What are the reasons for the decay of the life of lithium iron phosphate battery packs?

1. The internal resistance of the lithium-ion battery pack, especially the polarization internal resistance, makes the voltage of individual batteries change drastically during the charging and discharging process, leading to drastic changes in the entire battery pack; 2. The voltage of the single ultra-thin battery Disagreements will affect the peak shaving capability of the battery pack, and reduce the energy released by the overall lithium-ion battery pack; 3. Due to the exothermic and endothermic processes of ultra-thin batteries, the battery temperature will continue to change, and when it is overheated , It will bring performance degradation and safety hazards. Facts have proved that the fuse of electric vehicle operation and test fires produced in successive years is caused by over-temperature protection and inadequate battery heating and fire. Examples of batteries are not only lithium manganate, iron phosphate. The same is true for lithium-ion battery packs; 4. Capacity is the most serious factor in discreteness. The discrepancy in capacity is important to cause two functional problems. One is that some lithium iron phosphate battery packs will be overcharged and over-discharged, leading to Unrest factors such as combustion and explosion. Second, the low-capacity single battery ends early, which affects the energy of the other single cells in the entire ultra-thin battery pack cannot be fully released, which causes the life of the entire lithium-ion battery pack to decay. 5. Oxidation analysis and interface reverberation of electrolyte. The nature of electrolyte significantly affects the specific capacity, life, rate charge and discharge performance, working temperature range, and safety performance of lithium-ion batteries. Electrolyte mainly includes three sectors: solvent, electrolyte and additives. The analysis of solvents and electrolytes results in the loss of battery capacity. 6. Temperature is definitely one of the key factors affecting the life of lithium-ion battery packs. Too high temperature or too low temperature will cause a decrease in active lithium ion content, which will eliminate the life of lithium ion batteries. An important factor that causes the life decline of lithium iron phosphate battery packs is the Li loss caused by the reconstruction and development of the SEI membrane in the process of reincarnation. The essentials of NeelimaPaul's operation of neutron diffraction were invented after elucidating the batteries stored for 2 years (20% SoC) at 23°C after 4750 cycles of 1C cycle, that is, after the lithium ion battery pack is fully discharged (the positive electrode is in the state of lithium insertion). , The negative electrode is in the state of delithiation), but a considerable proportion of FePO4 is still investigated in the diffraction peak of the positive electrode. The ratio of LFP:FP is 67:33 in the battery with 4750 cycles, and the LFP:FP in the battery stored for 2 years The ratio is 75:25, and the diffraction peak of LiC6 is not investigated in the diffraction peak of the negative electrode. 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: Do you know any important uses of lithium-ion battery electrolytes?