Bus-Capacitor-Based Multi-path Equalization Topology

During the manufacturing and usage processes of individual battery cells, variations in parameters such as self-discharge rate, internal resistance, and temperature inevitably arise. These discrepancies can impede the maintenance of consistent performance, consequently affecting the overall performance and lifespan of the battery pack. Battery equalization technology improves the effective capacity and service life of series-connected battery packs through energy restoration. Capacitor-based equalizers boast a simple structure and low cost. However, the balancing speed of traditional switched-capacitor topologies is susceptible to the initial voltage distribution of the batteries. This paper proposes a bus-capacitor-based multi-path equalization topology. Through theoretical analysis and simulations, its effectiveness is verified by comparing it with traditional equalization topologies. Experimental validation of the equalization voltage and current demonstrates that the experimental results closely align with the simulation results, further confirming the feasibility of the circuit. The results indicate that the bus-capacitor topology enables equalization between any-cell(s)-to-cell(s) in the system. The equalization time is independent of the initial voltage distribution and the positions of the batteries. After equalization, the voltage differences among the batteries are reduced, and the voltages converge to uniformity. This topology is characterized by strong robustness and high stability.