1. Increased viscosity of electrolyte
The electrolyte of lithium battery consists of carbonate organic solvent and lithium hexafluorophosphate solute, under the low temperature condition, the viscosity of electrolyte increases, and the diffusion speed of lithium ion in electrolyte slows down, resulting in the decline of battery performance.
2. The compatibility between the electrolyte and the negative electrode and diaphragm deteriorates
In the low temperature environment, the compatibility between the electrolyte and the anode, diaphragm deteriorates, which affects the transmission of lithium ions and the performance of the battery.
3. Reduced reversibility of active substances
Under low temperature, the reversibility of the active substance of the lithium battery decreases, which means that the efficiency of the battery in the charging and discharging process decreases, leading to a reduction in battery capacity.
4. Reduced internal diffusion system of active substances
In low temperature environment, lithium ion battery in the active material internal diffusion system is reduced, charge transfer impedance (Rct) increases significantly.This means that the resistance of lithium ions to move inside the active substance increases, leading to a reduction in the capacity of the battery.
5. Increased resistance of the battery diaphragm
The diaphragm of a lithium battery becomes stiffer at low temperatures, leading to an increase in the resistance of lithium ions to pass through the diaphragm, which also affects the performance of the battery.
6. Decrease in thermal stability of battery components
At low temperatures, the thermal stability of the battery components decreases and the internal temperature of the battery is more likely to rise.Excessive temperatures can negatively affect the performance of the battery.
7. Negative electrode precipitation of lithium
At low temperatures, lithium precipitation from the negative electrode of lithium-ion batteries is severe, and the precipitated lithium metal reacts with the electrolyte, and the deposition of its products leads to an increase in the thickness of the solid electrolyte interface (SEI).This affects lithium ion transport and battery performance.
8. Lithium-ion batteries at low temperature lithium ion dispersion impedance increases
This is one of the important factors affecting the low-temperature performance of lithium-ion batteries, at low temperatures, lithium-ion diffusion impedance in the electrolyte increases, resulting in lithium-ion transport speed slows down, thus affecting the capacity of the battery.
