Experimental Comparison of Single-Tier and Multi-Tier Switched-Capacitor Active Cell-Balancing Topologies

Abstract

This paper presents an experimental comparison of capacitor-based active cell-balancing topologies implemented on a 12S1P lithium-ion battery pack. The study focuses on evaluating the balancing performance of single-tier switched-capacitor (SC), double-tiered switched-capacitor (DTSC), and extended double-tiered switched-capacitor with an additional capacitor (DTSCAC) configurations under identical initial conditions. A modular hardware platform was developed to enable controlled and repeatable experiments. The balancing process was evaluated based on voltage equalisation of individual cells, with completion defined as a maximum voltage difference of 50 mV between the highest and lowest cell. Experimental results show that the DTSC topology generally achieves shorter balancing times compared to the SC configuration, particularly for moderate cell distances. In contrast, the DTSCAC topology does not provide consistent improvement and may result in longer balancing times. In addition to balancing time analysis, current waveforms were measured at multiple nodes within the battery pack to provide insight into charge transfer behaviour. The results highlight the influence of topology and cell posit ion on balancing performance.