Design of Adaptive Multimode Equalization Circuit Based on Analysis of Inconsistency Parameters of Lithium Battery Packs

Abstract

In order to reduce the inconsistency of lithium battery packs and ensure the safety of battery charging and discharging, this paper presents an equalization topology structure with three working modes: direct cell to cell (DC2C), cell to pack (C2P), and pack to cell (P2C), which uses a flyback converter as the energy transmission element, and an adaptive three-threshold equalization strategy based on parameter analysis. To prevent overcharging and overdischarging, this equalization strategy defines the priority of each mode under different working states. By analyzing the real-time state of charge (SOC) parameters of the battery pack, the equalization circuit can adaptively select the current equalization mode to reduce the inconsistency of the current battery pack. Verified by simulation experiments, compared with the equalization circuit of the traditional flyback converter, the equalization circuit has increased the equalization speed by 26.96%, 38.25%, and 14.07%, respectively, under the three working states of standing, charging, and discharging, and the equalization efficiencies have reached 86.63%, 88.84%, and 90.91%, respectively.