Knowledge analysis of lithium battery charging and discharging

The number of cycles obtained by different cycle systems is completely different. For example, the other conditions above remain unchanged, just change the 4.2V constant voltage voltage to 4.1V constant voltage voltage to detect the cycle life of the same type of battery, so this The battery is no longer a deep charging method, and the cycle life can be increased by nearly 60% after the final detection. So if the cut-off voltage is increased to 3.9V for detection, the number of cycles should be increased several times. Lithium battery manufacturers parse the statement that one cycle of charging and discharging will result in one less life. What we should pay attention to is the meaning of the charging cycle of lithium batteries: a charging cycle refers to all the power of the lithium battery from full to empty, and then by The process of empty charging to full. And this is not the same as charging once. Lithium battery manufacturers say that when you talk about the number of cycles, you cannot ignore the conditions of the cycle. It is meaningless to talk about the number of cycles without the rules, because the number of cycles is a means of testing battery life, not an end! Misunderstanding: Many people like to The mobile phone lithium battery is automatically turned off and then recharged. This is completely unnecessary. In fact, it is impossible for users to use the battery in accordance with the national standard detection mode. No mobile phone will shut down at 2.75V, and its discharge mode is not a high-current constant-current discharge, but a mixture of GSM pulse discharge and normal low-current discharge. The way. Lithium battery charging and discharging requirements; 1. Lithium battery charging: According to the structural characteristics of the lithium battery, the maximum charge termination voltage should be 4.2V, and it cannot be overcharged, otherwise the battery will be scrapped due to too much lithium ions in the positive electrode. . The charging and discharging requirements are relatively high, and a dedicated constant current and constant voltage charger can be used for charging. Normally, the constant current charge to 4.2V/cell will switch to constant voltage charge. When the constant voltage charge current drops to less than 100mA, the charge should be stopped. Charging current (mA) u003d 0.1 to 1.5 times the battery capacity (such as a 1350mAh battery, the charging current can be controlled between 135 and 2025mA). The normal charging current can be selected at about 0.5 times the battery capacity, and the charging time is about 2 to 3 hours. 2. Discharge of lithium battery: Due to the internal structure of the lithium battery, all lithium ions cannot move to the positive electrode during discharge, and some lithium ions must be retained in the negative electrode to ensure that lithium ions can be inserted into the channel smoothly during the next charge. Otherwise, the battery life will be shortened accordingly. In order to ensure that some lithium ions remain in the graphite layer after discharge, it is necessary to strictly limit the minimum discharge termination voltage, which means that the lithium battery cannot be over-discharged. The final discharge voltage is usually 3.0V/cell, and the minimum should not be lower than 2.5V/cell. The length of battery discharge time is related to battery capacity and discharge current. Battery discharge time (hours) u003d battery capacity/discharge current. Lithium battery discharge current (mA) should not exceed 3 times the battery capacity. (Such as 1000mAH battery, the discharge current should be strictly controlled within 3A) Otherwise, the battery will be damaged. At present, the lithium battery packs sold on the market are equipped with a matching charge and discharge protection board inside. Just control the external charge and discharge current. 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 post: What are the advantages of lithium batteries and lithium polymer batteries?