What are the factors that affect the cycle performance of lithium-ion batteries?

The factors affecting the cycling performance of lithium-ion batteries mainly include the following aspects:
1. Material type

The choice of battery materials is the first factor that affects the performance of lithium-ion batteries. The matching of different cathode materials, anode materials, and electrolytes will have an impact on the cycling performance of the battery. The poor cycling performance of the material may be due to the rapid change of the crystal structure during the cycling process, which makes it impossible to continue to complete the lithium intercalation delithiumation, or because the active substance and the corresponding electrolyte cannot form a dense and uniform SEI film, resulting in the premature side reaction between the active substance and the electrolyte, which makes the electrolyte consume too quickly, and then affects the circulation.

Low temperature: Low temperature will reduce the ionic conductivity of the battery, resulting in a decrease in the charging and discharging efficiency of the battery, especially at low temperature, it is difficult for lithium ions to be effectively embedded in the negative electrode, which can easily lead to capacity loss. In addition, the charge-discharge reaction of the battery is slower at low temperatures, and over-discharge may cause damage to the battery.

4. Charge-discharge rate

The charge-discharge rate, that is, the size of the charge-discharge current, has an impact on the cycle performance of the battery. A high charge-discharge rate will cause a large current change in the battery in a short period of time, which may generate excessive heat, resulting in an increase in the internal temperature of the battery, thereby accelerating the aging of the battery and reducing the cycle life.

5. Battery Management System (BMS)
The battery management system (BMS) is used to monitor the status of the battery, including temperature, voltage, current, etc. The role of BMS is to ensure that the battery operates within a safe working range and avoid undesirable states such as overcharge, overdischarge and overheating. The BMS adopts a reasonable charging strategy (such as constant current and constant voltage charging) to effectively extend the service life of the battery and avoid overcharging or overdischarging. In a high or low temperature environment, BMS can adjust the working conditions of the battery, avoid overheating or overcooling the battery, and prolong its cycle life.

9. Separator and SEI Film

The integrity of the separator and the formation of the SEI film also have an impact on the cycling performance of the battery. The separator is an electrical isolation material between the positive and negative electrodes inside the battery, and the porosity, thickness and chemical stability of the separator will affect the internal resistance of the battery and the stability in long-term use. A diaphragm that is too thin may not be able to effectively isolate the positive and negative electrodes, resulting in a short circuit; If the separator is too thick, it may increase the internal resistance and affect the efficiency of the battery. And the uneven or unstable formation of the SEI film may lead to a decrease in battery performance.