18650 spot welding -how to- ULTIMATE REPOSITORY

flippy said:
i expect a lot of oxidation when the nickel, copper and solder/tin are going to have a reaction. dont know by memory but one metal is going to be the sacrifical one.

it also looks REALLY labour intensive. there is nothing to be gained by this method compared to just spotwelding the proper nickel strip or even copper if you can do that.

I want to spot weld nickel strip on battery terminals and I do not find a good one that can carry 22A continuous.
Where did you find the info about the oxidation? I need to check the soldering points of the balance wires on my current battery that was built in 2014.
 
Google sacrifical metals and start from there.


Does each cell actually carry 22A continous?
If that is the case then most batteries are drained in under 10 minutes.
For peak loads of 22A a 8x0.2mm strip would be enough, 8x0.3mm if you can weld that thick is well enough. Your cells will die before that strip does.
You can also double up on 0.2mm if you use 3 welds on the first layer.

Also, dont focus so much on the parralel current strip. That is almost zero amps, its just to keep the cells balanced. It does not need to handle any current. Start with the series strips and after all those are done you can weld the parralel strips and make the pack whole. It is also a lot safer when working on the battery as you only short 1 series string instead of the whole pack.
 
flippy said:
Google sacrifical metals and start from there.


Does each cell actually carry 22A continous?
If that is the case then most batteries are drained in under 10 minutes.
For peak loads of 22A a 8x0.2mm strip would be enough, 8x0.3mm if you can weld that thick is well enough. Your cells will die before that strip does.
You can also double up on 0.2mm if you use 3 welds on the first layer.

Also, dont focus so much on the parralel current strip. That is almost zero amps, its just to keep the cells balanced. It does not need to handle any current. Start with the series strips and after all those are done you can weld the parralel strips and make the pack whole. It is also a lot safer when working on the battery as you only short 1 series string instead of the whole pack.

Not peak! CONTINUOUS. I want to ride for 4-5 km at 90-100Km/h
Each cell will deliver 11A continuous so each strip in the middle section will see 22A continuous
20180508_113310_1.jpg


Also I forget to mention that I think that hot glue (also the Bosch) sticks very badly on the cells wrap but it sticks much better on Kapton tape. So for that reason and for added cell to cell protection I'm gonna wrap each cell in a turn of Kapton tape. I got the 30 and 35mm wide.
 
I can’t find where it is but search for pictures of maddin88’s battery builds.....NO ONE builds a better 18650 pack then he does.

Battery Hero even.....

Tom
 
Yep to much labor and problem with oxidation.
Use double strips of 0.2x10mm on top of each other, like so(well you cant actually see that they are doubled).
IMG_4591.jpg
In fact I have a better suggestion to you about your layout where you only have 1cell instead of 2 together like your pack today while maintaining the same measurements. With this layout you can even quadruple nickel strips - plenty enough to run your currents without even getting to the body temps.
Lets see if you can solve this puzzle :mrgreen: Its a 20s10p but hey, how is the rest of 5p connected? :wink:
IMG_4553.jpg
 
Yeah :D The lower picture is the way to go ..... with that setup there will be 14 nickel strips for series connection instead of the 7 that I actually have. Then each strip will carry 11A that is a great improvement.
In the upper picture instead I do not understand how did you connected the series cells.

About the oxidation problem is it not present also on the soldered end of the balance wires on nickel strips?
 
Well you can still have 14 strips with your current layout where you have 2pairs of cells, just weld the strips on top of each other. But the lower picture is a better layout because you have a better current distribution with only 1cell in a row instead of two.

The upper picture shows a pack with 11p where I have 14 strips in total. 7 + another 7 on top of them.
 
Sorry if this have been asked before.

But i`m going to spot weld my first li-ion pack, so i want to be sure i understand the Amp draw correctly, so i build my pack the right way with the right nickel stribs for the current.

Lets say my ESC draws 20 amp from my battery pack ( in this example a simple 4s1p pack) How many amps is going through the circuit in point A, B and C ? When all the 4 cells is giving 5 amp each to the total 20 amp. Thanks...


BTW. Where do people buy copper strips ? I`m from EU, but have a hard time finding a supplier. There is one on eBay, but he is on vacation until July :-(
 

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divide the current between the P. so 20A draw with a 5P pack means 20/5=4A per cell. it does not matter how much series cells there are, 20A is 20A.

also: make the serial connetions first. after those are done you can make the parrelel connections to make the pack a whole. there is almost no current across that parralel strip so just use one and put on top of the serial strips. those serial strips carry the current so they need to be on the cells directly.
 
I've welded all my parallel groups, but due to the geometry of my pack and about a 50A current draw, it'll be hard to get ideal current sharing using just nickel strips for series connections. I'm thinking about using copper wire but soldering only in between the parallel cells ontop of the nickel strips connecting them so with a 5P pack I'd have 4 series connections. Should I be worried at all about the current flowing through the parallel nickel strip since the series connections aren't ontop of each cell?
 
Kapton tape and sand paper are the best friend to glue the cells together with hot glue. :shock:
Yesterday still playing with some scrap cells after wrapping them in a loop of Kapton tape I tried to make the surface rough with 180 grit sandpaper and then glued the cells with hot glue. The result is amazing, it is almost impossible to detach the cells from each other by pulling with your hands.
 
flippy said:
i orderd this one:

https://www.aliexpress.com/item/0-15-x-8mm-1kg-roll-Pure-Nickel-Strip-99-96-for-battery-spot-welding-machine/32817896871.html

8mm wide and costs 59 USD. the 8mm fits better on most square spacers and if you need to overlap. it can also carry 15% more current.
when i get it i will fo the test and report back.

follow up: its'the good stuff.
 
Grrrr- It is so frustrating, I bought strips from Germany (NKON.NL genuine, but 0.3mm and too thick for my welder) and some off eBay and AliExp. Guess which is which. Grind then salt water test. :cry: Ideally I want some 0.2mm x 12mm but hard to find.
 

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eSK8r said:
Grrrr- It is so frustrating, I bought strips from Germany (NKON.NL genuine, but 0.3mm and too thick for my welder) and some off eBay and AliExp. Guess which is which. Grind then salt water test. :cry: Ideally I want some 0.2mm x 12mm but hard to find.

try here: https://www.aliexpress.com/item/1kg-0-15mm-12mm-Pure-Nickel-Plate-Strap-Strip-Sheets-99-96-pure-nickel-for-Battery/32852666249.html
 
0.2mm is where it's at. Perfect for welding, good current capacity. I'll see if I can find the AliExpress seller I used last time.
 
Last weekend I finished the assembly of my new 20S14P battery.
What do you think of the termination cables I made?
These are 14 18AWG cables soldered to a 8AWG one.
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I guess it COULD kinda act as a fusible link if all goes to hell in a hand Basket?

I would think you need a whole bunch more of parallel connections? Looks like only a thin piece of nickel at each parallel run?

What cells and what is total draw from pack?

Tom
 
Parallel strips are 0.2mmx5mm and they should be good for 5A that in my opinion is more than needed.
The battery is made with 280 Sony VTC6 and in the worst case I will draw from each series 11,5A peak and 10,5A continuos.
 
SigmaCLAD™ and how the metal system (Nickel, Stainless Steel, Copper, Stainless Steel, Nickel) can aid in issues of high amperages resulting in low battery life, connector material leads causing less voltage in the cell, and hot spots developing due to overheating.
Each layer of the composite material plays an integral role in providing a higher quality, more durable product. The central copper layer provides thermal conductivity. The two layers of stainless steel enable resistance welding with excellent pull strengths. The two outer Nickel layers deliver corrosion resistance and solderability.

The material endured 60 cycles of a corrosion dip test and displayed little to no corrosion. Its temperature was monitored with a Forward Looking Infrared camera and showed lower overall temperature and less hot spots. A number of welding tests were also preformed and concluded excellent pull strengths for multiple conductivity levels.https://endless-sphere.com/forums/posting.php?mode=edit&f=14&p=1395373#
 
dude, this is the third identical post with this advertisement crap.
 
flippy said:
dude, this is the third identical post with this advertisement crap.

This is not an ad.
I'm just trying to get the info out on this new battery weld tab material that is superior to nickle.
 
luminuty said:
flippy said:
dude, this is the third identical post with this advertisement crap.

This is not an ad.
I'm just trying to get the info out on this new battery weld tab material that is superior to nickle.

you posted 3 messages, all perfectly identical without any prior history. without seeing other postings actually interacting with other people i would take your postings as a bot spamming ads.

and "just trying to get the information out" looks just like an ad to me. you even went to the effort of putting the "tm" in the proper subscript.

am i wrong in assuming you have a stake in selling this stuff?
 
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