What are the main safeties of lithium batteries in electric vehicles?
From the perspective of fuel vehicles, the safety performance of automobiles mainly includes active safety configuration and passive safety configuration. The so-called active safety configuration is to prevent accidents, and the passive safety configuration is to effectively protect passengers after an accident. From the perspective of pure electric vehicles, there are still many differences in the structure of fuel vehicles, so there will be many differences in safety configuration. So when choosing a pure electric vehicle, which safety configuration should be mainly considered?
First, the battery materials.
Although most electric vehicles currently use lithium batteries, the lithium batteries currently equipped with different models are still different. Current electric vehicles are mainly based on NCM lithium batteries and lithium iron phosphate batteries. The safety performance of these two batteries in use is different. Lithium iron phosphate batteries can withstand punctures, short circuits, and will not spontaneously ignite after the collision. The NCM lithium battery has a high decomposition temperature. The electrode material of the NCM lithium battery will only decompose at 600 degrees Celsius, and it will not produce oxygen during decomposition, so it is relatively safe better.
Second, battery thermal management
The role of power batteries in electric vehicles is crucial, but the current power batteries are more “precious” and sensitive to temperature. Like the current NCM lithium battery, the normal operating temperature is directly from 0 to 60 degrees Celsius, and it works best when the temperature is 10 to 35 degrees Celsius. If the battery temperature is too high, it is easy to cause battery thermal failure and battery spontaneous combustion, so how to control the battery temperature is very important. There are mainly air-cooled, water-cooled, and direct-cooled methods, and water-cooled technology is currently relatively mature.
Third, battery protection configuration
Most of the power batteries are installed on the chassis of cars, and they are more likely to collide in usage. Therefore, how to increase the safety performance of the power battery under collision is also very important. And this kind of protection configuration generally includes two kinds, one is to increase the hardness of the battery casing and add some mechanical protection measures. Another aspect is to increase the battery’s control of the circuit after a collision. For example, Bosch has previously developed a power cable that can be directly explored in a collision, which can cut off the power battery during a collision to prevent short-circuit and spontaneous combustion of the power battery.
In fact, whether it is a fuel car or an electric car when choosing, we must pay more attention to the active safety configuration of the vehicle, which can effectively prevent accidents and increase the safety of the vehicle. The power battery of electric vehicles is the most important unstable factor for electric vehicles, so the safety of power batteries needs to be paid more attention to when choosing electric vehicles.