Power battery pack thermal runaway mechanism, many universities and research institutions in the special project research, and bus enterprises are now in urgent need of a theoretical basis, has been approved by the authority, while there is a technical content of the product. At present, bus companies are more confused about this, the main reason is that an assembly of the power battery pack is purchased by the bus factory, and the current power battery pack products are far away from the requirements of bus companies.
First, the power battery thermal runaway cause analysis
Power battery is bound to heat up after work, the normal state is controllable, but the extraordinary state will be out of control. If out of control, a fire is bound to occur. Technically it must be clear, the analysis of the reasons for loss of control is necessary. In summary, there are 2 basic causes, internal and external.
(1) external causes: thermal runaway triggered by overcharging, thermal runaway caused by external forces, thermal runaway triggered by overheating.
(2) internal causes: internal short circuit of the battery triggers thermal runaway.
Power battery is an energy system, work will definitely heat. To ensure absolute safety, it must be engineered, there is a reliable technology to ensure that its heat is controllable.
Protection of the basic way there are two: First, there is a warning beforehand, personnel intervention in advance, but if the warning function fails, there must be automatic effect of fire-fighting function. If the above two do, the safety of the power battery pack, naturally there is a guarantee.
Second, the power battery pack thermal runaway warning and fire extinguishing is a whole
Mainly by the single power battery fire warning control device and power battery special new gas automatic fire extinguishing device consists of two parts. Intervention control and automatic and efficient fire extinguishing in case of fire emergency, with multi-sensor composite detection, full-cycle fire detection, thermal runaway monitoring and analysis of early warning, emergency control of fire extinguishing and other features to detect and warn of intelligent control to solve the power battery pack fire hazards, the maximum protection of electric vehicles and the safety of drivers and passengers.
The actual vehicle-mounted products must require that the device is compact, flexible installation, convenient operation and maintenance, green, adaptable and other advantageous features, in function (performance) requirements, fire detection and warning, self-start, manual start, etc., to meet the fire extinguishing efficiency and effectiveness requirements.
Third, the basic functions of the power battery pack thermal runaway warning
Intelligent management of thermal runaway for power batteries, to achieve the initial detection of battery fire, intelligent analysis, early warning, the main functional requirements.
Early and accurate identification of the fire situation
Full-cycle fire detection records
Intelligent judgment, linkage fire extinguishing
Data black box function, data tracking
No residue of fire extinguishing agent, no damage to electrical equipment
Long life, light maintenance
Open interface, information sharing.
Fourth, the principle of power battery thermal runaway warning and fire extinguishing system
(A) Power battery thermal runaway warning system
The system monitors the real-time parameters and their change values of each detection point of CO gas, smoke, temperature and flame in the inner part of the battery box, and uses the data monitoring model to dynamically analyze and process the parameter changes to intelligently determine whether there is a risk of thermal runaway fire. Power battery fire early warning control system is as follows.
