How to improve the safety of lithium battery cells?

Researchers and battery manufacturers must continuously improve processes and technologies to improve the safety of lithium batteries. BMS system manufacturers should fully understand the functions of the battery, and plan a safe and reliable battery system according to the safety planning principles of power lithium-ion batteries. The correct use together is a barrier to ensure battery safety. Studying the failure modes of power lithium-ion battery systems is of great significance for improving the battery life, safety and reliability of electric vehicles, and reducing the cost of electric vehicles. This paper discusses the external failure modes of power lithium-ion battery systems, analyzes the results, and proposes corresponding treatment measures. In the design of the power lithium-ion battery system, the safety of the power lithium-ion battery is considered. The power lithium-ion battery system is usually composed of battery cells, battery processing systems, packaging systems with functional components, wiring harnesses, structural components and other related components. Power lithium-ion battery system failure modes can be divided into three different levels of failure modes, namely, battery battery failure mode, battery processing system failure mode, and packaging system integration failure mode. Packing system integration failure mode 1. Bus failure: In the case of bolt connection, in the future use process, if the bolt is loosened due to the oxidation drop of the bolt or vibration, a lot of heat will appear at the conductor connection, and in the case of two poles , The power battery will catch fire. Therefore, most power lithium-ion battery system manufacturers choose laser welding on the connection between the battery and the battery or between the module and the module during packaging planning, or add a temperature sensor to the connection to prevent busbar failure through detection. Invalidate. 2. The main circuit connector of the power lithium-ion battery system is faulty: the high-voltage wire of the power battery system is connected to the external high-voltage system through the connector. The coupling use is not reliable, virtual connection occurs under oscillation, and high-temperature ablation coupling occurs. Generally speaking, when the temperature of the coupling exceeds 90 degrees, the coupling will fail. Therefore, in the system planning, it is necessary to add a high-pressure interlocking function of the coupling, or add a temperature sensor to the coupling to continuously monitor the temperature of the coupling to prevent the coupling from failing. 3. High-voltage contactor adhesion: the contactor has a certain number of opening times under load, and most of the contactors open when the load is closed with a large current. In the system planning, in order to prevent the stickiness of the high-voltage contactor, the double relay method is generally used to close the control. 4. Fuse overcurrent protection failure: comprehensive consideration of the selection and matching of fuses in high-voltage system components, which fuse to cut first, and which fuse to cut after. Vibration or external knocking and knocking cause deformation of the power lithium-ion battery, sealing failure, and a drop in IP level. Therefore, the knock protection rate of the battery box structure should be tested during system planning. According to the power lithium-ion battery system of various failure modes above, researchers and battery manufacturers must promote the safety of lithium batteries through continuous improvement processes and technologies. BMS system suppliers fully understand the functions of the battery, according to the power lithium-ion battery The principle of safety planning, planning a safe and reliable battery system, plus correct use is to ensure the safety of the battery. Users should use the power lithium-ion battery system correctly to prevent mechanical misuse, thermal misuse and electrical misuse, and improve the safety and reliability of electric vehicles. 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 post: Analysis of the structure and working principle of lithium batteries