How will the performance of polymer lithium batteries be affected at low temperatures
How will the performance of polymer lithium batteries be affected at low temperatures
1, capacity attenuation
At low temperatures, the viscosity of the electrolyte of the polymer lithium battery will increase. It‘s like when a liquid gets thicker at low temperatures. The ionic conduction rate of the electrolyte slows down, making it difficult for ions to move around inside the battery. For example, at normal temperatures, ions can shuttle smoothly between positive and negative electrodes to ensure the normal charging and discharging process of the battery, but at low temperatures, ion movement is blocked, resulting in a decrease in the output capacity of the battery. In general, when the temperature drops below 0 ° C, the capacity of the battery will begin to decay significantly, and the lower the temperature, the more severe the capacity decay.
2, the discharge capacity is reduced
Low temperature will affect the discharge platform of the battery. The discharge platform refers to the stage in which the voltage of the battery remains relatively stable when a certain current is discharged. At low temperatures, the discharge platform of the battery will drop, resulting in a reduction in the voltage that the battery can provide under the same load, thus reducing the output power of the battery. This means that if used in some equipment with high power requirements, such as power tools, electric vehicles, etc., the battery may not be able to provide enough power, and the performance of the equipment will be greatly reduced. For example, in electric vehicles, the acceleration performance of the vehicle at low temperatures will be significantly weakened, and the driving range will be reduced.
3. The charging acceptance becomes worse
When charging polymer lithium batteries at low temperatures, lithium metal may deposit unevenly on the surface of the negative electrode. This is because the chemical reaction kinetics inside the battery is slowed down at low temperatures, and lithium ions do not embed well in the negative electrode material. This uneven deposition leads to the formation of lithium dendrites. Lithium dendrites are metal lithium like branches, which not only consume the active lithium in the battery, but may also puncture the diaphragm, causing a short circuit inside the battery and causing safety issues. In addition, the charging efficiency of the battery at low temperatures will also be reduced, and it will take longer to fully charge.
