Analysis of balanced charging methods for series lithium batteries

Connecting lithium batteries in series is a common phenomenon in the assembly process of battery packs. 1. The number of PWMs required for series-connected lithium batteries is 2×(n-1), where n is the number of batteries. There are relatively many. And energy transfer can only be transferred from one battery to the adjacent battery. If the number of batteries is large, the control algorithm is still quite complicated, so the key issue is just the cost. 2. If you use bq78PL114+BQ76PL102 in series lithium batteries, you can manage up to 8 batteries. If the electric vehicle needs 80 sections, then 10 such battery packs are managed separately. In this case, the cost is increased. So this IC should be suitable for handheld device lithium battery pack, 12.8V lithium battery pack, or laptop battery, or electric bicycle battery. 3. The selection of PWM frequency, duty cycle, and inductance capacity of the series lithium battery are interrelated. The recommended frequency of Ti IC is 200kHz, which can reduce the inductance, thereby reducing the cost. Lithium battery series knowledge. Because the battery is in the process of processing, it has to go through many processes from the beginning of coating to the finished product. Even after rigorous testing procedures, the voltage, resistance, and capacity of each group of power supplies are consistent, but after a period of use, there will be differences in one way or another. Just like twins born to a mother, they may look exactly the same when they are first born, and it is difficult to distinguish them as mothers. However, when the two children grow up, there will be differences in one way or another. Lithium-powered lithium-ion batteries are the same. After using for a period of time, the overall voltage control method is difficult to apply to lithium-powered lithium-ion batteries. When charging a group of lithium batteries in series, ensure that each battery is charged in a balanced manner, otherwise the performance and life of the entire group of batteries will be affected during use. Commonly used equalization charging techniques include constant shunt resistance equalization charging, on-off shunt resistance equalization charging, uniform battery voltage equalization charging, switched capacitor equalization charging, step-down converter equalization charging, inductance equalization charging, etc. 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: What to pay attention to when buying AGV lithium batteries