Analysis on Fire Accident of Electric Vehicle
Analysis on Fire Accident of Electric Vehicle,
Electric Vehicle,
▍What is CB Certification？
IECEE CB is the first genuine international system for mutual recognition of electrical equipment safety test reports. NCB (National Certification Body) reaches a multilateral agreement, which enables manufacturers to obtain national certification from other member countries under CB scheme on the basis of transferring one of the NCB certificates.
CB certificate is a formal CB scheme document issued by authorized NCB, which is to inform other NCB that the tested product samples conform to present standard requirement.
As a kind of standardized report, CB report lists relevant requirements from IEC standard item by item. CB report not only provides results of all required testing, measurement, verification, inspection and assessment with clearness and non-ambiguity, but also including photos, circuit diagram, pictures and product description. According to the rule of CB scheme, CB report will not take effect until it presents with CB certificate together.
▍Why we need CB Certification?
- Directly recognized or approved by member countries
With CB certificate and CB test report, your products can be exported to some countries directly.
- Convert to other countries certificates
The CB certificate can be directly converted to the certificate of its member countries, by providing the CB certificate, test report and difference test report (when applicable) without repeating the test, which can shorten the lead time of certification.
- Ensure the Safety of Product
The CB certification test considers the product’s reasonable use and foreseeable safety when misused. The certified product proves the satisfactory of the safety requirements.
▍Why MCM?
● Qualification: MCM is the first authorized CBTL of IEC 62133 standard qualification by TUV RH in mainland China.
● Certification and testing capability: MCM is among the first patch of testing and certification third party for IEC62133 standard, and has finished more than 7000 battery IEC62133 testing and CB reports for global clients.
● Technical support: MCM possesses more than 15 technical engineers specialized in testing as per IEC 62133 standard. MCM provides clients with comprehensive, accurate, closed-loop type of technical support and leading-edge information services.
According to data recently released by China’s Ministry of Emergency Management, 640 fire accidents of new energy vehicle were reported in the first quarter of 2022, a 32% increase over the same period last year, with an average of 7 fires per day. The author conducted statistical analysis from the state of some EV fires, and found that the rate of fire in the non-use state, driving state and charging state of EV are not very different from each other, as shown in the following chart. The author will make a simple analysis of the causes of fires in these three states and provide safety design suggestions.
Regardless of what situation causing the battery fire or explodes, the root cause is the short circuit inside or outside the cell, which resulting in thermal runaway of the cell. After the thermal runaway of a single cell, it will eventually lead to the entire pack catching fire if thermal propagation cannot be avoided due to structure design of module or pack. Causes of internal or external short circuit of the cell are (but not limited to): overheating, overcharge, over discharge, mechanical force (crush, shock), circuit aging, metal particles into the cell in production process, etc.
