Spot Welding Copper Strips to 18650 Battery Cells

[devmonkey]

Power leads have been attached. I 'butterflied' 8awg silicone cable and soldered to a piece of copper which was then welded to the cells. I formed a channel in the copper to wrap around the wire increasing the joint strength. Now just need to attach some balance leads (no BMS in this pack). Any recommendations on compact connectors I can mount on the packs for the occasional balancing exercise (99% of the time these packs will just be bulk charged). Was thinking of either sub-d or pcb headers.

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[garolittle]

I know it’s incredibly expensive, but has anyone here purchased the Orion Omega 250 system shown in the link below?

https://youtu.be/jDCY0buOI-A

[Hummina Shadeeba]

Power leads have been attached. I 'butterflied' 8awg silicone cable and soldered to a piece of copper which was then welded to the cells. I formed a channel in the copper to wrap around the wire increasing the joint strength. Now just need to attach some balance leads (no BMS in this pack). Any recommendations on compact connectors I can mount on the packs for the occasional balancing exercise (99% of the time these packs will just be bulk charged). Was thinking of either sub-d or pcb headers.

IMG_20201227_170630 (Large).jpg

https://www.amazon.com/jst-xh-connector ... +connector

what do you do to balance?

[docware]

Now just need to attach some balance leads (no BMS in this pack). Any recommendations on compact connectors I can mount on the packs for the occasional balancing exercise (99% of the time these packs will just be bulk charged). Was thinking of either sub-d or pcb headers.

You need reliable bullet-proof solution, I can reccomend Higo connectors.

https://www.higoconnector.com

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[Hummina Shadeeba]

Now just need to attach some balance leads (no BMS in this pack). Any recommendations on compact connectors I can mount on the packs for the occasional balancing exercise (99% of the time these packs will just be bulk charged). Was thinking of either sub-d or pcb headers.

You need reliable bullet-proof solution, I can reccomend Higo connectors.

https://www.higoconnector.com

Higo Mini B connectors.jpg
Mini F female connectors.jpg

All I can find is jst or Molex for 15 pin (14s). What you recommend?

[hallkbrdz]

Now just need to attach some balance leads (no BMS in this pack). Any recommendations on compact connectors I can mount on the packs for the occasional balancing exercise (99% of the time these packs will just be bulk charged). Was thinking of either sub-d or pcb headers.

I'd recommend surplus mil-spec connectors. I'm using a MS3126E22-55 for my 42S packs with external BMS. Not that expensive and very reliable.

https://www.ebay.com/itm/BRUNDY-MS3126E ... 1438.l2649

[devmonkey]

Finished pack, just bunged some JST on there for now as I had them already, far from ideal but will let me check the cells. Cells were within 2mV absolute straight out of the box which was amazing.

[youtube]utYveWc6Wrg[/youtube]

[Hummina Shadeeba]

Why’d you make it two batteries instead of one?

[devmonkey]

Why’d you make it two batteries instead of one?

Yeh the layout was quite constrained and it had to be curved to fit the harness, would have been possible to do them in blocks of 6 rather than 3 to end up with a single pack but then would have needed twice the copper thickness as each plate would be carrying the full current. I can't spot weld thicker copper so this the compromise was 2 packs. I did have an alternative layout where each physical pack carried one half of each pack, starting with the negative in the middle and ending with positive in the middle of the other half but required complicated interconnects to break the pack down. This could have been made into a single pack by wiring parallel connections across each side.

[garolittle]

Finally decided to buy the Omega 250i pulse arc welder from Sunstone Engineering. It was a really big investment but I’m very pleased with the results. I decided to practice with the most difficult spot weld of all ... thick copper. Here is a video of some sample spot weld using .4 mm thick pure copper. This is a rewrapped Samsung 25R cell.

https://youtu.be/h_XPnqejBYM

[jonescg]

Looks great - I reckon it's a winner.

What did it cost you? And how deep is the throat on it? Can you weld up a 350 mm deep pack?

[garolittle]

What did it cost you? And how deep is the throat on it? Can you weld up a 350 mm deep pack?

Thanks. It was a big investment at $27K (USD) but it comes with a micro pulse arc and tack welder. The weld head in the middle was used to make the welds on the .4 mm thick copper busbars in the video above. Here are a few photos of how the cells look after the bus bar is removed. Welds are very consistent and very strong. Still learning how to use the machine but so far the results are very pleasing.

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[garolittle]

20-second video of an assembled module ....

https://youtu.be/ljw1OvuyC-0

[amberwolf]

It was a big investment at $27K (USD) but it comes with a micro pulse arc and tack welder.

That's more than I've *earned* in some *pairs* of *years*, even recently. Still significantly more than I make in a whole year now....

I...can't imagine spending that kind of money on...well, anything...but I'm guessing you're looking into commercially manufacturing batteries, not just stuff for yourself.

[garolittle]

....but I'm guessing you're looking into commercially manufacturing batteries, not just stuff for yourself.

Definitely was a big investment. Had to take a deep breath before making the purchase. However, I have tried many other spot Welders over the years and finally concluded I needed a professional grade Welder like this. Definitely plan to “go commercial” with battery packs for go carts, E bikes, and electric motorcycles at some point in the future. I’ve learned many things from this forum and want to put the knowledge to good use now.

[spinningmagnets]

Definitely plan to “go commercial” with battery packs for go carts, E bikes, and electric motorcycles at some point in the future

Boats, forklifts, home power back-ups...

[garolittle]

Definitely plan to “go commercial” with battery packs for go carts, E bikes, and electric motorcycles at some point in the future

Boats, forklifts, home power back-ups...

Yes Sir. . Hoping to quit my regular job and go full time with battery assembly as soon as possible. Really enjoy this project.

[Hummina Shadeeba]

Why’s there such a huge gap in welders where we can get a welder for 230$ (Kweld)that will do .1mm copper but need to spend way more to get something to do .4? Cant they just make a welder with more/bigger bits on the board?

Kweld say it isn’t designed for copper though. .3mm nickel is it’s stated most conductive possibility.

My experience with a nickel then copper sandwich leaves me with just nickel and copper welded and not to the cell.

I found I can strongly weld .1mm copper to the negative side of a123 26650 cells with just 30 joules but the other side I have really weak welds at even 50 joules.

[garolittle]

Why’s there such a huge gap in welders where we can get a welder for 230$ (Kweld)that will do .1mm copper but need to spend way more to get something to do .4? Cant they just make a welder with more/bigger bits on the board?

That is actually a great question. I’ve often wondered the same thing. You would think there would be a $2k welder that would allow for enough power for at least .25 mm thick pure copper.

[john61ct]

Definitely plan to “go commercial” with battery packs for go carts, E bikes, and electric motorcycles at some point in the future

Boats, forklifts, home power back-ups...

Yes Sir. . Hoping to quit my regular job and go full time with battery assembly as soon as possible. Really enjoy this project.

What jurisdiction are you planning on locating wrt torts law?

[spinningmagnets]

Concerning laws, I would suggest forming any such business in the US as a welder-rental service, and the rental company rents the machines to the battery building company.

You don't have to be "at fault" for someone to sue you, and there are cases where liability insurance paid $15,000 for someone with NO CASE to simply "go away" instead of going to court to easily win, and THAT is a powerful incentive to sue, regardless of fault. Perhaps even a battery building competitor might sue.

The machine rental company and battery building company might be formed as LLC's to sheild your private assets.

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welding machines

It might be possible to weld 0.20mm and thicker copper with a rewired transformer-based RSU, and a 120V soid-state timer with foot-switch... I don't know. You would definitely need to use the infinite split (two completely separate strips that dont touch, instead of a single ribbon)

https://www.electricbike.com/resistance-soldering-unit/

[Hummina Shadeeba]

what about adding electrodes to one of these: https://www.harborfreight.com/120v-spot ... 65da628322 "1.5 kVA @ 50% duty cycle"



and there are also 240v versions.


in the link you just posted it looks like they were trying to make a welder for the same purpose as the one i posted: welding plates


or what's a good way to cut a slit in the copper?

[garolittle]

Concerning laws, I would suggest forming any such business in the US as a welder-rental service, and the rental company rents the machines to the battery building company.

Interesting idea. Thanks

[spinningmagnets]

If its an LLC, the person cannot be personally sued for the liabilities of the company, but the battery building company can have its assets seized to satisfy the judgement against a lawsuit that was successful (or a spurious lawsuit brought by competition in order to get paid $15,000 to drop the suit in a settlement). Funny thing is, if they can't get anything from you, no lawyer will take the case.

So court marshals/sheriffs will lock up the business and take any tools and materials to be auctioned off to give the money to the winner of the lawsuit, along with any completed battery packs. If the business owns the building and a delivery truck, they will seize that too.

However, if the building, delivery truck, and spot-welders are rented, they cannot be seized and auctioned off. To start the rental company, write a personal check, but the check must say on its face "loan number X to Chameleon rentals, LLC". Write a one-page contract, and the terms of the loan are a balloon payment plus high interest in 50 years. Of course, you can pay yourself back early if that benefits you.

I am personally aware of a company that was raided (wife left, and decided to make false claims about husbands business to the IRS). The problem was not getting their computer back, because they bought a new laptop the same day. The problem was getting the information that was on the seized computer.

Therefore, have an external memory drive hidden near where the laptop is stored for the night. Have it use bluetooth or some other wireless communication to automatically back-up everything that happens each day (once a week, put a back-up on an SD thumbnail card). Invoices, checks written, client addresses, phone numbers, and dates of business, etc...Plus, courts aside...you also can't discount a violent meth-head with a chronic gambling addiction breaking-in and stealing the laptop to try and sell it to get enough money for a new ebike...

There's another layer where you fly to Las Vegas and form the battery building LLC in Nevada, and all calls and mail are forwarded to your "branch" in the state you live in...

I am not a attorney, nor do I play one on TV, but...if this information has been helpful, send your social security number and mothers maiden name to: spinningmagnets, prisoner #41, Kansas state correctional facility for the criminally insane, Junction City, OU812.

[SlowCo]

I am not a attorney, nor do I play one on TV, but...if this information has been helpful, send your social security number and mothers maiden name to: spinningmagnets, prisoner #41, Kansas state correctional facility for the criminally insane, Junction City, OU812.