In this guide 6 sections
Trace a module by receiving every material lot with its own label, then binding those lots to a serial number at the stringer, before lamination. Each later station scans that serial. One scan afterwards shows the cell lot, EVA roll, glass batch, stringer settings and flasher result.
Start at the goods receipt, not the line
Traceability fails at the dock more often than on the line, because a pallet of cells arrives with a supplier lot and the store logs a part code. The chain breaks there.
Record the supplier lot, the cell efficiency bin and the colour grade for every pallet, and do the same for EVA rolls, backsheet, glass and junction boxes. Attach the incoming inspection result to that lot.
Then print your own internal lot label. Staff scan it when they issue material, so nobody types a lot number by hand and nobody guesses.
- Supplier lot and your internal lot label
- Cell bin, grade and datasheet version
- EVA roll number and expiry date
- Glass batch and thickness check
- Incoming inspection result and who signed it
Decide where the serial number is born
The serial should exist before the module is laminated, because afterwards the cells are sealed in. Most lines place a printed barcode inside the laminate corner, where the laminator cannot hide it.
Pick one moment to create it. Many plants choose the stringer or layup, and whichever you choose, never reuse a serial and never print one without recording where that label goes.
Keep the format plain. A plant code, a year and week code and a running count is enough, since model data in the number goes stale when models change.
Bind lots to the serial at each station
At the stringer, the operator scans the serial, the cell lot and the ribbon spool. At layup, the glass batch, EVA roll and backsheet lot go in. Each scan adds a row.
Two failures show up here. A roll is changed mid shift and nobody scans the new one. Or an operator scans a lot once and every module after it inherits an entry that no longer holds. Force a fresh scan whenever a spool runs out.
Station data belongs on the same record. Stringer tab temperature, soldering peel test, laminator cycle and the EL image file all hang off the serial.
- Stringer: cell lot, ribbon spool, tab temperature
- Layup: glass batch, EVA roll, backsheet lot
- Laminator: recipe name, cycle time, press log
- Framing: sealant lot, frame batch
- Junction box: box lot, potting batch
Pull the test files into the same record
A flasher writes a file for every module, with Pmax, Voc, Isc and fill factor. An EL tester saves an image, and a hipot tester logs insulation and ground continuity. Today these often sit in three folders on one test PC.
Import them by serial as they are written. A module that fails EL should be blocked at packing until someone reworks and retests it.
Power binning then follows from the record. The pallet label is printed from the flasher result, never typed.
Prove it with a trace drill
Pick a shipped serial at random and ask your team to list its cell lot, EVA roll, glass batch and flasher result, timing the answer. If it takes a day of digging through registers, the chain is not working yet.
Then run the drill backwards. Choose one cell lot and list every module it went into, noting which are already at a customer. This is the recall question, and an auditor asks it first.
Repeat the drill each quarter, write down every gap, and fix the station that caused it.
Module trace map worksheet
Every station from goods receipt to packing gets its own row. Columns are station name, what is scanned, the field it fills on the serial record, who scans it, and what happens when the scan is missed. Beneath that, a block names the test files to import by serial, and a final block holds the quarterly trace drill result.
Open a blank worksheet to printQuestions owners ask
Where should the serial barcode be placed?
Inside the laminate, in a corner visible through the glass, so it survives framing. Many plants also add an outer label on the frame or backsheet for handling.
Do we need to trace every material lot?
Trace anything whose failure would cause a field claim: cells, EVA, backsheet, glass, ribbon, sealant and junction boxes. Low-risk items such as packing cartons can stay batch-level.
Can a spreadsheet do this?
For a small pilot line, yes. It breaks once two shifts, rework loops and flasher files arrive, because nobody can enforce a scan before the next step.
What if a serial label is damaged?
Reprint it from the record, log who did it and why, and keep the old number as an alias. Never assign a fresh serial to a module already built.