Brief Analysis of Lithium Ion Battery Circuit Protection Components

Analysis of Lithium-ion battery circuit protection components In many previous articles, we have mentioned that due to high temperature, improper operation of lithium-ion batteries may cause explosions, and such accidents also occur from time to time. But accidents are rare. For some large lithium-ion battery manufacturers, other lithium-ion batteries they produce will have a protective measure to protect the circuit of lithium-ion batteries. Circuit protection requires many effective components. There are three important circuit protection components: thermal fuse, current fuse, and positive temperature coefficient thermistor. Today I will discuss with you the functions and differences of these three parts: PTC thermistor is mainly used for overcharge protection. The protection principle is to use the nature and characteristics of the PTC material with a positive temperature coefficient of resistance. The temperature rise caused by any reason (including overcurrent and environment) will cause the resistance of the material to increase. Once it rises to the Curie point, the resistance becomes It is large enough to cut off the charging current to achieve safety and protection functions. The advantage of thermistor protection is that it responds to current and temperature. When the battery is overcharged, the current can be limited in time. The disadvantage is that the response time is slow. The positive temperature coefficient thermistor is also called a resettable fuse, but there is no need for automatic recovery function to protect the battery of mobile phones, especially the overcurrent caused by circuit failure. If the fault and PTC self-recovering are not eliminated, there is no practical application significance. Thermal fuse is mainly used for overheating protection: the protection principle is that the melt made of low melting point alloy material will melt once it reaches the allowable temperature, thereby cutting off the circuit and achieving the function of safety protection. The advantage of using a thermal fuse to protect is the melting of internal and external temperature-sensitive elements, especially when the phone is placed in a high temperature environment or other reasons for excessive temperature will take action, but the overcurrent caused by excessive reaction temperature is relatively slow. Low precision and low reliability current fuse. Current fuse is mainly used for short-circuit protection: the protection principle is that once the battery is short-circuited, the large overcurrent will quickly break the thermal balance during normal operation, and the melt temperature will rise to the melting point of the material in an instant, and the circuit will be disconnected to achieve safety. Protection function. The advantage of using current fuse protection is that the circuit is cut off quickly and thoroughly, and the fuse characteristics are highly accurate. Whenever charging, using or standby, as long as any part is short-circuited, it will act quickly. But it is only sensitive to current, not to outside temperature. Therefore, when buying a lithium-ion battery, you must pay attention to which manufacturer it is from and how it works. Because small companies may not have any circuit protection in order to save money and cannot guarantee safety. Therefore, when you buy lithium-ion batteries in the future, you must find more safe lithium-ion battery manufacturers! Statement: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete the previous one: Introduction to the basics of lithium-ion batteries Composition and key materials