Spot Welding Copper Strips to 18650 Battery Cells

Batteries, Chargers, and Battery Management Systems.
vex_zg
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by vex_zg » Sep 20, 2017 6:14 am

ridethelightning wrote:
vex_zg wrote:
qwerkus wrote:Anyone tried to weld or solder 5*0.2mm nickel plated copper solar bus wire ? It's cheap, supposedly copper and already protected against corrosion and, with a cross sectional area of 1mm2, it should be able to handle 12A. I wonder how the plating would influence the welding process.
I just ordered, will report in few weeks.
great. im interested to know what happens.
i suspect the tinned coating might sort of explode with welding, as the current will need to be very high to weld the copper.
yeah, tin sort of boils and explodes when you weld. But It's worth a try for couple of $. Zink/nickel plating of copper seems to be easy but I haven't yet had time to explore how this plating impacts welding.

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ridethelightning
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by ridethelightning » Sep 20, 2017 6:21 am

i did a while ago and was not impressed.
i Ni plated the copper myself, and tried spotwelding it. the results were not too good from memory, but perhaps i was doing it wrong.
they do use it in power tool packs though, with spotwelding so there must logically be a way. it would be a nice material.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by geckocycles » Sep 22, 2017 10:33 am

vex_zg wrote:i tried tungsten, molybdenum, 30-70 copper tungsten. Tested for welding copper, nickel, copper-nickel.

pure copper electrodes still work best for me. Tungsten/molybdenum cause more sparks and blowouts and stick much more.

I have not yet tried zirconium copper (the electrodes I bought are quite big in diameter so need some machining first)

Anybody willing to experiment can get cheap on aliexpress/ebay.

Beware though - machining tungsten and molybden is quite hard. Those are hard materials. Eats grinding stone like it was cake.
Use green grinding wheels, aluminum oxide wheels will dissolve grinding tungsten.

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spinningmagnets
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by spinningmagnets » Jan 07, 2018 9:53 pm

https://endless-sphere.com/forums/viewt ... 5#p1349212

" Hummina Shadeeba » Sun Jan 07, 2018 6:30 pm

new info for me is that sodium benzotriazole is a good copper corrosion inhibitor. you can just dip the copper. haven't done it yet. electroplating [nickel] is pretty damn fun though"

xxxxxxxxxxxxxxxxxxx

ES member willow is having success spot welding thin 0.10mm copper

viewtopic.php?f=14&t=68005&sid=f18c217a ... 0#p1348986

Hummina Shadeeba
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Hummina Shadeeba » Jan 13, 2018 4:32 am

it looks like the "boss level" welder has no trouble with .1mm copper strip and this guide, which seems more conservative than most, shows .1mm nickel x7mm strip doing 3amps comfortably, so with copper being 4 times as conductive couldn't I do a .1mm x 28MM FOLDED STRIP and that would net me 48 amps?

with the low amount of contact of a spot weld how many welds would be best on each cell



chart from here:
https://endless-sphere.com/forums/viewt ... ding+18650
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vex_zg
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by vex_zg » Jan 14, 2018 10:45 am

.1mm copper is a really thin thing. Yes weldable, some people use it, but it's really weak mechanically. I'd rather use double .2mm nickel for the same conductivity. That's just my opinion, some will disagree.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Hummina Shadeeba » Jan 19, 2018 4:40 pm

I have some .14mm copper and it is weak but maybe that's actually a good thing. not saying necessarily and would depend on each instance but if the strip can bend then it isn't putting the strain on the welded connection to the cell

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Willow
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Willow » Jan 20, 2018 8:28 pm

vex_zg wrote:
Jan 14, 2018 10:45 am
.1mm copper is a really thin thing. Yes weldable, some people use it, but it's really weak mechanically. I'd rather use double .2mm nickel for the same conductivity. That's just my opinion, some will disagree.
Like I've said here before... the cells should be held together with glue or in holders. Never rely on the electrical connections to hold the batteries together... nickel, copper or otherwise, the spot welds are simply not enough... and hence they should bare no mechanical loading.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by fourbanger » Jan 22, 2018 1:14 am

So, these exist:

https://www.aliexpress.com/store/produc ... 407dNQrXvq

https://www.aliexpress.com/store/produc ... f54fsgLTdK

Don't find them much inspiring, myself, and a bit rich for my blood. Just thought I'd offer it up as an option (of sorts).

Hummina Shadeeba
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Hummina Shadeeba » Feb 14, 2018 10:30 pm

this one is most versatile I've see and only 2 cells. really nice design. easy to print.


https://www.aliexpress.com/item/High-Qu ... autifyAB=0


is there a reason not to do a single strip of .13mm strip 30mm wide and fold it in half? I read doing copper on copper is hard and rather just do this and keep within the niobi guidelines. a hair away from welding the pack and wondering why i dont read of more people doing thin copper and folding.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Joachim » Feb 22, 2018 3:36 pm

i have seen a compleet e-bike pack welded 2.5mm nickel platet copper so there are companys use copper for the battery packs.
This is a Taiwan company.

I will shoot pics of a pack and post here.

The welds are not so strong like nickel..but oke.you can see they use more current to get good welds an also a cut in the strips for maximal strong welds/good current flow over the tops from the cells.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by E1Allen » Apr 13, 2018 12:54 am

So. If I have .2mm copper strips with the nickel tabs spot welded to it. Could I take a 30mm wide copper strip and fold it to 10mm wide to increase the overall area and amp carrying ability while keeping it less than 18650 width. In the future I'm looking to do a 30q pack in the 8p size or more. But that puts you above 160a. Granted it's not a continuous draw number. I'm wondering how well some of the large P copper welded packs you guys have made are holding up and what kind of amp draw you're able to pull.

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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by Philaphlous » Apr 13, 2018 5:01 am

Hummina Shadeeba wrote:
Jan 13, 2018 4:32 am
it looks like the "boss level" welder has no trouble with .1mm copper strip and this guide, which seems more conservative than most, shows .1mm nickel x7mm strip doing 3amps comfortably, so with copper being 4 times as conductive couldn't I do a .1mm x 28MM FOLDED STRIP and that would net me 48 amps?

with the low amount of contact of a spot weld how many welds would be best on each cell



chart from here:
https://endless-sphere.com/forums/viewt ... ding+18650
Thanks for the chart! Good to know my 3.5mm pure copper wick wire is going to deliver a ton of amps without any issues!

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ridethelightning
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by ridethelightning » Apr 13, 2018 7:18 am

E1Allen wrote:
Apr 13, 2018 12:54 am
So. If I have .2mm copper strips with the nickel tabs spot welded to it. Could I take a 30mm wide copper strip and fold it to 10mm wide to increase the overall area and amp carrying ability while keeping it less than 18650 width. In the future I'm looking to do a 30q pack in the 8p size or more. But that puts you above 160a. Granted it's not a continuous draw number. I'm wondering how well some of the large P copper welded packs you guys have made are holding up and what kind of amp draw you're able to pull.
160 A from 8p30Q is a bit ambitious.
it might do it for a second but the sag will make it not very fun and you will be trashing the cells.

12p is another matter :D

my copper packs, 22s 12p and 18p 30q are holding up nicely.

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ridethelightning
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Re: Spot Welding Copper Strips to 18650 Battery Cells

Post by ridethelightning » Apr 14, 2018 6:46 am

just thought id put it out there-

has anyone toyed with using multiple mots in parallel to get enough juice to do copper welding?

perhaps someone could shed some light on weather or not it would, in theory, work and any other hints that would help?

cheers.

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