串聯電池模組間之平衡管理系統

Balance Management System for Battery Modules in Series

應用在電動船上的電池系統必須使用大量電芯串聯以達到所需的300～600V高壓，電池管理系統利用電芯平衡的方式來改善串聯電芯電壓不平衡的問題，但礙於技術上的瓶頸導致電池管理系統只能應用於串聯數量不大的電池模組上，如4串、8串、16串、20串，若要應用於高串聯的電動船上勢必將數個模組化的電池模組串聯成電動船所需的電壓，雖然此做法可改善各電池模組內不平衡的問題，但是電池模組間仍然有模組電壓不平衡的問題，本研究針對模組間電壓不一致的問題進行改善，開發一套高串聯電池模組間之平衡管理系統，本研究利用主動式平衡的方式來達到模組平衡的目的，本高串聯電池模組之平衡管理系統的電源與平衡電力皆來自於外部，利用主動式的平衡方式進行電池模組的平衡，透過本平衡管理系統對低壓的電池模組進行平衡充電，直到模組電壓達設定值後即換下一個低電壓電池模組充電，如此反覆來達到模組間的平衡，而本平衡管理系統亦能將電池模組的平衡狀態與各電芯的電壓狀態顯示於人機系統上，監控電池模組間平衡的過程，本文在一由5組24V電池模組串聯成額定120V的電池系統上驗證本研究所提出的模組間主動式平衡電路，實驗結果顯示本電路可以有效的達成電池模組間的平衡。 In order to meet 300V to 600V high voltage requirement, battery systems used in electric boats must use large numbers of battery cells in series. Existing battery management systems use various balance methods to deal with cell voltage imbalance problems within battery modules comprised of 4, 8, 16 or 20 cells in series. However for high voltage application like electric boats, imbalance problems also exist among battery modules. This study aimed to resolve voltage imbalance phenomena among battery modules in series. An active balance scheme was designed and tested in the current study. The current balance method actively balance the battery module with the lowest voltage among all the battery modules utilizing the charging power source. In other words this balance method pumped extra electrical energy into the module with the lowest voltage until all the modules reached equal voltage state. An accurate battery module voltage measurement circuits and selective switch matrix were also designed to complete the balance management system in the current study. One 128V battery system comprised of five 24V battery modules was tested in the current study. Good balancing performance was shown in the experiments.