I was trying to see if welding 0.2mm copper by itself without the copper brazing paste was possible.
These practice weld cells came out of my windows 7 pre 2009 era 3s2p aftermarket laptop battery. Wintonic 2200 mah, 6.6 amp CDR.
It could still power my laptop for aBout 20 minutes, but I needed test cells, so i opened it up.
The little raised portion on the Anode(-) side of can was indented on two cells by the chinese spot welder sometime in 2017. Those 2 cells hit 2.8v when the other 4 cells were still ~3.5 when I discharged them with the Jaro fan..
So likely compromised by being dented. I believe the design also allows the cell can to be thinner and weaker, and I managed to destroy two cells by puncturing them welding.
Good thing I had discharged then to below 0.06v first.
Siickly sweet smelling electrolyte shot out, and the electrode went deep enough to puncture the jellyroll, into the cathode/anode plastic separator, and melting it and drawing some out of the cell.
I was able to successfully weld 0.2 copper by itself, no flux, to the cathode, but the copper is pretty weak and whike the welds stuck, I could peel the copper away from the welds too easily, and thus in my opinion makes it unsuiitable for high physicaL stress batteries like in Esk8 when welded with no flux, no sandwich.
0.25mm copper felt much more than 20% stronger to me, but I think the nickel plated steel cap on top not only makes welding without flux (copper brazing paste) possible, but makes for a more physically robust weld.
My dad had some 316 stainless steel strip, 0.5mm thick in the garage.
I decided why not.
These welds were about 75% of max power, and its likely 60-65% would have been better.
The bond to the cell's anode was ridiculously strong. I couldn't just pull it off with needle nose plyers, I had to roll it off, using a lot of force, but once it started to movee it got easy.
If copper gets a score of 100 in electrical conductivity, pure nickel scores about a 25.
Steel is about 9 or 10, so nickel plated steel is about 10-12, depending on the steel alloy and thickness of nickel plating.
Stainless is about a 5.
When doing copper sandwich, the higher the resistance of the top cap material, the hotter it gets and the better the spot weld.
So nickel plated steel works better than pure nickel when sandwich welding pure copper.
Stainless steel works better than nickel plated steel.
But 0.5mm is ridiculous, but I bet I could weld 0.1copper, 0.5 stainless with the AwithZ P20b welder using the brazing paste, and maybe even without it.
The DIY500ampdot com proprietor is a good person and nerds out on stuff like this too.
He is getting some 0.1mm stainless strip and wants to send me some so i can continue exploring the limits of this machine.
Some fancy tabless cells might be in the box too, enough to perhaps upgrade my 7s1p cordless vaccuum battery. The thing is only 6 months old but It is obviously losing capacity quickly, and i now have to use a lower speed than i otherwise would to finish the house.
These practice weld cells came out of my windows 7 pre 2009 era 3s2p aftermarket laptop battery. Wintonic 2200 mah, 6.6 amp CDR.
It could still power my laptop for aBout 20 minutes, but I needed test cells, so i opened it up.
The little raised portion on the Anode(-) side of can was indented on two cells by the chinese spot welder sometime in 2017. Those 2 cells hit 2.8v when the other 4 cells were still ~3.5 when I discharged them with the Jaro fan..
So likely compromised by being dented. I believe the design also allows the cell can to be thinner and weaker, and I managed to destroy two cells by puncturing them welding.
Good thing I had discharged then to below 0.06v first.
Siickly sweet smelling electrolyte shot out, and the electrode went deep enough to puncture the jellyroll, into the cathode/anode plastic separator, and melting it and drawing some out of the cell.
I was able to successfully weld 0.2 copper by itself, no flux, to the cathode, but the copper is pretty weak and whike the welds stuck, I could peel the copper away from the welds too easily, and thus in my opinion makes it unsuiitable for high physicaL stress batteries like in Esk8 when welded with no flux, no sandwich.
0.25mm copper felt much more than 20% stronger to me, but I think the nickel plated steel cap on top not only makes welding without flux (copper brazing paste) possible, but makes for a more physically robust weld.
My dad had some 316 stainless steel strip, 0.5mm thick in the garage.
I decided why not.
These welds were about 75% of max power, and its likely 60-65% would have been better.
The bond to the cell's anode was ridiculously strong. I couldn't just pull it off with needle nose plyers, I had to roll it off, using a lot of force, but once it started to movee it got easy.
If copper gets a score of 100 in electrical conductivity, pure nickel scores about a 25.
Steel is about 9 or 10, so nickel plated steel is about 10-12, depending on the steel alloy and thickness of nickel plating.
Stainless is about a 5.
When doing copper sandwich, the higher the resistance of the top cap material, the hotter it gets and the better the spot weld.
So nickel plated steel works better than pure nickel when sandwich welding pure copper.
Stainless steel works better than nickel plated steel.
But 0.5mm is ridiculous, but I bet I could weld 0.1copper, 0.5 stainless with the AwithZ P20b welder using the brazing paste, and maybe even without it.
The DIY500ampdot com proprietor is a good person and nerds out on stuff like this too.
He is getting some 0.1mm stainless strip and wants to send me some so i can continue exploring the limits of this machine.
Some fancy tabless cells might be in the box too, enough to perhaps upgrade my 7s1p cordless vaccuum battery. The thing is only 6 months old but It is obviously losing capacity quickly, and i now have to use a lower speed than i otherwise would to finish the house.
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