Spot Welding Copper Strips to 18650 Battery Cells

st35326 said:

Is anybody selling .10 Copper strip to spot weld fuse with Nickle, sold in roll for like the Nickel is? Or must you cut your own?
Lastly, anyone have any experience with Nickel plated copper for serial connections? Does is spot weld just as well as the Nickel Does?

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I have not seen anything that is pre cut for battery welding. Copper is even easier to cut than nickel so its not huge problem unless you make lot of packs so it will take some time to cut your copper.

I plated at home some copper with nickel but it did not have pretty much any difference when welding. Nickel plating just turned dark and partly just burned away at weld spots. Its just too thin layer. Best way right now is to put your copper on your serial connections and lay 0.1 or 0.15mm nickel on top and weld through both of them. It takes less current than just copper..

ossivirt said:

st35326 said:

Is anybody selling .10 Copper strip to spot weld fuse with Nickle, sold in roll for like the Nickel is? Or must you cut your own?
Lastly, anyone have any experience with Nickel plated copper for serial connections? Does is spot weld just as well as the Nickel Does?

Click to expand...

I have not seen anything that is pre cut for battery welding. Copper is even easier to cut than nickel so its not huge problem unless you make lot of packs so it will take some time to cut your copper.

I plated at home some copper with nickel but it did not have pretty much any difference when welding. Nickel plating just turned dark and partly just burned away at weld spots. Its just too thin layer. Best way right now is to put your copper on your serial connections and lay 0.1 or 0.15mm nickel on top and weld through both of them. It takes less current than just copper..

Click to expand...

Ok. Sounds good. I found nickel plated Copper and placed an order (link below). I believe spinning magnets is somehow affiliated with the seller. Perhaps he has some insight on its use. I plan plan on giving it a try with my Kweld.

https://www.ebay.com/itm/Pure-Nickel-Plated-Copper-Strip-Tab-0-3mm-x-8mm-18650-Lithium-Battery-US-Sales/133104900615?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Dc27a9b9ee00e44abb78117e46c0bbadd%26pid%3D100675%26rk%3D4%26rkt%3D15%26sd%3D320900216893%26itm%3D133104900615%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A19ea2d25-2885-11ea-a01c-74dbd180bd02%7Cparentrq%3A468754bd16f0a4d276a33d56ff96e20f%7Ciid%3A1

st35326 said:

ossivirt said:

st35326 said:

Is anybody selling .10 Copper strip to spot weld fuse with Nickle, sold in roll for like the Nickel is? Or must you cut your own?
Lastly, anyone have any experience with Nickel plated copper for serial connections? Does is spot weld just as well as the Nickel Does?

Click to expand...

I have not seen anything that is pre cut for battery welding. Copper is even easier to cut than nickel so its not huge problem unless you make lot of packs so it will take some time to cut your copper.

I plated at home some copper with nickel but it did not have pretty much any difference when welding. Nickel plating just turned dark and partly just burned away at weld spots. Its just too thin layer. Best way right now is to put your copper on your serial connections and lay 0.1 or 0.15mm nickel on top and weld through both of them. It takes less current than just copper..

Click to expand...

Ok. Sounds good. I found nickel plated Copper and placed an order (link below). I believe spinning magnets is somehow affiliated with the seller. Perhaps he has some insight on its use. I plan plan on giving it a try with my Kweld.

https://www.ebay.com/itm/Pure-Nickel-Plated-Copper-Strip-Tab-0-3mm-x-8mm-18650-Lithium-Battery-US-Sales/133104900615?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Dc27a9b9ee00e44abb78117e46c0bbadd%26pid%3D100675%26rk%3D4%26rkt%3D15%26sd%3D320900216893%26itm%3D133104900615%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A19ea2d25-2885-11ea-a01c-74dbd180bd02%7Cparentrq%3A468754bd16f0a4d276a33d56ff96e20f%7Ciid%3A1

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Interesting. Its probably not electroplated since from side it is still copper. And its very thic so it must have alot nickel

Had this nickel plated copper strip come in just before Christmas.
I have 0.15mm x 8, 6 & 4mm.

I have done some test welds with my Arduino spot welder.
I'm having to use 80ms pulse to get good welds but it is burning and the welding tips get hot real quick.

I'm pretty new to this, any advice on welding this strip to 18650's



First attempt at welding with the strip. Looks a bit of a mess but had been aggressively pulling it to test it out
Anything less than 80ms pulse and the welds are hit and miss.
Is the burning around the welds a bad sign??

I believe spinning magnets is somehow affiliated with the seller

Click to expand...

That vendor is Keith at "18650 Heat Shrink & Cell Holders INC"

https://www.facebook.com/18650Shrin...BKOZGr8_fJMKoAeJwK34wOxxhrRJqfoDTcgWOi-K4zMN6

https://18650shrinkandcellholders.com/

We know of each other, but we are not affiliated in any way. I was the sole vendor in the US for kWeld for one year, Keith is the new vendor. I have bought products from Keith, and I am likely to buy from him in the future on occasion.

I started to work with cooper welding and there is my result 0.3 copper and 0.2 nickel.

I really like the idea with hols in cooper and nickel inside

Move test of weld.

https://www.instagram.com/p/B9ecqQEglCZ/?igshid=17b8vdfxqb6b6

183sunman said:

I started to work with cooper welding and there is my result 0.3 copper and 0.2 nickel.

I really like the idea with hols in cooper and nickel inside

Move test of weld.

https://www.instagram.com/p/B9ecqQEglCZ/?igshid=17b8vdfxqb6b6

Click to expand...

Very impressive.

What spotwelder did you used for this?

There is a tes of using it 48.8mOh whole pack 24S3P A123

183sunman said:

There is a tes of using it 48.8mOh whole pack 24S3P A123

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Very nice looking pack. Excellent work.

Here is my finished pack for copper and nickel spot. 20s20p

Neat. What continuous and peak current do you plan pulling per cell?

Awesome work! I also have noticed a bit stronger welds from the negative electrode with the same welder, but I haven't tried any copper like you're using yet. Do you have a source for the copper plates cut to shape, or are you doing that yourself?

Also do you have any shots of your positive an negative terminals connecting to the copper plate?

thundercamel said:

Also do you have any shots of your positive an negative terminals connecting to the copper plate?

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I might be wrong, but in my understanding he is welding a nickel strip joining the cell terminal and the copper sheet. So the copper is not directly welded to the cell.

I'm asking for pics of the outputs to the motor controller. Probably should have made that more clear.

Edit: found it here in the build thread. Rectangular copper on the left side:

Ah, I see.

I thought the point of such a process, is that the copper **is** the material most directly bonded to the cell ends.

The nickel is just required to provide the necessary resistance for the welding, far inferior in actual conductivity.

john61ct said:

I thought the point of such a process, is that the copper **is** the material most directly bonded to the cell ends.

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In my understanding, the point of this method is that you can use thick(er) copper, since it's not directly welded to the cell, and you can put more heat and pressure between the copper and nickel than you could to the top of the cell.

I didn't have any issues with the cell/copper/steel sandwich method, but I only used 0.1mm copper and 0.2mm nickel plated steel. I regularly pull 150A through this pack with no problems, so I don't think I'd change my method at this stage. It would be interesting if we could do a direct comparison to see which method has the least sag/resistance:

serious_sam said:

Neat. What continuous and peak current do you plan pulling per cell?

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Continuos 150-180 amp. Peak around 350amp for short period.

Here is the terminal

Beasty!

Those 3 holes are very close to the bend. Do you have enough room for fasteners ? How do you attach ?

serious_sam said:

Beasty!

Those 3 holes are very close to the bend. Do you have enough room for fasteners ? How do you attach ?
Untitled.jpg

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Good catch. I did not see that. Awesome project by the way!

I try one again with copper a bit better performance but still a lot to improwe methode like Up.

https://m.facebook.com/story.php?story_fbid=183408683216804&id=112288590328814

Would cutting up the nickel strips into squares and sandwiching it with copper tabs reduce resistance that nickel has? It is like the picture below, but instead of using magnets, I'll use nickel that is cut into little squares.

kdog said:

A pic for you all.
On the .1 Ni you can see it was a bit hot but the. 15 Ni is pretty good and has good much strength.
Same power level for all.

Click to expand...

What spot welder did you use?

badazzsteveo said:

Would cutting up the nickel strips into squares and sandwiching it with copper tabs reduce resistance that nickel has? It is like the picture below, but instead of using magnets, I'll use nickel that is cut into little squares.

Click to expand...

What is the thickness of copper in that pack ? I'm guessing around 0.05mm ? Adding nickel squares and welding would allow thicker copper (~0.1mm).

But, IMO, copper and magnets seems like the ideal method for electrical connection between cells. I'll definitely be trying out magnets in my next pack build. I really think the magnet method is better for a lot of applications.

Pros:
- It doesn't put any heat into the pack during assembly.
- Copper is excellent conductor.
- Requires no additional equipment.
- Relatively foolproof.
- Easy to disassemble for repairs or reuse.

Cons:
- Additional cost of magnets, is arguable.
- Current capacity. 0.05mm copper limits the amount of current to about 20A per cell (@25A/mm2) for acceptable use. This is probably not a "con" in the majority of applications though.
- Copper to cell connection. The copper needs to be thin enough to match the cell terminal and achieve maximum/flush contact area. 0.05mm is nice and malleable, and could easily and quickly be pressed to the ends of the cells by hand during assembly. I think 0.1mm is probably borderline too thick to be malleable enough for ideal contact. You could make it work, but more time would need to be spent shaping the copper (especially if those plastic cell holders are used).
- Potential for corrosion. Adding some dielectric grease on the cell terminals before putting the copper on would stop the corrosion.
- Movement of the copper/magnets. Since the copper isn't permanently fixed to the cells, there is a chance that it could move. It would be a good idea to bond the copper to the cells at a couple of locations around the edges, and the magnets to the copper too.
- For packs with 2nd hand cells, the cell terminal might be a little rough and bumpy. That won't be ideal for this type of connection. More preparation would be required (smoothing and flattening), compared to welding.

Really, for most applications, the "cons" aren't an issue, and you're mostly left with the "pros".

It does seem like a clever idea... Copper and magnets. “Elegant Simplicity“