"Copper/nickel sandwich" buses for series connections

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

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Re: "Copper/nickel sandwich" buses for series connections

Post by TrotterBob » May 09 2021 11:20pm

Oh dayum. That does not look like fun.

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Re: "Copper/nickel sandwich" buses for series connections

Post by fubgumfaw » May 12 2021 2:01pm

Back on topic... :)

I found this .3mm copper with nickel coating on each side. I have bought a roll of it to try out. Maybe it will spot weld like a little section of nickel does on top of copper? I've been buying nickel from this guy for a while now and just saw he had this.

https://www.ebay.com/itm/133104900617?var=432415150002

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ridethelightning   10 MW

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Re: "Copper/nickel sandwich" buses for series connections

Post by ridethelightning » May 13 2021 1:13am

ace man! that looks like good stuff. how did you get .3mm,? link is 0.15mm i saw

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Re: "Copper/nickel sandwich" buses for series connections

Post by john61ct » May 13 2021 1:15am

Cool!

key issue is, if the plating is thick enough to increase the copper's resistance enough

Please let us know!

Are you using Kweld with caps or lipo or? Optimizing the joules output might be critical

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Re: "Copper/nickel sandwich" buses for series connections

Post by fubgumfaw » May 13 2021 4:36pm

ridethelightning wrote:
May 13 2021 1:13am
ace man! that looks like good stuff. how did you get .3mm,? link is 0.15mm i saw
LOL...typo on my part...said the wrong thickness. Oopsie!
john61ct wrote:
May 13 2021 1:15am
key issue is, if the plating is thick enough to increase the copper's resistance enough
Please let us know!

Are you using Kweld with caps or lipo or? Optimizing the joules output might be critical
I posted it so that others might give it a try too, but yeah...I'll be posting if I can spot weld it or not.

I have a KWELD and 2 super cap modules in parallel and dual 50 amp PSU's keeping all of that powered up. Super cap voltage and charge level never lags behind my welding speed. I have to stop for hot weld probes, but not for the super caps to catch up. I also made the wires between everything as short as possible to reduce resistive losses to the minimum. For portable use, I built an LTO pack that is about 44Ah. Either way, it all plugs into the dual super cap modules.

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Re: "Copper/nickel sandwich" buses for series connections

Post by john61ct » May 14 2021 1:31am

Great stuff.

Best to also post this setup description with your results if successful to the main KWELD thread for reference there.

Using the kcap units in effect insulates the main unit from batteries that have too high/fast power output, is that correct?

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ridethelightning   10 MW

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Re: "Copper/nickel sandwich" buses for series connections

Post by ridethelightning » May 14 2021 2:59am

id be keen to see if you manage to weld the nickel plated copper.
i tried plating my own but the power of the weld pulse for copper just flashed off the nickel when i tried to weld it.

if i can find some tin it may prove to be better.

i dont know how the power tool packs are done, many use plated copper. i may try welding some of the strips from them onto cells.

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Re:

Post by fubgumfaw » May 14 2021 3:06am

john61ct wrote:
May 14 2021 1:31am
Great stuff.

Best to also post this setup description with your results if successful to the main KWELD thread for reference there.

Using the kcap units in effect insulates the main unit from batteries that have too high/fast power output, is that correct?
Uhhh...no idea about the super caps doing that or not.

I got the super cap modules because I wanted to run from a PSU instead of a battery for hours and hours of spot welding. I started with a 20 amp Meawell and that was OK, but my weld speed had to stay sloooow or else I'd run out of charge after a minute. 2 supercap modules got me a bit more weld time, but also doubled how long that PSU took to charge them up again. This got pretty tedious! I then bought a 50 amp Meanwell and that was much better, but I could still weld faster than it could keep up the charge on the super caps. I then bought a second 50A Meanwell to put in parallel with the first one. They do the trick! I never weld fast enough for long enough that they can't keep the super caps charged. Invariably, I need to stop to cut or place another piece of nickel or because the weld pens get hot and the 2 PSU's quickly catch up any deficit that I never notice.

With this setup...100 amps seems like a lot from a 15 amp AC circuit, but it's also stepped down to 9v. This is a bit over the limits for the super caps, but they are not harmed and the fans on them barely ever run. Anyway, 900 watts, 100 amps and 9v is about 7.5 amps at 120v. I've never popped a breaker with my KWELD setup.

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Re: "Copper/nickel sandwich" buses for series connections

Post by fubgumfaw » May 14 2021 3:09am

ridethelightning wrote:
May 14 2021 2:59am
id be keen to see if you manage to weld the nickel plated copper.
i tried plating my own but the power of the weld pulse for copper just flashed off the nickel when i tried to weld it.

if i can find some tin it may prove to be better.

i dont know how the power tool packs are done, many use plated copper. i may try welding some of the strips from them onto cells.
Probably the thickness of the nickel is the key. I know that spool of nickel plated copper has a really thin layer of nickel on it. It might not work at all since it's so thin. It will supposedly get here May 27.

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Re: "Copper/nickel sandwich" buses for series connections

Post by fatty » May 14 2021 4:04pm

Would the "nickel sandwich" spot-weld technique work with flat pouch cell tabs?

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spinningmagnets   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by spinningmagnets » May 14 2021 8:33pm

The tabs on pouch cells are typically aluminum for the positive, or sometimes nickel-plated aluminum. The negative tabs are copper core with nickel-plating. The nickel is to reduce oxidation, but I think if you put an additional nickel strip along both sides, and pinch them with the spot-welding probes, I am fairly sure they would bond well.

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Re: "Copper/nickel sandwich" buses for series connections

Post by silentbike » May 15 2021 1:56pm

if anyone wants to do this i highly recommend using nickel plated steel
i can weld 0.1mm copper at 1000A and it's really good welds, pure nickel doesnt stick at 1000-1300A
the only downside is it sparks alot, so wear eye protection. pure nickel doesnt spark

thanks author for good info

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Re: "Copper/nickel sandwich" buses for series connections

Post by Nashton » May 19 2021 2:04pm

How much current are you able to pull by using 0.15mm copper using this strategy?
I want to make a 16s11p or 12p with 21700 pack using the p42a molicel. Those cell claim 45amp discharge. I plan to draw pulses at 30amps max per cell which would be about 330a or 360a. Has anyone doing this been able to push this kind of current? I don't think i saw or read anyone mentioning what current they are able to push using copper/nickel sandwich vs only nickel.
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spinningmagnets   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by spinningmagnets » May 19 2021 2:30pm

Copper is four times as conductive as nickel, so 0.15mm copper is equal to 0.60mm nickel, plus the copper will also act as a heat sink.

ZiaMag   10 µW

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Re: "Copper/nickel sandwich" buses for series connections

Post by ZiaMag » May 23 2021 5:18am

Not a whole lot to contribute here (planning on changing that in the coming weeks) but I've joined the copper club. I'm successfully welding copper to both anode and cathode of throwaway 18650 cells, facilitated by a small portion of nickel of course.

My setup is quite simple and creating a strong sandwich weld came with not much effort or struggle. I'm using -

• 12v 51ah MX Powered Gel lead acid, abused and still cranking out amps.
• 12v Duralast Gold Solenoid from AutoZone, seems reasonably heavy duty
• Flexible welding cable with electrodes from a rather unimpressive but convenient, cheap, and small Amazon spot welder
•Timer relay, linked below also from Amazon. An easy, functional, and inexpensive timer. Straight forward to program, can do extremely short intervals to trigger the solenoid, single and multiple with the ability to adjust on and off times between
pulses. No affiliation, just the link.

https://www.amazon.com/dp/B07RGT5G1X/re ... UTF8&psc=1

•Pure nickel strip, 7 x .15mm as well as 7 x .10mm.
•Pure copper sheet, .10mm thickness.

Really just a standard DIY spot welder, the same as every other DIY setup on YouTube, instructables, etc...

I was unable to create a weld that ripped the copper around the weld area, a proper strong weld, with a single pulse firing from my setup. Programming the timer for up to 25ms, but felt uncomfortable going any longer as this is a powerful rig. The success came when programming the timer for two pulses.

Footswitch -> 10ms ON -> 4ms off ->10ms ON

Had success with both .10mm and .15mm nickel on top of the .10mm copper. The results are a weld requiring pliers and tearing the copper. The welds are left on the cell afterwards. I will get pictures up. But for the moment I can say the real success came with two short pulses, I could not get a weld with a single long pulse.

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ridethelightning   10 MW

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Re: "Copper/nickel sandwich" buses for series connections

Post by ridethelightning » May 23 2021 6:31am

if the single long pulse did not deliver, it just means you need to get a bigger battery source for more amps, and possibly thicker electrodes/cables. ideal is the fastest pulse with most energy.
some high c lipo packs are a good solution, or what i did is banks of old 25r cells from fried ebike packs plus some other mongrel trash cells i had lying around from old cordless tool packs.

as for double pulse, i cant comment, but sounds good, as long as the cells arnt taking heat.

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Cowardlyduck   1.21 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by Cowardlyduck » May 23 2021 6:46am

I still haven't tried the sandwich but I do get good results from my battery setup with my JP spot welder.
I use a few old car batteries, one 750cca and one 450cca in parallel, as well as some old NiMH cells from a Prius in a 2S2P config in parallel with that.
Packs a real punch!

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serious_sam   10 kW

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Re: "Copper/nickel sandwich" buses for series connections

Post by serious_sam » May 23 2021 7:20am

I did try the dual pulse method. Tried some different timings. But in the end, I found that the single pulse did a better job.

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spinningmagnets   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by spinningmagnets » Jun 08 2021 6:59am

Frank Peavy on facebook. https://www.facebook.com/groups/2021407 ... 0224656047

3S LiPo 11.1V, 7600-mAh 75C

https://scontent.fmci1-3.fna.fbcdn.net/ ... e=60E664D1

0.10mm copper sheet, 0.15 nickel, kWeld @ 55-joules
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Re: "Copper/nickel sandwich" buses for series connections

Post by ZiaMag » Jun 22 2021 3:56am

Putting my desktop CNC to work. Designed in Inkscape.
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john61ct   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by john61ct » Jun 22 2021 6:15pm

Beautiful

ready to go into business!

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spinningmagnets   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by spinningmagnets » Jul 03 2021 7:47am

From Ian M Molina on facebook. 0.20mm copper sheet, 0.15mm nickel, kWeld at 60J

https://www.facebook.com/10000064516554 ... 0929021460

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Re: "Copper/nickel sandwich" buses for series connections

Post by Xoon » Jul 03 2021 9:31am

Has anyone tried to weld the copper sheet to a busbar when terminating the battery pack?

john61ct   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by john61ct » Jul 03 2021 1:43pm

spinningmagnets wrote:From Ian M Molina on facebook. 0.20mm copper sheet, 0.15mm nickel, kWeld at 60J

https://www.facebook.com/10000064516554 ... 0929021460

Image
Any way for those that don't FB?

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spinningmagnets   100 GW

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Re: "Copper/nickel sandwich" buses for series connections

Post by spinningmagnets » Jul 03 2021 9:29pm

There is a very short video that looks exactly like any other kWeld video. Then, he shows that it is hard to pull the welded strip off of the cell, which leaves behind the welded points.
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