How many times is the lithium battery life cycle? With the promotion of social energy conservation and environmental protection, more and more environmental protection lithium battery are applied to the market. In the battery industry, lithium battery quickly occupied the market with many advantages, and gradually replaced the traditional lead-acid battery. For traditional batteries, lithium batteries have the advantages of long service life, energy conservation, environmental protection, no pollution, low maintenance cost, complete charge and discharge, light weight and so on. How long is the service life of lithium batteries?
Types of lithium batteries
In the market, there are two two types of lithium batteries on the market- NCM battery and LFP battery
NCM battery means NiCoMn ternary lithium battery.
LFP battery means LiFePO4 lithium battery.
What is the difference between NCM battery and LFP battery?
In fact, ternary lithium and lithium iron phosphate batteries are not absolutely good or bad, but each has its own merits. Among them, lithium iron phosphate also has advantages in two aspects. One is high safety, because the thermal runaway temperature of lithium iron phosphate batteries is generally more than 500 degrees, that of ternary lithium batteries is less than 300 degrees, and that of some high nickel batteries is even less than 200 degrees. In contrast, lithium iron phosphate batteries have a low risk of spontaneous combustion during high-speed driving and rapid charging;
Second, the cycle life is longer, because the lithium iron phosphate battery begins to decay after the number of charge and discharge cycles is greater than 2000, that is, its service life can be up to about 10 years, but the number of charge and discharge cycles of ternary lithium battery is only 1000, which means that its service life is only 3 years, which shows the gap between the two;
However, the advantages of ternary lithium battery lie in energy storage density and low temperature resistance. Firstly, in terms of energy storage density, ternary lithium battery can basically reach 240wh / kg because of its high voltage, which is almost 1.7 times that of lithium iron phosphate battery 140wh / kg
At the same time, compared with NCA (nickel cobalt aluminum) and NCM (nickel cobalt manganese), NCA has better performance. However, due to the low temperature of thermal runaway, high requirements for manufacturing process, high cost and technology in the hands of Japanese and Korean car enterprises, NCM batteries are mainly developed in China. At present, they are divided into 111, 523, 622 and 811 according to the proportion of ternary materials, Among them, 881 high nickel battery has become the key breakthrough direction, because it is the key to improve the energy density of the cell;
Secondly, in terms of low temperature resistance, the lower limit of low temperature use of ternary lithium battery is minus 30 degrees, which is more advantageous than the lower limit of low temperature of lithium iron phosphate battery of minus 20 degrees. At the same time, under the same low temperature conditions, the attenuation of ternary lithium battery in winter is less than 15%, significantly higher than that of lithium iron phosphate battery of more than 30%, which is more suitable for the northern market. This is why BYD sells well in the south, However, it is difficult to open the market in the north. In order to adapt to the low-temperature environment, Keheng has developed a low-temperature lithium iron phosphate battery. Under the extreme low temperature, the battery can also operate normally, effectively making up for this short board.
What is NCM lithium battery? How long is the service life of ternary lithium battery?
In the battery industry, ternary lithium battery quickly occupied the market with many advantages, and gradually replaced the traditional lead-acid battery. For traditional batteries, ternary lithium batteries have the advantages of long service life, energy conservation, environmental protection, no pollution, low maintenance cost, complete charge and discharge, light weight and so on. How long is the ternary lithium battery?
In nature, lithium is the lightest metal with the smallest atomic mass. Lithium has active chemical properties, easily loses electrons and is oxidized to Li +, the standard electrode potential is -3.045v and the electrochemical equivalent is 0.26g/ah. These characteristics of lithium determine that it is a material with high specific energy. Ternary lithium battery refers to a lithium secondary battery using three transition metal oxides of nickel, cobalt and manganese as cathode materials. It fully integrates the good cycle performance of lithium cobalt oxide, the high specific capacity of lithium nickel oxide 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 coordinated composite lithium intercalation oxides. It is a kind of lithium-ion rechargeable battery widely studied and applied at present.
The theoretical life of ternary lithium battery is about 1000 cycles, which is medium in commercial rechargeable lithium battery. Lithium iron phosphate has about 2000 cycles, while lithium titanate is said to have 10000 cycles. At present, the mainstream battery manufacturers promise more than 500 times (charge and discharge under standard conditions) in the specification of ternary cell produced by them. However, after the cell is assembled into a battery pack, due to the consistency problem, the main reason is that the voltage and internal resistance cannot be exactly the same, and its cycle life is about 800 times. The manufacturer recommends that the SOC service window is 10% ~ 90%, and deep charge and discharge is not recommended, otherwise irreversible damage will be caused to the positive and negative electrode structure of the battery. If calculated by shallow charge and shallow discharge, the cycle life will be at least 1000 times. In addition, if lithium batteries are often discharged in high rate and high temperature environment, the battery life will be significantly reduced to less than 200 times.
What is LFP lithium battery? How long is the service life of lithium iron phosphate battery?
Lithium iron phosphate battery: refers to a lithium-ion battery that uses lithium iron phosphate as the positive electrode material. The characteristic of this type of battery is that it does not contain precious metal elements (such as cobalt, etc.). Because it does not contain precious metal materials, the raw material cost of lithium iron phosphate battery packs can be compressed very low. In actual use, lithium iron phosphate battery has the advantages of high temperature resistance, strong safety and stability, low price and better cycle performance.
When the quality of the lithium iron phosphate battery is relatively good, the attenuation can be controlled within 5% in the first year and within 10% in the second year. For the ternary lithium battery type, the decline is 7-10% in the first year and 20-25% in the second year. Of course, the details are also related to the usage load and usage frequency. This is just a general expression.
Lithium iron phosphate battery packs have longer cycle life than lead-acid batteries and ternary lithium batteries. The “long life” of the lead-acid battery is only about 300 times; the ternary lithium battery theoretically can reach 2000 times, and the capacity will be reduced to 60% when it is actually used about 1000 times; and the true life of the lithium iron phosphate battery is 2000 times. , There is still 95% capacity at this time, and its conceptual cycle life reaches more than 3000 times.
lithium battery life
The number of life cycles of lithium batteries is determined according to the battery quality and battery materials:
- The cycle times of ternary materials are about 1000 times.
- The cycle times of lithium iron phosphate battery are about 2000 times.
- There is a difference between the cycle times of genuine batteries and defective batteries. Genuine batteries are designed and produced according to the cycle number