Studies on Self-balance of Lithium Battery and Charging Enhancement of Independent Solar Power System

本研究旨在探討鋰電池自平衡技術以及利用電容增強充電技術，以提升獨立型太陽光發電系統的性能。鋰電池自平衡管理系統是利用切換控制技術，當偵測到電芯異常時，將鋰電芯從串聯轉為並聯，進行自平衡。實驗結果顯示自平衡技術明顯改善電芯電壓一致性，並且明顯改善壽命，自平衡過程也不會產生大量熱能，且電路設計簡單便宜。 另外，有鑑於鉛酸電池並聯超電容時，對提升太陽能充電量有顯著效果。本研究針對鋰電池並聯超電容，從時域響應與頻域阻抗的角度切入，搭配戶外實測，分析電容大小及混合儲能裝置阻抗對充電量的影響，結果顯示混合儲能系統阻抗降低，且電容法拉數夠大時，才能有效提升混合式儲能裝置的充電量。This research develops a self-balancing technique for lithium battery and study the use of hybrid battery storage to enhance charging performance of independent solar PV power system. The battery self-balancing is employed by switching the battery cell connection from series to parallel. The self-balancing is activated when an abnormal cell voltage is detected. A simple controller was developed in the present study for battery self-balancing. The experiments show that self-balancing technology can improve not only voltage uniformity between cells but also the life of Li-ion battery. Lithium battery connecting a super-capacitor (SC) to enhance charge performance of independent solar PV power system was also studied using overall impedance of the hybrid storage in frequency domain. It is found theoretically and experimentally that it needs a larger SC for lithium battery to obtain low overall impedance to enhance solar charging performance