What is the damage of high temperature and low temperature to lithium battery

High temperature damage to lithium battery:

As the temperature decreases, the electrode reaction rate also decreases. It is assumed that the battery voltage will not change, the charging and discharging electric flow will decrease, and the charging battery power will also decrease. From the perspective of various environmental factors, temperature does great harm to the charging characteristics of rechargeable batteries. The electric level is closely related to the electrochemical corrosion of the electrolyte page of lithium batteries and the working temperature. The electrolyte page of lithium batteries is considered to be the cardiovascular system of rechargeable batteries. On the contrary, the temperature rises, that is, the power of lithium polymer lithium battery rises. In addition, the temperature will continue to endanger the transportation rate of lithium battery electrolyte, the temperature rise will accelerate, the transportation temperature will decrease, the transportation rate will slow down, and the charging characteristics of lithium battery will continue to be endangered. However, the high temperature exceeding 45 ℃ will destroy the internal chemical reaction balance of the rechargeable battery and cause adverse reactions.

Damage of lithium battery at low temperature:

When applied in low-temperature natural environment for a short time, or when the temperature is not low enough, the lithium battery only temporarily endangers the battery power, but is not easy to cause permanent damage. However, long-term application in low-temperature natural environment or -40 ℃ low-temperature natural environment is likely to lead to "freezing" of lithium battery and permanent damage.

In addition, when the lithium battery is charged at low temperature, the metal lithium will be dissolved in the anodic oxidation surface of the rechargeable battery, and the whole process is irreversible. This will cause permanent damage to the rechargeable battery and reduce the safety factor of the rechargeable battery. Therefore, many lithium battery devices are equipped with protection devices, so that the battery can not be charged at low temperature.

In the power supply system of pure electric vehicles, temperature control is one of the most important main parameters, and it is also a key element that endangers the battery performance. In all battery test system software, the temperature must be marked. Because the temperature is very harmful to the battery performance, including the internal resistance, filling characteristics, charging and discharging characteristics, safety factor, service life, etc. of rechargeable batteries.

The average charge discharge working voltage and volume of lithium battery decrease with the decrease of temperature, especially at -20 ℃, the charge discharge capacitance and average charge discharge working voltage of rechargeable battery decrease rapidly.

According to electrochemical analysis, SEI film resistor and aqueous solution resistor do not change much in all temperature ranges, and do little harm to the low temperature characteristics of rechargeable batteries; The charge transfer resistor changes greatly in the whole temperature range, and the change range is larger than that of aqueous solution resistor and SEI film resistor. The reason lies in that, with the decrease of temperature, the positive ion conductivity of lithium battery electrolyte decreases, and SEI film resistor and electrochemical corrosion resistor increase, resulting in the improvement of Euro bus polarization, concentration polarization and photocatalysis polarization at low temperature. On the charge discharge curve of rechargeable battery, the average working voltage and charge discharge capacitance decrease with the decrease of temperature.

The best lithium battery application temperature is 0 to 35 ℃. The specificity of lithium-ion battery is reduced under the low temperature standard, the charging and discharging ability of rechargeable battery is weakened, and the service time is reduced. In the short-term low-temperature natural environment, the destruction of lithium batteries is only temporary, which is not easy to cause harm to the battery power. After the temperature warms up, the feature will be repaired.

However, if the rechargeable battery is charged in the ultra-low temperature working environment for a long time, the metal lithium will be dissolved in the anodic oxidation surface of the rechargeable battery. This whole process is irreversible and will cause permanent damage to the battery power. Due to the product quality problems of the rechargeable battery itself, as well as its own product quality problems and embrittlement problems, the mobile phone will turn off automatically at low temperature. On the one hand, it is due to the protection of the battery, on the other hand, it is also due to the unqualified manufacturing and aging of its own battery.

Summary: due to the low working voltage service platform of lithium battery during low-temperature charging and discharging, the low-temperature charging and discharging capacitance is significantly reduced. However, with the development of battery charging at room temperature, the damage will be fully compensated automatically and belongs to reversible damage. However, when charging low-temperature batteries, too low temperature or too high rate will usually cause irreversible lithium dendrites and irreversible volume damage of lithium cells, and then endanger the safety factor of rechargeable batteries.