Brief analysis of the detection process of lithium batteries

Lithium battery classification: The detection process of lithium batteries mainly includes five stages: constant current charging stage, constant voltage charging stage, charge-discharge interval stage, discharge interval stage and cycle interval stage. In the constant current charging stage, there is a peak voltage that limits the charging of the constant current charging terminal. When the battery voltage reaches the upper limit of 4.1v or 4.2v, the constant current charging phase ends, and the battery enters the next phase, that is, the constant voltage charging phase. Constant voltage charging refers to charging the battery without changing the voltage across the battery. At this stage, the charging current is gradually reduced to zero, so that the battery is fully charged. During the charge-discharge interval, the battery is in a self-discharge state. The discharge stage is the key stage of battery detection and sorting. The capacity of the battery at this stage is calculated by the product of the discharge current and the discharge time. Before and after the battery is placed on the shelf, measure the battery impedance. After the test is over, the data is combined with the battery capacity value to perform battery sorting. Generally speaking, the lower the battery impedance, the better the battery performance and the better the overall performance. The formation and separation of batteries is very important, especially in the application process of lithium batteries, often in parallel, series or a combination of multiple groups of batteries. Good-shaped batteries are classified according to certain rules. For example, according to the discharge capacity or discharge curve, the batteries with similar performance are divided into one category and assembled into a battery pack to ensure the good operation of the battery. Lithium battery charging characteristics: Lithium batteries are prone to damage due to overcharge, deep discharge and short circuit, and the charging voltage must be strictly limited. The charging rate generally does not exceed 1C, and the minimum discharge voltage is 2.7~3.0v. Re-discharging will damage the battery. Lithium batteries are charged under constant flow and pressure. When the 1C constant current is charged to 4.1v (or 4.2v), the charger should be switched to constant voltage charging immediately. The charging current gradually decreases. Lithium battery charging is divided into two stages. When charging with constant current for the first time, it becomes constant voltage charging when it is close to the termination voltage. Assuming a lithium battery with a capacity of 800mAh, its terminal charging voltage is 4.2v. The battery is charged at a constant current of 800mA (charging rate is 1C). When charging starts, the battery voltage rises sharply. When it is close to 4.2v, change to 4.2v constant voltage charging, the current gradually decreases, and the voltage changes little; when the charging current drops to 0.1c (about 80mA), it is considered to be close to saturation, and the charging can be terminated (some chargers reach 0.1 Start timing after c, and end charging after pressing the time). If the lithium battery is overcharged, overdischarged, or overcurrent during charging and discharging, it will damage the battery or reduce its service life. In order to prevent overcharge or overdischarge, not only must the lithium battery be equipped with internal safety components, the charger must also take safety protection measures to monitor the charge and discharge status of the lithium battery. 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: Why is lithium battery so easy to replace lead-acid battery?