A novel charging/discharging balancing strategy for lithium battery pack based on mixed charging mode

摘要

Series-connected lithium batteries can be charged in the pack-charging mode, which is most widely used in the lithium battery application field. But the pack-charging mode will lead to cell imbalance because of the difference in the electrochemical characteristics of the cells of series-connected batteries. On the other hand, the cell-charging mode can avoid the imbalance problem by charging each cell independently, but it will reduce the charging efficiency and increase the cost. In this paper, a novel balancing strategy is proposed with a mixed pack-charging and cell-charging mode to implement the balancing algorithm. The proposed strategy aims to solve the problem of charge/discharge imbalance with the simplest balancing algorithm with high balancing performance. There is no complex balancing behaviors during the charging process - as is the case with many other existing schemes - so the control algorithm can be greatly simplified. Because each cell can be fully charged and discharged with the proposed algorithm, it helps to make full use of the energy and capacity of each cell. The system stability and reliability of the proposed system, as well as its good performance, are verified through experiments. (c) 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.