Analysis of charging process and principle of 18650 lithium battery

Lithium battery charging control is divided into two stages. The first stage is constant current charging. When the battery voltage is lower than 4.2V, the charger will charge with a constant current. The second stage is the constant voltage charging stage. When the battery voltage reaches 4.2V, due to the characteristics of lithium batteries, if the voltage is higher, it will be damaged. The charger will fix the voltage at 4.2V and the charging current will gradually decrease. When it is reduced to a certain value (generally 1/10 of the set current), the charging circuit is cut off, the charging completion indicator light is on, and the charging is completed. Excessive charging and discharging of lithium batteries can cause permanent damage to the positive and negative electrodes. Excessive discharge causes the negative carbon sheet structure to collapse, and the collapse will cause lithium ions to be unable to be inserted during the charging process; overcharging causes too much lithium ions to be inserted into the negative carbon structure, causing some of the lithium ions to be unable to be released anymore. The charging principle of 18650 lithium battery The working principle of lithium battery refers to its charging and discharging principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode has a layered structure. It has many micropores. The lithium ions that reach the negative electrode are embedded in the micropores of the carbon layer. The more lithium ions are inserted, the higher the charging capacity. In the same way, when the battery is discharged (that is, the process when we use the battery), the lithium ions embedded in the carbon layer of the negative electrode are released and move back to the positive electrode. The more lithium ions returned to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity. It is not difficult to see that during the charging and discharging process of lithium batteries, lithium ions are in a state of movement from positive → negative → positive. If we compare the lithium battery to a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium ion is like an excellent athlete running back and forth on both ends of the rocking chair. Therefore, the experts gave the lithium battery a lovely name, rocking chair battery. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the basic methods for charging lithium batteries?