An Active Direct Cell-to-Cell Balancing Circuit in Continuous Current Mode for Series Connected Batteries

Han Han,Liu Liu,Yang Yang

doi:10.3390/en12203978

Abstract

Bi-directional cell-to-cell balancing circuits can well prevent voltage imbalance of batteries that are connected in series. However, it is a challenge to achieve high equalization speed and equalization efficiency with low complex circuit structure. In order to overcome this challenge, it is proposed that a direct bi-directional cell-to-cell active equalization method that works in continuous current mode (CCM) is used. The proposed balancing circuit allows energy to transfer directly from the source cell to the target cell in one step, which guarantees high balancing speed and efficiency. The experiments in which six-20 Ah lithium-ion batteries are connected in series have been carried out, and the results show that the balancing circuit achieves a good comprehensive performance of equalization in efficiency, speed, and circuit complexity.

Highlights

Series connected battery packs are used to provide adequate power in applications such as electric vehicles and uninterruptible power supplies
Inspired by Park et al [17], we propose a direct cell-to-cell balancing circuit that uses a multi- the equalizer work in continuous current mode (CCM)
The experimental results clearly show that the proposed equalizer has a good equalization performance with high balancing speed the batteries connected in series due study to the focuses small number

Summary

Introduction

Series connected battery packs are used to provide adequate power in applications such as electric vehicles and uninterruptible power supplies. Series connected lithium-ion batteries are commonly used in these areas due to the merit of non-memory effect, high working cell voltage, low environmental population, low self-discharge rate, and high power density in volume and high specific energy and energy density [1,2]. Many factors, such as internal impedance and stage-of-charge difference, may cause an imbalance in the voltage of the cells connected in series. Numerous balancing topologies have been developed and well summarized They can be classified into two categories: passive and active [5].

Methods

Discussion

Conclusion