Lithium iron phosphate lithium battery

Lithium iron phosphate has recently heated up rapidly in the lithium battery industry. The main reason is that BYD Wang Chuanfu said in public that one of the company's main development paths in the future will be the lithium iron manganese phosphate route. Compared with the original lithium iron phosphate, the voltage of the discharge platform increased from 3.4V to 4.1V, and the energy density increased by 21%. The production technology is similar to lithium iron phosphate, and the raw material cost is relatively low. May be a better choice for the future.

The compaction density (2.3) of lithium iron manganese phosphate is lower than that of the ternary material (3.4). Therefore, from the final energy density index of the battery, lithium iron manganese phosphate is still inferior to the ternary material, but can be mixed with the ternary material. Matching, on the one hand to increase the safety of the battery, on the other hand, to achieve higher energy density, may be an important development direction in the future.

The advantages of lithium iron manganese phosphate are outstanding: First, it is convenient for battery management. The electrode potential of lithium iron phosphate material relative to Li+/Li is 4.1V, while lithium manganese phosphate has two voltage platforms. The high voltage platform can increase the voltage of the battery, and the low voltage platform can judge the remaining capacity of the battery. Provides a simple solution for battery capacity management. The second is high cycle performance. Compared with the 500 cycle life of ternary materials, the cycle life of lithium manganese iron phosphate is 2000 times. The third is high bulk density. Small particles of lithium manganese iron phosphate can be filled into the voids of the large particle ternary material to increase the bulk density of the positive electrode material. At the same time, it has an energy density increase of 20% compared to the first generation lithium iron phosphate material. The fourth is high security.

Lithium iron phosphate retains the thermal stability of the phosphate cathode material and greatly improves the safety of the power battery. The fifth is low cost. Because the price of lithium manganese iron phosphate is relatively low, the cost of the cathode material can be reduced by 30% after large-scale production. Finally, the low temperature performance is excellent, and the nanometer manganese iron iron material is nanometer, and the discharge capacity of -20 degrees can reach 80% of the normal temperature discharge capacity.

Lithium iron phosphate makes higher demands on the electrolyte. Because the voltage of lithium iron manganese phosphate is 4.1V, it is necessary to develop a special electrolyte for lithium iron phosphate. It is necessary to withstand high pressure and to inhibit the dissolution of Mn, and it is difficult to take into account low temperature performance.

At present, there are no enterprises in the world that have large-scale production capacity of lithium iron manganese phosphate. Only Phostech and Osaka Cement have achieved pilot-scale small-scale production.