Influencing factors of low temperature characteristics of lithium iron phosphate batteries
Although compared with other rechargeable batteries, lithium iron phosphate batteries have great advantages in terms of cycle system service life and rechargeable battery multiples, but their characteristics are slightly reduced under low temperature standards. Therefore, improving and improving the low temperature characteristics of lithium iron phosphate batteries can more reasonably improve their competitiveness.
First, the positive electrode material of the battery selected in the lithium iron phosphate battery has a weak electronic device conductivity, which is very prone to electric polarization, thereby reducing the volume of the lithium ion battery.
Second, the negative level of the negative lithium-ion battery is very harmful to the low temperature battery charging, which will endanger the safety factor of the rechargeable battery.
3. Lithium-ion battery electrolyte Lithium iron phosphate battery under the low temperature standard, its internal lithium-ion battery electrolyte viscosity increases, which in turn improves the characteristic impedance of lithium-ion battery transfer.
Ways to improve and improve the low temperature characteristics of lithium iron phosphate batteries
1. The three elements of positive electrode particle size, resistance and resistance, from the perspective of the positive level of lithium iron phosphate rechargeable batteries, will harm the ultra-low temperature characteristics of rechargeable batteries. The low-temperature charge-discharge characteristics of lithium batteries can be improved according to the positive-stage production process. Increasing the length of the axis of the plan view can expand the transfer safety channel of the lithium-ion battery, which is beneficial to increase the volume of the rechargeable battery. According to the research, the low-temperature charge and discharge characteristics of lithium iron phosphate batteries can release 914 particles at minus 20 ℃, and the particle size is 100-200nm. discharge characteristics.
2. The negative electrode is more harmful to the lithium iron phosphate battery charged by the low temperature battery, and the key lies in the change of the negative electrode particle size and the negative stage interval. Human high-purity graphite is a battery cathode material with different layer spacing and particle size. The particle high-purity graphite layer with a large layer spacing has a slightly smaller characteristic impedance and positive ion transfer characteristic impedance from the antigen. Because the interval of the artificially synthesized high-purity graphite layer is enlarged and the particle size is reduced, the charging of the low-temperature constant-current power supply battery has a great improvement on the lithium iron phosphate battery.
3. When the temperature of lithium-ion battery electrolyte drops to minus 20°C or lower, the electrolyte of lithium iron phosphate battery is prone to freezing, viscosity increase, and deterioration of characteristics. Experiments show that the harm of organic solvents to the low temperature of rechargeable batteries varies from 70% to 90%, reaching more than a dozen points. In addition, different lithium salts also have certain harm to the battery charging characteristics. The experiment found that if only the preservative was changed, the low-temperature preservative could increase the charge-discharge capacity of the rechargeable battery from 8% to 90%.
The above exemplifies several aspects and key points for improving and enhancing the low-temperature characteristics of lithium iron phosphate batteries. The key is the composition of the internal raw materials of the rechargeable battery. In fact, in order to improve the characteristics of lithium iron phosphate batteries at lower temperatures rapidly and faster, not only should the internal composition of the rechargeable battery be improved, but also according to a variety of methods, such as rechargeable battery intelligent management systems, overall Circulation system, etc., to improve its high efficiency.