The charging process and principle analysis of 18650 lithium battery

1. The charging process of 18650 lithium battery is terminated by some chargers with cheap methods, and the control accuracy is not good enough, which simply constitutes abnormal battery charging and even damages the battery. When choosing a charger, try to choose a big brand of 18650 lithium battery charger, the quality and after-sales are guaranteed, and the service life of the battery is extended. The brand-guaranteed 18650 lithium battery charger has four maintenance functions: short-circuit maintenance, over-current maintenance, over-voltage maintenance, and battery reverse connection maintenance functions. Overcharge maintenance: When the charger overcharges the lithium battery, it is necessary to stop the charging condition in order to guard against the increase in internal pressure caused by the temperature rise. For this reason, the maintenance device needs to monitor the battery voltage, and when it reaches the battery overcharge voltage, it activates the overcharge maintenance function and continues charging. Over-discharge maintenance: In order to guard against the over-discharge condition of the lithium battery, when the voltage of the lithium battery is lower than its over-discharge voltage test point, the over-discharge maintenance is activated, the discharge is continued, and the battery is kept in a standby mode with low quiescent current. Over-current and short-circuit maintenance: When the discharge current of the lithium battery is too large or a short-circuit condition occurs, the maintenance device will activate the over-current maintenance function. 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 high, 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 (usually when the current is set to 1/10), the charging circuit is cut off, the charging end indicator light is on, and the charging ends. Excessive charging and discharging of lithium batteries will cause permanent damage to the positive and negative electrodes. Excessive discharge leads to depressions in the negative carbon sheet structure, and depressions will cause lithium ions to be unable to penetrate during the charging process; overcharging will cause too many lithium ions to be embedded in the negative carbon structure, and some of the lithium ions can no longer be released. . 2. 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 of using 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 that return to the positive electrode, the higher the discharge capacity. The battery capacity we generally refer to is the discharge capacity. 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: Advantages and future development of lithium battery ternary cathode materials