A module is only as reliable as its worst weld. Before a tab welding process runs at full rate, four checks separate a stable process from a lucky one.
Qualify the joint, not just the machine
Weld schedules transfer between materials poorly. Qualify every tab and busbar combination separately — same alloys, same platings, same thicknesses as production parts. A schedule proven on bare nickel tells you little about plated steel, and the difference shows up as resistance spread months later.
Pull tests are cheap; field failures are not
Destructive pull and peel tests on a sampling plan give the fastest honest signal about joint strength. Record the failure mode, not just the force: a weld that tears through parent material is a different process state from one that peels at the interface, even at the same reading.
Watch resistance, not just appearance
A weld can look right and still read high. Four-wire resistance measurement across sampled joints catches marginal welds that visual inspection passes, and the trend over a shift says more about electrode and sonotrode condition than any single value.
Log everything against the module ID
When process signals log per weld against the module identifier, a question from the field becomes a database query instead of an investigation. Set the logging up before ramp, while the data volume is still friendly.
