由於串聯電池組中各個電池的充放電特性並不一致,充電時易造成電池電量的不平衡,因而縮短電池的壽命,甚至損害電池。為了延長電池使用壽命,電池組之充電器需具備均勻充電的功能,其主要是為了使串聯電池快速達到平衡充電,並且避免電池過度充電的情況而擬定之控制策略。 本論文主要研製出一個鋰電池均勻充電器,以交換式電源轉換器提供定電流充電及定電壓充電二段式充電方式,以提升充電效能,串聯電池組中的每一電池都配屬一組返馳式轉換器,並且用微處理器來處理每個電池狀態與電位。回授信號用以調整充電器脈寬調變,使電池組均可達平衡電壓,減少單電池間電量不平衡的狀況,因而可獲得較佳的充電效率。
Due to the differences in batteries of a series-connected battery, the restored capacity in each battery may not be the same when being charged. In order to extend battery cycle life, the charger for the battery must have the capability of charging equalization. The objective of the proposed strategy is to attain fast charging while avoiding destructive overcharging. In this thesis, an equalization charger for Lithium-ion batteries is investigated. This charger uses a switching mode power converter with two charging steps, constant current charging and constant voltage charging, to increase the charging efficiency. Each of the series-connected battery is associated with a flyback converter. Using microprocessor in this converter to detect the voltage and state of each battery, those signals will feedback to microprocessor to control pulse width modulation. Batteries voltage can reach a balance, to reduce power unbalances between single cell status, and thereby better charging efficiency.