Brief analysis of charging and discharging knowledge of 18650 lithium battery

In the case of charging and discharging 18650 lithium batteries, according to industry standards, the nominal capacity is generally the minimum capacity. This capacity is a batch of batteries, at room temperature 25 degrees, first charge cc/cv0.5c, and then stand for a period of time (usually 12 hours). Discharge with a constant expiratory current of 0.2 to 3.0vc (there is also a specification of 2.75v, but the effect is not significant, 3v2.75 drops quickly, and there is not much capacity), the release capacity value, because a batch of batteries must have individual The difference is the battery capacity with the lowest value of the capacity released in practice. In other words, the actual capacity of this batch of batteries should be greater than or equal to the nominal capacity. 1. The charging process of the 18650 lithium battery is realized by some chargers using cheap methods, and the processing accuracy is not good enough, which simply constitutes abnormal battery charging, or even damages the battery. When choosing a charger, try to choose a big brand of 18650 lithium battery charger, quality and after-sales guarantee to extend the battery life. The brand-guaranteed 18650 lithium battery charger has four maintenance functions: short-circuit maintenance, over-current maintenance, over-voltage maintenance, and battery reverse maintenance. Overcharge maintenance: When the charger overcharges the lithium battery, in order to prevent the internal pressure from rising due to temperature rise, intermittent charging is required. Therefore, the maintenance device should monitor the battery voltage, and when the battery overcharge voltage is reached, the overcharge maintenance function is activated and intermittently charged. Over-discharge maintenance: In order to prevent the over-discharge of the lithium battery, when the voltage of the lithium battery is lower than its over-discharge voltage detection point, the over-discharge maintenance is activated, intermittent discharge, and the battery is in a low quiescent current standby state. Over-current and short-circuit maintenance: When the lithium battery discharge current is too large or a short-circuit occurs, the maintenance device will start the over-current maintenance function. Lithium battery charge control is divided into two stages. The first stage is constant current charging. When the battery voltage is lower than 4.2v, the charger charges with 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, assuming that the line voltage is high, it will be damaged. The charger will be fixed at 4.2V and the charging current will gradually decrease. When the current must be current ( Usually 1/10 group), blocking the charging circuit, charging instructions, charging end. Excessive charging and discharging of lithium batteries can cause permanent damage to the positive and negative electrodes. Excessive discharge causes depressions in the negative carbon sheet structure, forming depressions that cannot be penetrated by lithium ions during the charging process. Excessive charging will cause lithium ions to be embedded in the carbon structure, some of which can no longer be released. 2. 18650 lithium battery charging principle The working principle of lithium battery is charging and discharging. When the battery is charged, lithium ions are formed at the positive electrode of the battery, and the lithium ions reach the negative electrode through the electrolyte. Carbon is the negative electrode and has a layered structure with many micropores. Lithium ions reaching the negative electrode are inserted into the micropores of the carbon layer. The more lithium ions are inserted, the greater the charging capacity. Similarly, when the battery is discharged (the process we use the battery), the lithium ions embedded in the carbon of the negative electrode will come out and return to the positive electrode. The more lithium ions return to the positive electrode, the greater the discharge capacity. The battery capacity we usually call 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 the positive electrode to the negative electrode and then to the positive electrode. Suppose the lithium battery is like a rocking chair. The two ends of the rocking chair are the north and south poles of the battery. 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 their favorite name: rocking chair battery. In fact, about lithium batteries, the reasons for blasting can also be understood.After all, the main stability is not that fierce, but in 18650, as a lithium battery with relatively high functions, its use will become more and more widespread. What about the lack of batteries? 18650 lithium batteries are the best choice. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.