What effect does low temperature have on the performance of lithium iron phosphate batteries?

The impact of low temperature on lithium iron phosphate batteries At present, lithium iron phosphate batteries are the most widely used battery in electric vehicles. They are safe and have a long life, but lithium iron phosphate has a fatal disadvantage: its low temperature performance is slightly worse than other technical systems. Low temperature has a certain effect on the positive and negative electrolytes and binders of lithium iron phosphate. For example, the conductivity of the lithium iron phosphate positive electrode itself is very poor. Under the influence of low temperature, the rate at which graphite inserts lithium is reduced, and the metal lithium on the negative surface is short-lived. If there is no time to put into use after the charge, the lithium metal cannot be completely embedded in the graphite, and a part of the metal lithium continues to exist on the negative surface, and it may form lithium Dendrites affect the safety of the battery; at low temperatures, the electrolyte viscosity increases, and the lithium ion removal resistance increases. In addition, in the processing of lithium iron phosphate, the adhesive is also a very critical element, and low temperature will also have a greater impact on the function of the adhesive. The impact of low temperature on lithium titanate batteries is also lithium batteries, and lithium titanate batteries have better low temperature resistance. The lithium potential embedded in the spinel structure of the lithium titanate cathode material is about 1.5V, which does not form lithium dendrites, and the volumetric strain during charge and discharge is less than 1%. Nano lithium titanate battery can be charged and discharged with high current, and charged quickly at low temperature, which ensures the durability and safety of the battery. Yinlong New Energy, which is based on lithium titanate batteries, has normal charge and discharge capabilities at -50-60°C. Lithium titanate battery has the material advantage of low temperature and fast charging, which is difficult for other batteries. Why charge more temperature than discharge? Many companies' battery products can be discharged normally at low temperatures, but at the same temperature, it is difficult to charge normally, or even unable to charge. When Li+ is embedded in the graphite material, the first thing to do is to dissolve it. This process consumes a certain amount of energy to prevent Li+ from being dispersed in the graphite. In contrast, there is a solvation process for Li+ entering the solution from the graphite material, and the solvation process does not consume energy, so Li+ can quickly come out of the graphite. Therefore, the charge acceptability of graphite materials is significantly lower than the discharge acceptability. At low temperatures, there is a certain risk of battery charging. Because as the temperature decreases, the dynamic characteristics of the graphite anode have changed. During the charging process, the electrochemical polarization of the negative electrode is significantly enhanced. The separated metallic lithium temporarily forms lithium dendrites, which break through the diaphragm and cause a short circuit between the positive electrode and the negative electrode. Prevent charging lithium batteries at low temperatures. When the battery must be at a lower temperature, it is necessary to choose a small current (ie slow charging) rechargeable lithium battery, and the position after the lithium battery is charged, and then ensure that the metal lithium negative electrode reacts to separate the graphite, and the graphite negative electrode is embedded in the beginning. Industrial companies and scientific research institutions have conducted research and research on the low-temperature resistance of batteries. Most of them have focused on the improvement of the existing positive and negative material technologies, and the positive ambient temperature of the battery has been tested at low temperature. Work under conditions. With the further development of this technology, lithium batteries will have further breakthroughs in low temperature environments. 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: 3C Lithium-ion battery certification process and test solutions