Every year, there are automobile spontaneous combustion accidents. According to public information, there were 29 fire accidents involving about 40 new energy vehicles in the country in 2016. Among them, pure electric vehicles are the types of vehicles with high fire accidents, accounting for up to 79%. It is 10% of hybrid electric power, 7% of plug-in hybrid, and 4% of undisclosed power type. So, how do new energy vehicles do fire and flame retardant?
The difference between a new energy vehicle and a fuel vehicle lies in the use of electricity as a driving power source. Therefore, the safety of electricity is particularly important. In the event of a short circuit or high voltage breakdown, parts will stop working, and the vehicle will be anchored. Leakage, but it may cause auto-ignition of the car. In addition to insulation pressure and corrosion resistance, new energy vehicles need to consider flame retardancy. Today, we will briefly introduce the different parts of the new energy vehicle market. Part of the main flame retardant material.
1, battery module
At present, there is no uniform vehicle voltage standard in the world, and the voltages used by major new energy auto companies are different. Vehicles like BYD use low-, medium-, high-voltage multi-voltage platforms for high-voltage voltages. 690V, and the instantaneous pulse can reach more than 800V. Therefore, if the flame retardant material is not used, once the voltage is broken down or encounters high temperature, it may cause accidents such as electric leakage or spontaneous combustion of the whole vehicle. Therefore, the flame retardant material becomes the cladding of the battery module. Preferred.
The battery pack casing can generally be used: cast steel plate, aluminum alloy, SMC composite material, carbon fiber reinforced composite material, long glass fiber flame retardant reinforced polypropylene material, PP-LGF35, etc.
SMC composite material, ie sheet molding compound. Mainly composed of GF (special yarn), UP (unsaturated resin), low shrinkage additive, MD (filler) and various additives. The plastic shell has a good cost advantage and Comprehensive performance is the main development material for the development of power battery housing. After the clear flame retardant requirements for power batteries, more and more companies such as AVIC Lithium, Bosch, Leitian, etc., began to use flame retardant plastics. Battery case.
2, charging facilities
The standards for charging facilities are not yet consistent. Due to the different voltage platforms of different electric vehicles, coupled with different technical factors such as interfaces and communication protocols, this directly leads to the incompatibility between piles and piles, and the piles are not The matching problem is very prominent. Charging facilities include high-voltage components such as charging piles, high-voltage lines, high-voltage connectors and charging guns. The importance of the charging equipment is the same as that of the power battery in the car, and it is necessary to consider the flame retardancy, safety and other aspects of charging. At present, the standards and requirements for charging facilities released in China, we have sorted the flame-retardant materials of the charging pile and the charging gun casing, the socket plug and the internal high-voltage wire harness, and listed the products of the current charging facilities, and the corresponding material performance characteristics. Perform analysis.
3, electrical connectors
Electrical connectors such as relays, high voltage connectors, etc. need to add flame retardant materials, which is the basic requirement. The metal terminals of the connectors need to be inserted and removed many times, and the life is required to be long, so as to avoid aging, breakage and heat resistance. PBT, PA and other materials.
According to these requirements, some common materials and some corresponding material properties are listed as shown below.
Automotive flame retardant materials for the future
In China, the flame retardant of high polymer (various plastics including engineering plastics) is mainly based on added brominated flame retardants with low dosage, high flame retardant efficiency and wide adaptability. Phenyl ether (PBD PO) produces toxic carcinogenic polybrominated benzidine (PBDD) and polybrominated benzofuran (PBDF) when burned, and halogen flame retardants generate a large amount of smoke and toxic during combustion. Corrosive gases can cause serious corrosion of circuit system switches and other metal objects that are not caused by fire and cause serious harm to human respiratory tract and other organs.
At present, China has also formulated new fire protection standards for automotive interior parts. The draft has been issued. On the basis of retaining GB8410, several indexes such as vertical combustion, oxygen index and smoke density have been added. The increase of smoke density index is very Great progress, when the fire broke out, most people were suffocated by smoke. However, the national standard still did not consider the toxicity of smoke.
People pay more and more attention to environmental protection, safety and health issues. Countries also regard environmentally-friendly flame retardant materials as the key development and research objects. National standards will be more perfect and strict, and the resulting flame retardant materials for vehicles will be environmentally friendly. Diversified development.