Lithium iron phosphate battery is greatly affected by temperature, so thermal management is needed to improve the efficiency of the battery.Lithium iron phosphate battery is promising in the new energy industry, the battery cycle life can reach about 3000 times, stable discharge, is widely used in power batteries and energy storage and other fields.
What effect does temperature have on lithium iron phosphate batteries?
Lithium iron phosphate battery charging is a process in which lithium ions are removed from the positive electrode and embedded into the negative electrode material through electrolyte migration. Lithium ions polymerize to the negative electrode and one lithium ion is captured by six carbon atoms.At low temperature, chemical reaction activity decreases and lithium ion migration slows down. Lithium ions on the negative electrode surface have not been embedded in the negative electrode, but have been reduced to lithium metal, and lithium dendrites are precipitated on the negative electrode surface, which is easy to puncture the membrane and cause short circuit in the battery, thus damaging the battery and causing safety accidents.
Low temperature has influence on anode and cathode, electrolyte and adhesive of lithium iron phosphate battery.For example, the anode of lithium iron phosphate battery itself has poor electron conductivity, and it is easy to generate polarization at low temperature, thus reducing the battery capacity. Affected by low temperature, the speed of graphite lithium, easy to precipitate metal lithium on the surface of the negative electrode, if the charge after shelve time is not enough to put into use, metal lithium can not be re-embedded into the graphite, part of the metal lithium continued to exist on the surface of the negative electrode, it is very likely to form lithium dendrites, affecting the safety of the battery.
At low temperature, the viscosity of electrolyte will increase, and the resistance of lithium ion migration will also increase. In addition, in the production process of lithium iron phosphate battery, adhesive is also a very critical factor, low temperature will have a great impact on the performance of adhesive. Not only that, the lithium iron phosphate battery charging at low temperatures, lithium ion may be too late to embed graphite anode, thereby precipitate in the cathode surface metal lithium dendrite formation, the reaction will consume can be repeated charge and discharge of the lithium ion battery, and greatly reduce the battery capacity, the precipitation of metallic lithium dendrite may puncture the diaphragm, which affect the safety performance.