Cyclic performance The importance of lithium-ion batteries does not require confusing; in addition to macro, longer cycle life means less resource consumption. Thus, the factors affecting the cycle performance of lithium ion batteries are the problems that each with the person related to the lithium industry has to consider. A few in the following may affect the battery cycle performance factors for your reference.1. Material species: Material selection is the first element affecting the performance of lithium ion battery. The material of the cycle performance is selected, the process is reasonable, the process is improved, and the circulation of the battery must not guarantee; the better materials are selected, even after subsequent production, the cycle performance may not be poor. Too leaving (lithium cobalt acid, only 135.5mAh / g) and the lithium battery, 1C, although more than 100 diving but 0.5c, 500 times 90%; the primary battery is opened after the negative electrode has black graphite particles The battery, normal cycle performance). From a material point of view, a circulating performance of a whole battery is determined by the circulating performance of the positive electrode and the electrolyte, the negative electrode and the electrolytic solution, and the poor generation is determined by one. The circulating performance of the material is poor, one hand may be that the crystal structure changes excessive during the circulation process, which cannot continue to complete the embedded lithium deod lithium, one hand, may be due to the active substance and the corresponding electrolyte unable to generate a dense uniform SEI film causes active substance The electrolytic solution occurs too early to cause the electrolyte too fast to consume the cycle. When the battery is designed, if an element is used to confirm that the content of the cycle performance is poor, the other is not necessary to select a material having better cycle performance, waste.
2, the positive and negative compaction: the positive and negative is too high, although the energy density of the battery can be improved, but it will also reduce the cycle performance of the material to a certain extent. Analysis from theory, the more compacted, the larger the structural damage to the material, and the structure of the material is the basis of the lithium-ion battery can be recycled; in addition, the electrical core of the positive and negative compaction is difficult The amount of high vent is, and the amount of water is the basis for the battery cell to complete the normal cycle or more.
3, moisture: Excessive moisture will have a side reaction with positive and negative active substances, destroying its structure to affect circulation, and too much moisture is not conducive to the formation of SEI membranes. However, while trace moisture is difficult to remove, trace water can also ensure the performance of the battery to a certain extent. Unfortunately, civil and military experience is almost zero, can't say too much. Everyone is interested in searching for information on this topic in search forum, still a lot.
4, coating film density: a single variable considers the impact of membrane density on cycles is almost an impossible task. The membrane density does not match the difference in capacity, or the difference in the number of core windings or laminates. In the case of the same type of electrical cells with the same type, reduce the film density correspond to increasing one or more layers of winding or laminate layers, and the corresponding increased diaphragm can absorb more electrolyte to ensure cycle. Considering a thinner membrane density can increase the magnification performance of the battery, the baked water of the pole and the bare core can be easily, and of course the error of too thin film density can be more difficult to control, active substances The large particles may also have a negative impact on coating, rolling, more layers mean more foil and diaphragm, which in turn mean higher cost and lower energy density. Therefore, it also needs to be considered in the assessment.
5, an negative excess: The cause of the negative electrode except for the first irreversible capacity and the impact of the circulating performance is also considered. For the lithium cobalt-added graphite system, the negative electrode graphite is more common in the 'short board' in the cycle. If the negative electrode is not sufficient, the cell may not analyze lithium before the cycle, but the positive electrode structure changes in the cycle, the negative electrode structure is destroyed, and the lithium ion provided by the positive electrode is not fully received, and the lithium, resulting in a capacity Early decline.
6, the amount of electrolytic liquid: There are three main reduction in the amount of electrolytic liquid on the cycle. First, the amount of liquid is insufficient. Although the amount of liquid is sufficient but the aging time is not enough or the positive electrode is immersed due to compaction The liquid is insufficient, and the third is that the internal electrolyte of the circulating cell is consumed. Since the amount of liquidation is insufficient and the amount of water is insufficient. "The impact of the electrolyte deletion on the performance of the battery". For the third point, the positive and negative electrode, especially the matching of the negative electrode and the electrolytic solution is formed in the formation of dense and stable SEI, and the performance of the right eye visible is only the rate of consumption of the electrolyte during the cycle. In the case of an incomplete SEI membrane, the negative electrode and the electrolytic solution cannot be effectively prevented from consuming the electrolyte. On the one hand, the portion of the SEI film is defective will regenerate the SEI film as the cycle is carried out, and the Silver source and electrolyte are consumed. Whether it is a battery cell that is loop or even thousands of batches for dozens of diving, if the electrolyte has been completed, the electrolyte has been consumed after the electrolyte has been consumed, and the amount of electrolyte is likely to be certain. Degree improve its cycle performance.
7. Objective conditions of the test: charge and discharge rate, cutout voltage, charging cutout during the test process, overcharge, test room temperature, sudden interruption during testing, test point and battery contact internal resistance Waiting for an external factor, there will be more or less influence of the cycle performance test results. In addition, different materials have different degrees of sensitivity of the objective factors, unified test standards and understanding of the characteristics of commonality and important materials should be used in daily work.
Summary: Like the principle of wooden buckets, many factors affecting the circular performance of the battery, the final decisive factor is the shortest plate in many factors. At the same time, there are interactive effects between these influencing factors. Under the same material and manufacturing ability, the higher the cycle, the lower the lower energy density, find the joint point just satisfied with customer needs, try to ensure the consistency made of the battery, and the party is the most important task. . Recommend: LiFePO4 Battery Manufacturer Energy storage battery Manufacturer Integrated machine energy storage battery series Manufacturer Lead lithium battery Manufacturer Outdoor Backup Battery Manufacturer Portable outdoor power supply Manufacturer Power battery Manufacturer Powerwall LiFePO4 Battery Manufacturer Battery rack Manufacturers Telecom LiFePO4 Battery Manufacturer Wall mounted battery storage Manufacturer China Lifepo4 Battery
