Harvesting Issue

cyberblob

New member
Joined
Sep 10, 2020
Messages
3
Have a question for the more experienced battery harvesters.
I have been harvesting some old cells and found a few that have a hole from where the weld pulled the bottom case open.
Is this safe to charge and use?

image_xjdqpl.jpg
 
Bin them. No damage what so ever is allowed that is visible.
If that happens cut the strip off instead. Its a common issue on ebikes and high power packs where the welds often are stronger.
 
Thank you all.
I suspected as much that it would be a recycle bin item.
Just hate wasting cells that are now getting harder to come by in my area.
Now that laptops are coming with flat weaker lithium ion phosphate batteries.
I have come up with a nice disposing method as well.. Rapping the battery in a 21700 shrink wrap with an full insulator ring with center. That way i know it is done for and safe.
 
Yup, toss it. not worth the risk.
 
Although I agree with you from a safety perspective, I don't recycle them if they test fine.
That lower part is insignificant from the general p.o.v.
I won't use them in packs but for many other applications they're perfectly fine.
 
Overmind said:
Although I agree with you from a safety perspective, I don't recycle them if they test fine.
That lower part is insignificant from the general p.o.v.
I won't use them in packs but for many other applications they're perfectly fine.

If there are holes in the cell during charging and discharging or even just sitting there, toxic and flammable gases may escape.

Seeing that they are used in and near electronics or even a flashlight, you run the risk of a fire (or worse)
You also don't want to breath the gases.

I would tape the ends and toss them. Trying to discharge them is too dangerous. (such as HF)

From Wiki --> Hydrogen fluoride is a highly dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. The gas can also cause blindness by rapid destruction of the corneas.
 
Yes, hydrogen fluoride (HF) may be generated, generally between 20 and 200?mg/Wh of nominal battery energy capacity.
On top of that, 1525?mg/Wh of another potentially toxic gas, phosphoryl fluoride (POF3),

But the bottom end does not trigger that. In fact, with some skill, you can completely remove it (at least for some brands of cells, I'll try to recall with what type I did that) without triggering a gas release.
 
I haven't kept any of the cells that have holes pulled in them but I'm wondering if they would be salvageable if they are used in a soldered application instead of welded with the solder covering and filling the hole?
 
Personally - I wouldn't fool with it / risk it. Almost new cells are very cheap these days- not as if they are $10 each :)
 
Hello guys, Im new and i luckily can't add this from my experience yet. I always seemed to twist them with pliers. It sometimes damaged the wrap but from a few 100 harvested cells i've never had a leaking cell happen.
 
quadrofource said:
Hello guys, Im new and i can add this from my experience too. I always seemed to twist them with pliers. It sometimes damaged the wrap but from a few 100 harvested cells i've never had a leaking cell happen.
If you pull hard/sharp-enough it can happen. The 'cans' of 18650 cells are not 'thickmetal' as they seem and if you pull out a really strong spot weld (instead of clipping the nickle off)you can get a hole:)
 
OffGridInTheCity said:
quadrofource said:
Hello guys, Im new and i can add this from my experience too. I always seemed to twist them with pliers. It sometimes damaged the wrap but from a few 100 harvested cells i've never had a leaking cell happen.
If you pull hard/sharp-enough it can happen. The 'cans' of 18650 cells are not 'thickmetal' as they seem and if you pull out a really strong spot weld (instead of clipping the nickle off)you can get a hole:)
im lucky it never happened to me yet :D
 
OffGridInTheCity said:
quadrofource said:
Hello guys, Im new and i can add this from my experience too. I always seemed to twist them with pliers. It sometimes damaged the wrap but from a few 100 harvested cells i've never had a leaking cell happen.
If you pull hard/sharp-enough it can happen. The 'cans' of 18650 cells are not 'thickmetal' as they seem and if you pull out a really strong spot weld (instead of clipping the nickle off)you can get a hole:)

I just have to lay off the Wheaties then.
I have started to try twisting them off. It seems to be more of a problem with dewalt battery packs with thick metal tabs.. All the ones that have had holes are from those packs..
Wish there was an easier way to disassemble them with out causing lots of sparks. Gets me every time at least once.
Metal drops below the protective ring then zap sparks.. Makes me jump every time.. :)
 
cyberblob said:
OffGridInTheCity said:
quadrofource said:
Hello guys, Im new and i can add this from my experience too. I always seemed to twist them with pliers. It sometimes damaged the wrap but from a few 100 harvested cells i've never had a leaking cell happen.
If you pull hard/sharp-enough it can happen. The 'cans' of 18650 cells are not 'thickmetal' as they seem and if you pull out a really strong spot weld (instead of clipping the nickle off)you can get a hole:)
dropping bits of tabbing through the vents can cause a welded short you cannot remove.
if its a good cell with enough charge this can mean an "oh shit" event.
when i am cleaning cells i use magnetized flush cutters.
the crumbs stick to them and i can clear them off.
never had any short a cell.

I just have to lay off the Wheaties then.
I have started to try twisting them off. It seems to be more of a problem with dewalt battery packs with thick metal tabs.. All the ones that have had holes are from those packs..
Wish there was an easier way to disassemble them with out causing lots of sparks. Gets me every time at least once.
Metal drops below the protective ring then zap sparks.. Makes me jump every time.. :)
 
cyberblob said:
Have a question for the more experienced battery harvesters.
I have been harvesting some old cells and found a few that have a hole from where the weld pulled the bottom case open.
Is this safe to charge and use?

image_xjdqpl.jpg
This happened to me only once on an old Sanyo cell in my experience harvesting 100+ laptop batteries.
Easiest to remove:
1. Green Sony ones used copper strips, they are easiest and safest to remove without damaging the negative side of the cell. You can just pull it with bare hands, it just leaves 4 copper dots without spikes.
2. Some Panasonics have only 2 weld spots, remove it rocking back and forth without pulling and not applying much force.

Some Sanyos have tough full nickel strips, I prefer to leave them ON, cutting around the wled spots withside cutting pliers and bending the edges back to the cell bottom. Looks clean and 100% safe.
Are you harvesting power tool batteries? They have thick 0.2mm full nickel strips and bigger spot weld points, I recommend to not remove them on the negative sides, just cut it around.
 
To the questions regarding holes:

NO. If you already made a hole that means you have contaminated the inside.

Cells with damage should be binned. It is not worth the gamble. Keep it safe.
 
Back
Top