Picture of the box they came in

The cells.



1 amp discharge test with 4 cells gave me a 9144mah per cell. They don’t get hot at all no matter how hard I discharge them. The less amps the better they test on mah. I have enough to make one hell of a solar battery. I was going to hole punch them all and bolt them together maybe 4p or two stacks of 4p and 7s. Then use crimp ring connectors and wire them together. I’m trying to size the wire now.

I have maybe one in 30-45 cells that are lose or bloated and they test low on volts around 2.5

Close up
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#10

They are coming along. 7s5p. 1100 watt hour each minimum. I do a discharge test on the pack soon I hope.
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