What is the reason for the life decay of lithium-ion batteries

1. The influence of the operating voltage window on the growth of the negative SEI film is that due to the wide electrochemical window, the dissolution of positive transition metal elements is enhanced, and the dissolved transition metal elements migrate to the surface of the negative electrode, accelerating the growth of the negative electrode transition metal film. The results show that the kinetic conditions of the negative electrode accelerate the decay of lithium ions, so the negative electrode precipitates lithium ions, leading to an earlier non-linear decay. 2. The influence of charge and discharge rate. Because the nonlinear attenuation of lithium ion batteries is mainly caused by the precipitation of lithium ion metal on the negative electrode surface, the charge and discharge current is closely related to the occurrence of the nonlinear attenuation of lithium ion batteries, and has the greatest impact on the battery. Non-linear decay is the charging current of the battery. A battery charged at a rate of 1C shows a trend of non-linear decay almost from the beginning, but if we reduce the charging current to 0.5C, then the time node of the battery is that the non-linear decay will be greatly delay. The influence of the discharge current on the non-linear attenuation of the battery is almost negligible. This is important because as the charging current increases, the polarization of the negative electrode is also significantly increased, which leads to a significant increase in the risk of lithium ions being released from the negative electrode. The precipitated porous metallic metal promotes and accelerates the decomposition of the electrolyte. The decrease in the dynamic performance of the negative electrode leads to the early occurrence of nonlinear decay. 3. The influence of temperature Temperature has a very important influence on the dynamic characteristics of the negative electrode, so the temperature also has an important influence on the time when the non-linear decay of the battery occurs. The battery cycled at 35C has a non-linear drop at the latest. If we reduce the voltage window of the battery to 3.17-4.11v, the battery decay rate of the early 35C and 50C cycles is relatively the same, but at the end of life, the battery that cycles at 35C begins to show a non-linear decline. This is important because the kinetic conditions of the battery deteriorate at low temperatures, which makes the negative electrode easier to be analyzed as lithium ions, which accelerates the growth of the sei film, causes the negative kinetic conditions to further deteriorate, and leads to the non-linear decline of early lithium-ion batteries. 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 long is the life of the gel battery?