How to ensure that electric vehicles are safe and secure on the road? The guide answers one by one

The "Electric Vehicle Safety Guidelines" compiled under the guidance of the Ministry of Industry and Information Technology and the National Energy Administration were recently released

The overall development quality and level of electric vehicles in China need to be improved

Text/Photo Yangcheng Evening News all-media reporter Qi Yaoqi

The "Electric Vehicle Safety Guidelines" (hereinafter referred to as the "Guidelines"), compiled under the guidance of the Ministry of Industry and Information Technology and the National Energy Administration, were recently released. The guide sets out detailed technical standards and operating specifications for the safety requirements of electric vehicles. For example, in response to the common fire problems of electric vehicles, key prevention and guidance have been carried out.

At present, the safety level of electric vehicles needs to be improved urgently

The guide points out that China's electric vehicle lightweight, power drive system, power battery and other key components industry has initially formed a scale, and the gap with the world's advanced level has been significantly narrowed. However, the overall development quality and level of China's electric vehicles still need to be improved, especially the level of vehicle safety needs to be improved, at present, the industry as a whole has insufficient understanding of safety, the safety requirements of product design are not accumulated enough, and the mechanism of safe interaction in the whole chain has not been formed, resulting in a number of electric vehicle fire accidents.

What is the cause of the electric vehicle fire? The guide points out that the causes of electric vehicle safety accidents are more complex, and are related to material selection, battery cell and module structure, system integration, connection structure, vehicle matching design, production control, product test verification, after-sales service, charging equipment and engineering electronics, charging operation and maintenance management, recycling process safety management, fire control methods and other factors. Therefore, in 2018, the Association of Automobile Manufacturers and others launched the compilation of the "Electric Vehicle Safety Guidelines", which aims to promote the whole industry chain to strengthen safety awareness and improve the safety level of the whole life cycle of electric vehicles. The 2021 edition released this time has been revised and improved on the basis of the 2020 edition.

Vehicle wading safety requirements are more

In terms of vehicle waterproof requirements, in order to ensure the electrical safety of vehicle wading, cleaning and other use conditions, it is necessary to simulate the vehicle wading, simulated cleaning test, and conduct an insulation resistance test after the test to assess whether the vehicle has a risk of electric shock. The test requirements for simulated wading and simulated cleaning shall be carried out in accordance with the requirements of the national standard. After completing each test, the first insulation resistance test should be performed immediately, followed by a second insulation resistance test 24 hours later. The results of the two insulation resistance tests should meet the requirements of the insulation resistance. Waterproofing of high-pressure components Requires That all high-pressure components be well-assembled, the waterproof level of the high-pressure parts outside the trunk and the crew compartment should be at least IPX7, and the high-pressure components in the trunk and crew compartment should be at least IPX4.

In terms of driving safety, when the vehicle is driven at a low speed in pure electric mode, the surrounding pedestrians should be reminded by the sound emitted by the low-speed driving sound system. The driver actively stops the low-speed driving prompt system, which should be prompted by a conspicuous prompt signal. The driver drives the vehicle directly, switches from non-driving gear to driving gear in the vehicle stationary state, and should press the brake pedal.

Battery thermal runaway should be able to alarm in advance

For electric vehicles that place the power battery under the chassis outside the occupant compartment, it is recommended that the vehicle enterprise evaluate the high-voltage electrical safety performance of the bottom collision of the vehicle, such as the design protection for the common bottom stone strike, bottom scratching condition, etc., define the corresponding standard working conditions, and put forward the bottom protection performance requirements of the power battery pack. At the same time, guards are added to the high-voltage connectors and wiring harnesses placed under the chassis.

The whole vehicle should be able to effectively dissipate and cool down the battery system to ensure that the battery system temperature is always within the normal range of use, so as not to affect the battery system life of the temperature too high. Vehicle design should consider that if the battery temperature exceeds the normal range of use, the power output should be limited and reminded. If there is a risk of thermal runaway, the vehicle should have an early reminder and alarm function to ensure the safe evacuation of drivers and occupants in advance. The sound alarm should continue to sound according to the unique sound, it is recommended that the vehicle horn can support the alarm sound; the instrument alarm is recommended as a combination of the power battery symbol and the fire/explosion graphic, and the prompt is in the form of text, which can reflect the intention of "please stop and immediately stay away from the vehicle". It is recommended to add a reminder of the rapid flashing of the double flashing lights.