EV Battery Cell Flame-Retardant PU Potting Line in China

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Haifeng successfully delivered and commissioned a fully automated polyurethane potting and encapsulation system for a Tier-1 Chinese EV power battery manufacturer, achieving zero-void micro-gap filling and compliant thermal barrier protection for high-energy battery cell packs. The project encompassed the turnkey engineering of closed-loop high-pressure dual-component metering units, multi-axis automated dispensing gantries, precision thermal conditioning skids, and integrated module visual inspection stations.

Driven by the stringent GB 38031-2025 regulatory requirements—mandating that a battery system must endure 120 minutes without fire or explosion following a single-cell thermal runaway—the client needed to transition from legacy silicone or low-pressure dispensing. Previous setups exhibited cycle bottlenecks, inconsistent chemical ratios, and micro-air entrapments between closely packed cells, creating localized hot spots and dielectric breakdown risks under 150J shock vibrations. The customer required a rapid-curing, high-pressure dispensing solution capable of dosing flame-retardant (UL94 V-0) PU formulations with micro-second cut-off accuracy and closed-loop temperature control.

Operational since mid-2025, the automated potting cell delivers continuous two-shift production across an efficient 260 m² footprint. By deploying Haifeng's closed-loop Ratio Lock metering algorithms and high-velocity impingement heads, the plant sustains uninterrupted battery pack assembly with rigorous dielectric insulation and optimal cell-to-cell thermal mitigation.

Haifeng deployed an advanced high-pressure closed-loop dispensing architecture specifically optimized for low-viscosity, fast-foaming flame-retardant polyurethane potting systems, achieving 35% shorter cycle times and continuous bubble-free cell penetration:

1. Closed-Loop Stoichiometric Ratio Lock: Isocyanate and formulated flame-retardant polyol are continuously metered via servo-driven magnetic coupling pumps, maintaining a ±0.5% stoichiometric precision despite viscosity swings.
2. Dual-Channel Thermal Conditioning: Integrated heat exchangers and dual-jacketed storage tanks maintain raw resin temperatures within ±0.5°C, ensuring predictable rise profiles and controlled reaction exotherm during in-module foaming.
3. Multi-Axis Robotic Gantry & Anti-Drip Dispensing: An L-shaped self-cleaning high-pressure mixing head mounted on a 3-axis CNC gantry delivers high-speed dynamic trajectory pouring into narrow cell crevices (<3 mm) with 0.3-second sharp needle shut-off to eliminate dripping.
4. End-to-End Inline Quality Telemetry: The master PLC system records flow rate, injection pressure curves, shot weights, and mold fixture temperatures per battery pack, synchronizing with the customer's MES for complete traceability.

Implementation & Training:
– Installation & Commissioning Timeline: 18 days from mechanical positioning and piping hookup to battery module trial runs.
– Operator Training: 4 days covering precision calibration, recipe parameter adjustment, automated flush validation, and daily seal preventative maintenance.
– Key Commissioning Milestones: Dry-run servo repeatability tests, chemical ratio verification, high-pressure impingement cell penetration trials, and post-cure foam dielectric breakdown testing.