What are the important causes of fire in lithium battery packs?

Battery overheating: Overheating of the battery will cause thermal runaway. This overheating is most likely to occur during the charging and discharging of the battery. Since the lithium battery has a certain internal resistance, a certain amount of heat will appear while outputting electric power to supply power for pure electric power, which makes its own temperature rise. When its own temperature exceeds its normal operating temperature range, it will damage the life of the entire battery. And safety. External force impact: Under the use of external force, lithium battery cells and battery packs deform, and different parts of themselves undergo relative displacement, which causes the battery diaphragm to be torn and an internal short circuit occurs. The flammable electrolyte leaks and eventually causes a fire. In the impact of external force, the puncture injury is the most serious. It may be directly inserted into the battery body, causing a direct short circuit of the positive and negative electrodes. Improper use of electricity: When an external short circuit occurs, when the heat generated by the battery cannot be dissipated well, the battery temperature will also rise, and the high temperature triggers thermal runaway. Over-discharge is the least harmful of the improper behavior of using lithium battery packs, but the rise of lithium dendrites caused by over-discharge will reduce the safety of the battery and increase the possibility of thermal runaway. The most harmful one is the improper behavior of using lithium battery packs when overcharging. Due to excessive lithium insertion, lithium dendrites grow on the anode surface. Secondly, the excessive deintercalation of lithium causes the cathode structure to collapse due to heat generation and oxygen release (oxygen release of the NCA cathode). The release of oxygen accelerates the decomposition of the electrolyte, and a large amount of gas appears. Due to the increase in internal pressure, the exhaust valve opens and the battery begins to exhaust. After the active material in the battery comes into contact with the air, it reacts violently and releases a lot of heat, which triggers the burning of the lithium battery. Loss of heat control: The high temperature of the external environment or the unusable temperature control system causes the battery heat to be too high, which causes a short circuit of the lithium battery, which causes thermal runaway. In fact, the collision and damage of the lithium battery, the internal structure and performance of the battery, or the failure of other thermal management systems and air-conditioning systems may cause the heat to run out of control. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Is it better to use polymer lithium batteries for power banks or lithium batteries?