What are the factors affecting the health of lithium-ion batteries

1 The influence of temperature on battery SOH. Temperature is generally considered to be an important factor affecting battery health. Temperature has a dual effect on battery performance. On the one hand, high temperature will speed up the chemical reaction inside the battery and improve the efficiency and performance of the battery. At the same time, high temperature It will also accelerate the occurrence of some irreversible chemical reactions, causing the battery's active material to decrease, causing the battery's aging and capacity degradation. Some experimental data show that high temperature will accelerate the rise of the SEI film of the battery electrode, and the difficulty of lithium penetrating the SEI film is increased, which is equivalent to the increase of the internal resistance of the battery. 2 The impact of charge and discharge current rate on battery SOH. The charge and discharge rate will affect the life of the battery. The Sony 18650 battery was subjected to 300 cycles of three different discharge rates, and the battery capacity was attenuated by 9.5%, 13.2% and 16.9%, respectively. The internal resistance was increased by 12.4%, 18.3%, and 27.7% respectively. At the same time, high-rate discharge will generate more heat inside the battery and accelerate battery aging. The SEI film on the electrode surface of the high-rate battery discharge is observed under the electron microscope than the low-rate discharge. To be thick. 3 The effect of depth of discharge on battery SOH The depth of battery charge and discharge has an impact on battery health and aging. There is a view that the battery has accumulated total transferred energy, and the capacity attenuation and aging analysis of the battery is based on the total transferred energy. Gao Fei et al. analyzed the relationship between the cumulative transfer energy of the battery and the attenuation of the battery capacity through the cycle detection of different discharge depths of the lithium-ion battery, and found that the cumulative transfer energy of the battery is in the deep charge and deep discharge before the battery capacity decays to 85%. It is basically the same as the two modes of shallow charge and shallow discharge. When the battery capacity decays to 85%~75%, the accumulated energy transferred by the battery and the energy efficiency of the deep charge and deep discharge mode are better than the shallow charge and shallow discharge mode. 4 The influence of the cycle interval on the battery SOH. The battery charge and discharge cycle interval will also affect the battery aging process. The internal resistance of the charge and discharge battery is different for different cycle intervals. Therefore, the battery heat and reaction during the cycle are slightly different, which will affect the battery's long-term Health and aging. Therefore, some experts suggest that the battery SOC should be in the range of 20% to 80%, which is conducive to battery health and cycle life. 5 The impact of the charge-discharge cut-off voltage on the battery SOH. Overcharge and over-discharge of the battery will have an impact on battery health, and inappropriate upper and lower voltage limits have an impact on the battery. The lower the discharge cut-off voltage, the greater the internal resistance of the battery, which will cause internal heating of the battery, and at the same time cause additional side reactions, the reduction of battery active materials and the collapse of the negative electrode graphite sheet, accelerated battery aging and capacity degradation. Too high charge cut-off voltage causes the internal resistance of the battery to increase, the internal heating of the battery increases, overcharging causes the phenomenon of lithium ion evolution in the negative electrode and the corresponding side reactions increase, which affects the capacity and aging of the battery. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What is the principle of repairing lithium-ion batteries