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What Are The Factors That Affect The Life Of Lithium Batteries?

Feb 05, 2021

How many life cycles are lithium batteries?

The basic theoretical life of ternary lithium battery is about 800 cycles, which belongs to the medium level among rechargeable lithium batteries of commercial value. Lithium iron phosphate is about 2000 cycles, while lithium titanate is said to be capable of 10000 cycles. 

At present, the mainstream battery manufacturers promise more than 500 times of service (charging and discharging under industry standard conditions) in the specifications of ternary cells produced by them. However, after the cells are assembled into battery packs, considering the consistency problem, the main reason is that the voltage and internal resistance are unlikely to be completely the same, and the cycle life is about 400 times. 

The manufacturer strongly recommends that the SOC use window is 10% ~ 90%. It is not recommended to conduct deep charge and discharge, otherwise it will cause irreversible damage to the positive and negative electrode structure of the battery. 

If it is estimated by shallow charge and shallow discharge, the cycle life is at least 1000 times. In addition, if lithium batteries are often discharged in high rate and continuous high temperature environment, the battery life will be greatly reduced to less than 200 times.

How long is the service life of polymer lithium battery?

According to international industry standards, battery life is not expressed in terms of duration, but in terms of cycle frequency, that is, complete discharge is calculated once. 

Generally, lithium battery is between 500 and 800 times, and product a polymer battery can achieve 800 times. Therefore, the quality of the battery products of the selected battery manufacturers will be guaranteed, and the service life will be longer.

The life of polymer lithium battery is closely related to its application performance. Polymer battery is also called polymer material battery. 

From the appearance design shape, the polymer battery is packaged with aluminum plastic shell, which is different from the metal shell of plasma lithium battery. 

The main reason why the aluminum-plastic shell can be used is that the polymer battery uses some colloidal substances to help the battery plate to fit or absorb electrolyte, thus greatly reducing the use of plasma electrolyte. 

With the improvement of structure design, the polymer battery has the advantages of high energy density, more intelligent and ultra-thin. Compared with the plasma lithium battery, the polymer battery has a longer life and can achieve at least 500 cycles.

Life of ternary lithium battery

The so-called lithium battery life refers to the battery after a period of use, the capacity loss is 70% of the nominal capacity (room temperature 25 ℃, standard atmospheric pressure, and 0.2C discharge battery capacity), you can feel the end of life. 

In the industry, the cycle life of lithium battery is usually estimated by the number of cycles of full charge and discharge. In the process of use, irreversible electrochemical reactions will occur in the lithium battery, which will lead to the reduction of capacity, such as the decomposition of electrolyte, the deactivation of active materials, the collapse of positive and negative structures, which will lead to the reduction of the total number of lithium ion intercalation and de intercalation, and so on. Scientific experiments show that higher discharge rate will lead to faster capacity loss. 

If the discharge current is lower, the battery voltage will be close to the balance voltage, and more energy can be released.