Talk about the impact of winter on the performance of lithium batteries

Talking about the impact of winter on lithium batteries. Recently, electric car owners across the country have found that their car's driving distance has suddenly shortened. They can't run far, and have no strength to step on the accelerator? Don't worry about the cold in winter, especially in the north. Friends, so the climate not only affects travel plans, but many people are unwilling to turn on the warm wind in order to save some electricity, and the car outside is almost at a temperature. This experience makes people almost doubt the value of the initial decision to buy an electric car. Friends in the Northeast, it seems that the temperature of minus 20 degrees in winter seems to be poor. What can they do with electric vehicles? Why the battery life of electric vehicles will be shortened in the cold winter, I have never thought that this is related to low temperature. The author is thinking that this may be a smart phone that clearly shows that the battery is fully charged in a low temperature state, but the reason for the momentary shutdown is the same. But why the low temperature has such a big impact on their endurance, make up for the skills that you don’t know, check the information, and give us a scientific method. Why is the service life of electric vehicles shorter in winter? Generally speaking, most electric vehicles on the market, and even electronic digital products, use lithium batteries, so choose first, what about lithium batteries in winter. Let's start with principles. Lithium batteries used in electric vehicles are mainly lithium iron phosphate, ternary lithium and lithium manganate. Their basic reflection principles are similar, and they are all electrochemical energy storage processes in rocking chairs. The discharging process of the lithium battery is shown in the figure. During the charging process, due to the influence of the external terminal voltage of the battery, the electrons close to the positive electrode collector move to the negative electrode under the drive of the electric field. When they reach the negative electrode, they combine with the lithium ions guessed by the positive electrode. The negative electrode of lithium ions is consumed, and the concentration of lithium ions decreases. A difference in ion concentration between the positive electrode and the negative electrode is formed. Driven by the difference in concentration, the lithium ions guessed by the positive electrode move from the inside of the data to the surface of the positive electrode, and then along the electrolyte, through the gap, to the surface of the negative electrode. In addition, driven by the electric potential, it penetrates the SEI film and diffuses to the depth of the negative data. It meets electrons from an external circuit, partially showing the remaining electrical neutrality in the negative data. The discharge process is just the opposite. After the circuit including the load is closed, when electrons flow from the negative collector to the positive electrode through the external circuit, the discharge process begins. Finally, the lithium ions are inserted into the anode data and the electrons from the external circuit are combined. The anode graphite has a layered structure, and the embedding method and spraying method of lithium ions are not significantly different between different lithium ion types. The lattice structure of different positive electrode data is different, and the dispersion of lithium ions during charging and discharging is also slightly different. In the process of discharging, lithium ions want to go from the negative electrode to the positive electrode. They have to overcome some resistance and be driven by some power. These negative SEI membranes including resistance are overcome by dispersing from the negative structure; dispersion along the electrolyte needs to overcome the conductive impedance of the electrolyte. Through the gap between the positive electrode and the negative electrode, the gap impedance must be overcome; from the electrolyte to the positive electrode, the positive SEI film (its structure is not particularly obvious) and the internal dispersion impedance of the data must be overcome. So where does lithium get its energy to overcome these resistances? On the one hand, it comes from the potential difference between the positive and negative electrode data. The greater the potential difference between the positive data and the negative data, the higher the open circuit voltage displayed by the battery, and the more energy the battery can store. This feature is also the basic driving force for battery discharge. On the other hand, the concentration of ions in different orientations in the electrolyte drives the movement of ions from the orientation of high concentration to the orientation of low concentration, which is the so-called concentration drive. 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: Discharge characteristics and life of lithium iron phosphate batteries