Surrounding overheating, overcharging, internal short circuit, collision, etc. are several key factors that cause thermal runaway of power battery

　　The safety problem of power battery is summed up as "thermal runaway", that is, it becomes uncontrollable after reaching a certain temperature, the temperature rises linearly, and then it burns and explodes.

　　Surrounding overheating, overcharging, internal short circuit, collision, etc. are several key factors that cause thermal runaway of power battery:

　　(1) Surrounding overheating triggers thermal runaway

　　This should be solved from two aspects of overall design and battery management. From the overall design perspective, it is necessary to consider the non-battery heat source, heat dissipation, firmness and other conditions as a whole; from the battery management perspective, different temperature ranges can be predicted, different safety levels can be defined, so as to carry out hierarchical alarms.

　　(2) Overcharge triggers thermal runaway

　　The solution is first to check whether the charging equipment is faulty, and secondly to check the comprehensiveness and anti-interference of the BMS function.

　　It is worth noting that as the battery ages, the consistency between the batteries will get worse and worse, and overcharge is more likely to occur at this time.

　　(3) Internal short circuit triggers thermal runaway

　　The Boeing 787 passenger plane caught fire due to a battery explosion. When searching for the cause of the accident, it was found that there were metal objects on the electrode and the diaphragm, which caused an internal short circuit. Although experts cannot 100% confirm that the thermal runaway is triggered by an internal short circuit, it is the most probable cause because there is no other reason, and the internal short circuit cannot be "reproduced".

　　Battery manufacturing impurities, metal particles, expansion and contraction of charge and discharge, lithium evolution, etc. may all cause internal short circuits. This internal short circuit occurs slowly and takes a very long time.

　　To solve the problem of internal short circuit, we must first find a battery manufacturer with good product quality, which means we must choose a battery with high consistency.

　　(4) Mechanical trigger thermal runaway

　　Collision is a typical mechanical trigger for thermal runaway. Tesla's repeated fire accidents are the reason for this.

　　The solution to the thermal runaway triggered by a collision is to do a good job in the overall safety protection design of the car.

　　Lithium-ion battery (LIB) has become the main energy storage solution in modern social life. Among them, lithium iron phosphate batteries are a perfect replacement for lead-acid batteries, and they are the first choice for grid-connected peak shaving, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.

　　In short, in terms of controlling thermal runaway, R&D personnel must start from two aspects: safety protection design and battery management.