Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Batteries, Chargers, and Battery Management Systems.
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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Mar 06 2021 9:23pm

Wire fusing amps is about 5. I often blow them when building reconfigured packs.
If you can teach me how to spot weld anything to positive terminal, it will save me a lot of time and money. I need a way to repair my mistakes.
I've tried aluminum, copper, and nickel ribbon. Enough power to puncture the ribbon. Nothing seem to weld to aluminum.
Same with 40khz ultrasonic and the horn I use for pouch tabs.
Last hope is a small longitudinal mode horn I have ordered. Pics. "LM wire bonding"
How are others doing it?
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flippy   100 MW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by flippy » Mar 07 2021 4:48am

Inwo wrote:
Mar 06 2021 9:23pm
Wire fusing amps is about 5. I often blow them when building reconfigured packs.
just remove the wife wire with a dremel and a blue or red stone abrasive wheel, clean the cells, rebuild your pack with cell holders if possible and get some of those green paper sticky rings at the correct size or ask a company on alibaba to make some for you at the correct size to insulate the negative ring on the top and just build your pack as a regular 18650 pack with nickel strip and a kweld+kcap setup.

the kweld should be powerful enough to break the aluminium top layer. but dont forget to remove the oxide layer first with a dremel and weld IMMEDIATLY. the oxide layer reforms basically immediatly.
The bitterness of low quality remains long after the sweetness of low price is forgotten

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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Mar 07 2021 6:30pm

I'm not building a pack. Just need to repair a few fused wires on the pack.
The K-weld site says no, just as every other post I can find. I have not yet bought a new welder.
Price is trivial if it works.
Do you have cells to try? Glad to send some out for test welds. (usa)

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flippy   100 MW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by flippy » Mar 08 2021 7:20am

no, i like in EU, so that wont work.
i did a small battery a while back as a favour with these cells and if you use nickel plate with those slits in them you can weld it at very high power levels and removing the oxide layer and welding it immediatly.
but its simply such a pain in the ass to work with that its simply not worth it for anyone.

you can use ALU-SOL (farnell sells it under 629443) if you want to solder the connections. but still: nothing will work if you dont remove the oxide layer first and weld or solder within seconds after doing so.
The bitterness of low quality remains long after the sweetness of low price is forgotten

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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Mar 10 2021 10:35pm

Tnx, good info. Worth any amount of work for me. Saving a 12 brick battery by repairing one or two cells is a win.
Is there anything to coat tops with to prevent oxidation before welding?
I tried split plated strip at full power with Sunoco welder. Not enough power? It melts the strip. More power less time needed?

I'm going to try copper plating the aluminum and see if it solders or welds better.
Also trying a cold tig welder and possible high voltage arc. 10kv.

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flippy   100 MW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by flippy » Mar 11 2021 5:51am

sukko's are a joke. you need a kweld with a kcap or bigger to do this.

tig welder will also work but unless its a really high end machine with really good control you will not be able to turn it down far enough not to murder the cell. what the control panel says and what it actually does are 2 different things. so be sure to test on trash metal and cells first before committing.

and no, you cant stop the oxidation from happening, that is like aksing iron to stop rusting.

the only thing i have seen work properly is laser welding as the machines are extremely accurate in their control. with DC tig not so much.
The bitterness of low quality remains long after the sweetness of low price is forgotten

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jonescg   1.21 GW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by jonescg » Mar 11 2021 6:15am

flippy wrote:
Mar 11 2021 5:51am
sukko's are a joke. you need a kweld with a kcap or bigger to do this.
You know, when I was welding nickel tabs to nickel-coated aluminium busbars, the only welder that did the job was the Sunkko. Capacitive welders just vaporised the tabs while the old transformer just hummed and stuck it on (satisfactorily). I was shocked and surprised, but it worked the best...!

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flippy   100 MW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by flippy » Mar 11 2021 6:37am

jonescg wrote:
Mar 11 2021 6:15am
You know, when I was welding nickel tabs to nickel-coated aluminium busbars, the only welder that did the job was the Sunkko. Capacitive welders just vaporised the tabs while the old transformer just hummed and stuck it on (satisfactorily). I was shocked and surprised, but it worked the best...!
the problem is control. most welders have shitty control. the sukko's are simple and you can only adust pulses and duration. but i burned out several of them on "hard" welds as the transformer was basically dead shorting for too long on difficult welds and popped a winding. my previous house still has a couple black spots on the wall from a transformer that yeeted himself out of this world.

for the cost you are better off buying 1 good welder with good control over its pulse, current and total energy output (like the kweld does for example).

the sukko's are generally low amps and lots of heat. they melt more then they weld. as you have no amp control you only can increase the pulses to shove more power into the weld. with capacitor/battery based welders you can get much higher currents but if you need to be more delicate you can simply dial back the voltage, something that i think you will find difficult with mains power transformer based welders.
The bitterness of low quality remains long after the sweetness of low price is forgotten

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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Mar 29 2021 4:15pm

Practicing spot welding tig on a beer can.
This 100ms and 60 amps.
Nickel plated strip.
Small 18awg aluminum wire is tough to do.
Also able to weld copper plated aluminum for soldering.
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flippy   100 MW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by flippy » Mar 29 2021 4:28pm

sand the aluminum. remove the oxide layer. you have only a minute or 2 before new oxide forms.

and steel strips dont work.
The bitterness of low quality remains long after the sweetness of low price is forgotten

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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Mar 30 2021 6:23pm

Solid nickel better, easier? Not sure I have nickel. Any other material, cu etc.?
Also trying cca button. Weld al to al and solder to cu side. Some success but not ready to do batteries yet.

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Inwo   10 kW

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Re: Best Method for Battery Build??? 16s4p Telsa 2170 Cells

Post by Inwo » Apr 02 2021 8:52pm

Think I got it now. These are cca buttons that I can solder to easily.
Tig spot welded to cells.
Testing on a beer can 60 amp 100ms pulse.
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