Trace cell lots, weld records and end-of-line tests to each battery pack built.

A battery pack begins as cylindrical or prismatic cells sorted on a cycler for capacity and DCIR. They are grouped into modules, joined by laser welded or ultrasonic bonded busbars and fitted with a battery management system (BMS) board. Each cell carries its own history. Every step leaves data that a vehicle maker may ask to see years after the pack has shipped.

EV component software keeps all of it on the pack serial. Cell lot, weld record, BMS firmware and end-of-line result sit together, so an engineer answers a warranty query from one screen. Without that, the engineer opens cycler exports, torque logs and tester printouts side by side, still unsure they describe the same pack.

Orders arrive from two-wheeler makers, bus builders and fleet converters with a pack variant and a build schedule. Stores hold cells in graded trays, and a tray is closed to a module only after the cycler file for that lot is matched to its label. Operators stack cells into the fixture, fit busbars and record nutrunner torque or weld parameters. Then the BMS is fitted and flashed, the cooling plate and thermal pad go in, and the case is closed.

Each pack goes to an end-of-line station for insulation resistance, hipot, cell voltage balance and CAN communication checks. Results are saved against the serial. A passed pack is brought to storage voltage, labelled with its UN 38.3 transport marking and packed. A failed pack goes to the rework bay with a defect code, then back to the tester. Nothing ships untested.