What is the reason why the life of high specific energy lithium-ion battery decays faster?

From a micro point of view, during the use of lithium-ion batteries, there will be irreversible electrochemical reactions such as electrolyte differentiation, inactivation of active materials, and collapse of the positive and negative electrodes, which will reduce the number of lithium intercalation and deintercalation and lead to a decrease in capacity. Especially under high voltage and high temperature conditions, the appearance of the positive electrode material with a high degree of lithium ion removal is very easy to react with the electrolyte. For example, the activity of the NCM811 reacting with the electrolyte in the charged state is much greater than the activity of the NCM111 reacting with the electrolyte. Therefore, the higher the charge and discharge voltage and the higher the temperature, the faster the capacity of the lithium-ion battery will decrease. From a macro point of view, how to accurately measure current, voltage and temperature, and do a good job of thermal management, power management and energy management? How to perceive the life status of high specific energy power lithium-ion batteries and extend their service life? There is no doubt, The battery management system plays an important role. Exploring the solution from different dimensions on the problem of excessively fast decay of the lifespan of high specific energy power lithium-ion batteries such as NCM811. Now the solutions in the industry mostly start from the aspects of data, electrolyte, diaphragm and battery management system. In terms of data, the appearance of the particles of NCM811 can be modified to improve its performance. Due to different electrolyte additives, the polarization degree and polarization speed of the battery are also different. Therefore, the use of electrolyte that can reduce the internal parasitic reaction of the battery can improve the cycle life and safety of the high specific energy power lithium-ion battery. Through the application of ceramic and polymer multi-functional composite coatings, Penghui Power has improved the stability and safety of high specific energy power lithium-ion batteries under high temperature and high pressure; in addition, Penghui Power has also developed a dedicated silicon carbon anode The advanced process system and electrolyte have improved the first efficiency of the battery to 86% and above, solved the problem of rapid decay in the first 50 weeks of the battery, and improved the capacity and test life of the battery. At the level of battery management system, Professor Wei Xuezhe, deputy dean of the College of Cars of Tongji University, proposed a battery pack optimization design method based on the electricity-heat-life coupling model, which can measure the impedance and capacity of the battery cells, and collect multiple spaces and time. Dimensional data. At the same time, the design can ensure the consistency of the battery pack and complete multi-factor and multi-physics coupling. According to Professor Wei Xuezhe's analysis, this is the third-generation battery management system centered on life estimation, prediction and management (the first-generation battery management system is centered on cell safety monitoring, and the second-generation battery management system is centered on SOC estimation. ), the management system has a complete series-parallel method, equilibrium method and thermal management method, which can effectively manage the life decay of high specific energy power lithium-ion batteries. 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: How to test whether the lithium ion battery meets the safety indicators