How many times is the life cycle of lithium battery?

With the society's emphasis on energy saving and environmental protection, more and more environmentally friendly products are widely used in the market. In the battery industry, lithium ternary batteries have rapidly occupied the market with its many advantages, and gradually replaced the traditional lead-acid batteries. Compared with traditional batteries, lithium ternary batteries have the advantages of long life,Battery recycling energy saving and environmental protection without pollution, low maintenance costs, complete charging and discharging and light weight. So, how long is the life of lithium ternary batteries?

First of all, let's understand what is a ternary lithium battery. In nature, lithium is a light metal, small atomic mass, its atomic weight is 6.94g/mol, density is 0.53g/cm3. lithium's chemical properties are active,cylindrical cell assembly machine it is very easy to lose electrons and be oxidized to Li+, so its standard electrode potential is negative, -3.045V, electrochemical equivalent of 0.26g/Ah. These characteristics of the element lithium make it a very high specific energy material. Ternary lithium battery refers to the use of nickel-cobalt-manganese three transition metal oxides as the cathode material of lithium secondary battery. It fully integrates the features of good cycling performance of lithium cobalt oxide, high specific capacity of lithium nickel oxide and high safety and low cost of lithium manganese oxide, and synthesizes the composite embedded lithium oxides of nickel, cobalt and manganese in synergy with other elements through molecular level mixing, doping, cladding and surface modification, etc. At present, ternary lithium battery is widely used as the anode material for lithium secondary batteries. At present, ternary lithium batteries are widely studied and applied as a kind of lithium-ion rechargeable battery.

Next, let's discuss the life of ternary lithium battery. The so-called lithium battery life refers to the battery after a period of time, the capacity decay for the nominal capacity (room temperature 25 ℃, standard atmospheric pressure,battery making machine and 0.2C discharge battery capacity) of 70%, can be considered as the end of life. The industry is generally based on the number of cycles of lithium batteries full of full discharge to calculate the cycle life. In the process of use, irreversible electrochemical reactions will occur within the lithium battery leading to a decrease in capacity, such as the decomposition of the electrolyte, deactivation of the active material, and the collapse of the positive and negative electrode structure leading to a decrease in the number of lithium ions embedded and de-embedded, and so on. Experiments have shown that a higher rate of discharge will lead to a faster capacity decay, while 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 Li-ion ternary batteries is about 800 cycles, which is medium level among commercialized rechargeable lithium batteries. The life of lithium iron phosphate batteries is about 2,000 cycles, while lithium titanate batteries are said to be able to reach 10,000 cycles. Currently the mainstream battery manufacturers in their production of ternary battery cell specifications committed to greater than 500 times (standard conditions of charge and discharge), but the battery cell in the formation of battery packs, due to consistency issues, mainly voltage and internal resistance can not be exactly the same, its cycle life of about 400 times. Manufacturers recommend a SOC use window of 10% to 90%, and deep charging and discharging is not recommended, or it will cause irreversible damage to the positive and negative structures of the battery. If you calculate with shallow charging and discharging, the cycle life is at least 1000 times. In addition, if lithium batteries are often discharged at high rates and high temperatures, the battery life will drop dramatically to less than 200 cycles.

The cycle times of lithium batteries are determined by the quality of the battery and the battery material:

The cycle times of ternary materials are about 800 times. The cycle times of lithium iron phosphate batteries are about 2500 times. There is a difference in the number of cycles between genuine and defective batteries. Genuine batteries are designed and produced according to the number of cycles in the battery manufacturer's specifications, while the number of cycles of defective batteries may sometimes be even less than 50.

In today's lithium battery market, the lithium ternary battery is one of the most widely used. In terms of performance, it is moderate; in terms of price, it is lower. Therefore, the use of ternary lithium batteries have a high cost-effective. People often say that ternary lithium batteries have a long life, so how long is its life? Ternary lithium polymer batteries are lithium batteries that use lithium nickel cobalt manganate (Li(NiCoMn)O2) ternary cathode material for the cathode material. The ternary composite cathode material precursor product is made of nickel salt, cobalt salt and manganese salt, of which the proportion of nickel cobalt and manganese can be adjusted according to actual needs. Batteries with ternary material as the positive electrode have higher safety compared to lithium cobalt acid batteries, but the voltage is lower, and when used in cell phones (the cut-off voltage of cell phones is usually around 3.4V) there will be an obvious feeling of insufficient capacity.

Finally, let's discuss the performance of Li-ion ternary battery. Ternary lithium batteries are more balanced materials in terms of capacity and safety, and their cycle performance is better than normal lithium cobaltate. For technical reasons, the nominal voltage of lithium ternary batteries in the early stage was only 3.5-3.6V, which limited their use. However, with the continuous improvement of the formula and structural perfection, the nominal voltage of lithium ternary battery has reached 3.7V, and has reached or exceeded the level of lithium cobalt acid battery in terms of capacity.