Here is 0.15mm copper atop 0.1mm copper, with flux, gear 850, preheating 0.15ms, 04ms interval, double pulse.
The peel off strength was good, but obviously 0.25mm stacked copper felt a bit flimsier than solid 0.25 copper would.
I think this is very Viable nickel Sandwich free option with this welder.
The other copper bits on the cell were half hearted attempts with 0.1mm copper atop 0.2 and gear under 750. I wasn’t feeling it, then decided to go down 0.05mm.
I was trying the flux between the copper layers too which was unnecessary.
I had never considered being able to skip the nickel plated steel sandwich. i thought it was absolutely necessary. Conductivity wise 0.25 copper beats 0.2 copper with 0.1 nickel plated steel on top, but the latter takes a lot more force to peel off the cell, but how relevant is that if the welds are strong and the material has to tear?