What affects the cycle performance of lithium batteries?

What affects the cycle performance of lithium batteries Everyone in the lithium ion industry must consider the recycling of lithium batteries. A longer cycle life means less resource consumption. So what on earth to choose the cycling function of lithium batteries? Material diversity: Material selection is the primary factor that affects the performance of lithium batteries. Choose a material with poor circulation function, no matter how reasonable the process is, and then make it perfect, the battery circulation may not be guaranteed; if you choose a better material, even if you do some follow-up problems, the circulation function may not be too bad and too outrageous (Lithium Cobalt acid grams only play around 135.5mah/g and lithium batteries. Although 1C has more than 100 jumps but 0.5c, 500 times more than 90%; after the battery is removed, the battery with black graphite particles on the negative electrode has a normal cycle function. From the material point of view , A complete battery cycle function is the cycle function after the positive electrode and the electrolyte are matched, and the cycle function after the negative electrode and the electrolyte are matched. The poor choice. The material cycle function is poor, and on the one hand, it may be circulating In the process, the crystal structure changes too fast to continue to end the lithium insertion. On the one hand, it may be because the active material and its corresponding electrolyte cannot generate a unified SEI film composition of the active material and the electrolyte. The liquid runs quickly, and then affects the cycle. In the battery design, if one pole admits that the material with poor circulation function is selected, the other pole should not choose the material with better circulation function, which is wasted. Positive and negative electrode compaction: positive and negative Extreme compaction is too high, although it can increase the energy density of the battery, it will definitely reduce the cycle function of the material. Theoretically, the greater the degree of compaction, the greater the damage to the material structure, and the material structure is to ensure the lithium battery The basis of recycling; in addition, cells with a higher degree of positive and negative compaction cannot guarantee higher liquid retention, which is the basis for cells to complete normal or more cycles. Water: Excessive water will interact with the positive and negative electrodes The active substance reacts, destroys its structure and affects the circulation. Excessive water is not conducive to the composition of the SEI membrane. However, while the trace water is difficult to remove, the trace water can also ensure the function of the cells. Unfortunately, Wenwu himself is here The relevant experience in this area is zero, which can’t be said too much. We have a preference material on the topic of the search forum, and there are many. Coating film density: It is an impossible task to consider the single variable of film density on the cycle. The inconsistency of the film density will lead to the difference in capacity or the difference in the number of layers of winding or layering. For the same type of battery with the same capacity and the same material, the reduction in film density is equivalent to adding one or more layers of windings or laminates. The corresponding new gap can absorb more electrolyte and ensure circulation. Considering more film density can increase the proportion of cell functions, it will be short-lived for the pole pieces and bare cells to bake out of water. Of course, when the film is coated The density error of the layer may be more difficult to control, and the active material in the large particles may also have a negative impact on the coating, rolling, and the more layers of foil and separation, which means higher cost and lower energy density. Therefore, the evaluation is also To balance. Negative interference: The reason for the negative interference is not only the influence of the first irreversible capacity and the plating density error, but also the influence of the cycle function. In the lithium cobalt oxide plus graphite system, negative graphite often becomes Short board. If the negative electrode is too much and not enough, the cell may not disintegrate before the lithium cycle, but the positive electrode structure changes very little in a few hundred cycles, but the negative electrode structure has been severely damaged, and it cannot be completely absorbed The supplied lithium ion positive electrode then disintegrates the lithium, leading to a premature decline in capacity. 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 article: How does lithium battery solve the problem of battery life of wearable devices?