Disaster!

[qdlaty]

retepsnikrep
I'm really sorry to hear about your accident.
What cells you are using ? I guess by the description of swelling that some kind of prismatic, soft cells in pouch bags.
Such situation happened to me too, I left unmaintained pack of 36 cells in series with constant, small load and fully equalized pack discharged itself down to 1.2 V per cell.
Using very small current (0.05C) and constantly monitoring each cell's voltage and temperature I've charged it back and surprisingly the Battery Pack fully recovered. Honestly I did not see single cell damaged. But on the other hand - pack has lost it's high current performance - I see increased "internal resistance" in low SOC area much earlier than before.
So, to compare - I was able to discharge the pack using nominal current down to 90% of its nominal capacity before I hit the cut-off voltage. Now it's 76-70%. The remaining region is usable at lower current.
If you are able to do such verification and share with us the results (or comments) we will see if it's common or only one case (my).

Marcin

[retepsnikrep]

Back in operation

I tested van this morning, short 12 mile test run, seemed OK.

When weather is better I'll try again. IR is probably a bit higher as mentioned by Marcin. Regen put's them over max voltage fairly easily.

Capacity will probably be slightly diminished, but getting the power in and out as IR increases due to age is the main problem now. My TS cells are getting on for 4.5 years old.

The two swollen duds ones I have clamped tightly in my vice to reduce swelling, and hooked them up to my 60A single cell charger. One has charged OK upto 4.2V from 0.6v, the other one is on charge now. I shall test them with my dummy load later and report back.

I'm fairly relieved seem to have recovered pack at present.

[qdos]

It's good to hear you're getting life back into the batteries. Patience usually pays off

[MalcolmB]

Good news Peter. Any idea why the TS cells swell or what actually happens when you compress them? Just curious. I've not heard of it happening with any other cells.

[retepsnikrep]

TS Cells are supposed to be compressed during use so they can't swell. However my abuse of them overcame my cell strapping and two swelled.
Hopefully I can recompress them.

Swelling of uncompressed cells is a known issue for TS cells. Some reaction in electrolyte I assume causes it when abused.

[ChrisB]

Phew sounds like you got away with it ......just

Malcolm, if my memory serves me correct they naturally expand in use and you need to strap them as when they expand the electrolyte looses contact with the electrodes and hence thye start to go or do go high resistance.
Must admit I wasnt aware you could mend them afterwards by recompression
I've got a couple of lappy batts which have swollen up and burst there cases and are now high resistance, I'm wondering if I recompressed these some how they would come back
Or I'll end up blowing myself up

ChrisB