Study on Safety of Lithium Battery for Electric Vehicle -Lithium - Ion Battery Equipment
DEKRA Company plans to conduct a series of tests on electric vehicle batteries. During the test, three important electric vehicle batteries in the market will be tested to make the batteries burn and then extinguish them with different emergency extinguishing methods. Markus Egelhaaf, the head of DEKRA accident research team, said: "The purpose of the test is to explore the performance of the car battery during combustion, the degree of combustion and the performance of the battery after the flame cup is extinguished."(Lithium - Ion Battery Equipment)
The battery burns with gasoline. After being enveloped by 800 ℃ flame for a period of time, the battery itself starts to burn. At this time, the smoke from the flame and combustion is much smaller than that from gasoline combustion. Excess pressure in the battery will finally be ejected through the pressure reducing valve inside the battery. This causes the battery to burn slightly, much less intensely than when burning gasoline. Egelhaaf also said: "The flame does not travel as fast as gasoline and diesel when burning, and the flame when burning liquid cannot spread to nearby objects."
Researchers conducted a series of experiments to test how to extinguish the flame of electric vehicle batteries. In the first test, water was used to extinguish the flame. Although it did have an effect, it was very time-consuming. In many experiments, the flame was "born again when the spring wind blows". This was because the temperature of the car or battery compartment was still very high, and the battery was natural again, so it was not easy to extinguish the flame completely with water. This also means that it is necessary to reduce the ambient temperature around the battery while putting out the flame to completely put out the flame. As a result, a large amount of water is used, which is important to reduce the temperature rather than put out the flame.
In the second test, some additives were added to the water to enhance the fire extinguishing and cooling effects. For one thing, the gel is mixed with water to make the water less fluid and stay on the burning battery, so the cooling effect is better than pure water. Other additives reduce the surface tension of water, increase its evaporation rate, and thus enhance the cooling effect. DEKRA experts said: "All substances have shown high efficiency in the combustion test. By adding additives, the amount of water required to extinguish the flame is greatly reduced, and the time required is also greatly shortened."
The researchers concluded: "When the lithium-ion battery in hybrid electric vehicles and electric vehicles burns, it is at least safer than when gasoline and diesel vehicles catch fire."