Three national standards to improve the safety and quality of new energy vehicles

These three safety standards for electric vehicles cover the multi-level safety requirements for components, systems and whole vehicles of electric vehicles and electric buses. The main contents are fully in line with the United Nations Global Technical Regulation for electric vehicle safety (ungtno. 20), and some testing indexes are stricter than those of international regulations.

Wang Binggang, a special expert of the 863 Program of the Ministry of science and technology of the people's Republic of China on major electric vehicle science and technology, said in an interview with China consumer daily that improving the safety of new vehicles is the basis of the development of new energy vehicles. After years of strong subsidy policy support, the current market size of new energy vehicles has been changed. The industry should cherish this hard won situation.

Because of the importance of safety, three compulsory national standards put forward the requirements for improving the safety standard of electric vehicles, enhancing the test accuracy and adding the thermal event alarm signal of battery system to electric vehicles.

According to the monitoring data of national new energy vehicle big data alliance, the main reason for the Spontaneous Combustion Accident of new energy vehicle is the lack of thermal management in the early stage of battery and the high internal temperature in high temperature season, which is easy to cause the battery thermal runaway. To some extent, this also explains the frequent occurrence of self ignition accidents of new energy vehicles in summer.

In order to solve this problem, the electric vehicle safety requirements has added the requirements of thermal event alarm signal of battery system, and strengthened the provisions of vehicle waterproof, insulation resistance and monitoring. At the same time, the insulation resistance, capacitance coupling and other test methods are optimized to improve the test accuracy and ensure the high-voltage electrical safety of the whole vehicle.

In recent years, the endurance mileage of new energy vehicles has increased faster than expected. This is not only related to the subsidy policy and the endurance mileage, but also related to the improvement of consumers' demand for the endurance capacity of new energy vehicles.

According to the notice on improving the financial subsidy policy for the promotion and application of new energy vehicles, only new energy vehicles with a endurance of more than 300 km can enjoy the subsidy policy.

Wang Binggang said that the R & D of power battery should follow a relatively mature validation cycle before it can be used commercially. However, some vehicle enterprises are eager to improve the energy density of the monomer, which is accompanied by the decrease of the stability of the electric core. Once the vehicle is out of control, the risk of spontaneous combustion will increase. That is to say, if we blindly increase the endurance mileage, there will be certain risks.

Safety requirements for power battery of electric vehicle not only optimizes the safety requirements for battery unit and module, but also strengthens the requirements for thermal safety, mechanical safety, electrical safety and functional safety of battery system. The thermal diffusion test of the battery system is mainly added, which requires that the battery system will not fire or explode within 5 minutes after the thermal runaway of the battery unit, so as to reserve a safe escape time for the personnel in the vehicle.

In addition, according to the characteristics of large passenger capacity, large battery capacity and high driving power of electric bus, the safety requirements of electric bus put forward more strict safety requirements for collision of battery compartment, charging system and waterproof test conditions of the whole vehicle, and increased the requirements for high-voltage components flame retardant and the minimum tube of battery system The assessment requirements for thermal runaway of management unit further improve the fire risk prevention ability of electric bus.

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