What are the main reasons for the fire of electric vehicles?

Date:Oct 14, 2019

In just a few days, electric vehicles such as Tesla, Weilai and BYD were on fire. This “fire” burned new energy vehicles, and the eyes of the whole industry once again focused on the safety of new energy vehicles. Why does the electric car burn spontaneously? What are the reasons for spontaneous combustion? Is there really no fuel car safety for electric cars? Is there a way to solve the problems encountered in current electric vehicles?

The reasons for the spontaneous combustion of electric vehicles are many and complicated, but in general, it is mainly a battery problem. The battery problem is mainly reflected in the following aspects, one is the internal short circuit of the battery. For example, after the vehicle is under vibration, the material on the coating of the positive and negative electrodes of the battery plate is detached, and a short circuit occurs inside the battery. Since such an internal short circuit of the battery is relatively difficult to control, it may be one of the causes of spontaneous combustion. Second, the connection of the battery is loose and the external contact is poor. For example, Tesla uses 5,000 to 9000 18650 batteries or a battery pack of 21700 batteries. Each battery can work because it is connected. The connection of the battery is mainly by welding or screwing. During the welding process, if there is individual welding or the screw and nut are not tightened, it will loosen when the car vibrates, which will cause the heating of the battery system to increase, so there will be a fire. Third, the battery is overcharged or over-discharged. In the use of the link, if the battery enters the later stage of the life cycle, there will be inconsistency due to aging, and if the over-charging or over-discharging will cause some internal resistance to become larger, the internal temperature of the battery will rise, and spontaneous combustion will occur. phenomenon. At the same time, because there is a process of self-ignition due to the temperature rise, it will be like the Tesla car. It is neither charged nor in the process of driving. It will also catch fire when it is placed in the basement.

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