Switching Control for Voltage Balancing of Lithium Batteries

Abstract

Battery system consists of many battery cells or modules with different characteristics, in order to achieve reliable, efficient and long time use of the battery system, and to avoid the performance difference between single cells due to manufacturing and aging, we need to balance the voltage of single cells. At present, the research and development progress of battery balancing technology lags far behind the development of battery technology. In order to achieve effective balancing of single cells in a battery pack, we propose a “switching tube + resistor” type passive balancing technology for single cell voltage, which is a method to distribute the switching time of the shunt circuit according to the voltage of each single cell, so as to control the charging current of single cells and achieve battery voltage balancing, but The traditional passive balancing method will make the battery management system unstable therefore it is difficult to put it into use, this paper proposes a new switching control algorithm to overcome the problem of passive balancing making the BMS unstable, thus providing an effective balancing method that can be used practically in the use of lithium batteries.