How long is the true cycle life of ternary lithium battery?

　With the promotion of social energy conservation and environmental protection, more and more environmentally friendly products have been applied to the market. In the battery industry, the ternary lithium battery quickly occupied the market with numerous advantages and gradually replaced the traditional lead-acid battery. For conventional batteries, ternary lithium battery has a long life, energy saving and pollution-free, low maintenance cost, fully charge and discharge, light weight and so on edge, always said three yuan lithium long battery life, long and to what extent?

　Ternary lithium battery

　What is a ternary lithium battery?

　In nature, lithium is a light metal with a small atomic mass*, its atomic weight is 6.94g/mol, ρ=0.53g/cm3. Lithium is chemically active, and it is easy to lose electrons to be oxidized to Li+. Therefore, the standard electrode potential is negative, -3.045V, and the electrochemical equivalent * is small, 0.26g/Ah. These characteristics of lithium determine that it is a kind of Very high energy material. The ternary lithium battery refers to a lithium secondary battery using three kinds of transition metal oxides of nickel, cobalt and manganese as a positive electrode material. It fully integrates the good cycle performance of lithium cobaltate, the high specific capacity of lithium nickelate and the high safety and low cost of lithium manganate. It synthesizes nickel by molecular level mixing, doping, coating and surface modification. A multi-element synergistic composites with lithium intercalation oxide, such as cobalt manganese. It is a lithium ion rechargeable battery that has been widely studied and applied.

　The life of the ternary lithium battery is the life of the

　It means that after the battery has been used for a period of time, the capacity is reduced to 70% of the nominal capacity (room temperature 25 ° C, standard atmospheric pressure, and battery capacity discharged at 0.2 C). In the industry, the cycle life is generally calculated by the number of cycles in which the lithium battery is fully charged. During the process of use, irreversible electrochemical reactions occur inside the lithium battery, resulting in a decrease in capacity, such as decomposition of the electrolyte, deactivation of the active material, collapse of the positive and negative structures, and reduction in the number of lithium ion insertion and deintercalation. Experiments have shown that higher rate discharges result in faster attenuation 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 a ternary lithium battery is about 800 cycles, which is medium in commercial rechargeable lithium batteries. lithium iron phosphate is about 2000 times, and lithium titanate is said to reach 10,000 cycles. At present, the mainstream battery manufacturers promise more than 500 times in the ternary battery specifications produced by them (charge and discharge under standard conditions), but after the batteries are assembled into battery packs, due to consistency problems, mainly voltage and internal The resistance cannot be exactly the same, and its cycle life is about 400 times. The manufacturer recommends that the SOC use window be 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 a high rate and high temperature environment, the battery life will be greatly reduced to less than 200 times.