# EV Battery Pack End-of-Line (EOL) Test Checklist for Suppliers > Source: https://netray.co/tools/ev-battery-pack-end-of-line-test-checklist > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer A checklist of the typical end-of-line checks for a battery pack: electrical safety, BMS, leak and enclosure, torque and traceability. ## Category quality ## Industry Automotive and EV ## Audience - Test engineer - Quality engineer - Production supervisor - Battery pack assembler ## Tool **Kind:** checklist **Groups:** #### Safety and test setup **Items:** **Text:** Operators are trained and authorised for high voltage work **Critical:** true **Text:** Test area is barriered with signage and an emergency stop within reach **Critical:** true **Text:** Insulated PPE and tools are inspected and in date **Critical:** true Test equipment calibration labels are valid and recorded Pack is identified by serial number before connection Lockout and discharge procedure is available at the station Fire response and thermal event plan is posted #### High voltage electrical tests **Items:** **Text:** Insulation resistance measured between HV terminals and chassis at the specified test voltage **Critical:** true **Text:** Dielectric withstand test performed if the control plan requires it **Critical:** true Protective earth or equipotential bonding resistance verified **Text:** Pack open-circuit voltage within specified range **Critical:** true Contactor and pre-charge function verified **Text:** High voltage interlock loop (HVIL) continuity verified **Critical:** true Main fuse or disconnect continuity checked Results are compared with limits and stored #### BMS and communication **Items:** **Text:** BMS powers up and communicates on the expected CAN or bus address **Critical:** true **Text:** Firmware and calibration version match the released build **Critical:** true All cell voltage channels read and are within the allowed spread All temperature sensor channels read plausibly Current sensor offset checked at zero current State of charge initialised to the specified value No active or stored fault codes remain; test faults cleared Balancing function checked as per procedure #### Enclosure, cooling and mechanical **Items:** **Text:** Enclosure leak test passed at the specified method and pressure **Critical:** true **Text:** Cooling circuit leak and flow test passed **Critical:** true **Text:** Busbar and terminal fasteners torque-verified with recorded values **Critical:** true Seals, gaskets and vents inspected for position and damage Connectors fully seated with locks engaged Visual inspection for dents, scratches and contamination complete Pack weight within tolerance #### Traceability and release **Items:** **Text:** Pack serial linked to cell lot, module and BMS serial numbers **Critical:** true Test results uploaded to the MES or quality system automatically **Text:** Failed packs are tagged, segregated and entered in the nonconformance process **Critical:** true Rework retest is a full retest, not a partial one Label content and barcode verified against the customer specification Packaging and transport requirements for dangerous goods checked Release signed by authorised quality person **Scoring Note:** Critical items must all pass before a pack is shipped. This is a general starting list. Test voltages, limits and methods come from your customer specification and control plan. ## Content **Intro:** End-of-line testing is the last chance to catch a defect in a battery pack before it reaches the vehicle. This checklist groups the usual checks into safety, electrical, BMS, mechanical and traceability so you can build or review an EOL station and its control plan. **Sections:** #### How to use the checklist **Body:** Work through each group with the test engineer and the quality engineer. Mark each item as done, and use the critical items as a gate. Add or remove items to match the customer specification and the pack design, and record the actual limits next to each one in your control plan. Export the completed checklist to PDF as evidence for an audit or an internal station release, then review it again after any change to the pack, test equipment or software. #### What the main tests do **Body:** Insulation resistance and dielectric withstand confirm that the high voltage circuit is isolated from the chassis. Open-circuit voltage and cell spread detect wrong cell assembly or a weak cell. HVIL and contactor tests prove that the safety interlocks work. Leak tests of the enclosure and cooling circuit prevent water ingress and coolant leaks, which are serious in a high voltage product. Torque verification of busbars guards against high resistance joints that heat up in use. **Bullets:** - Isolation tests protect against shock hazards - BMS checks confirm monitoring and protection are active - Leak tests protect against ingress and coolant loss #### Records and control plan links **Body:** Every measured value should be stored against the pack serial number, not just a pass or fail. Link this checklist to the control plan and the PFMEA so each test traces to a failure mode. The same record supports containment if a cell lot is later found suspect, because you can list every pack that contains it. If your tests are automated, ensure that the data is written to the MES or quality system without manual retyping. #### Common mistakes **Body:** A frequent weakness is that rework packs are retested only on the failed item. After any rework a full retest should run, because a repair can disturb other joints and sensors. Another is letting the station software or limits change without change control. A third is calibrating the test equipment but forgetting the fixtures, seals and probes, which also wear. Treat the station as a controlled process with its own FMEA. **Cta:** If your EOL data needs to reach quality, warranty and ERP records for traceability, Netray can discuss a private on-prem assistant that answers questions from that data. **Faq:** #### What test voltage is used for insulation resistance? **Answer:** It depends on the pack voltage class and the customer specification. Do not assume a figure from a generic checklist. Take the test voltage, minimum resistance and dwell time from the customer requirement or the applicable standard, and record them in the control plan. #### Is a leak test mandatory for every pack? **Answer:** Many customers require leak testing of the enclosure and cooling circuit on every unit, but the method and pressure vary. Check your customer specification. Where it is sampled rather than 100 percent, the control plan should state the reason and frequency. #### Why must rework packs get a full retest? **Answer:** Rework can disturb connectors, sensors, seals or fasteners that passed earlier. A full retest confirms that the repair did not create a new fault and keeps the traceability record complete for the pack. #### Does this replace the customer test specification? **Answer:** No. It is a general checklist to prompt discussion and review. The customer specification, applicable standards such as ISO 6469 for electrical safety, and your PFMEA define the actual tests, limits and sample plans. ## Search terms battery pack end of line test, EV battery EOL checklist, insulation resistance battery pack, battery pack leak test, BMS end of line verification, HV battery quality checklist, battery pack hipot test, battery pack traceability --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json