Lithium iron Phosphate Batteries Advantages
Lithium iron phosphate batteries are characterized by high safety, high rate charge discharge characteristics and long cycle life. The literature shows that the charging condition is charged to 3.65V at 1C ratio, then the constant voltage to the current drop to 0.02C, then the 1C multiple discharge to the cut-off voltage 2.0V, after 1600 cycles, the battery capacity still has the initial capacity of 80%.
PS: Charge and discharge ratio = charge and discharge current / rated capacity; for example: rated capacity of 100 Ah battery with 20A discharge, its discharge ratio is 0.2C. Battery discharge C rate, 1C, 2C and 0.2C are battery discharge rates: a measure of discharge speed. The capacity is 1 hours after discharge, it is called 1C discharge, and the 5 hour discharge is called 1/5=0.2C discharge. In general, the capacity of the battery can be detected by different discharge currents. For 24AH batteries, the 2C discharge current is 48A and the 0.5C discharge current is 12A.
Lithium iron phosphate battery also has good fast charging characteristics, 3C rate charging conditions, 15 minutes can charge 55%, 30 minutes charge capacity more than 95%. Note that this is a laboratory condition, in addition to a single 20Ah, 3.65V nominal voltage single battery, and the car with 400V voltage 100Ah and above capacity of the battery group can not be compared with the two, the charge power of the two is more than a hundred times.
In addition to long life and excellent charging and discharging performance, the greatest advantage of lithium phosphate lithium battery is its safety, chemical properties of lithium phosphate, stable high temperature, high temperature stability, 700-800 C decomposition, and no oxygen molecules to be released in the face of impact, acupuncture, short circuit and so on. High performance.
However, the disadvantage of lithium iron phosphate battery is that its performance is greatly affected by temperature, especially in low temperature environment, discharge capacity and capacity will be greatly reduced. In addition, the energy density of lithium phosphate is low, only the weight and energy density of the battery is only 120Wh/kg. If the whole reactor is calculated, the energy density of the battery management system, heat dissipation and other parts will be lower. The "energy conservation and new energy auto industry development plan (2012-2020 years)" issued by the State Council clearly proposed that the demand for the energy density of the battery module is more than 150 watts per kilogram.