How to improve the low temperature performance of lithium iron phosphate battery pack?

As for the positive electrode, it is now all nanocrystalline. Its particle size, resistance, and AB plane axis length will affect the low temperature characteristics of the entire battery. Different processes have different effects on the positive electrode. Lithium iron phosphate batteries with a particle size of 100~200nm have good low-temperature discharge characteristics, and can release 94% of the electricity at -20°C. In other words, nano-sized lithium iron phosphate can shorten the migration path and improve low-temperature discharge performance, because the discharge of lithium iron phosphate is importantly related to the positive electrode. Taking into account the negative charging characteristics of lithium batteries, low-temperature charging of lithium batteries is mainly affected by the negative electrode, including changes in the size of the negative electrode and the gap between the negative electrodes. Three different types of artificial graphite were selected as negatives, and the effect of different interlayer spacing and particle size on low-temperature characteristics was studied. Among the three materials, the bulk resistance and ion migration resistance of granular graphite are smaller than those of granular graphite with larger interlayer spacing. In terms of charging, the problem of low-temperature degradation of lithium battery packs in winter is not serious, and low-temperature charging is important. In terms of cross-flow ratio, the cross-flow ratio of 1C or 0.5c is very critical, and it takes a long time to reach a constant pressure. By improving the comparison of three different types of graphite, it is found that with the increase of the interlayer spacing and the decrease of the particle size, the constant current ratio of one of the three types of graphite has been greatly improved, from 40% to more than 70%. The electrolyte freezes at -20 degrees and -30 degrees, which increases the viscosity and deteriorates the performance of the formation. The electrolyte is divided into three aspects: solvent, lithium, and additives. The influence of solvents on low-temperature packaging of lithium iron phosphate batteries is more than 70% to 90%. Secondly, different lithium salts have a certain impact on low-temperature charge and discharge characteristics. We fixed the solvent system and lithium base, and low-temperature additives can increase the discharge capacity from 85% to 90%. That is to say, in the entire electrolyte system, solvents, lithium and additives have a certain effect on the low-temperature characteristics of our power lithium-ion batteries. The impact of other material systems. As for the adhesive, the charging and discharging at 20 degrees, the two types of points exceeding 70-80 after the cycle, the current binding of the entire plate fails, and the use of linear adhesives will not have this problem . The whole system, from the positive and the negative, the improved binder of the electrolyte, and the lithium iron phosphate battery monomer do good results, one is the charging characteristics, the temperature of 20, 30, and 40 degrees is 0.5 degrees Celsius and the constant current charging rate can reach 62.9%. 94%, 20 degrees lower temperature can release electricity, which is better than some characteristic cycles. 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: Analysis of regulations on carrying lithium batteries in civil aviation passengers’ luggage