Standardized Procedure for Maintenance of Power Batteries in New Energy Vehicles

Yangzhou Yaxing Motor Coach Co., Ltd.

Standardized Procedure for Maintenance of Power Batteries in New Energy Vehicles

1 Pre-maintenance verification

1.1 Comprehensive Battery Safety Testing

Conduct comprehensive safety inspections, including visual inspection (for shell deformation, damage, leakage, and bulging), insulation testing, internal resistance and voltage measurement, thermal management system verification, and BMS battery management system fault code reading, to identify and address potential safety hazards such as short circuits, thermal runaway, and electrical leakage.

1.2 Battery Performance Evaluation

Based on battery technical standards, determine the fault type and distinguish between serviceable faults—such as wiring issues, sensor malfunctions, BMS software anomalies, and minor module deviations—and non‑serviceable faults—including severe module damage, thermal runaway risks, and significant capacity degradation—thereby preventing repairs performed while the system remains defective and prohibiting unauthorized reassembly.

2 Standardized Maintenance Operations

2.1 Power-Off Work

Strictly follow the high-voltage power‑off procedure, wait for the capacitor’s residual charge to fully dissipate, affix high‑voltage warning signs, implement appropriate insulation and protective measures, and prohibit any live‑working operations.

2.2 Itemized Maintenance

Carry out precise repairs at the fault locations, including replacing damaged wiring, calibrating sensors, upgrading the BMS, and performing cell‑level balancing and repair. Unauthorized modifications to the battery structure or the use of non‑OEM, non‑standard components are strictly prohibited.

2.3 Replace Control Measures

If individual modules or battery components need to be replaced, only compliant, genuine manufacturer‑supplied parts may be used. The new part’s code and model must be registered promptly, and proof of replacement must be retained. Assembling or refurbishing substandard batteries is strictly prohibited.

3 Post-Maintenance Inspection and Traceability Updates

3.1 Performance Testing of Each Item

Following completion of maintenance, full‑charge/fully‑discharged testing, insulation re‑testing, temperature control checks, and differential pressure measurements are conducted to ensure that all battery performance parameters meet factory specifications and that no safety hazards remain.

3.2 Organize and maintain the maintenance ledger

Maintain a maintenance log, meticulously recording battery codes, repair dates and times, fault descriptions, repair procedures, replaced components, test data, the disposition of end-of-life batteries, and operator information.

3.3 Battery Repair Information Update and Maintenance

In strict accordance with policy requirements, log in to the traceability platform within the prescribed time limit to submit information on repairs and battery replacements, ensuring that the traceability data is accurate, complete, and readily accessible.

4. Short-term maintenance tracking

Within 7 to 15 days after maintenance delivery, track the vehicle’s battery performance data, verify the stability of the battery’s operating conditions, re‑inspect the quality of the repair, and establish a closed-loop maintenance record.