Why does the life and capacity of lithium batteries decrease when used in winter?

Why does the life and capacity of lithium batteries decrease when they are used in winter? In winter, the mileage of new energy vehicles decreases, which is actually a normal reason. Because lithium batteries are very affected by low temperature conditions. In the range of 0-40 degrees, lithium batteries are not very sensitive. Once it crosses this temperature range, its life and capacity will be compromised. Regarding lithium batteries, there is currently no clear theory to support the internal resistance, discharge platform, life and capacity of lithium batteries at different temperatures. The related calculation formulas and mathematical models are still in the exploratory stage. Generally speaking, lithium batteries are not sensitive to temperatures of 0-40 degrees Celsius. However, once the temperature exceeds this range, the life and capacity of the lithium battery will be reduced. There is no way to quantify lithium batteries, because lithium batteries are too active and consistency is the biggest problem. Even the same batch of products, the same material, and the same process will have very different properties. A lot of experiments have been done, and the low-temperature performance of lithium batteries of different materials is also different. Currently, the hottest lithium iron phosphate is the worst at low temperatures. At -10°C, the release capacity of our product is 89% of the maximum capacity. It should be relatively high in the industry. The output capacity at 55°C can reach 95%, while the attenuation at lower temperatures is still relatively small. This is still a product to be inspected. Everyone knows that the quality of normal processing lines is much higher than that of general processing lines. Lithium batteries of different materials have different low temperature resistance. For example, the low temperature resistance of the battery in Sanyuanli is slightly better, and the low temperature resistance of the lithium iron phosphate battery is relatively poor. Car consumers can also feel that the use of lithium batteries in winter is shorter than in summer. Especially in the northern part of our country, the feeling is more obvious. For example, when the lithium iron phosphate battery is at minus ten degrees, the discharged capacity is 89% of the maximum capacity. The working principle of a lithium battery is that the internal electrolyte changes through a chemical reaction, and there is a potential difference between the positive and negative electrodes, which results in current. In a low temperature environment, the electrolyte moves quite slowly, which affects the transfer activity of lithium ions between the positive and negative electrodes, resulting in a decrease in the charge and discharge performance of the battery. Factors restricting the low-temperature performance of lithium batteries ●Under low-temperature environments, the viscosity of the lithium battery electrolyte increases, and even partially solidifies, resulting in a decrease in the conductivity of the lithium battery. ●The compatibility between the electrolyte, the negative electrode and the separator becomes poor in a low temperature environment. ●Under low temperature environment, the negative electrode of the lithium battery has serious lithium precipitation, and the precipitated metal lithium reacts with the electrolyte, and the product deposition causes the thickness of the solid electrolyte interface (SEI) to increase. ●In the low temperature environment, the diffusion system of the lithium battery in the active material is reduced, and the charge transfer resistance (Rct) is significantly increased. Reminder: In winter and summer, when there is a big temperature difference, it is best to charge in time, otherwise it will affect the life of the lithium battery. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: How to judge the quality of lithium iron phosphate battery pack?