I would like to build my own 18650 pack. I was thinking of Samsung 25R cells and 2x5S packs in series with 3 or 4 cells in parallel. This way I could balance charge them separately with my 6S charger and would not need a BMS.
However for a single battery it is not economical to buy a spot welder so soldering is my only chance.
After reading about nickel strips, or copper welding rods for the connection of cells I was wondering what the actual best method for soldering 18650 packs is. Can you simply use 10mm^2 cables, remove the insulation at the position of a cell and solder them onto the cell? Or use 2x6mm^2 speaker cables?
Also I read about the danger of the cells becoming hot - can that be solved by dipping the rest of the cell into a liquid (distilled water or isopropyl) to allow for fast heat dissipation while soldering the cable onto the other end?
If there is a tutorial on how to solder 18650 packs let me know - so far I only read about finished products and not so much about the actual process.