What is the difference between LiFePO4 and Ternary lithium battery
In today's power battery market, mainly lithium iron phosphate batteries and ternary lithium batteries. The main characteristics of the two are the difference between energy density and safety. Energy density is related to the endurance of power batteries. Safety is also one of the most important indicators of power lithium batteries. Let’s compare the differences between the two batteries.
1. Energy density
From the current technology point of view, the energy density of ternary lithium batteries is generally 200Wh/kg, and may reach 300Wh/kg in the future; while lithium iron phosphate batteries are currently 130~150Wh/kg, but it is very difficult to break through 200Wh/kg.
As far as the material system is concerned, the decomposition temperature of the positive electrode material of the ternary lithium battery is around 200°C, and the decomposition temperature of the positive electrode material of the lithium iron phosphate battery is around 700°C. In the laboratory test environment, short-circuit lithium iron phosphate battery cells basically do not catch fire, and the chemical reaction of ternary lithium materials is particularly strong. However, ternary lithium batteries have better low-temperature resistance and are the main reason for manufacturing low-temperature lithium batteries. Technical route. At minus 20°C, the ternary lithium battery can release 70.14% of the capacity, while the lithium iron phosphate battery can only release 54.94% of the capacity.
3. Charging efficiency
Ternary lithium batteries are even higher. Lithium battery charging adopts current limiting and voltage limiting method, that is, constant current charging is performed in the first stage, at this time, the current is large and the efficiency is high. After the constant current charging reaches a certain voltage, it enters the second stage of constant voltage charging. At this time, the current is small and the efficiency is low. Therefore, to measure the charging efficiency of the two, the ratio of the constant current charging power to the total battery capacity is called the constant current ratio. The experimental data shows that there is little difference between the two when charging under 10C, but the distance above 10C will increase the distance. When charging at 20C, the constant current ratio of the ternary lithium battery is 52.75%, and the constant current ratio of the lithium iron phosphate battery is 10.08 %, the former is 5 times that of the latter.
4. In terms of cycle life
The lithium iron phosphate battery is better than the ternary lithium battery. The theoretical life of the ternary lithium battery is 2000 times, but basically, the capacity decays to 60% after 1000 cycles; while the lithium iron phosphate battery goes through the same cycle cycle, and 80% capacity.
Conclusion: Lithium iron phosphate battery is safe, long life and high temperature resistance; ternary lithium battery is light in weight, high charging efficiency, and low temperature resistance.