Lithium-ion batteries have been widely used in various fields as a green energy source, but their poor low temperature performance limits their application in special fields such as special, aerospace and special fields. Generally, when the temperature drops to -10°C, the discharge capacity and operating voltage of the lithium-ion battery will decrease.
It is well known that temperature has a very important impact on the performance of lithium-ion batteries. When the temperature is too low, due to the increase in the viscosity of the electrolyte, the resistance of the SEI film increases, and the kinetic performance of the graphite anode deteriorates, which will lead to an increase in the electrochemical polarization of the battery. , which greatly reduces the battery discharge capacity. For example, an electric vehicle that can travel 105 miles at 23.9°C can only travel about 60 miles at -6.7°C.
At the same time, low temperature charging is very dangerous, which will lead to the appearance of lithium dendrites and cause serious safety problems.
At low temperatures, the viscosity of the electrolyte decreases. As the conductivity decreases, the activity of the active material also decreases. The concentration difference of the electrolyte will become larger, the polarization will be enhanced, and the charging will be terminated in advance. More importantly, the diffusion rate of lithium ions in the carbon anode will be slower. Lithium is easily precipitated. As the temperature decreases, the reaction rate of the electrode also decreases.
