An important reason for the decrease in discharge capacity of lithium batteries at low temperatures

The important reasons for the decrease in the capacity of lithium batteries at low temperatures include: poor electrolyte conductivity, poor wettability and/or permeability of the separator, slow lithium ion migration, and slow charge transfer at the electrode/electrolyte interface. In addition, the impedance of SEI increases at low temperatures, which slows down the speed of lithium ions through the electrode/electrolyte interface. The reason for the new SEI impedance is that lithium ions easily escape from the negative electrode at low temperatures and are difficult to insert. When charging, metal lithium will appear and react with the electrolyte, forming a new SEI film covering the original SEI film, adding the impedance of the battery, resulting in a decrease in battery capacity [19]. Li Lianxing et al. [20] conducted 300 charge-discharge cycle experiments on the same batch of lithium batteries at 60°C and room temperature, respectively. In the initial stage, the battery showed a higher discharge capacity at 60°C. However, with the development of cycles, battery capacity decays faster, cycle stability decreases, and battery swelling may even occur in the later stage. At high temperatures, the charge-discharge cycle of lithium batteries is unstable. The high temperature causes the electrochemical polarization of the battery electrodes to increase, the appearance of gas, and the bulging phenomenon. At the same time, the charge transfer resistance increases, and the kinetic performance of ion transfer decreases. Devices using lithium batteries may be subject to vibration, shock, shock, and other tests during transportation or normal operation. Some lithium batteries charge and discharge when communicating with the system, and receive data information according to a certain frequency. The frequency when the device vibrates may interfere with the frequency of the battery, causing chip data errors or triggering the protection circuit action [22]. The electrode ears, external wires, terminals, solder joints, etc. of lithium batteries will break or fall off under strong vibration or impact, and the active materials on the battery electrodes will also fall off, which will affect the battery life and even cause dangerous situations. The impact of the charging and discharging system during the cycle The process of using lithium batteries is a process of charging and discharging cycles. The charging and discharging system, such as the size of the charging and discharging current, the selection of the charging and discharging cut-off voltage, the charging and discharging method, etc., also have a very important influence on the cycle life of the lithium battery. Blindly adding the operating current of the battery, adding the charging cut-off voltage, and reducing the discharge cut-off voltage will reduce the performance of the battery. Conclusion Through analysis, it can be seen that there are many factors that affect the cycle life of lithium batteries during the design, manufacture and use of lithium batteries. The application of lithium batteries is becoming more and more extensive, and the requirements for the quantity and quality of lithium batteries are getting higher and higher. The cycle life directly affects the service time and quality of lithium batteries. Only by grasping the various factors that affect the life cycle in the process of Ru0026D and processing, the company can occupy an active position in the fierce market competition. Consumers should pay attention to the characteristics of lithium batteries during use, and use the batteries correctly according to the instructions. 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: Will the lithium iron phosphate battery be replaced by ternary?