Do you know any factors that affect the cycle performance of lithium-ion batteries?

The importance of cycle performance to lithium-ion batteries is self-evident; in addition, from a macro perspective, a longer life cycle means less resource consumption. Therefore, the factors that affect the cycle performance of lithium-ion batteries are issues that every practitioner in the lithium-ion battery industry must consider. The following are some factors that may affect battery cycle performance for your reference. Material type: Material selection is the primary factor affecting the performance of lithium-ion batteries. Choose a material with poor cycle performance, the process is reasonable and complete, and the cycle of the battery cannot be guaranteed; if you choose a better material, even if some problems are subsequently created, the cycle performance may not be too bad or too outrageous (one gram of lithium cobalt acid) It can only play around 135.5mah/g, and although the 1C is more than 100 dives, the lithium-ion battery is 0.5c, 500 times more than 90%; after the battery is removed, the battery cycle performance with black graphite particles on the negative electrode is normal. From the material point of view The cycle performance of the full battery is determined by the poorer of the cycle performance of the positive electrode and the electrolyte and the cycle performance of the negative electrode and the electrolyte. The material cycle performance is poor, on the one hand, it may be in the circulation process The crystal structure changes too quickly to continue to complete the lithium insertion. On the one hand, it may be due to the fact that the active material and its corresponding electrolyte cannot have a dense and uniform SEI film active material and electrolyte premature side reactions, so that the excessive consumption of the electrolyte will affect the cycle. In the battery design, if one pole confirms that a material with poor cycle performance is selected, the other pole should not choose a material with better cycle performance, which is wasted. Positive and negative electrode compaction: The positive and negative electrode compaction is too high, although it can be improved The energy density of the battery, but it will also reduce the cycle performance of the material to a certain extent. Theoretically, the greater the degree of compaction, the greater the damage to the material structure, and the material structure ensures that the lithium ion battery can be recycled Basic; In addition, it is difficult for cells with higher positive and negative density to ensure higher liquid retention, which is the basis for cells to complete one or more normal cycles. Moisture: Excessive moisture will interact with the active materials in the positive and negative electrodes. It reacts, destroys its structure and affects circulation. At the same time, too much water is not conducive to the formation of SEI film. However, although trace amounts of water are difficult to remove, trace amounts of water can also ensure the performance of cells to a certain extent. Unfortunately, Wenwu himself The relevant experience in this area is almost zero, can not say too much. If you are interested, you can search for information on this topic in the forum. Film density: It is almost impossible to consider the effect of film density on univariate cycles The task to be completed. The inconsistency of the film density will lead to the difference in the capacity or the difference in the number of layers of winding or layering. Regarding the battery of the same type, the same capacity, and the same material, reducing the film density is equivalent to adding one or more winding layers Or the number of laminates, the new diaphragm can absorb more electrolyte and ensure circulation. Considering more film density can improve the performance of the battery, it will be easier to remove the water from the battery pole pieces and bare baking. Of course, when the film is coated The density error of the layer may be more difficult to control, and the active material in larger particles may also cause a negative impact on the coating, rolling, more layers means more foil and diaphragm, which means higher cost and lower Energy density. Therefore, the evaluation should be balanced. Negative excess: The reason for excess negative electrode is not only the influence of the first irreversible capacity and the deviation of coating density, but also the cycle performance. Regarding the cobalt-graphite lithium system, the negative electrode graphite is often in the cycle process. Become a short board. If the negative electrode is too much and not enough, the battery may not be able to get rid of lithium before cycling, but the structure of the positive electrode does not change much after hundreds of cycles. However, due to the negative electrode junction The structure is destroyed, and the lithium ions supplied by the positive electrode cannot be fully received, resulting in a premature decrease 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: How to protect lithium-ion batteries?