What effect does prelithiation have on the storage life of lithium-ion batteries

Lithium-ion batteries are stored in a high-charge state for long-term storage, and there are two types of capacity loss: one is reversible capacity loss, which can be recovered by charging, which generally depends on the design of raw materials and the battery manufacturing process, through the selection of intrinsic self-discharge For raw materials with a low rate, strictly controlling the moisture and surplus in the processing process can greatly reduce the reversible capacity loss; the other is the irreversible capacity loss, which is irreversible and mainly comes from side reactions, active material shedding, and structural changes. Etc. The irreversible capacity loss caused by the negative electrode accounts for the vast majority. The pre-lithiation process is an electrochemical pre-lithiation method, which is simple to operate, can accurately control the amount of pre-lithiation, and improve the first-time efficiency of the battery. Through negative electrode pre-formation, the negative electrode active lithium is artificially supplemented, so that after the battery is fully charged, the negative electrode active lithium is greater than the positive electrode lithium demand. Even if the negative electrode has a certain capacity loss, it is still sufficient to meet all the needs of the positive electrode. This method is expected to be greatly improved. Reduce battery capacity loss and improve storage life. (1) The 6-month capacity retention rate of the pre-lithiated soft-packed storage battery is 99.4%, which is much higher than the 94.2% of the comparative battery. The capacity is not attenuated after 300 cycles, while the comparative battery is only 96.9%. (2) In order to prevent the pre-lithiation of the negative electrode from lithium, it is necessary to accurately compare the amount of pre-lithiation to the excess of the negative electrode, and monitor the negative electrode potential interval through three electrodes, etc., to ensure that it is in a reasonable charge and discharge interval to ensure the cycle life of the battery . (3) Excessive pre-lithiation will increase the excess ratio of the negative electrode, which will cause the negative electrode area density to be too large and affect the rate performance of the battery. (4) The 18650 battery was developed on the basis of the design of the soft pack storage battery. The pre-lithiation process was also used, and a comprehensive evaluation of the rate, storage performance and cycle performance was carried out, which again verified the effect of pre-lithiation on improving battery storage. The life span has a significant effect. In the future, further in-depth research will be conducted on the influence of pre-lithiation on the storage life of lithium-ion batteries, and the influence of pre-lithiation amount, negative electrode excess ratio, and pre-lithiation process on battery performance will be explored. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.