Jidian Yanjiusuo (Electromechanical Lab) builds a 16.8V screwdriver drill pack. The BMS negative is at the top-left, so the cells are laid out in the BMS’s order; spot-welded with an AWithZ H2 (screen reads 25°C), the excess nickel strip trimmed off, negative and positive welded; the cells are tinned; a small piece of nickel strip is welded on to make soldering the leads easier; fish paper stuck on; the BMS + and − soldered; the two leads at the bottom of the pack soldered; foam stuck on; into the case for a test, a ‘high-power power Li-ion battery, charge once every two months’ sticker applied, test fine, done. Comments ask which welder / how much the welding pen costs, whether the nickel strip is 0.1 and too thin, whether four cells in series is enough capacity; one suggests just welding on a small piece of nickel without tinning.