What is the basis for the number of life cycles of lithium batteries?

3. There is a difference in the number of cycles between genuine batteries and defective batteries. The cycle number of a genuine battery is designed and produced according to the cycle number in the battery manufacturer's manual, while the cycle number of a defective battery can be less than 50 times. Life of ternary lithium-ion battery The so-called lithium-ion battery life refers to the battery's capacity decay after a period of time, which is 70% of the nominal capacity (room temperature 25℃, standard atmospheric pressure, 0.2C discharge battery capacity), which can be considered as the end of the battery life. Generally speaking, the cycle life of a lithium-ion battery is calculated based on the number of cycles of full discharge. In the process of use, an irreversible electrochemical reaction occurs inside the lithium-ion battery, resulting in a decrease in output, such as the decomposition of electrolyte, the deactivation of active materials, and the collapse of the positive and negative electrode structure, resulting in a decrease in the number of lithium ions inserted and embedded. ,and many more. Experiments show that the higher the discharge rate, the faster the capacity decay. If the discharge current is low, the battery voltage will be close to the equilibrium voltage, releasing more energy. The theoretical life of a ternary lithium-ion battery is about 800 times, which is at a medium level among commercial rechargeable lithium-ion batteries. Lithium iron phosphate has about 2,000 cycles, while lithium titanate is said to have 10,000 cycles. At present, mainstream battery manufacturers promise 500 times (charge and discharge under standard conditions) in their ternary battery specifications. However, due to consistency issues, the important thing is that the voltage and internal resistance cannot be exactly the same. The cycle life is about 400 times. The manufacturer recommends that the SOC use window is 10%~90%, and deep charging and discharging is not recommended, otherwise it will cause irreversible damage to the positive and negative structure of the battery. If the battery is calculated by light charging and light discharge, then the cycle life of the battery is at least 1000 times. In addition, if lithium-ion batteries are often exposed to high-power and high-temperature environments, the battery life will be significantly reduced to less than 200 times. 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: Five Tips to Extend the Life of Lithium Battery