Method and circuit for improving bypass equalization effectiveness

Abstract

The invention provides a method and circuit for improving bypass equalization effectiveness. The method simplifies the design of the part-time time-share equalization circuit when the battery cells are approximately fully charged, widens the matching requirements for the charger, and shortening the equalization working time. The method comprises the following steps: in the process of charging a battery pack composed of battery cells connected in series, when the battery cells are approximately fully charged, setting m gradually increasing voltage thresholds, and setting a certain voltage threshold in the m voltage thresholds as the ith voltage threshold, wherein the highest voltage threshold is corresponding to the cell maximum charging voltage; when the voltage of a certain cell or cells reaches the ith voltage threshold, starting the bypass equalization; and if the ith threshold voltage is not the cell maximum charging voltage, keeping charging while equalization, and closing the charging channel while equalization only when the ith threshold voltage reaches the cell maximum charging voltage.

Description

technical field [0001] The invention relates to the technical field of battery management, in particular to a method and a circuit for improving the effectiveness of bypass equalization. Background technique [0002] In various types of battery applications, battery series connection is a very common application method. The biggest problem brought by the series application of batteries is the balance between individual batteries. Battery balancing is to make the fullness of each battery in the series battery pack consistent, so as to ensure that each battery can be fully charged, or to fully discharge each battery in the series battery pack. In a series battery pack, the working current of each battery is the same whether it is charging or discharging. However, due to the differences between individual batteries, the charging and discharging in the series battery pack are respectively subject to the first charge to the highest allowable voltage. section and the section fir...

AI Technical Summary

Problems solved by technology

[0005] The problems of the above scheme are: 1. As mentioned in 1, this scheme only starts bypass equalization when a battery section reaches the highest voltage, and stops charging when the bypass is turned on; this design can ensure that the small current can also be used for The large battery pack completes the equalization, but the time to resume charging after the equalization is started is limited by the discharge capacity of the bypass, and the discharge and step-down cannot be completed quickly, and the charging speed quickly slows down

2. As mentioned in 2.a) and 2.b), the sequential discharge algorithm of adjacent high-voltage nodes is complicated, which is not conducive to simple implementation

3. When the error of the charging power supply voltage shows that the charging power supply is lower than the sum of the highest voltages of the nodes of the equalization circuit, it is possible that the equalization cannot be triggered, or the equalization cannot be achieved, or when the voltage of the charging power supply is higher than the sum of the highest voltages of the nodes, it may not be judged until charging is complete

Images