Electric Vehicle Charging Pile Testing Technologies and Failure Analysis

1. Detection Technology for Electric Vehicle Charging Piles

EV charging piles are primarily divided into two categories: DC charging piles and AC charging piles. Let's start with DC charging piles: they communicate with the EV's battery management system (BMS) and directly charge the power battery through the DC charging interface. AC charging piles, on the other hand, rely on the EV's AC charging interface and use the vehicle-mounted charger to complete the charging process. These two types of charging piles differ in detection equipment and methods.

The detection system must test the interoperability, electrical performance, and communication protocol consistency of DC off-board chargers and AC charging piles. It typically consists of equipment such as oscilloscopes, AC power supplies, AC loads, DC loads, AC interface simulators, battery simulators, and DC interface simulators.

Regarding safety detection technology, it generally includes the following:

• One-time charging operation, technical detection, and diagnostic protocols for charging piles. Innovating charging equipment can reduce influencing factors in test field preparation and detection.

• Application of photovoltaic power generation systems. For such systems, stability and safety are critical for installation and power supply. During external vehicle inspections, monocrystalline silicon photovoltaic solar panels can be converted via an inverter into power for experimental equipment. This ensures experiments can proceed smoothly even without access to on-site test power, providing timely power supplementation.

2. Fault Analysis of EV Charging Pile Detection
2.1 Detection Content

The complexity of EV charging piles not only affects EV usability but also directly impacts user safety. Thus, the importance of EV charging pile detection cannot be overstated.

• AC charging piles: Prioritize detecting power-on status, particularly load-breaking circuits, and check for abnormal connections between these circuits and high-power AC loads. Test verification and charging preparation are critical processes for AC charging pile interoperability.

• Off-board charging piles: Focus on detecting output voltage deviations, charger current, and output current deviations. Current adjustment time detection must align with AC power supplies and DC loads, as must output current control deviation detection.

• Communication protocols for off-board chargers: Detect charging processes and related configuration parameters. Environmental and temporal factors easily affect detection results, so content optimization is necessary.

2.2 Fault Analysis

As shown in Table 1, most charging pile issues are software-related (Items 1–10). Charging piles are complex systems heavily reliant on software. Variations in manufacturers' interpretations and implementations of standards often lead to software malfunctions. Therefore, manufacturers must deeply understand standards and enforce them strictly.

Hardware-related issues (Items 6, 7, 11), such as faulty electronic locks, discharge resistors, or charging modules, require manufacturers to optimize product quality.

3. Conclusion

The EV and charging pile industries are growing rapidly. Due to complex charging interfaces and numerous detection items, testing is time-consuming and inefficient. With millions of charging piles in operation, future development must focus on reducing testing time and improving efficiency. Achieving this goal requires collaboration among standards bodies, testing institutions, and manufacturers. Together, we can drive progress in this field.