Introduction of ternary lithium battery and detailed explanation of charging times and life

Introduction of ternary lithium battery and detailed explanation of charging times and life

What is a ternary lithium battery?

Ternary lithium battery refers to a lithium secondary battery using three transition metal oxides of nickel, cobalt and manganese as positive electrode materials. 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 uses molecular level mixing, doping, coating and surface modification to synthesize nickel. Cobalt manganese and other multi-element synergistic composite lithium intercalation oxides. It is a lithium-ion rechargeable battery that has been widely researched and applied.

Ternary lithium battery life

The so-called lithium battery life means that after the battery has been used for a period of time, the capacity decays to 70% of the nominal capacity (the capacity of the battery at room temperature 25°C, standard atmospheric pressure, and the battery capacity discharged at 0.2C), which can be considered as the end of life. In the industry, the cycle life is generally calculated by the number of cycles of full discharge of lithium batteries. In the process of use, irreversible electrochemical reactions will occur inside the lithium battery, resulting in a decrease in capacity, such as the decomposition of the electrolyte, the deactivation of active materials, and the collapse of the positive and negative structures, resulting in a reduction in the number of lithium ions intercalated and deintercalated, etc. . Experiments have shown that a higher rate of discharge will lead to faster capacity decay, and 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 capable of 10,000 cycles. At present, mainstream battery manufacturers promise more than 500 times (charge and discharge under standard conditions) in their ternary battery specifications. The resistance cannot be exactly the same, and its cycle life is about 400 times.

The manufacturer recommends that the SOC use window is 10%~90%. It is not recommended to perform deep charge and discharge, otherwise it will cause irreversible damage to the positive and negative structure of the battery. If it is calculated by shallow charging and shallow discharging, 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.