What are the important factors that affect the low temperature performance of lithium-ion batteries

The factors that restrict the low-temperature performance of lithium batteries are as follows: ◆Positive structure The three-dimensional structure of the positive electrode material restricts the diffusion rate of lithium ions, and the effect is particularly clear at low temperatures. The cathode materials of lithium batteries include commercial lithium iron phosphate, nickel cobalt manganese ternary materials, lithium manganese oxide, lithium cobalt oxide, etc., as well as high-voltage cathode materials in the development stage such as lithium nickel manganese oxide, lithium iron manganese phosphate, Lithium vanadium phosphate, etc. Different cathode materials have different three-dimensional structures. The current cathode materials used as power lithium-ion batteries for electric vehicles are mainly lithium iron phosphate, nickel cobalt manganese ternary materials and lithium manganate. Wu Wendi and others studied the discharge performance of lithium iron phosphate batteries and nickel-cobalt-manganese ternary batteries at -20°C, and found that the discharge capacity of lithium iron phosphate batteries at -20°C can only reach 67.38% of the capacity at room temperature, while nickel-cobalt-manganese batteries The cell battery can reach 70.1%. Du Xiaoli and others found that the discharge capacity of lithium manganate batteries at -20°C can reach 83% of the capacity at room temperature. ◆High melting point solvents Due to the presence of high melting point solvents in the electrolyte mixed solvent, the viscosity of the lithium battery electrolyte increases in a low temperature environment. When the temperature is too low, the electrolyte solidification will occur, resulting in a decrease in the transmission rate of lithium ions in the electrolyte. ◆Lithium ion diffusion rate The diffusion rate of lithium ions in the graphite anode is reduced in a low temperature environment. Xiang Yu systematically studied the influence of graphite anode on the low-temperature discharge performance of lithium batteries, and proposed that the increase in charge transfer resistance of lithium batteries under low-temperature environments, resulting in a decrease in the diffusion rate of lithium ions in the graphite anode, is an important reason for affecting the low-temperature performance of lithium batteries. ◆Under the low temperature environment of SEI film, the SEI film of the negative electrode of the lithium battery becomes thicker, and the impedance of the SEI film increases, which causes the conduction rate of lithium ions in the SEI film to decrease. Finally, the lithium battery is charged and discharged in a low temperature environment to form polarization and reduce the charge and discharge efficiency. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Introduce Ni-MH battery charging methods and precautions