DC charging pile quality appraisal

DC charging pile is based on the core principle of high-power power transmission and intelligent control collaboration. By optimizing charging efficiency, output power and protocol compatibility, it achieves collaboration of fast charging, safety protection and remote management. It is widely used in electric vehicle charging stations, highway service areas and urban public charging networks. In overcharging scenarios, it is used for extremely fast energy replenishment of 800V high-voltage platform models; in public charging stations, it meets the needs of multi-model adaptation and dynamic power distribution; in high-cold/high-temperature environments, it ensures stable operation from -30°C to +55°C. Compared with AC charging piles, DC charging piles have the characteristics of high power density, low power conversion loss and high degree of intelligence (integrated user authentication/billing/fault diagnosis). They are the core equipment of new energy vehicle energy supplement systems.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide DC charging pile quality appraisal services. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for DC charging pile quality appraisal.

As the popularity of new energy vehicles accelerates, related quality dispute cases have increased significantly. The judicial dispute focuses on:

1, performance index dispute: charging power is not up to standard, charging efficiency is low;

2, material defects: charging gun cable bending resistance life, liquid cooling module has poor corrosion resistance;

3. Process problems: uneven heat dissipation of power modules and incompatible communication protocols;

4. Contract performance disputes: core modules (such as SiC power device brands, intelligent dispatching system versions) are inconsistent with technical agreements.

DC charging pile quality appraisal usually includes the following technical methods:

1. Appearance inspection: Visually inspect the appearance, structure, and accessories of the charging pile to see if there are defects such as deformation, damage, rust, etc.

2. Performance test: Use special equipment to test the charging power, voltage, current, temperature and other performance parameters of the charging pile, and compare them with national or industry standards.

3. Safety testing: Simulate the actual use environment and test the safety performance of the charging pile such as insulation strength, leakage protection, and grounding protection.

4. Disassembly analysis: Disassemble the charging pile and check the internal structure, components, circuit connections, etc. for quality defects or non-compliance with specifications.

A charging operator of the applicant signed a "150kW DC Pile Procurement Contract" with an equipment manufacturer of the respondent, agreeing that the charging efficiency is ≥95%. In actual operation, the efficiency is only 88%. The manufacturer argued that it was caused by unstable power grid voltage.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "DC charging pile", contract technical agreement, on-site inspection case materials and other data, and made the following quality scores Analytical opinion:

The switching loss of the DC charging pile power module involved in the case exceeded the protocol value by 30%, and the thermal conductivity of the heat dissipation substrate was only 150W/(m·K) (protocol ≥ 200W/(m·K)); the communication protocol compatibility test failure rate was 12% (protocol ≤ 3%), resulting in frequent reconnections.

The appraisal conclusion determined that defects in power devices and heat dissipation design were the main reasons for insufficient efficiency.

DC charging pile quality appraisal report should include:

1, appraisal purpose (such as performance dispute attribution, safety compliance verification) and reference standards;

2, involved equipment model, software version, operation and maintenance records;

3, testing method and equipment list ( Such as charging characteristic tester, protocol analyzer);

4, correlation analysis of test data and failure (such as the impact of heat dissipation performance on efficiency);