What are the important reasons for the thermal runaway of the power lithium battery pack?

The thermal runaway phenomenon of the power lithium battery pack means that the battery pack has a safety problem and must be dealt with in time, otherwise it is likely to cause danger and loss to the user. Since thermal runaway of power lithium battery packs is a very dangerous thing, it is also more important to know the cause of thermal runaway and how to solve it. It is best to get a warning from the cause and use lithium Pay attention to the battery pack to prevent thermal runaway. Causes of thermal runaway of power lithium battery pack. Mechanical abuse. Under the use of external force, the lithium battery pack is affected and deformed, and different parts of itself undergo relative displacement. The lithium battery pack’s cells are subjected to external forces, causing internal collisions, squeezing and punctures, etc. All belong to mechanical abuse. In mechanical abuse, the most dangerous is puncture. The conductor is inserted into the battery body, causing the positive and negative poles to be directly short-circuited. Compared with collisions, squeezing, etc., internal short-circuit occurs probabilistically. The probability of losing control is higher. Electrical abuse The electrical abuse of lithium battery packs generally includes external short circuit, overcharge, and overdischarge. Among them, the most prone to develop into thermal runaway is overcharge. External short circuit. When two conductors with a voltage difference are connected outside the cell, an external short circuit occurs. From external short circuit to thermal runaway, the important link in the middle is excessive temperature. When the heat generated by the external short circuit cannot be dissipated well, the battery temperature will rise and the high temperature triggers thermal runaway. Overcharge, because of its full energy, is the most harmful type of electrical abuse. The appearance of heat and gas are two common features in the overcharging process. The heat comes from ohmic heat and side reactions. The abuse mechanism of over-discharge is different from other forms of abuse mechanism, and the potential danger is far higher than people think. Copper ions caused by overdischarge dissolve and migrate through the membrane and form copper dendrites with a lower potential on the cathode side. As the growth increases, copper dendrites may penetrate the diaphragm, causing serious thermal runaway problems. Heat abuse Local overheating may be a typical heat abuse situation that occurs in battery packs. Heat abuse rarely exists independently, it often develops from mechanical abuse and electrical abuse, and it is the link that ultimately directly triggers thermal runaway. Regarding the thermal runaway caused by mechanical abuse, the best way to deal with it is to replace the faulty lithium battery pack and discard the battery that has damaged physical components. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the specific types of lithium battery cells?