Finished spot-welding 240 cells (20S12P from 5 separate 4S12P packs, LG HG2 cells, 3000mAh/ea, 20A continuous each, total of 2.6kwh). Used 0.2mm x 8mm pure nickel, carefully laid out to achieve approximately 160-170A ampacity.
JP Welder has not been perfect, but I got through it! I blew a trace...