Vehicle Fire Suppression Used For Electric Drive Vehicle Batteries

Cause analysis of lithium ion battery fire

As a source of energy for pure electric vehicles, the main cause of fire in lithium-ion batteries is thermal runaway caused by overheating of the battery, which is most likely to occur during charging and discharging of the battery.Because lithium ion battery itself has a certain internal resistance, in the output of electrical energy at the same time will produce a certain amount of heat, its temperature becomes higher, when the temperature is beyond its normal operating temperature range, will damage the life and safety of the entire battery.In pure electric vehicles, the power battery system is composed of multiple single power battery cells, which generate a large amount of heat in the process of operation and gather in the narrow battery box.If the heat doesn't dissipate quickly and in a timely manner, high temperatures can affect battery life or even cause heat to run out of control, triggering fires and explosions.

Main technical parameters:

The operation principle of system

When the electric vehicles fails and begins to vent pressure and heat, the detector can detect abnormal changes, and send out early warning signals to the driver through the CAN bus or wire harness for the potential stage, smoke stage, high temperature stage and open fire stage of the fire, which is to realize the classified early warning and the control of fireextinguishing device. The system can intelligently judge and automatically initiate the fire extinguishing device to prevent the deterioration of the fire situation, and can also activate the fire extinguishing device manually during the emergency. The fire extinguishing device controls the fire in seconds through its high-efficiency fire extinguishing agent and maximizes the safety of the electric vehicles.

System structure

The intelligent management for thermal runaway of electric vehicles, it is necessary to realize the detection of initial battery fire, intelligent analysis, early warning, main functional requirements:

• Fire detection records of whole circle
• Intelligent judgement, linkage fire extinguishing
• No residual fire extinguishing agent, no damage to electrical equipment
• Early accurate identification of fire
• Function of data black box , data tracking
• Long service life, easy maintenance

Domestic automobile consumers have increasingly higher requirements on the mileage of electric vehicles, exceeding the pace of technological progress.As a result, more and more car manufacturers have turned their attention to lithium batteries, which are powerful but prone to fire in collisions.We learned that the percentage of electric cars and suvs using fire-prone lithium batteries soared to 74.3 percent in 2017, while the percentage using relatively safe iron batteries dropped to 23.7 percent.Battery type determines collision fire probabilityAt present, the mainstream electric vehicles mainly use two battery types:One is the ternary lithium battery, referred to as lithium battery, the advantages of lithium battery is light weight, power, the disadvantage is easy to catch fire after the collision.

Tesla USES lithium batteries;Another kind of battery is called lithium iron phosphate battery, referred to as iron battery. The advantage of iron battery is that it is not easy to catch fire after collision. The disadvantage is that the weight is slightly heavy and the power is slightly small.Byd is the world's largest producer of iron batteries.

New Energy Vehicle Battery Pack Application