There is no need to talk about the importance of cycle performance for lithium-ion batteries; in addition, macroscopically, longer cycle life means less resource consumption. Therefore, the factors affecting the cycle performance of lithium-ion batteries are issues that every person involved in the lithium battery industry has to consider. Several factors that may affect battery cycling performance are listed below for your reference.
1. Material type:
The choice of materials is the first factor affecting the performance of lithium-ion batteries. The material with poor cycle performance is selected, the process is reasonable, and the process is perfected. The cycle of the battery core is inevitably impossible to guarantee; the better material is selected, and even if there are some problems in subsequent fabrication, the cycle performance may not be bad. Too ridiculous (one lithium cobaltate gram is only 135.5mAh / g and lithium battery, 1C although more than 100 times diving but 0.5C, 500 times more than 90%; after the core is disassembled, the negative electrode has black graphite particles The battery has a good cycle performance). From the material point of view, the cycle performance of a full battery is determined by the poor performance of the cycle performance after the positive electrode is matched with the electrolyte and the cycle performance after the negative electrode and the electrolyte are matched. The cycle performance of the material is poor. On the one hand, the crystal structure changes too rapidly during the cycle, so that the lithium insertion can not be completed. On the one hand, the active substance and the corresponding electrolyte cannot form a dense and uniform SEI film to cause the active substance. A side reaction occurs prematurely with the electrolyte to cause the electrolyte to be consumed too quickly to affect the cycle. In the design of the battery core, if one pole confirms the selection of materials with poor cycle performance, the other pole does not need to select materials with better cycle performance and waste.
2, positive and negative compaction:
The positive and negative compaction is too high, although the energy density of the cell can be increased, but the cycle performance of the material is also reduced to some extent. From the theory to analyze, the greater the compaction, the greater the structural damage to the material, and the structure of the material is the basis for ensuring that the lithium-ion battery can be recycled; in addition, the higher the positive and negative compaction of the battery is difficult to guarantee High liquid holding capacity, while the liquid holding capacity is the basis for the cell to complete a normal cycle or more cycles.
Excessive moisture may cause side reactions with the positive and negative active materials, destroying its structure and affecting the cycle, and too much moisture is also detrimental to the formation of the SEI film. However, trace amounts of water can also ensure the performance of the cell to a certain extent while the trace amount of water is difficult to remove. Unfortunately, Wenwu’s personal experience in this aspect is almost zero, and there is not much to say. Everyone is interested in searching the forum for information on this topic, or a lot.