Jim, actually soldering to nickel is very extremely easy using regular radio shack 60/40 solder. I have already done that to put together a battery pack without having a welder. I had to solder all the nickel tabs to the battery.
This is what I bought specifically for welding, but it solders to...
If this makes it easier to understand. In the picture below you have the wire on the left delivering 10 amps. The wire on the right taking the 10 amps.
The nickel plate between the two wires has the exact mass (cross sectional area) to handle 10 amps without heating up if the 10 amps were...
I'm going to weld nickel plates/tabs to 18650 cells. Each two batteries will be welded together with a nickel plate. In the center of the nickel plate will be a copper wire to take the 20 amp current flowing from the two cells at 10 amps per cell.
Since I have .2 mm thick nickel plates, to get...