Life of ternary lithium battery Advantages and disadvantages of ternary lithium battery

Life of ternary lithium battery The so-called lithium battery life refers to the battery's capacity decay to 70% of the nominal capacity (the battery capacity at room temperature 25°C, standard atmospheric pressure, and 0.2C discharged at 0.2C) after a period of use, which can be considered as the life. termination. In the industry, the cycle life is generally calculated by the number of cycles of overflowing lithium batteries. In the process of use, an irreversible electrochemical reaction occurs inside the lithium battery, which leads to a decrease in capacity, such as the analysis of the electrolyte, the deactivation of active materials, the collapse of the positive and negative structures, and the decrease in the number of lithium ions intercalation and deintercalation, etc. . The test shows that a higher rate of discharge will lead to a faster attenuation of capacity. If the discharge current is lower, the battery voltage will be close to the equilibrium voltage and more energy can be released. The theoretical life of a ternary lithium battery is about 800 cycles, which is medium among commercial rechargeable lithium batteries. Lithium iron phosphate is about 2,000 cycles, while lithium titanate is said to be able to reach 10,000 cycles. At present, mainstream battery manufacturers promise more than 500 times (charge and discharge under standard conditions) in the specifications of their processed ternary cells. However, after the cells are assembled into a battery pack, due to consistency issues, the voltage and internal The resistance can not be exactly the same, and its cycle life is about 400 times. The manufacturer recommends that the SOC use window is 10%~90%. Deep charging and discharging are not recommended, otherwise it will cause irreversible damage to the positive and negative structure of the battery. If it is calculated by shallow charge and shallow discharge, the cycle life will be at least 1000 times. In addition, if lithium batteries are often discharged in high-rate and high-temperature environments, the battery life will be drastically reduced to less than 200 times. Advantages and disadvantages of ternary lithium battery The ternary lithium battery is more balanced in terms of capacity and safety, and is a battery with excellent overall performance. The important uses and advantages and disadvantages of the three metal elements are as follows: Co3+: Reduces the mixed cation space, stabilizes the layered structure of the material, reduces the impedance value, improves the conductivity, and improves the cycle and rate performance. Ni2+: It can increase the capacity of the material (increase the volume energy density of the material), and due to the similar radius of Li and Ni, too much Ni will also cause lithium and nickel to be mixed due to the dislocation phenomenon of Li, and the concentration of nickel ions in the lithium layer The larger the value, the more difficult it is to deintercalate lithium in the layered structure, resulting in poor electrochemical performance. Mn4+: Not only can reduce the cost of materials, but also can improve the safety and stability of the materials. However, an excessively high Mn content will easily form a spinel phase and destroy the layered structure, reducing the capacity and reducing the cycle. High energy density is the biggest advantage of ternary lithium batteries, and the voltage platform is an important indicator of battery energy density, which determines the basic efficiency and cost of the battery. The higher the voltage platform, the larger the specific capacity, so the same volume, weight, and even the same Ampere’s battery, the ternary material lithium battery with a higher voltage platform has a longer battery life. The discharge voltage platform of the single ternary lithium battery is as high as 3.7V, the lithium iron phosphate is 3.2V, and the lithium titanate is only 2.3V. Therefore, from the perspective of energy density, the ternary lithium battery is better than lithium iron phosphate, lithium manganate or Lithium titanate has absolute advantages. Poor safety and short cycle life are important shortcomings of ternary lithium batteries, especially safety performance, which has been an important factor that has always limited their large-scale matching and large-scale integrated applications. A large number of actual measurements stated that it is difficult for ternary batteries with larger capacity to pass safety detections such as acupuncture and overcharge. This is the reason why more manganese elements are generally introduced in large-capacity batteries, or even mixed with lithium manganate. The cycle life of 500 times is in the middle of the lithium battery, so the most important application of the ternary lithium battery is 3C digital and other consumer electronic products. 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 does a good lithium-ion battery look like?