Analysis on Fire Accident of Electric Vehicle,
Electric Vehicle,

▍What is PSE Certification?

PSE (Product Safety of Electrical Appliance & Material) is a mandatory certification system in Japan. It is also called ‘Compliance Inspection’ which it is a mandatory market access system for electrical appliance. PSE certification is composed of two parts: EMC and product safety and it is also an important regulation of Japan safety law for electrical appliance.

▍Certification Standard for lithium batteries

Interpretation for METI Ordinance for Technical Requirements(H25.07.01)， Appendix 9，Lithium ion secondary batteries

▍Why MCM?

● Qualified facilities: MCM is equipped with qualified facilities which can be up to the whole PSE testing standards and conduct tests including forced internal short circuit etc. It enables us to provide different customized testing reports in the format of JET, TUVRH, and MCM etc.

● Technical support: MCM has a professional team of 11 technical engineers specialized in PSE testing standards and regulations, and is able to offer the latest PSE regulations and news to clients in a precise, comprehensive and prompt way.

● Diversified service: MCM can issue reports in English or Japanese to meet clients’ need. So far, MCM has completed over 5000 PSE projects for clients in total.

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.