Spot Welding Copper Strips to 18650 Battery Cells

Batteries, Chargers, and Battery Management Systems.
ossivirt   10 W

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by ossivirt » Dec 26 2019 8:26am

st35326 wrote:
Dec 25 2019 11:06pm
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?
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..

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by st35326 » Dec 27 2019 3:46am

ossivirt wrote:
Dec 26 2019 8:26am
st35326 wrote:
Dec 25 2019 11:06pm
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?
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..
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-Pl ... %7Ciid%3A1

ossivirt   10 W

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by ossivirt » Dec 27 2019 4:08am

st35326 wrote:
Dec 27 2019 3:46am
ossivirt wrote:
Dec 26 2019 8:26am
st35326 wrote:
Dec 25 2019 11:06pm
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?
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..
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-Pl ... %7Ciid%3A1
Interesting. Its probably not electroplated since from side it is still copper. And its very thic so it must have alot nickel :roll:

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by My2c » Jan 18 2020 3:56pm

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

Image

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??

Image

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spinningmagnets   100 GW

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by spinningmagnets » Jan 18 2020 4:06pm

I believe spinning magnets is somehow affiliated with the seller
That vendor is Keith at "18650 Heat Shrink & Cell Holders INC"

https://www.facebook.com/18650Shrink/?e ... WOi-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.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by 183sunman » Mar 08 2020 9:19am

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 ... 8vdfxqb6b6
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by CharlySierraGolf » Mar 17 2020 3:00pm

183sunman wrote:
Mar 08 2020 9:19am
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 ... 8vdfxqb6b6

Very impressive.

What spotwelder did you used for this?

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by 183sunman » Mar 22 2020 10:07am

There is a tes of using it 48.8mOh whole pack 24S3P A123
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by garolittle » Mar 22 2020 9:48pm

183sunman wrote:
Mar 22 2020 10:07am
There is a tes of using it 48.8mOh whole pack 24S3P A123
Very nice looking pack. Excellent work.
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by artvk » Apr 12 2020 1:00am

Here is my finished pack for copper and nickel spot. 20s20p
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serious_sam   1 kW

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » Apr 12 2020 3:25am

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

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by thundercamel » Apr 12 2020 3:55pm

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?
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serious_sam   1 kW

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » Apr 12 2020 6:02pm

thundercamel wrote:
Apr 12 2020 3:55pm
Also do you have any shots of your positive an negative terminals connecting to the copper plate?
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.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by thundercamel » Apr 12 2020 6:29pm

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:

Image
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » Apr 12 2020 6:33pm

Ah, I see.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by john61ct » Apr 12 2020 7:07pm

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.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » Apr 12 2020 7:45pm

john61ct wrote:
Apr 12 2020 7:07pm
I thought the point of such a process, is that the copper **is** the material most directly bonded to the cell ends.
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:
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by artvk » Apr 15 2020 11:05am

serious_sam wrote:
Apr 12 2020 3:25am
Neat. What continuous and peak current do you plan pulling per cell?
Continuos 150-180 amp. Peak around 350amp for short period.

Here is the terminal
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » Apr 15 2020 11:59pm

Beasty!

Those 3 holes are very close to the bend. Do you have enough room for fasteners ? How do you attach ?
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by garolittle » Apr 16 2020 6:38am

serious_sam wrote:
Apr 15 2020 11:59pm
Beasty!

Those 3 holes are very close to the bend. Do you have enough room for fasteners ? How do you attach ?
Untitled.jpg
Good catch. I did not see that. Awesome project by the way!
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by 183sunman » May 08 2020 4:03pm

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_ ... 8590328814

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by badazzsteveo » May 29 2020 6:18pm

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.
Image

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by badazzsteveo » May 29 2020 6:45pm

kdog wrote:
Jun 01 2019 9:21pm
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.
What spot welder did you use?

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by serious_sam » May 29 2020 8:19pm

badazzsteveo wrote:
May 29 2020 6:18pm
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.
Image
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".

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garolittle   1 kW

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by garolittle » May 29 2020 8:45pm

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