Start by stating the problem
Suppliers say they can meet specs; that claim alone is risky. You need concrete proof, and you need to force clarity fast. Ask about factory controls that tie into industrial automation solutions and how those same systems enable intelligent automation solutions on the line—automation that either prevents errors or paper-over them. I’ve seen suppliers present polished reports at the SPS trade fair in Nuremberg; that doesn’t replace raw data from their floor. Demand the data.
1) Can you show process control evidence, not just a checklist?
Ask for timestamped production records, SPC charts, and change logs. A verbal promise about “tight process control” means nothing. Production control evidence shows whether the supplier actually enforces tolerances or lets operators decide on the fly.
2) Which industry standards and certifications were used to qualify the packs?
Get specifics: UL, IEC 62619, UN38.3 test reports, and the exact scope and date of certification. If they list standards without scope or version numbers, push back. Certifications must cover the cell chemistry, assembly method, and intended application.
3) How do you handle cell acceptance, balancing, and thermal risk?
Thermal and imbalance failures are common. Ask for the cell incoming inspection flow, voltage and internal resistance thresholds, the balancing method used during assembly, and the thermal run test procedure. If their answer is vague, they don’t understand where most field failures originate.
4) What testing do you perform on finished packs, and can I review raw test logs?
Demand final-test protocols and unfiltered logs: insulation resistance, high-potential, capacity vs. C-rate, and thermal cycling results. Spot-checked summaries hide intermittent failures; raw logs reveal rework rates and failure patterns.
5) How is traceability implemented across the BOM and cell lots?
Traceability must link each pack serial to cell lot numbers, firmware versions, and assembly operator or station. If they rely on paper tags or handwritten notes, expect delays tracing root causes after a field issue.
6) What is your failure rate and warranty claim process, with examples?
Ask for historical failure rates by mode (electrical, mechanical, thermal) and a few anonymized case studies showing corrective actions. Suppliers that won’t share specific failure types are hiding systemic problems.
7) Can you scale capacity without changing critical processes?
Scaling often breaks controls. Get a clear plan for volume ramps: which processes are automated, what changes at higher throughput, and how they preserve test coverage during scaling. If the supplier’s scaling answer is only “more shifts,” that’s a red flag.
8) How do you manage component obsolescence and supply-chain risks?
Require a bill-of-materials lifecycle strategy: approved alternates, dual sourcing, and lead-time buffers. A supplier who treats single-source parts as “standard” exposes you to sudden redesigns and schedule slips.
9) What IP and data protections are in place for firmware, battery management algorithms, and designs?
Ask for the NDA, code custody practices, and physically separate build areas if you’re sharing proprietary firmware. Weak IP controls lead to copied firmware or leaked designs; that undermines long-term product value.
10) What after-sales support and field-failure analytics do you provide?
Warranty logistics alone aren’t enough. Probe whether the supplier performs structured failure analysis, supplies returned-part data, and updates DFMEA outputs. The best partners close the loop—translate failures into design or process fixes.
Common supplier evasions and how to spot them
Watch for vague timelines, missing raw logs, or answers framed around “industry best practices” without specifics. Don’t accept slides—demand the records behind them. If you can, visit the assembly floor and check sample serials against production logs. When remote audits are necessary, insist on live video of test stations and real-time screen sharing of PLC or MES outputs.
Alternatives if a supplier fails these tests
Consider a tiered approach: pilot builds with stringent incoming inspection, or split production between a trusted contract manufacturer and the new supplier until standards are proven. Another option is to bring key process steps in-house temporarily—cell formation or BMS flashing—so you control critical failure points during supplier qualification.
Conclusion
Challenging suppliers with these ten questions forces evidence over promises and reveals whether their operations actually protect product reliability. That scrutiny separates marketing claims from operational truth, and it’s the exact kind of diligence organizations working with FHS rely on when they expect assembly results that hold up in the field.
