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90% CID trip
#1
Hi all,

I'm kinda new to the whole cell harvesting but have quite a lot of knowledge of electronics and past experience with lithium batteries.
I got a e-bike batterypack (Bosch Powerpack 400 rear mount) which didn't work anymore and got the cells out and cleaned them all. There are 40 LG LGDBMG11865 cells in the pack but 90% of them supposedly have a CID trip. Four cells show a good voltage close to 3V but the other 36 all show 0V. I randomly took about four cells from the 36 and pushed the cover under the positive terminal back in a bit. All four now show the same voltage of about 3.12V and accept charge (tried it for a short time with a low current, no heating and they keep their charge). This makes me think they all tripped at the same time.

1. What could be the cause of this many cells tripping? Could it be possible that the e-bike was under direct sunlight for too long which caused the pack to heat up and trip?
2. What to do with these cells? Are they still somewhat safe to use (with proper precautions)?

Thanks!
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#2
1. Heated yes or to high current to long. Both generates heat in some kind and will gas and trip cid
2. You bin them. You just destroyed the CID by pushing t back. No they are not safe since the safety is voided.
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#3
(05-07-2020, 01:26 PM)jarrow Wrote: 1. What could be the cause of this many cells tripping? Could it be possible that the e-bike was under direct sunlight for too long which caused the pack to heat up and trip?
2. What to do with these cells? Are they still somewhat safe to use (with proper precautions)?

Thanks!
From everything I've read - these tripped due to a 'harsh event' that caused a significant enough 'gas expansion' from within the cell to to pop the CID.   A harsh event could be something like an overload of power being pulled out and/or overheating - but I don't know.  Its not good!

The strong and consistent recommendation is to avoid using these - throw them away.
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#4
Let's take the example of a wire fuse. If enough current passed across it to make it snap, but not burn up completely, would you take that same wire and resolder it to a cell and expect it to function as normal?  No, we wouldn't. The fuse would now probably pop sooner.

So pushing the CID back in doesn't really do anything positive. Sure, you can "kinda" use your cell for awhile. But the problem is, if it gets just a little warm and a little bit of pressure builds up, would it pop again really quickly?  Or, since it was pushed back in, could it get caught and "not" vent as soon as it should and allow pressure to build up until explosion???

I would never ever trust a CID popped cell that's been reset in any kind of application. The "only" thing it is good for, recycling.
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#5
Thanks guys! Will definitely toss them.
Think it is kinda like a puffed up LiPo, it still works but could go at any moment with catastrophic results. Got myself another ebike battery with good Samsung cells so that's what I'll be working with.
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#6
(05-08-2020, 08:00 AM)jarrow Wrote: Thanks guys! Will definitely toss them.
Think it is kinda like a puffed up LiPo, it still works but could go at any moment with catastrophic results. Got myself another ebike battery with good Samsung cells so that's what I'll be working with.
Its true - if these were the last/only cells left on earth (think Mad Max era) then I'd probably risk it.    But in this day and age there are probably billions of 18650 cells in the world now.... so just toss them and get some others Smile
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