What are the influencing factors of the cycle performance of lithium batteries?

Excessive water will cause side reactions with the positive and negative active materials, destroy its structure and affect the cycle. At the same time, too much water is not conducive to the formation of SEI film, but while the trace of water is difficult to remove, the trace of water will also The performance of the battery cell can be guaranteed to a certain extent. 2. Positive and negative electrode compaction The positive and negative electrode compaction is too high, although it can increase the energy density of the cell, it will also reduce the cycle performance of the material to a certain extent. From the theoretical analysis, the greater the compaction, the equivalent to the material The greater the damage of the structure, and the structure of the material is the basis to ensure that the lithium battery can be recycled; in addition, it is difficult to ensure a higher liquid retention capacity for batteries with higher positive and negative electrode compaction, and the liquid retention capacity is that the batteries are completed normally The basis for loops or more loops. 3. Objective conditions of the test Charge and discharge rate, cut-off voltage, charge cut-off current during the test, overcharge and overdischarge during the test, temperature of the test room, sudden interruption during the test, contact internal resistance between the test point and the cell, etc. External factors will more or less affect the cycle performance test results. In addition, different materials have different sensitivity to the above objective factors. A unified test standard and knowledge of common and important material characteristics should be enough for daily work. 4. Excessive negative electrode In addition to the influence of the first irreversible capacity and the density deviation of the coating film, the reason for the excessive negative electrode is also the influence on the cycle performance. Regarding the lithium cobaltate plus graphite system, the negative electrode graphite becomes the cycle process. The shortcomings of the negative electrode are more common. If the negative electrode is excessively insufficient, the battery cell may not release lithium before the cycle, but the positive electrode structure changes little after hundreds of cycles, but the negative electrode structure is seriously damaged and cannot completely receive the lithium ions supplied by the positive electrode. As a result, lithium is precipitated and the capacity drops prematurely. 5. Considering the single variable of coating film density. The influence of film density on the cycle is almost an impossible task. Inconsistent film density will either bring about a difference in capacity, or a difference in the number of winding or laminated layers of the battery. For batteries of the same model and capacity and material, reducing the film density is equivalent to adding one or more layers of winding or lamination. The new diaphragm can absorb more electrolyte to ensure circulation. Thin film density can increase the rate performance of the cell, and it will be easier to bake the pole pieces and bare cells to remove water. Of course, the error of coating with too thin film density may be more difficult to control, and the active material is large. Particles may also have a negative impact on coating and rolling. More layers means more foils and diaphragms, which in turn means higher costs and lower energy density. Therefore, the evaluation should also be balanced Consider. 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 use lithium batteries correctly?