When lithium-ion batteries are exposed to sub-zero temperatures, their performance can be greatly affected. The electrolyte inside the battery can become more viscous, making it harder for lithium ions to move freely between the electrodes. This can lead to a decrease in the battery's capacity, resulting in a decrease in the amount of energy the battery can store. Additionally, the internal resistance of the battery can increase, causing the battery to heat up and potentially fail.
Another issue that can occur in sub-zero temperatures is the formation of ice crystals within the battery, which can damage the electrodes and separator. This can lead to a decrease in battery performance and an increase in the risk of failure.
Furthermore, in extreme cold temperatures, the electrolyte can freeze which can cause permanent damage to the battery. In some cases the battery can become unusable.
To minimize the effects of sub-zero temperatures on lithium-ion batteries, it is important to keep them warm. One way to do this is by using a heating system to maintain a moderate temperature. Another way is to use a battery management system (BMS) that can monitor and control the battery's temperature.
In general, it is advisable to avoid using lithium-ion batteries in sub-zero temperatures if possible, or to take extra precautions to protect the batteries when they are in use in such temperatures.