As the cruising range of new energy vehicles is limited, how to improve the battery life affects the entire market. In the battery industry, the ternary lithium battery quickly occupied the 3C, automotive and other markets with many advantages, and gradually replaced the traditional lead acid. Battery. For traditional batteries, ternary lithium battery has long life, energy saving, no pollution, low maintenance cost, complete charge and discharge, light weight, etc. In some publicity materials, some people think that ternary lithium battery has long life. Is this really true? How many times does its life cycle cycle? Let us uncover the truth.
What is a ternary lithium battery?
In nature, lithium is the lightest, the smallest atomic metal, lithium is chemically active, easily lost electrons are oxidized to Li+, standard electrode potential is -3.045V, electrochemical equivalent is 0.26g/Ah, lithium element These characteristics determine that it is a material with a very high specific energy. The ternary lithium battery refers to a lithium secondary battery using nickel, cobalt and manganese three transition metal oxides as a positive electrode material. It is fully integrated with lithium cobaltate. Cyclic performance, high specific capacity of lithium nickelate, high safety and low cost of lithium manganate, synthesis of multi-element complex of nickel, cobalt and manganese by molecular level mixing, doping, coating and surface modification Lithium intercalation oxide is a lithium ion rechargeable battery that has been widely studied and applied.
Theoretical life is only moderate
The life of the ternary lithium battery is calculated after the use of a certain degree, the proportion of capacity attenuation, directly to the end of the capacity life is zero. The industry algorithm is generally ternary lithium battery discharged after full charge, this is called cycle life. In use During the process, irreversible chemical reactions inside the lithium battery may cause a decrease in battery capacity, such as improper use, or use at extremely high or very low temperatures. For example, decomposition of the electrolyte, deactivation of the active material, structure of the positive and negative electrodes The collapse caused a reduction in the number of lithium ion insertion and deintercalation, etc. Experiments have shown that higher rate discharges lead to faster decay of the capacity. If the discharge current is lower, the battery voltage will approach the equilibrium voltage and release more energy. .
The theoretical life of the ternary lithium battery is 1200 times full charge and discharge, which is the complete cycle life. According to the frequency of use, it is fully charged and discharged once every three days, and fully charged and discharged 120 times a year. The service life of the ternary lithium battery reaches ten years. Even if there is loss during use or the number of days of charge and discharge is reduced, it can reach eight years. Note that here is the capacity life. After eight years, the capacity of the ternary lithium battery will still be more than 60%. This is the standard. Sex.
The theoretical life of a ternary lithium battery is medium in commercial rechargeable lithium batteries. Lithium iron phosphate is about 2,000 times, and lithium titanate is said to reach 10,000 cycles. Currently mainstream battery manufacturers are producing three of them. In the specification of the cell, the promise is more than 500 times (charge and discharge under standard conditions), but after the battery is assembled into a battery pack, due to the consistency problem, the voltage and internal resistance are not exactly the same, and the cycle life is about 400 times. The manufacturer recommends SOC use window of 10%~90%. It is not recommended to carry out deep charge and discharge. Otherwise, it will cause irreversible damage to the positive and negative structures of the battery. If it is calculated by shallow charge and shallow release, the cycle life is at least 1000 times. In addition, if the lithium battery is often discharged in high-rate and high-temperature environments, the battery life will drop significantly to less than 200 times.
