Making a spot welder??
There are several types of spot welders, but the best for spot welding batteries is the Capacitive Discharge welder.
The advantages are repeatable energy delivery,and minimum heat effected zone.
A nice production unit is about $6-12K with the weld head.
Since I don't have that kind of money, I have to try building my own.
I did some scrounging in my extensive junk pile, and came up with some possible components.
I found 700,000 Uf of 15V or better capacitors. I mounted them so the lead length would be as short as possible, but did not have the 1"X 1/4" copper bus bars that I would have preferred to use, but the 1/2" X 1/4 that I had should be good enough for the prototype testing.
I got the huge hockey puck SCR to work, and found that it is one of the rare GTO or Gate turnoff types, which means I could pulse the discharge without totally discharging the caps like a regular SCR would.
I spoke with PowerX, but they could not find the part number so I really don't know much about the device except that it is huge, and that it worked when I tested it by firing a smaller cap into a resistor.
I also dug up a small spot welding head.
Not the components I would have bought for the machine, but hopefully it will be close enough to see some welds and get a starting point.
The buss bars are too small, The caps are not big enough, and the weld head is kinda small