TIG welding battery strips

[slomobile]

I have an Everlast PowerTIG 210EXT https://www.everlastgenerators.com/product/tig-stick/powertig-210ext to weld copper strips to batteries. I've heard of success here
https://endless-sphere.com/forums/viewtopic.php?f=14&t=84680&p=1476967&hilit=TIG#p1476967
and here
https://endless-sphere.com/forums/viewtopic.php?f=14&t=110373&p=1619469&hilit=TIG#p1619469

What is the TIP used in the video? Does it maintain electrode gap or direct contact? No argon, or helium shielding gas? Does the tip fit a #9 or #27 torch?

Are there any other recommended TIG electrode setups or guidance? I asked the machine manufacturer and they said it was "out of their scope".

I plan to determine, unless you can tell me, which available process is better, contact GMAW (stick welding) setting, TIG (lift start), or TIG (non contact high frequency arc start), appropriate other settings. Materials on hand are .008" copper, aluminum, and stainless. Any other materials or thickness which you would like to see?

I do not have a capacitive welder, don't plan to ever buy one, have never welded on a battery, don't have any dead cells to test on. I'm a bit nervous about starting a lithium fire. What is the safest way to open up a new cell to practice welding on the entire case? Is it safe to assume that case and button material are the same?

 

[qwerkus]

I have an Everlast PowerTIG 210EXT https://www.everlastgenerators.com/product/tig-stick/powertig-210ext to weld copper strips to batteries. I've heard of success here
https://endless-sphere.com/forums/viewtopic.php?f=14&t=84680&p=1476967&hilit=TIG#p1476967
and here
https://endless-sphere.com/forums/viewtopic.php?f=14&t=110373&p=1619469&hilit=TIG#p1619469

What is the TIP used in the video? Does it maintain electrode gap or direct contact? No argon, or helium shielding gas? Does the tip fit a #9 or #27 torch?

Are there any other recommended TIG electrode setups or guidance? I asked the machine manufacturer and they said it was "out of their scope".

I plan to determine, unless you can tell me, which available process is better, contact GMAW (stick welding) setting, TIG (lift start), or TIG (non contact high frequency arc start), appropriate other settings. Materials on hand are .008" copper, aluminum, and stainless. Any other materials or thickness which you would like to see?

I do not have a capacitive welder, don't plan to ever buy one, have never welded on a battery, don't have any dead cells to test on. I'm a bit nervous about starting a lithium fire. What is the safest way to open up a new cell to practice welding on the entire case? Is it safe to assume that case and button material are the same?

You must have mad welding skills to attempt this! Those cell caps are sooo thin - it's easy to burn through with a simple diy spot welder; can't imagine doing this with a full scale TIG welder, especially since the energy required to weld copper is way past the energy required to burn through the cell cap. About your material question: yes, it's all plated steel, but the top button is better insulated from the battery body than the bottom one (negative pole), which makes it less sensitive to abuse. For an instance, you can easily tin solder the top button, while the same procedure will probably damage the bottom cap.

In any case, I'd suggest going to your local garbage station or whatever they call it and get some used li-ion cells. Plenty of them in discarded powertool packs for an instance. Then make sure they are effectively dead, or with very little charge remaining, and finally, go wild on them and weld whatever you feel like.

Also don't forget to report back here you failures or sucessess!

 

[agniusm]

There are full scale TIGs with pulse welding that can go down very low, as low where you can weld aluminium foil.
I have Kempi mastertig mls3000 and it has microtack function. I have not tried it but it would be interesting.
Where would you clamp your ground? On the strip?

Btw, if you have space, you can look into my solution with no welding or soldering

 

[Chalo]

A cylindrical lithium cell is a very thin steel capsule full of even thinner plastic films and moist electrically active chemicals. Welding one at all is a bad idea. Welding one with TIG is a stupendously bad idea.

 

[Jrbe]

I have not attempted to weld a battery yet.
A really good tig welder (person) can weld a cut beer can together.
A good tig welder (machine) can set the current to 1A, can set a duration, pulse time, etc. The pedal / finger controller gives you 0-100% of the current setting.
Problem is without destroying a cell you don't know how much power is required to weld it unless you do trial and error.
Of course overheating the cell would be bad. Weld time would probably have to be very low.
Some tig welders have a spot weld feature / settings.
That said, don't blow yourself up!

 

[Chalo]

I have not attempted to weld a battery yet.
A really good tig welder (person) can weld a cut beer can together.

Even the most skillful TIG welder can't weld a cut in a full beer can.

The contents of a lithium cell capsule are heat sensitive. That's the problem with all cell welding, but most especially when you're talking about heat duration that's longer than a few milliseconds.

 

[fatty]

As always, learn what major OEMs do first.
Do they TIG weld battery strips? No -- for the good reasons explained in this thread.

 

[Jrbe]

https://weldingweb.com/vbb/threads/138901-How-do-you-guys-weld-pop-soda-beer-cans-together/page4
Beer can cut in half and welded.

https://www.amadaweldtech.eu/knowlegde-base/welding-conductive-battery-interconnects
A battery "spot welder" that is effectively a tig welder from ze Germans. See their note about less heat than a resistance welder.

https://endless-sphere.com/forums/viewtopic.php?f=14&t=84680
Building battery packs with a battery spot welder.

https://m.youtube.com/watch?v=t0n5RAYAaf0
Settings to use a higher end tig welder like the second link.

Can you do this very wrong with disastrous results? Yes.
Is it possible to do this with a high end tig with a properly set sequencer? I think so. Spot welding some strips and some shot cells should be able to tune the sequencer to do this consistently.

I'd be very surprised if the tig welder linked has a sequencer and could do this safely.

I'd be interested in seeing a comparison with temperature indicating paint for different methods of welding on tabs.

If I'm missing something please share.

 

[Chalo]

https://weldingweb.com/vbb/threads/138901-How-do-you-guys-weld-pop-soda-beer-cans-together/page4
Beer can cut in half and welded.

Not full of beer, it wasn't.

A battery can is full of battery. Battery filling is more heat sensitive than beer can filling.

 

[Vbruun]

Please don't listen too much to Chalo. He knows a lot about pouch cell batteries and for some reason he hates welded batteries in spite of the fact that most bike batteries and tool batteries are made this way out of 18650s by OEMs.

What you want can for sure be done. If it can be done by you is entirely unsure and needs to be tested. I suggest using used cells and going outside. You can discharge the cells entirely down to 0v and they Will be much less reactive, but they Will never be able to recharge again.

The weld can easily be tested by pulling off the metal strip and seeing whether it is the strip or the weld that fails.

 

[Chalo]

Please don't listen too much to Chalo. He knows a lot about pouch cell batteries and for some reason he hates welded batteries in spite of the fact that most bike batteries and tool batteries are made this way out of 18650s by OEMs.

Mass manufacturers often use ultrasound or laser welding, for a much cooler process. Even when they're using resistance welding, they have process control that nobody here does.

I challenge you to find a single commercial manufacturer that uses arc welding to join cylindrical batteries. It's a stupid idea that requires much more heat than any of the common means of cell welding.

 

[flippy]

Mass manufacturers often use ultrasound or laser welding, for a much cooler process. Even when they're using resistance welding, they have process control that nobody here does.
I challenge you to find a single commercial manufacturer that uses arc welding to join cylindrical batteries. It's a stupid idea that requires much more heat than any of the common means of cell welding.

(as usual) you'd be wrong, tig and plasma-like welding styles is used in the very higest end of products. just not mass produced ones due to the cost and low speed. but you will see it in plenty of millitary gear like the hush-hush special forces electric 1~2 person submarines and most electrical connections used in sattelites and so on.
welding like that is REALLY expensive and slow compared to ultrasonics. but when cost is litteraly the last factor in the economical vs reliabillity equasion its pretty much the go-to option. spending 30~50k on welding gear is not a factor when you can sell a 2kWh waterproof battery to the millitary for 30k a piece that has less then 1k of parts in it and they order a couple dozen every year for the next 20 years. some goes with sattelites. they really dont give a shit about spending 30k on a 300 million dollar gold plated box when welding battery connections that the thing needs to rely on for thousands of heat cycles.

 

[Chalo]

I challenge you to find a single commercial manufacturer that uses arc welding to join cylindrical batteries.

(as usual) you'd be wrong, tig and plasma-like welding styles is used in the very higest end of products. just not mass produced ones due to the cost and low speed. but you will see it in plenty of millitary gear like the hush-hush special forces electric 1~2 person submarines and most electrical connections used in sattelites and so on.

Show me arc welded cylindrical cells anywhere.

 

[flippy]

The shops that use those types of welders dont allow cameras or phones to enter the work area. Should be obvious. I only know 1 company in my country that has a welder like that and they only do work for the millitary and sattelite manufacturing, and they got armed guards, so good luck whipping out a phone at those kinds of companies :lol: they usually take everything electronic from you before entering the building.
The only reason i know of that is because i worked for them on a couple projects as a external consultant. Sadly i was not allowed to play with their welding gear...

You can find a couple youtube videos where they show these kinds of welders on presentations during electronics congresses and stuff. Go look for those if you are really interested. Pricing is generally "if you have to ask you cant afford it".

Still, its utterly useless in regular volume production and should never be recommended. 1 mistake and it poof, no more house. Even i use a regular capacitor welder and not a ultrasonic because of the insane cost and lack of mobillity on the welding head.

 

[Chalo]

Okay then, it's isn't a thing.

 

[flippy]

Okay then, it's isn't a thing.

Not for you no. Not me either, or anyone else on this forum.

 

[G8trwood]

Curious on if those “cold welders” would work. Realizing they are just really a micro tig spot welder

 

[flippy]

Curious on if those “cold welders” would work. Realizing they are just really a micro tig spot welder

not really. they are too "violent" for the really senstive work as they give too hard of a pulse. its like tryng to close a glass door with a swing of a sledgehammer.

personally i prefer laser welding. the control is insane and extremely localized. but again: not for us peasants at 20k a pop...

 

[kartoon]

This is my attempt to weld 0.3mm pure copper strips to 18650 batterys.
CNC machined copper welded with an Everlast welder and a self made weldeing torch. The welding tested out on a ABS plastic sheet, and the final setup not melting the ABS but welding together the copper with the blade as you see on the picture. After a day to fine tune, working well with batterys even on the negative side, which is thinner than the positive.

I would make a few pieces for sale if there is interest in it. The picture shows the prototype.
I tested the torch with pure copper from 0.2 soft and hard to 0.4 S-H and working well, with a stable weldpool.

CNC machined 0.3mm soft copper sheet

Testing weldpool sizes. On top is too small, but sticks ok to battery. When removing leaving small flags of copper. On the bottom is decent contact points.

The torch itself. Reqires argon gas for shielding.

Good welds from a different angle. Hard to take good photos from reflective materials.
The welded surface after four weling spots are cold enough to touch by hand.

 

[agniusm]

Are you pulse welding? What settings like pulse timing, amps etc?
Have you made the torch yourself? Is the ground connectwd to external bell? Is it made of brass? What tungsten you use?

 

[fechter]

Those look like pretty nice welds. One thing about copper is it will draw the heat away from the weld and cool very quickly.

Does your torch apply pressure to the work to keep them clamped during welding?

 

[spinningmagnets]

I'd like to see how this turns out.

Micro TIG welding is a highly efficient non-contact method for generating localized heat. Like resistance welding, a controlled and therefore easily monitored current is passed into the elements to be welded. Unlike resistance welding, the heat generated is due to the resistance of the electric arc and its associated current, and hence is independent of the product conductivity. This therefore provides a highly controlled method of developing localized welding temperatures that are suitable for joining materials up to 0.5 mm in thickness onto conductive battery cans.

Since copper is four times as conductive compared to pure nickel, 0.50mm thick copper is equal to 2.00mm nickel, which is insane. I can imagine that the new Tesla 4680 cells are capable of very high amps per cell, but my main interest is the minimum thickness of copper needed to properly conduct 50A per cell, such as the current from a high-amp 21700 cell...

A TIG-welder is clearly able to generate enough energy to blow up an 18650 cell, but they are adjustable, and if a very low setting can work well for pure copper, I want to know the energy setting and model of welder. If it turns out to be a bad idea, I want to see pics of the carnage...

A TIG is very expensive, so I don't see this as much use for the ES DIY crowd, but...all data is useful data. Since getting feedback on the nickel-copper sandwich, I am pleased that there is an existing method to bond 0.10mm-0.15mm copper to 18650 cells. That being said, I still want to see where this goes...

 

[cricketo]

A TIG-welder is clearly able to generate enough energy to blow up an 18650 cell, but they are adjustable, and if a very low setting can work well for pure copper, I want to know the energy setting and model of welder. If it turns out to be a bad idea, I want to see pics of the carnage...

Dedicated Tig welders (and a few high end multiprocess ones) go down to 5A, and some even down to 3A, with voltage being on average about 10V (depends on the settings for the process). That's basically the energy of a moderate soldering iron, except much more focused and controllable. I think with a small electrode like 1mm, well sharpened and a fuse weld between the cell and copper strips edge it should be possible to transfer less heat into the cell than with any other method. It's a slow process, and takes some skill to pull off consistently.

A TIG is very expensive, so I don't see this as much use for the ES DIY crowd, but...all data is useful data. Since getting feedback on the nickel-copper sandwich, I am pleased that there is an existing method to bond 0.10mm-0.15mm copper to 18650 cells. That being said, I still want to see where this goes...

Tig is expensive (relatively) if the only reason one is getting the machine is to weld the battery cells At that point indeed it's a bad idea,
especially since there is a steep learning curve so it will take a while before one can weld something this small reliably.

 

[qwerkus]

[ ... ]

You forget the need for a gas bottle! Has always been the main drawback of shielded arc welding in my opinion.

 

[Chalo]

Dedicated Tig welders (and a few high end multiprocess ones) go down to 5A, and some even down to 3A, with voltage being on average about 10V (depends on the settings for the process). That's basically the energy of a moderate soldering iron, except much more focused and controllable. I think with a small electrode like 1mm, well sharpened and a fuse weld between the cell and copper strips edge it should be possible to transfer less heat into the cell than with any other method.

I don't think so. First of all, much or most of the heat from a soldering iron is discharged elsewhere, whereas almost all the heat of welding is dumped first into the workpiece. In the case of soldering, only the solder is being melted, and in the case of resistance spot welding, the mass of material being melted is less than with arc welding, and it's concentrated right at the surface.

I would like to see measurements, but I have my doubts that TIG welding can be used without causing greater cell heating than resistance welding.