Cleaning cells


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Chablism

Member
Joined
Jan 27, 2018
Messages
177
Is there a standard for cleaning cells that look to have fluid under the wrapper.

No actual fluid, but has appearance of such.

Not sure if fluid is from leaking adjacent cells or water exposure

An example might be

Dispose wrapper
Lightly sand cell wall
Clean with alchihol
Add clear wrapper and monitor

All cells have tested ok for capacity and have held charge for Six weeks
 

ajw22

Member
Joined
Nov 16, 2018
Messages
715
Not sure, but I think some manufacturers have oil or something left on their cells. I doubt that's something to be concerned about, unless it has oozed out from inside the cell (electrolyte, has sweetish fruity smell) or dripped on from an external source.
 

daromer

Moderator
Joined
Oct 8, 2016
Messages
5,662
Never sand the cell. You remove the protective coating. IF you cnanot clean Them with just ert tissue bin the cell. IF There is any sign it stuff att the positive pole then bin the cell.

IF you cannot guarantee the cid function on positive end bin the cell.
 

Chablism

Member
Joined
Jan 27, 2018
Messages
177
daromer said:
Never sand the cell. You remove the protective coating. IF you cnanot clean Them with just ert tissue bin the cell. IF There is any sign it stuff att the positive pole then bin the cell.

IF you cannot guarantee the cid function on positive end bin the cell.

Interesting that this may be something left on durring manufacturing.

for sure not something leaking from positive end and no smell.

with wrapper off, there is no liquid as it is more of a stain.

do all cells have the protective coating, as it would be interesting to know the thickness


Here are some sample pics where others asked same question and de not get a reply


image_kusorp.jpg

image_admuqn.jpg

image_oegtzu.jpg


image_fvicmh.jpg
 

TheBatteries

Administrator
Joined
Oct 8, 2016
Messages
2,127
If it looks like there is any kind of moisture under the heat shrink, it's best to just discard the cell. You could remove the shrink and see what's going on, but chances are it's harmful in the long run... My guess would be a tiny bit of electrolyte leaked out from the crimp area or moister/water damage.
 

Chablism

Member
Joined
Jan 27, 2018
Messages
177
Here is one of my cells. 2300 mah


image_tlfnzc.jpg


If I clean up, but on a new wrapper and put in a power bank for six months I should be able to gain a higher confidence.

Yes/No
 

krlenjuska

New member
Joined
Sep 24, 2019
Messages
26
If you try to squeeze that with your nail - that "moisture" will disappear. Its often case with some sony cells. it seems its only air between cell and heat shrink.
 

Geek

Member
Joined
Aug 15, 2017
Messages
920
I would defiantly remove the shrink and see what is going on. I would consider using clear shrink when re-wrapping so you can observe if there is a leak.

With all lithium batteries, I subscribe to the 'if in doubt, throw it out' policy.
 

Overmind

Member
Joined
Jan 16, 2019
Messages
457
I try not to remove the original plastic cover. I clean it with high concentration alcohol. If there is rust below, like in the Sony cell picture, I usually let it like that because the rust will not be removable easy anyway.

If the original case is damaged, I remove it completely and use a heat-shrink tube to replace it.
 
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