What are the factors influencing the service life of power lithium-ion battery cells?

The influencing factors of the service life of the power lithium-ion battery unit are aimed at the end of the service life of the power lithium-ion battery used in electric vehicles, which means that the attenuation of the battery reaches 20% of the initial capacity. The service life of the power lithium-ion battery will be degraded due to the continuous occurrence of side reactions inside the lithium battery when the battery is repeatedly charged and discharged on the electric vehicle. This decline is due to the following aspects: changes in the lattice structure of the electrode material; the decomposition, peeling or corrosion of the electrode material causes the reduction of the active material; the decrease in conductivity and the increase in impedance caused by the decomposition and consumption of the electrolyte; Or the side reaction causes the deintercalation of lithium ions to be consumed; the gas generated by the side reaction, insoluble substances, and the increase in impedance caused by the modification of the binder and the corrosion of the current collector. From the actual use of environmental conditions, the important factors affecting the service life of power lithium-ion battery cells include charge-discharge cut-off voltage, charge-discharge rate, use temperature, and shelf conditions. There have been many documents showing that within a certain range, the cycle life of different charging cut-off voltages decreases with the higher the charging voltage. This shows that the charge cut-off voltage has a great influence on the service life of the battery. A high charge cut-off voltage will aggravate the side reactions of the battery and shorten the service life of the battery. When the power lithium-ion battery is used in the whole vehicle, due to the various driving conditions of the electric vehicle, the battery is prone to decline and the performance drops more severely when charging and discharging in the higher potential area. The power lithium-ion battery adopts different charging and discharging ratios in order to meet different driving conditions during the use of electric vehicles. Research on rate charge and discharge of power lithium-ion battery shows that high rate charge and discharge will accelerate the attenuation of battery capacity. The greater the charge and discharge rate, the faster the battery capacity attenuation. This is mainly due to the change in the structure and properties of the positive electrode material and the thickening of the negative electrode surface film, which results in the difficulty of lithium ion diffusion. If the charge-discharge rate is too large, it may also cause the single battery to overheat, short-circuit and cause an explosion. Different power lithium-ion batteries have different optimal operating temperatures, and too high or too low temperatures will affect the service life of the batteries. As the temperature decreases, the discharge capacity of lithium-ion power lithium-ion batteries will decrease. This is because as the temperature decreases, the ionic conductivity of the electrolyte decreases, causing the internal resistance of the battery to increase rapidly, resulting in poor output performance of the battery at low temperatures. 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: What types of batteries for new energy vehicles?