Easy way to remove spot welds on cells

What does it do - does it simply cut the weld leftovers? I prefer to grind it with a dremel or something, takes a weebit longer but gives you very smooth results.
 
Made a small chisel point out of an old carbide endmill, same concept, slower process(i.e. one spot at a time.) Works the same for both ends? Any issues with the shrink wrap getting damaged? Nice work.
 
I use a angle grinder with a 180 grid sanding disc(automotive part), works perfect and quick.
I put them in a "special" tray/box, run the grinder on their buds, flip tray, run the grinder on their tops.
 
I use very small 6mm diamond dust grinders - they make very small dust particles and i hold the cells slightly upwards so that no particles could easily drop into the positive terminal. I never had a problem so far.
 
The biggest issue with grinding the metal on the cells is removing too much of the Nickel coating. It's not really the metal particulates that's the issue.
Removing the coating allows the steel shell underneath to be exposed to air, more importantly the moisture in the air, and can start the rusting process.
If doing the sanding to remove anything from a cell, either hit it with some solder afterwards, or put a dab of petroleum jelly, tape or something to cover the ends to give them extra protection. Spot welding a nickle strip on top of the area doesn't protect it, either, as the moisture can still cause issues. Just look at how well it can rust a cell inside the shrink wrapping.
 
It looks quick, but the results don't seem to be as good as what I get using a side cutter and just doing it by hand. I admit that is an annoying process, but it's hard to argue with the results.

Cheers, John
 
@Korishan, a lot of plusses from me.
But i think i found THE solution:
Put this one in a standing fixed drill.

After grinding off the face, if i did touch the cell itself! my 100w soldering iron will be ready.
Indeed the moister on unprotected steel

With my angle grinder i had a lot of succes, but also some burned (cell) parts, also due to to much plastic ect.
I really think this one will speed up my proces and improve my quality and yield.
I am waiting for its delivery to test it.

I will report back of course.

With best regards Igor
 
paulie said:
sturdy quality pair of flat side cutters is all you need. The above gadgets are utter bollocks. I'll get my coat now.
Click to expand...
Although the piece of developed equipment is somewhat ingenious and kudos to the inventor I'm with @paulie except I never took my coat off.
DG98 said:
It looks quick, but the results don't seem to be as good as what I get using a side cutter and just doing it by hand. I admit that is an annoying process, but it's hard to argue with the results.
Click to expand...
@DG98 agreed! +1
I also fail to see the infatuation and fetish of having absolutely cleaned off spot welds. I clean the extra nickel strip as best as possible.
As I handle each cell from first touch (and initial clean) 5 times, sounds like a lot doesn't it,
1 liberate cell, and clean.
2 initial V, IR, label, and place into C/D/C unit.
3 remove and test V and IR.
4 test 30 day V drop and IR.
5 Final test of V and IR before commitment to pack/battery.
By the time I have handled the cell this much, slid it in and out of my test rig the spot welds are pretty much smoothed over.
The ones that are not "just so" once in the holders I run the handle of an all steel scissor handle lightly across them.
Just happened to be the first tool that seemed to do the trick in my reach.
I also consider the spot welds a good thing as I line the cells up to mimic my spot welds position, i.e. I try to spot weld to the spot weld.
I figure the manufacturer knows what the best spot weld penetration is and I just stack mine on top.:p
Wolf
1690134896223.png
 
The problem i encountered a couple of times if i cut with a side cutter some welds (especially from "gazelle ebike's batts) they all vent at the bottom.
From a single e-bike batt off 50 cells i can keep ~10 in oke order, and that is before testing.
Indeed that cutter machine is a bit over the top, faster maybe.
I also dont think that cutter machine can help me with those really solid welds without venting the cells.
 
100kwh-hunter said:
I also dont think that cutter machine can help me with those really solid welds without venting the cells.
Click to expand...
Exactly and in the case where the spot welds are so good I would just trim the strips as best as you can without necessarily removing it.
You will either spot weld to those leftover or solder. If you choose to grind the strips just do it enough to allow you to free the strip from the cell without pulling the spot welds out of the can thereby never touching the actual plating on the cell. Yea you will be left with a bump but better than a rust and corrosion magnet.
Wolf
 
You know i love my grinder.
Even that one did not give me a higher yield...to much plastic, to deep ect.
And beleef me i tried with my grinder.
Even with a cutter disk(so no grinding or sanding disk) I (yes I)....failed.
But as always I will win.....those cells are my to work in my powerwall:cool::sneaky::cool::sneaky:
I could not even cut them.
 
When trying to remove the spot-welded strip of e-bike packs, a lot will be ruptured.
20230805_164033.jpg


First i tried with my grinder with a thin cutting blade.
But the cells were to deep in the plastic.
So i ordered a end mill.
The results are promising, but then i would need a better "standing drill".


20230805_164026.jpg

20230805_163104.jpg

20230805_163152.jpg

20230805_163120.jpg


So now i am using a thicker blade in my grinder.
Anyway, my harvest is now 100% instead of 50-60%
Maybe a good idea for someone that has a good "fixed standing drill"?
 
@100kwh-hunter -- what speed are you turning your drill with that end mill? Looks to me like you might get better results if you cranked it up a little bit. All the end mills I've used have liked really high speeds -- like speeds you get in a mill, not a drill press. I see your drill can get up to 2500, so I was just curious where you had it set for this task.

Cheers, John
 
@DG98
I had the speed at 1750 rpm
I placed the belt at the poelies for 2500 rpm.
Yes the speed is a bit low now i think about it.

I also tightened the engine.
It was a bid lose.

When i have a other ebike pack i will try again, thanks for your input, i will keep you posted.

Best Igor
 
Wondering if a end cutting carbide burr(see pic) would give a better cut? End mills in a drill press is one way to go, but have to keep that cell pack clamped or something to keep it from getting out of hand, literally. The burr will be a slower cut, but maybe more controllable.
 

Attachments

  • Carbide Burr.jpg
    Carbide Burr.jpg
    24.1 KB · Views: 27
You must log in or register to reply here.
Back
Top