Comparative Evaluation of Thermal and Voltage Behavior of Multi-Topology Li-Ion Battery Packs For UAVs Using Virtual Interconnection Method

Abstract

This study comparatively investigates the electrical and thermal performances of four different lithium-ion battery configurations (1S1P, 2S1P, 2S2P, 3S1P) for unmanned aerial vehicles (UAVs) at 0.5C-3C discharge rates. The main innovations of the study are as follows: (1) A new virtual connection method is developed that eliminates the need for physical busbars, which reduces the battery pack weight by ~15% while increasing the thermal uniformity by up to 20%. This method, validated by NTGK electrochemical-thermal model simulations and experimental studies, provides a significant advantage in the design of compact and lightweight energy systems for UAVs. (2) Parallel topologies (especially 2S2P) are shown to perform better than series-weighted configurations - voltage drop is limited to <5% at 3C discharge rate and thermal gradients are significantly reduced (ΔT < 2.2K, 4.0K for 1S1P). (3) The findings provide quantitative guidelines for UAV designers: 2S2P configuration in 3C increases the operation time by 25% compared to 2S1P, while 3S1P configuration exhibits superior voltage stability with a drop from 12.11V to 9.89V in 1080 seconds. These results clearly demonstrate that parallel configurations and hybrid cooling strategies should be adopted in high-performance UAV applications and provide guidance for future battery pack designs. The study provides significant contributions to the development of optimized battery systems, especially for long-range and high-payload UAVs.