Analysis on Fire Accident of Electric Vehicle,
Electric Vehicle,

▍What is TISI Certification?

TISI is short for Thai Industrial Standards Institute, affiliating to Thailand Industry Department. TISI is responsible for formulating the domestic standards as well as participating in international standards formulation and supervising the products and qualified assessment procedure to ensure the standard compliance and recognition. TISI is a governmental authorized regulatory organization for compulsory certification in Thailand. It is also responsible for formation and management of standards, lab approval, personnel training and product registration. It is noted that there is no non-governmental compulsory certification body in Thailand.

There is voluntary and compulsory certification in Thailand. TISI logos (see Figures 1 and 2) are allowed to use when products meet the standards. For products that have not yet been standardized, TISI also implements product registration as a temporary means of certification.

▍Compulsory Certification Scope

The compulsory certification covers 107 categories, 10 fields, including: electrical equipment, accessories, medical equipment, construction materials, consumer goods, vehicles, PVC pipes, LPG gas containers and agricultural products. Products beyond this scope are fall within the voluntary certification scope. Battery is compulsory certification product in TISI certification.

Applied standard: TIS 2217-2548 (2005)

Applied batteries：Secondary cells and batteries(containing alkaline or other non-acid electrolytes – safety requirements for portable sealed secondary cells, and for batteries made from them, for use in portable applications)

License issuance authority:  Thai Industrial Standards Institute

▍Why MCM?

● MCM cooperates with factory audit organizations, laboratory and TISI directly, capable to provide best certification solution for clients.

● MCM possesses 10 years abundant experience in battery industry, capable to provide professional technical support.

● MCM provides one-stop bundle service to help clients enter into multiple markets (not only Thailand included) successfully with simple procedure.

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.
When the cell receives heat external or self-generated heat and cannot dissipate in time, and the temperature of the cell exceeds the temperature of the internal material (separator), the separator will contract, resulting in a short circuit between the positive and negative electrodes.