鋰電池充電的原理解析
鋰電池充電器的基本要求是特定的充電電流和充電電壓,從而保證電池安全充電。增加其它充電輔助功能是為了改善電池壽命,簡化充電器的操作,其中包括給過放電的電池使用涓流充電、電池電壓檢測、輸入電流限制、充電完成后關斷充電器、電(dian)池部分放電(dian)后自動啟動充(chong)電(dian)等。
鋰離子電池的充電過程可以分為四個階段:涓流充電(低壓預充)、恒流充電、恒壓充電以及充電終止。
鋰電池充電器的基本要求是特定的充電電流和充電電壓,從而保證電池安全充電。增加其它充電輔助功能是為了改善電池壽命,簡化充電器的操作,其中包括給過放電的電池使用涓流充電、電池電壓檢測、輸入電流限制、充電完成后關斷充電器、電池部分放電后自動啟動充電等。
鋰電池的(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)是(shi)限壓恒流(liu),都(dou)是(shi)由IC芯片(pian)控制的(de),典(dian)型的(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)是(shi):先檢測(ce)待充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓,如果電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓低于3V,要(yao)先進(jin)行(xing)(xing)預充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian),充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)為設定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)1/10,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓升到(dao)3V后,進(jin)入標準充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程。標準充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程為:以設定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)進(jin)行(xing)(xing)恒流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian),電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓升到(dao)4.20V時(shi),改(gai)為恒壓充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian),保持(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓為 4.20V。此時(shi),充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)逐(zhu)漸(jian)下(xia)(xia)降(jiang),當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)下(xia)(xia)降(jiang)至設定充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)1/10時(shi),充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)結束(shu)。下(xia)(xia)圖為充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)曲線。
階段1:涓流充電——涓流充電用來先對完全放電的電池單元進行預充(恢復性充電)。在電池電壓低于3V左右時采用涓流充電,涓流充電電流是恒流充電電流的十分之一即0.1c(以恒定充電電流為1A舉例,則涓流充電電流為100mA),
階段2:恒流充電——當電池電壓上升到涓流充電閾值以上時,提高充電電流進行恒流充電。恒流充電的電流在0.2C至 1.0C之間。電池電壓隨著恒流充電過程逐步升高,一般單節電池設定的此電壓為3.0-4.2V.
階段3:恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)—— 當電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓上升到(dao)4.2V時(shi),恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)結束,開始恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)階段。電(dian)(dian)(dian)(dian)(dian)流根據電(dian)(dian)(dian)(dian)(dian)芯的飽和(he)程(cheng)度,隨著(zhu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)的繼續充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流由最大值慢慢減少,當減小到(dao)0.01C時(shi),認(ren)為充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)終止。(C是(shi)(shi)以(yi)電(dian)(dian)(dian)(dian)(dian)池標稱容量對照電(dian)(dian)(dian)(dian)(dian)流的一種表示方法,如電(dian)(dian)(dian)(dian)(dian)池是(shi)(shi)1000mAh的容量,1C就是(shi)(shi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流1000mA。)
