Lithium ion battery, as the most common battery type at present, has been widely used in electric vehicles, mobile phones, notebook computers and other fields. However, as the number of cycle charge and discharge of the battery increases, the performance of the battery will gradually decrease, that is, the phenomenon of cycle aging occurs. This article will discuss the mechanism research of lithium ion battery cycle aging, in order to better understand the causes and laws of battery aging.

1. Definition of cyclic aging of lithium ion batteries

cycle aging of lithium ion battery refers to the phenomenon that the battery capacity gradually decreases, the internal resistance increases, and the cycle efficiency decreases with the increase of cycle times during the cycle charging and discharging process of the battery. Cyclic aging is one of the main reasons for the deterioration of lithium ion battery performance, which directly affects the service life and stability of the battery.

2. Mechanism of cyclic aging of lithium ion batteries

2.1 Lithium ion migration

• during the cyclic charging and discharging process of the battery, the migration of lithium ions between the positive electrode and the negative electrode is one of the main causes of cyclic aging. As the number of cycles increases, the migration speed of lithium ions slows down, resulting in the decrease of battery capacity.

2.2 Structural damage of electrode materials

• as the number of cycles increases,The structure may change and damage, resulting in the loss of electrode active materials, affecting the performance and cycle life of the battery.

2.3 Electrolyte degradation

• long-term cyclic charging and discharging will lead to the gradual degradation of dissolved solutes in the electrolyte, generating gases, solid precipitation and other substances, affecting the performance of the electrolyte, and further affecting the cycle performance of the battery.

3. Influence of cycle aging of lithium ion batteries

3.1 battery capacity decrease

• cyclic aging will cause the available capacity of the battery to decrease gradually, affecting the endurance and service time of the equipment.

3.2 Increase of internal resistance

• with the aggravation of cyclic aging, the internal resistance of the battery will gradually increase, resulting in the decrease of the power output of the battery and affecting the performance of the equipment.

3.3 cycle efficiency decline

• cyclic aging will also lead to the decrease of the cycle efficiency of the battery, that is, the energy loss increases during the charging and discharging process, which affects the energy utilization efficiency of the battery.

4. Research progress on cyclic aging of lithium ion batteries

• for lithium ion battery for the problem of cyclic aging, researchers have carried out a lot of research work, including material design optimization, electrolyte improvement, cyclic charging and discharging strategy optimization, etc., aiming at prolonging the battery life and improving the performance.

5. Strategies to deal with cyclic aging of lithium ion batteries

5.1 optimize charging and discharging strategies

• reasonable parameters such as charge and discharge rate and voltage range of control battery can slow down the cycle aging of the battery.

5.2 improve electrolyte formula

• optimize the composition and formula of electrolyte, improve the stability and cycle resistance of electrolyte, and prolong the cycle life of battery.

5.3 material design and structure optimization

• further optimize the structural design of electrode materials, improve the stability and cycle performance of electrodes, and reduce electricityThe cycle aging rate of the pool.