18650 spot welding -how to- ULTIMATE REPOSITORY

Batteries, Chargers, and Battery Management Systems.
BenjAZ   100 mW

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Re: 18650 spot welding -how to- ULTIMATE REPOSITORY

Post by BenjAZ » Apr 01 2019 4:11am

DasDouble wrote:
Nov 06 2018 9:34am
Just as a note: The average Amperage/mm² =
4,459A/mm² pure nickel @ "optimal Temperature"[/b]
6,619A/mm² pure nickel @ "acceptable Temperature"[/b]
8,918/mm² pure nickel @ "poor/hot Temperature"[/b]
How/where could I get a similar data (amps/mm2) for pure copper?

Thanks

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Post by ossivirt » Apr 03 2019 11:03pm

BenjAZ wrote:
Apr 01 2019 4:11am
DasDouble wrote:
Nov 06 2018 9:34am
Just as a note: The average Amperage/mm² =
4,459A/mm² pure nickel @ "optimal Temperature"[/b]
6,619A/mm² pure nickel @ "acceptable Temperature"[/b]
8,918/mm² pure nickel @ "poor/hot Temperature"[/b]
How/where could I get a similar data (amps/mm2) for pure copper?

Thanks
I don't know how to calculate those values but conductivity of copper is like 4times better than nickel so multiply by 4 and I think you are close enough. And thermal "properties" are also better in copper or at least it's used in cooling systems and nickel is just plated for the looks.

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Post by BenjAZ » Apr 04 2019 6:12am

Thanks

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cal3thousand   1.21 GW

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Post by cal3thousand » Apr 16 2019 12:51pm

Has anyone here tried layering copper on top of nickel? I read that you can layer strips to increase the current capability. So why not increase it with copper?
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Post by flippy » Apr 16 2019 1:17pm

because you are still dependant on the nickel strip and its welds. and wels are almost impossible to solder over.

if you need such massive current capacity you need to rethink your setup. there is no cell that can survive that current load.
if you need .3 nickel or better you need to change the setup, its as simple as that.

fun fact: .3 is what they use in dewalt battery packs. if you draw those kinds of currents on a diy bike battery with crappy cells you really need to rethink what your are doing.
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Post by spinningmagnets » Apr 16 2019 3:30pm

Makita and several others use nickel-plated copper, and they are spot-welded

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Post by flippy » Apr 16 2019 3:36pm

spinningmagnets wrote:
Apr 16 2019 3:30pm
Makita and several others use nickel-plated copper, and they are spot-welded
the lastest dewalts also have it. but its less wide and a bit thinner then the older packs. i have never seen non-spotwelded batteries from any brand.
its probably because of the newer devices they sell like the chainsaws and stuff, they really hammer the batteries and i have repaired a couple older dewalts packs that were used in a few chainsaws and i could see the tabs were melting the insulation/wrap of the cells. so dewalt knew that even .3 nickel was insufficient.
but then again: dewalt lives on selling batteries, not equipement. they sell 250 euro batteries with less then 25 euro worth of cells in them. they dont care how long they last, as long as they survive the warranty period.
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Post by Willow » Apr 16 2019 6:04pm

BenjAZ wrote:
Apr 01 2019 4:10am
.

What's the max current that 0.1mm piece can handle?

Thanks
if your layout is good - as much as your battery can output.

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Post by izeman » Apr 16 2019 6:09pm

I'd say it depends on width of nickle as well.

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Post by Cowardlyduck » Apr 16 2019 9:37pm

...and the number of layers.
I've had good success drawing over 125A from 4 layers of nickel x 7 series strips of 0.15 x 7mm nickel. So 28 links total, although the top most layers won't contribute as much so it's not a simple multiplication of current capability, but theoretically 28 layers could take 196A.

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Post by Offroader » Apr 16 2019 11:25pm

spinningmagnets wrote:
Apr 16 2019 3:30pm
Makita and several others use nickel-plated copper, and they are spot-welded
Saw this in this thread. https://endless-sphere.com/forums/viewt ... 0#p1395373

Would be nice to have some kind of technology out there which is better than using 100% nickel strip, that can also be easily welded.

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Post by Cowardlyduck » May 10 2019 7:16pm

My stuff:
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Cowardlyducks - Videos - Ride videos
BikeE recumbent commuter - 9C, 6Fet Grinfineon, internal 17AH, 52V, + on-board solar.

For Sale:
Custom made 18650/21700 battery packs - Australia only
High Power LiPo wiring harnesses - 4P - XT90, HXT4mm, 5.5mm. 200Amp+ capable. Global shipping.

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Post by flippy » May 12 2019 4:54am

Offroader wrote:
Apr 16 2019 11:25pm
Would be nice to have some kind of technology out there which is better than using 100% nickel strip, that can also be easily welded.
that already exists, its ultrasonic welding. really shitty budget units are about 5k from aliexpress. proper units are on the spectrum of "if you have to ask you cant afford it".
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Post by BenjAZ » May 20 2019 9:21am

flippy wrote:
May 12 2019 4:54am
that already exists, its ultrasonic welding. really shitty budget units are about 5k from aliexpress. proper units are on the spectrum of "if you have to ask you cant afford it".
:lol:

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Post by benha » Jun 26 2019 7:30pm

Question about spot welding batteries:

I inherited a Hughes resistance welder years ago that's been collecting dust in my garage. Turns out I've now got an electric vehicle project in the works and I'm wondering if this thing is well suited to spot welding the battery tabs. Finding information on this has been tricky.

It's an HRW-50B, which is a 50 watt second unit. It seems like most of the spot welders for batteries are more in the 100-200 watt second range. If I put the work into rigging up electrodes and figuring out a trigger mechanism for this, is there going to be enough current from this welder to make a good weld on a battery tab?

And a bonus question:
There's a two-pin round connector for the trigger on the front of the welder. It's a 40+ year old amphenol connector. Anyone know what I'd need to buy to find a mating connector??? :-)

-Ben

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Post by fechter » Jun 27 2019 8:26am

benha wrote:
Jun 26 2019 7:30pm

It's an HRW-50B, which is a 50 watt second unit. It seems like most of the spot welders for batteries are more in the 100-200 watt second range. If I put the work into rigging up electrodes and figuring out a trigger mechanism for this, is there going to be enough current from this welder to make a good weld on a battery tab?

And a bonus question:
There's a two-pin round connector for the trigger on the front of the welder. It's a 40+ year old amphenol connector. Anyone know what I'd need to buy to find a mating connector??? :-)

-Ben
That's really hard to tell. I would get some nickel strips and try welding them to scraps of steel sheet metal. I've seen guys typically use the side of a utility knife blade as a 18650 simulator. If you can get good welds on a test piece then try some actual cells.

Many of those Amphenol connectors are still available. Places like Digi-key or Mouser might stock them. I would probably remove the connector and replace it with something I have on hand.
"One test is worth a thousand opinions"

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Post by eikido » Jul 03 2019 6:24am

Would such a 12v battery be enough for spot welding with kweld or maltronics?

https://www.biltema.se/en-se/car---mc/m ... 2000029838

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Post by ossivirt » Jul 03 2019 6:54am

eikido wrote:
Jul 03 2019 6:24am
Would such a 12v battery be enough for spot welding with kweld or maltronics?

https://www.biltema.se/en-se/car---mc/m ... 2000029838
It looks like very tiny cm battery so maybe it can weld very thin nickel but it will be very hard for the battery. It is also very expensive compared to car batteries or even lipos. If you have it and don't need it for anything else you can try but if I'd have that expensive battery in my motorcycle I would not risk damaging it with welders.. :roll:

Edit : Just noticed that the price was in sek so in eur it is 20. So not expensive at all. Still don't have high hopes for it but with 0.15 or thinner nickel or plated steel just maybe..
Last edited by ossivirt on Jul 03 2019 7:03am, edited 2 times in total.

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Post by eikido » Jul 03 2019 7:14am

ossivirt wrote:
Jul 03 2019 6:54am
eikido wrote:
Jul 03 2019 6:24am
Would such a 12v battery be enough for spot welding with kweld or maltronics?

https://www.biltema.se/en-se/car---mc/m ... 2000029838
It looks like very tiny cm battery so maybe it can weld very thin nickel but it will be very hard for the battery. It is also very expensive compared to car batteries or even lipos. If you have it and don't need it for anything else you can try but if I'd have that expensive battery in my motorcycle I would not risk damaging it with welders.. :roll:

Edit : Just noticed that the price was in sek so in eur it is 20. So not expensive at all. Still don't have high hopes for it but with 0.15 or thinner nickel or plated steel just maybe..
Thanks.
I can't figure out what to look for in a car battery when buying it for a spot welder such as malectrics.

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Post by ossivirt » Jul 03 2019 7:30am

eikido wrote:
Jul 03 2019 7:14am
ossivirt wrote:
Jul 03 2019 6:54am
eikido wrote:
Jul 03 2019 6:24am
Would such a 12v battery be enough for spot welding with kweld or maltronics?

https://www.biltema.se/en-se/car---mc/m ... 2000029838
It looks like very tiny cm battery so maybe it can weld very thin nickel but it will be very hard for the battery. It is also very expensive compared to car batteries or even lipos. If you have it and don't need it for anything else you can try but if I'd have that expensive battery in my motorcycle I would not risk damaging it with welders.. :roll:

Edit : Just noticed that the price was in sek so in eur it is 20. So not expensive at all. Still don't have high hopes for it but with 0.15 or thinner nickel or plated steel just maybe..
Thanks.
I can't figure out what to look for in a car battery when buying it for a spot welder such as malectrics.
Any new car battery should be fine. I have stupidly large and heavy 110ah used battery and it gives me 1500a with kweld. It is just enough to weld 0.1mm copper and should also do 0.3mm nickel. I guess even batteries around 45-55ah should handle nickel welding up to at least 0.2mm nicely. Car batteries have capacity marked in ah and usually there is maximum starting current also marked which is more or less accurate. More current is better in spot welding until its too much for the welder..

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Post by ccgarnaal » Jul 17 2019 10:51am

Anyone here ever use this: https://www.amadamiyachi.eu/products/micro-tig-welding ?????

Is this something I could do with my AC/DC tig welder. Setting the startupcurrent high but short and the welding current to 0.
I can modify a torch to have the conductive base as on this image.

I can try it but to know actual heat to battery I need a IR camera? Or would simpy measuring with IR thermometer gun after welding be sufficient?

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Post by fechter » Jul 17 2019 11:15pm

Pulse arc welding should be similar to resistance spot welding for the same size spot. But those welders are not cheap.
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Post by jonescg » Jul 19 2019 1:25am

Well I have reluctantly bought a spot welder for building 18650 battery packs. I really loathe these cells are they are not easy to work with - unless you're ultrasonically wirebonding the terminals to a busbar, you are limited to low power applications. But it is typically the cheapest way to buy battery storage - typically about AUD$270 to $350 per kWh, and LiPo pouches are more like $700 per kWh, let alone what they cost as a built pack.

So I have ordered a Sunkko 709 AD and a single hand electrode holder. I plan on using the Kart_PS kit for building hexagonal close-packed batteries. Their nickel strip seems to look the goods, and in the case of the pack I'm building, it will be *just* enough to handle the currents.

Goal is to incorporate a cooling system so that the battery packs can live a reasonably long life. If your half-price battery dies after less than 2 years, was it really half price?

I will probably start a new thread, but will post specific experiences here.

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Post by flippy » Jul 21 2019 1:38pm

jonescg wrote:
Jul 19 2019 1:25am
So I have ordered a Sunkko 709 AD
please cancel that order as fast as humanly possible.
that thing is nothing but grief.
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Post by jonescg » Jul 21 2019 7:33pm

I've heard this, but also seen plenty of reviews saying it worked fine. It sounds like you either get a good one or a lemon. I can always return it if it doesn't do the job.

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