Introduce the cause of self-discharge of lithium-ion battery

Reasons for self-discharge: 1. Reasons for the loss of reversible capacity: The reason for the loss of reversible capacity is that a reversible discharge response occurs, and the principle is the same as the normal discharge response of the battery. The difference is that the electronic route of normal discharge is an external circuit, and the response speed is very fast; the electronic route of self-discharge is the electrolyte, and the response speed is very slow. 2. The reason for the loss of irreversible capacity: When an irreversible reaction occurs inside the battery, the constituted capacity loss is the loss of irreversible capacity. The types of non-reverse reactions that occur mainly include: A: Non-reverse reactions between the positive electrode and the electrolyte (relatively, it mainly occurs in two kinds of materials that are prone to structural defects, such as lithium manganate ion and lithium nickel oxide ion, such as lithium manganate ion. The reaction between the positive electrode and the lithium in the electrolyte: LiyMn2O4+xLi++xe-→Liy+xMn2O4, etc.); B: No adverse reaction between the negative electrode material and the electrolyte (the SEI film formed during formation is to protect the negative electrode from electrolysis Corrosion of the liquid, the possible reaction of the negative electrode and the electrolyte is: LiyC6→Liy-xC6+xLi++x, etc.); C: Irreverse reaction caused by impurities in the electrolyte itself (for example, the possible reaction of CO2 in the solvent: 2CO2＋2e-＋2Li＋→Li2CO3＋CO; the reaction of O2 in the solvent: 1/2O2+2e-+2Li+→Li2O). A similar response irreversibly consumed the lithium in the electrolyte, and then lost the battery capacity. D: Irreversible reaction caused by micro-short circuit formed by impurities during manufacture. This phenomenon is the most important reason for the large self-discharge of a single battery. When the dust in the air is made, the metal powder on the pole piece and the barrier will cause an internal micro short circuit. It is impossible to be dust-free at the time of production. When the dust is not enough to reach the pierced barrier and then short-circuit the positive and negative electrodes, the impact on the battery is not great; but when the dust is severe enough to pierce the barrier, The impact on the battery will be very significant. Because of the existence of whether the barrier is pierced, when checking the self-discharge rate of a large number of batteries, it is often found that the self-discharge rate of most batteries will be combined in a small plan, but only a small part of the battery self-discharge Significantly high and scattered, these should be the batteries whose barriers have been pierced. Disclaimer: Some pictures and content of articles published on this site are from the Internet, please contact to delete if there is any infringement. Previous: Analysis of the advantages of lithium-ion batteries for electric vehicles