Briefly describe the influencing factors of battery life

Temperature can be said to be the most important influencing factor of lithium-ion batteries. It is also mentioned above that lithium-ion batteries are electrochemical power sources with complex electrochemical processes inside, and temperature is the determinant of the activity of most chemical reaction processes. At high temperatures, the electrochemical reaction is more active, and the battery has better performance, such as enhanced discharge capacity and reduced internal resistance. However, high temperature will aggravate the side reactions between the electrolyte and the anode and cathode materials, and accelerate the consumption of the electrolyte, the anode and cathode materials and lithium. This loss is permanent and will cause the battery capacity to attenuate and the internal resistance to increase. Contrary to low temperature and high temperature, the side reaction level is low, and the internal chemical activity of the battery is also reduced, and the single-point ability of the active material is also reduced. If this is the case with high current discharge, the electrode material will not meet the load requirements, which will cause the structure of the cathode material to be destroyed; low-temperature high-current charging, lithium ion evolution and dendrite growth problems may occur. 2. Overvoltage charging is one of the important reasons for the abnormal attenuation of lithium-ion batteries. The relationship between cycle life and charge cut-off voltage The figure above is the relationship curve between charge cut-off voltage and cycle life of a ternary lithium-ion cell. It is not difficult to find that the battery life caused by the voltage difference of 0.15V has a great impact. If the applied voltage is too high, higher than the voltage window that the electrolyte can withstand, it will aggravate the decomposition process of the electrolyte. The decomposition products also contain combustible gas and damage the conductivity of the electrolyte. As for the overvoltage charging, as for the battery anode, it is trying to pack too much lithium into its limited space, which may be squeezed, or the road may be blocked; while for the cathode, too much lithium is driven. As it leaves the anode lattice structure, the stability of the structure is affected, causing local collapse. Excessive lithium can not be inserted in the anode, it will be deposited on the surface of the electrode, forming dendritic growth. 3. Excessive current is divided into two types: excessive charging current and excessive discharging current. If the charging current is too large, charging is a process in which lithium is separated from the positive electrode lattice and inserted into the graphite layered structure. The rapid separation from the crystal lattice will impact the structural stability. If you want to quickly insert the anode, the diffusion rate cannot keep up, and lithium ions will appear. The simple substance is deposited on the surface of the anode. The loss of lithium during high-current charging and discharging is reflected in the life parameters, which are the attenuation of available capacity and the increase of charge and discharge resistance. The damage of the electrode structure leads to a loss of capacity. When the discharge current of the battery is too large, a large amount of lithium will pass through the SEI film in a short time, which may cause large-scale damage to the film structure, which will cause the old film to fall off, and then a large-scale repair process, which also consumes a lot of money. The process of lithium. A large amount of lithium comes to the cathode and wants to squeeze into the crystal lattice in a short time. If the diffusion speed cannot keep up, the channel will be blocked and the lattice structure will be impacted. The thermal effect brought by the large discharge current will further expand the influence range of the large current discharge. The heat dissipation capacity cannot keep up, the battery temperature rises too high, the decomposition of the electrolyte, and the melting of the separator may occur one after another. Therefore, the impact of the current on the life expectancy is not only the impact of lithium on the internal microstructure, but it is important to show through the use of heat. Therefore, the heat dissipation capacity of the battery system is different, and the same large current has very different effects on the life. 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 are the important applications of lithium-ion batteries?