18650 spot welding -how to- ULTIMATE REPOSITORY

My pack build is coming along nicely.
DSC_0001.jpg


However, I would not recommend doing any spot welding in any location that is not situated directly over the cell top/bottom.
I misunderstood how a spot welder works and thought the pulse would only penetrate the top and next layers...i.e. 2 layers of nickel would leave whatever was underneath unaffected. This is not the case :!: :!: :!:
Instead, it appears that the pulse penetrates deeper. I saw the paper insulation rings char and burn slightly and also the heat shrink vaporise, before I stupidly tried welding between a spot on the cell bottom and a point with nothing underneath it...then this happened:
[youtube]C_FC4XTzx74[/youtube]
I'm lucky it wasn't on the positive side or it could have been a lot worse.
It's hard to see from the video, but it actually completely blew the nickel strip apart at the cell edge leaving no link at that point. You can see the charred mark on the heat shrink in these photo's taken after I fixed it.
DSC_0003.jpg

DSC_0005.jpg

As you can see above I was able to fix it by welding another strip over the top. Anyway, I was planning on having a few 5P blocks made up as spares for my 12S5P pack and this will be one of them...unless I change my mind and make it 14S5P.

As you can see from my first photo, I didn't make the rest of my parallel blocks with just one link and instead opted for 2 links on either side. I'm sure you could make a single link configuration work you welded it to the middle of the 2 cells nickel strip FIRST, before placing it on the cells and welding all the rest.

Anyway, hope others can learn from my mistake.

Cheers
 
The first time it did it to me I nearly fell off my stool. Then the anxiety of it happening again was almost as bad as it actually happening. I just did that trying to spot weld brass to the cells and blew a hole through the bottom of the battery.....not sure where the sound came from but it kinda sounded like a little girl seeing a spider for the first time! :shock:

Tom
 
litespeed said:
The first time it did it to me I nearly fell off my stool. Then the anxiety of it happening again was almost as bad as it actually happening. I just did that trying to spot weld brass to the cells and blew a hole through the bottom of the battery.....not sure where the sound came from but it kinda sounded like a little girl seeing a spider for the first time! :shock:

Tom
Click to expand...
Lol, yeah well it's an experience best avoided either way I reckon. That sound was just my 4 y/o daughter chatting to mum about being pretending to be a goose. :)

riba2233 said:
Yeah that's only one of the many reasons for you to use paper insulators on positive pole :)
Click to expand...
Yeah, I'm so glad I did or the reverse side of this battery would have ended up in a dead short.

Has anyone experienced a dead short from spot welding on the positive side? I'm curious to know how quickly it becomes catastrophic. i.e. would I have had a chance to run outside with a smouldering/smoking cell, or would it have instantly exploded in my face?

Cheers
 
i'd like to add a little something based on magnets said about washers, it would appears it's such an issue, that there are actually already pre-made insulation washers just like the pre-made slit ones.


https://www.imrbatteries.com/12-battery-terminal-protectors-insulators-flat-top-18650/

while i havn't tried those myself, i googled for 18650 insulator discs
 
I used those stick on paper insulators. They work well. You just have to make sure you buy ones with a large enough hole in the middle. There are lots out there with a very small hole in the centre, not good for spot welding.

DSC_3643.jpg


Cheers
 
Allex said:
Found this neat configurator on e4bike site you can play with
http://e4bike.ru/page/battery-shape-configurator
Click to expand...

I would be cool if it could render nickel strips placement.
 
I use 0.15mm nickel strips and my selfmade spotwelder. It works perfect.

https://www.youtube.com/watch?v=VSGhcC35Z6Q

Thumbnail_01_klein.JPG
 
Need nickel faster than china and just want 10 feet?

"This listing is for 3m (9.84 ft) x 8mm x 0.18mm of 99.6 Pure nickel strip. Generally it's intended to be used for battery welding."

Great communicator,

http://www.ebay.com/itm/332072740842?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

$9 shipped
 
Anybody here welding with energies higher than 200J ? (that is 1F @ 20V)

Anybody using 0.3mm nickel? What voltage/capacity/pulse are you using for your welds?

My electrodes stick a lot with this config.
 
My First 18650 battery with arduino spot welder :D
GA cells, 14S6P 21AH 1kwh

37991220170128131800.jpg


65981020170128205359.jpg
 
vex_zg said:
Anybody here welding with energies higher than 200J ? (that is 1F @ 20V)

Anybody using 0.3mm nickel? What voltage/capacity/pulse are you using for your welds?

My electrodes stick a lot with this config.
Click to expand...

I have 3F @ 23 volts but have only used .2mm because I had a hard time finding .3mm. I'm using the glidcop electrodes from Sunstone engineering. They stick way less than copper probes.

I'm hoping after my shoulder heals up (just had rotator cuff surgery) I can figure out how to weld copper (probably a pipe dream) or brass.

Tom
 
litespeed said:
vex_zg said:
Anybody here welding with energies higher than 200J ? (that is 1F @ 20V)

Anybody using 0.3mm nickel? What voltage/capacity/pulse are you using for your welds?

My electrodes stick a lot with this config.
Click to expand...

I have 3F @ 23 volts but have only used .2mm because I had a hard time finding .3mm. I'm using the glidcop electrodes from Sunstone engineering. They stick way less than copper probes.

I'm hoping after my shoulder heals up (just had rotator cuff surgery) I can figure out how to weld copper (probably a pipe dream) or brass.

Tom
Click to expand...

Since 1F is enough for .2mm, you better use that 3F for copper

I found and bought and tested genuine .3mm nickel strips but getting inconsistent welds and afraid to punch the cell wall. Also tried molybdenum and copper-tungsten and even more sticking

I thought glidcop was tungsten copper alloy.
 
I really don't know what they are made of but they do work well.....better than copper by a long shot.

As I wrote in another thread you should try just using wider nickel instead of thicker. Madin in my opinion has the battery building down better than anyone on this board. I am Using 23mm wide nickel connecting both the series and parallel groups together IS the hot ticket. .2mm nickel is perfect thickness and the wide strips add more current carrying capabilities with out risking blowing through the end caps of the cells. Less connections means less resistance which in turn means more power output.

Tom
 

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litespeed said:
I really don't know what they are made of but they do work well.....better than copper by a long shot.

As I wrote in another thread you should try just using wider nickel instead of thicker. Madin in my opinion has the battery building down better than anyone on this board. I am Using 23mm wide nickel connecting both the series and parallel groups together IS the hot ticket. .2mm nickel is perfect thickness and the wide strips add more current carrying capabilities with out risking blowing through the end caps of the cells. Less connections means less resistance which in turn means more power output.

Tom
Click to expand...

yeah perhaps you are right. Using .3mm is so much more effort than .2 (requiring better electrodes+an additional capacitor+punching cell wall risk).

Where did you source those 23mm nickel strips?
 
vex_zg said:
litespeed said:
I really don't know what they are made of but they do work well.....better than copper by a long shot.

As I wrote in another thread you should try just using wider nickel instead of thicker. Madin in my opinion has the battery building down better than anyone on this board. I am Using 23mm wide nickel connecting both the series and parallel groups together IS the hot ticket. .2mm nickel is perfect thickness and the wide strips add more current carrying capabilities with out risking blowing through the end caps of the cells. Less connections means less resistance which in turn means more power output.

Tom
Click to expand...

yeah perhaps you are right. Using .3mm is so much more effort than .2 (requiring better electrodes+an additional capacitor+punching cell wall risk).

Where did you source those 23mm nickel strips?
Click to expand...

I bought 1.4 inch wide and cut it to the width I needed. I asked before I bought and was told it was pure nickel but it is not. Mine rusted a bit. http://www.electricrider.com/Nickel-Strip-1-4w-x-008t-1-unit-1-foot-p/nickel-36.htm?CartID=1 I'd source better stuff if I was you.

Tom
 
Allex said:
Has anybody seen these holders before, the pack would be very compact with them.

Also does anybody have a good Ali-source for the big black rubber heat shrink? It is more durable than PVC alternative.
41pQKvWHkoL._AC_US160_.jpg
Click to expand...

I just made a 17S7P LG HG2 pack using those offset packing cell holders. The white stuff you see there is neutral silicone sealant used to stick the batteries to the plastic holders.

GcGT5qj.jpg

MzyKdcN.jpg

w491O8A.jpg
 
It requires a thick sheet of nickel for current 40 amp 48V
NCR18650GA cell 13S6P
 
I am in the process of building a new battery pack for my Q76R frame and MAX-E. I calculated that I can easily fit 180 cells using spacers. That will give me a nice pack of 20S9P. Given that a single VTC4 can burst at 30A, nickel won't cut it.

I tried various options:
- Solder copper wires to nickel and then spot weld nickel to cells (too much hassle).
- Spot weld nickel strips to copper sheet, poke holes in the copper and then spot weld nickel onto the cells (nickel does not weld to copper easily).

Things I haven't tried and I won't be trying:
- Solder copper wires to cells.

However, what works extremely well is "spot welding" 0.3mm copper strip onto cells using a small piece of solder in between. I have a slightly modified Sunkko 788H spot welder that does the job perfectly. I have it running at 70/2 and current setting at 8 (will probably need to fine tune that as I go). The cell does get hot, but it is OK to touch after 1-2s,

See pictures for yourself, also, please tell me why this is such a bad idea before I go ahead and "spot solder-weld" onto expensive cells.

View attachment 2

IMG_20170328_122800.jpg

IMG_20170328_122749.jpg
 
I think you are heating cells too much. After normal welding you can't feel any heat on the cells. Just make parallel packs with 0.15 8 mm nickel, and then connect them in series with bare copper 1.5mm2 solid wire soldered on nickel tape between each cell. I guarantee that will be more than sufficient and cells will like it.
 
Hello Riba!

I was wondering if the additional diodes used on the latest designs, the arduino welder are something that might be useful on your welder?
You really started quite the revolution!

Thanks!

Tom
 
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