This addresses the core sourcing risk overseas buyers face — glossy samples online, short circuits and fires in the delivered batch. TIANQIU publishes its full process control: automated cell sorting, high-frequency laser welding, 100% full charge/discharge ageing and Class 9 dangerous-goods packing discipline, backed by third-party SGS / TÜV resident audit standards.
verifiedSGS / Bureau Veritas / TÜV resident audits supported · ISO 9001:2015 quality system
Specification notice:Reference values only — batch and duty-cycle variation applies. Contact us for detailed specifications.
No black-box manufacturing. TIANQIU standardises and digitises every quality gate, so buyers and third-party inspectors can verify it on site and re-check the data at any time.
Specification notice:The figures above are engineering reference values. They may differ with production batch, configuration and actual duty cycle, and the percentages for life, efficiency, availability and coverage are engineering estimates and bench references. Contact us for the detailed specification sheet.
From weld metallography and terminal pull testing to −20℃~65℃ thermal-humidity cycling, ISO 7637-2 automotive immunity and Class 9 packing certification — four process gates, every one recorded and re-checkable.
Overseas buyer representatives can be stationed on site. Automated laser weld metallography, terminal pull tests (≥250N) and module dimensional tolerance held inside ±0.5mm.
Weld tear / pull 100% inspected · PASS 99.9%−20℃~65℃ wide-temperature damp-heat cycling, with dual galvanically isolated CAN/RS485 buses at a bit error rate below 10⁻⁹. Vehicle ignition surge protection and millisecond hardware cut-off on reverse polarity.
Immunity per ISO 7637-2 pulse, Level IVMeets the legal import and export standard for Class 9 dangerous goods by sea (UN3480). We issue the formal commodity-inspection packing certificate (usage appraisal result) and the maritime authority container stuffing certificate.
Certificates UN38.3 + MSDS · Class 9Automatic cell sorting, flame-retardant insulating potting, and full EOL functional test offline (dielectric withstand, short-circuit trip, internal resistance) hold the container-batch pass rate at ≥99%.
EOL 100% uploaded to cloud · OEE > 92%These seven dimensions decide whether a pack serves 6–8 years in hot, heavy-duty conditions or comes back for repair in batches after three months.
| Quality-control dimension | TIANQIU automotive-grade plant | Low-cost workshop / parts assembler |
|---|---|---|
| 01. Cell source and grade | Tier-1 new A-grade motive cells (CATL / CALB / EVE and equivalents) Original factory QR coding supplied, verifiable instantly in the cell maker client; cycle life ≥3,500 cycles to 80% SOH. | Salvaged storage cells, graded B material and re-marked or sanded cells. Internal resistance varies widely, and severe capacity fade with high self-discharge shows up within three months. |
| 02. Pack matching standard | 100% laser sorting by resistance and capacity, with range control Intra-batch ΔV ≤ 3mV, ΔIR ≤ 0.5mΩ, self-discharge K-value tracked and sorted automatically so cells inside a pack stay closely matched. | Open-circuit voltage checked by hand (AC internal resistance often not checked at all), then stacked straight into series and parallel. One weak cell overcharges or over-discharges the pack and starts a fire. |
| 03. Busbar and welding process | Nickel-plated copper stamped busbars + six-axis high-frequency fibre laser welding Weld penetration 1.2–1.8mm, pull strength ≥250N, impedance below 0.05mΩ, with 100% metallographic sectioning and non-destructive inspection. | Hand soldering irons or simple pneumatic spot welders. Cold joints and spatter cause micro-shorts, and joints crack on corrugated routes such as East African dirt tracks and Indian unpaved roads. |
| 04. BMS battery management system | In-house automotive dual-channel opto-isolated smart BMS Withstand voltage ≥120V, generous MOSFET thermal margin, dual temperature probes for accurate control, and CAN 2.0B / RS485 surge-resistant protocol comms. | Unisolated commodity boards taken from storage or low-speed cart applications. With no surge protection, the high-voltage spike from regenerative motor braking punches straight through the MOSFET and the pack loses control. |
| 05. Enclosure structure and sealing | 1.5mm cold-rolled high-strength steel, powder-coated, dual IP67 seals High-rebound EVA flame-retardant insulation plus a waterproof explosion-proof breather (Gore valve), validated through 15kPa pressure hold, rain and vibration. | Blue PVC shrink film, or 0.8mm sheet steel joined with silicone. Water ingress and short circuits in the rainy season, with no pressure-relief or explosion-proof valve of any kind. |
| 06. End-of-line testing and ageing | 100% two full charge/discharge cycles in automated high-temperature ageing cabinets Includes comprehensive EOL testing (2,500V DC dielectric withstand, insulation resistance ≥500MΩ), with a dedicated step curve supplied per pack. | A five-minute power-on spot check after assembly, with no full charge/discharge cycle run. Latent early-failure cells are never screened out. |
| 07. Marine compliance and export evidence | Genuine, compliant Class 9 dangerous-goods export packing appraisal certificate Full UN38.3 reports, MSDS and the sea-transport safety assessment, booked and declared properly as a full container. | No genuine packing certificate. Buyers are routinely advised to declare the goods as "hardware parts" or an "empty container" on a double-clearance grey route — one port inspection can destroy the whole container. |
Behind a 15–30 USD per kWh price gap sit serious safety exposure and legal return-shipment risk. Use this table to audit whatever you are currently buying overseas; for the safety envelope and destructive validation see the battery safety and thermal runaway whitepaper.
Specification notice:The figures above are engineering reference values. They may differ with production batch, configuration and actual duty cycle, and the percentages for life, efficiency, availability and coverage are engineering estimates and bench references. Contact us for the detailed specification sheet.
Whether you appoint a third-party inspection body or join by video conference, insist that the supplier shows and verifies these five pieces of physical evidence on the spot:
SGS / Bureau Veritas / TÜV resident audits are supported, with the ISO 9001:2015 quality system covering the whole process.
The contract traps and technical misrepresentation importers and fleet operators meet most often when dealing with a domestic lithium battery contract manufacturer:
A senior powertrain engineer will host a 45-minute live walk-through of the automotive-grade production floor. You choose what the camera looks at — laser spot welders, ageing cabinet step curves or packing certificates.
Specification notice:The figures above are engineering reference values. They may differ with production batch, configuration and actual duty cycle, and the percentages for life, efficiency, availability and coverage are engineering estimates and bench references. Contact us for the detailed specification sheet.
A mutual NDA can be signed. Volumes, vehicle drawings and commercial details you submit stay strictly confidential and are never disclosed to third parties.
