如何為您的電池組設計出優秀的電池充電器方案

 

 在可充電池化學電池或物理電池的運用過程中，充電器是其成功運用的重要裝置， 所以可充電池一出世，充電器便是個關鍵問題，因為充電器的好壞直接影響到電池的兩個重要技術指標：可充電池的使用容量；可充電 池的循環使用次數，即使用壽命。然而直到六十年代以前，充電器技術并沒有得到長足發展，普遍采用的方法主要是恒流或恒壓充電方法， 充電效果不是太理想。這種狀況直到六十年代基于最低出氣率可充曲線原理發現電池可接受充電電流大小隨時間按指數規律下降這一規律后， 才證實恒流或恒壓充電均不是最適合的方法。因為恒流充電時，其起始充電電流總是低于電池的可接受能力，造成充電效率低，充電時間長， 而在充電后期，最終的充電電流又總是高于電池可接受的程度，因而電池內部氣體析出率不斷增加，到充電結束時，所有充電電流全部供給氣 體析出，電池內部電壓迅速增加，電池溫度也隨之迅速上升，造成每次充電電極上都有活性物質脫落，從而大大降低了電池的壽命，而恒壓 充電(dian)方法在充電(dian)初(chu)期電(dian)池內阻(zu)極低致使充電(dian)電(dian)流過大，而隨時間并不按指數規律下降常偏離制定曲線

 

根據充電曲線研究實驗，又提出了所謂的兩段式、三段式或更多段式充電。所謂兩段式充電指首先對電池進行恒流或恒壓充電，當電池電壓達到 一定程度，然后對電池進行涓流充電：所謂三段式一般是首先對電池進行恒流充是，待電池電壓達到電壓閥值后轉化為第二階段，即所謂限壓充 電階段，當充電電流小到某種程度后轉化為第三階段．即所謂限壓充電。另外，由于實際運用的需要，往往還希望對電池進行快速充電．影響充 電器快速充電還有兩個重要因素：一是極化電壓：二是記憶效應，其中極化電壓是在充電過程中，電荷堆積于電池電極上而產生的反問電壓，實 際上表現為對電池內阻的增加上，消除它的有效方法是采用負脈沖方法在電池兩端瞬間放電去除電極上堆積的電荷．并由此產生了脈沖充電方法： 記憶效應并不是所有電池都有，可以通過多次的充放電即可消除。上述兩種效應應該在充電控制器設計中予以重視。

 

實際上，充電控制器在近年采取得了長足的發展，一個明顯的標志就是世界上大多數的半導體廠商大都出品了自己的充電器芯片，有的還帶有 中央處理器 (即CPU)。 盡管已經有了多種充電方法，而且也有一定的效果，然而大多忽略了一個重要事實，即充電電池并不是工作于理想狀態， 每個電池都有自己獨特的個性．確切地說每個充電電池都有自己有別干其它甚至是同類電池的充放電曲線，該曲線甚至在充電過程中還足動態變 化的，這就意味著好的充電控制模式應該是變化的，而且應該與電池的充放電曲線變化一致才是最佳的。事實上，每個電池在充電的(de)任意時刻總 存在一個(ge)最(zui)佳的(de)充(chong)電電流和(he)充(chong)電模式的(de)，問題是我們如何才能逼近這個(ge)最(zui)佳值。 ;

綜合(he)起(qi)來，判(pan)斷(duan)規則有如下幾種：

●定時控制；

●電壓(ya)(ya)控制(含最高電壓(ya)(ya)：電壓(ya)(ya)負增量：電壓(ya)(ya)零增量等)；

●溫度(du)控制(包(bao)括最高溫度(du)，最高溫升：溫度(du)變化率等)；

●電流控制等。

較好的(de)辦法是采用(yong)綜合判(pan)斷(duan)方法，對(dui)每個指標進行(xing)跟(gen)蹤，并按(an)模糊數學原理分別記分，按(an)照置信度做出最(zui)佳判(pan)斷(duan)。 電(dian)池快速充電(dian)分為幾個階段(duan),見本文(wen)所述及通用(yong)充電(dian)器運行(xing)簡圖.[圖1]

　

 

圖1.通(tong)用電(dian)(dian)池充(chong)(chong)電(dian)(dian)器(qi)充(chong)(chong)電(dian)(dian)參數(shu)圖表.

 

起始階段

起(qi)始階(jie)(jie)段(duan)在充(chong)(chong)電(dian)(dian)過程(cheng)(cheng)中(zhong)雖(sui)不(bu)(bu)屬于真正起(qi)作用(yong)的(de)(de)那幾個(ge)階(jie)(jie)段(duan),但在整(zheng)個(ge)充(chong)(chong)電(dian)(dian)過程(cheng)(cheng)中(zhong),起(qi)始階(jie)(jie)段(duan)仍是一個(ge)非常重(zhong)要的(de)(de)滿(man)足(zu)條件. 充(chong)(chong)電(dian)(dian)器(qi)(qi)啟(qi)動(dong)以(yi)(yi)后開始自測,如電(dian)(dian)源出現(xian)故(gu)(gu)障或反(fan)復起(qi)動(dong),充(chong)(chong)電(dian)(dian)過程(cheng)(cheng)就會(hui)被(bei)(bei)打斷(duan)(duan).如果(guo)缺乏相應智能(neng)或時(shi)間(jian)關斷(duan)(duan)裝(zhuang)置(zhi)以(yi)(yi)及電(dian)(dian)池(chi)密 封性能(neng)不(bu)(bu)能(neng)得到改善,那么此(ci)種現(xian)象往(wang)往(wang)會(hui)被(bei)(bei)忽(hu)視.幾乎所有的(de)(de)充(chong)(chong)電(dian)(dian)器(qi)(qi)在電(dian)(dian)源出現(xian)故(gu)(gu)障以(yi)(yi)后都(dou)可(ke)以(yi)(yi)完全(quan)重(zhong)新(xin)啟(qi)動(dong),但如過充(chong)(chong)不(bu)(bu) 被(bei)(bei)允許(xu),充(chong)(chong)電(dian)(dian)器(qi)(qi)要能(neng)夠進行(xing)特(te)別(bie)的(de)(de)自測程(cheng)(cheng)序以(yi)(yi)判斷(duan)(duan)電(dian)(dian)池(chi)是否(fou)早已充(chong)(chong)滿(man).電(dian)(dian)池(chi)狀態要顯現(xian)在充(chong)(chong)電(dian)(dian)器(qi)(qi)指示燈或類(lei)似的(de)(de)顯示裝(zhuang)置(zhi)上. （不(bu)(bu)好的(de)(de)案例：例如只靠定(ding)(ding)時(shi)的(de)(de)充(chong)(chong)電(dian)(dian)器(qi)(qi),用(yong)四個(ge)小(xiao)(xiao)時(shi)間(jian)隔的(de)(de)固定(ding)(ding)時(shi)間(jian)給電(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian).如果(guo)充(chong)(chong)電(dian)(dian)三小(xiao)(xiao)時(shi)59分鐘,電(dian)(dian)源出現(xian)故(gu)(gu)障斷(duan)(duan)電(dian)(dian), 當故(gu)(gu)障清除重(zhong)新(xin)送(song)電(dian)(dian)以(yi)(yi)后,充(chong)(chong)電(dian)(dian)器(qi)(qi)又會(hui)開始重(zhong)新(xin)一輪的(de)(de)四小(xiao)(xiao)時(shi)固定(ding)(ding)充(chong)(chong)電(dian)(dian),從而造(zao)成電(dian)(dian)池(chi)過充(chong)(chong)四個(ge)小(xiao)(xiao)時(shi).這種結果(guo)往(wang)往(wang)會(hui)對(dui)電(dian)(dian)池(chi) 造(zao)成損壞。因(yin)此(ci)原因(yin),定(ding)(ding)時(shi)充(chong)(chong)電(dian)(dian)器(qi)(qi)很(hen)少(shao)被(bei)(bei)采用(yong)。）

充電時可充電池應備條件

當(dang)電(dian)(dian)池(chi)連接(jie)上充電(dian)(dian)器以后,此充電(dian)(dian)階段(duan)之充電(dian)(dian)器要能夠有所感(gan)應顯(xian)示以及彼(bi)電(dian)(dian)池(chi)是否(fou)可(ke)以進(jin)行充電(dian)(dian).一般當(dang)充電(dian)(dian)器電(dian)(dian)源(yuan)關(guan)斷 的(de)(de)情況(kuang)下,此電(dian)(dian)池(chi)感(gan)應裝置(zhi)通(tong)常(chang)(chang)根據充電(dian)(dian)器接(jie)頭(tou)的(de)(de)端口(kou)電(dian)(dian)壓(ya)來(lai)進(jin)行判斷,但當(dang)電(dian)(dian)池(chi)已經(jing)反復過度(du)使用或端口(kou)電(dian)(dian)壓(ya)極(ji)低的(de)(de)情況(kuang)下, 這(zhe)(zhe)種感(gan)應裝置(zhi)往往會產生問題.作為一種替代(dai)方法,充電(dian)(dian)器經(jing)常(chang)(chang)根據溫度(du)或電(dian)(dian)壓(ya)瞬時跳變來(lai)達到(dao)上述目的(de)(de).這(zhe)(zhe)種硬件(jian)設置(zhi)同(tong)樣適(shi) 用于電(dian)(dian)池(chi)組.

一(yi)(yi)旦充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器感應(ying)連接到了可充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi),它還必須判斷出(chu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)是否(fou)具(ju)備良好可充(chong)(chong)(chong)條(tiao)件.在這個次級階(jie)段[限定條(tiao)件],電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)要能夠 被檢測出(chu)其(qi)基(ji)本功能狀態;開(kai)路,短路,高溫或(huo)是低溫.以此來(lai)檢測電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)是否(fou)具(ju)備可充(chong)(chong)(chong)性,一(yi)(yi)些(xie)鉛酸(suan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器類型特(te)別需要一(yi)(yi)個可通(tong)過 LED燈來(lai)顯示出(chu)其(qi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)的主充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)流[大約(yue)以五分之一(yi)(yi)的快充(chong)(chong)(chong)額定電(dian)(dian)(dian)(dian)流],并允許(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)在一(yi)(yi)固定充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)時間段內(nei)達到其(qi)特(te)定的電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)壓. 這種技(ji)術(shu)對已經反(fan)復過度(du)使用的鉛酸(suan)[PbSO4]蓄電(dian)(dian)(dian)(dian)池(chi)(chi)(chi),應(ying)避免出(chu)現反(fan)接的問題.

對外圍(wei)設備(bei)和(he)電池溫度(du)的(de)(de)(de)檢(jian)測也(ye)是本階段必要(yao)條(tiao)件之一.當充(chong)(chong)電器(qi)檢(jian)測到電池的(de)(de)(de)溫度(du)過(guo)(guo)高或(huo)過(guo)(guo)低,一般會等待一段預先設定(ding)的(de)(de)(de) 時(shi)間以使其(qi)恢復正常.如在設定(ding)時(shi)間內并未恢復正常,充(chong)(chong)電器(qi)會自動(dong)改(gai)變(bian)充(chong)(chong)電電流,這(zhe)個動(dong)作相(xiang)應就調整了電池溫度(du),所以充(chong)(chong)電效率 會大大增(zeng)加.最后,充(chong)(chong)電器(qi)需要(yao)檢(jian)測一下與電池的(de)(de)(de)連接狀(zhuang)態(tai)是開(kai)路抑或(huo)短(duan)路.通常開(kai)路狀(zhuang)態(tai)容易檢(jian)測,而(er)一旦出現短(duan)路顯示,就需要(yao)進 一步(bu)確認,以避(bi)免造(zao)成事故的(de)(de)(de)發生.如果所有檢(jian)測都(dou)獲得通過(guo)(guo),就可以給電池充(chong)(chong)電了.這(zhe)種(zhong)設置相(xiang)當領(ling)先,請(qing)參閱附圖(tu)1

預先充電條件設置[自選類型]

有一(yi)些(xie)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器[如早期(qi)出(chu)現的鎳鎘電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)]都設計有一(yi)個充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)期(qi)預測階段,用以(yi)判斷在重新充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)，待測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)是(shi)否已‘完(wan)(wan)全(quan)’放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian). 所謂‘完(wan)(wan)全(quan)’放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)系指每節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的端(duan)口電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)到(dao)1V的水(shui)平(ping),以(yi)去除電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)液中的枝(zhi)狀結構,這(zhe)也是(shi)人們為什(shen)么經常(chang)錯誤(wu)地理解(jie)‘記(ji)憶 效應(ying)’的原因[通常(chang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)一(yi)次(ci)可充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容量是(shi)上(shang)次(ci)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容量的104—110百分比].這(zhe)種所謂的‘記(ji)憶效應(ying)’特指電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)內部(bu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解(jie)液枝(zhi)狀結 構狀態的自我(wo)恢復能力,如受到(dao)破壞,將減少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的使用壽命.所以(yi)按(an)正常(chang)時(shi)間周期(qi)進(jin)行的充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian),往往會(hui)解(jie)決這(zhe)個問題(ti).

在(zai)(zai)每(mei)次充電前,此(ci)預測階段(duan)(duan)都會被自動(dong)(dong)完成,或在(zai)(zai)電池充電剩余過(guo)半(ban)顯示[通過(guo)連接測試或其它(ta)操作]之(zhi)后.預測階段(duan)(duan)一般從一到十小 時不(bu)(bu)等.在(zai)(zai)一小時之(zhi)內(nei)放空(kong)電池通常不(bu)(bu)予考慮.而通過(guo)連接電阻縮短預測階段(duan)(duan)時間(jian),會產生散熱(re)困(kun)難的問(wen)題.而大于十小時的階段(duan)(duan)設(she)計 也往(wang)往(wang)不(bu)(bu)被采用(yong),除非可(ke)以用(yong)手動(dong)(dong)方式開始(shi)探(tan)測減少(shao)的電池容量.因(yin)此(ci),由(you)于對鎳鎘(ge)電池’記憶效應’的不(bu)(bu)知(zhi)和(he)種種誤解,設(she)計人員應 避免在(zai)(zai)充電器(qi)上(shang)設(she)置相關按(an)鈕來與此(ci)’效應’進行對抗.

快充階段及充電終止

快充(chong)和終止(zhi)充(chong)電方式(shi)使(shi)用(yong)要根據(ju)蓄電池(chi)(chi)(chi)及其它設(she)計因素考慮.以下探討涉及到當今通用(yong)蓄電池(chi)(chi)(chi)快充(chong)技術(shu)的全面使(shi)用(yong).如需(xu)詳細建 議資(zi)料,可(ke)與(yu)電池(chi)(chi)(chi)制造商應(ying)用(yong)部門聯系查詢.

鎳鎘,鎳氫蓄電池

鎳(nie)鎘(ge)和鎳(nie)氫蓄電(dian)(dian)(dian)(dian)池的(de)快充(chong)(chong)程序非常類似,主(zhu)要區別在(zai)于(yu)充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)終止(zhi)階段.在(zai)每一個樣例中,當(dang)充(chong)(chong)電(dian)(dian)(dian)(dian)器監測電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓及其(qi)它數據,以(yi)(yi) 判斷何(he)時終止(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)時,都需(xu)要一個恒定電(dian)(dian)(dian)(dian)流(liu).超過(guo)2C的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)是可以(yi)(yi)做到的(de),但一般最常用C/2左右的(de)電(dian)(dian)(dian)(dian)流(liu).因充(chong)(chong)電(dian)(dian)(dian)(dian)效率無論怎樣都 要小于(yu)100%, 所以(yi)(yi)用C/2電(dian)(dian)(dian)(dian)流(liu)稍多于(yu)兩個小時的(de)全(quan)充(chong)(chong)是可以(yi)(yi)被接受(shou)的(de).

在恒流充電(dian)(dian)(dian)(dian)階段(duan),電(dian)(dian)(dian)(dian)池端口電(dian)(dian)(dian)(dian)壓緩慢上(shang)升,最終到達頂點(dian)(dian)[即坡度為零的(de)電(dian)(dian)(dian)(dian)壓最高點(dian)(dian)].鎳氫(qing)電(dian)(dian)(dian)(dian)池應(ying)在此點(dian)(dian)[0DV點(dian)(dian)]終止(zhi)充電(dian)(dian)(dian)(dian).而鎳鎘 電(dian)(dian)(dian)(dian)池則應(ying)在此點(dian)(dian)之后某點(dian)(dian)[系(xi)電(dian)(dian)(dian)(dian)池端口電(dian)(dian)(dian)(dian)壓首次出(chu)現(xian)微小降(jiang)低點(dian)(dian)即-DV點(dian)(dian)]結(jie)束,請(qing)參閱圖(tu)2,可允許有少部(bu)分(fen)過充.快充如超過這(zhe)兩(liang)個設 定關斷點(dian)(dian)[最高電(dian)(dian)(dian)(dian)壓點(dian)(dian)和略小的(de)-DV點(dian)(dian)],都會(hui)對電(dian)(dian)(dian)(dian)池造成損壞(huai).這(zhe)是因(yin)為快充電(dian)(dian)(dian)(dian)流遠大于正常慢充狀態所致.

圖2.對鎳鎘電池用C/2電流進行充電的參數特性

以(yi)大(da)于C/2電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)[充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時間不會(hui)超過(guo)兩個小時],充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器仍要監測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)溫度(du)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓.因(yin)為當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充滿時,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)溫度(du)將上升(sheng)很快,所以(yi) 溫度(du)監測(ce)元(yuan)件(jian)要啟動另一(yi)關(guan)斷(duan)(duan)(duan)裝置(zhi).在(zai)這(zhe)正向上升(sheng)溫度(du)曲線(xian)上的關(guan)斷(duan)(duan)(duan)點被稱為T關(guan)斷(duan)(duan)(duan)點.除溫度(du)關(guan)斷(duan)(duan)(duan)外,其(qi)它監測(ce)數據,包括已(yi)充時間,最 大(da)限定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)保護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓,都可參預(yu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器關(guan)斷(duan)(duan)(duan).所以(yi)設(she)計(ji)成功(gong)的充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器自動關(guan)斷(duan)(duan)(duan)應(ying)依據這(zhe)幾種監測(ce)因(yin)素[溫度(du)關(guan)斷(duan)(duan)(duan),充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時間關(guan)斷(duan)(duan)(duan),電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)最大(da) 限定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓關(guan)斷(duan)(duan)(duan)等(deng)]的組合.

備(bei)注;當電(dian)池首次充(chong)(chong)電(dian),會產生模仿關斷狀態的(de)(de)特定效應(ying),因(yin)此在激活關斷模式監測(ce)曲(qu)線(xian)(xian)前,充(chong)(chong)電(dian)器會引入一(yi)個 一(yi)到(dao)五分鐘的(de)(de)緩沖(chong)期.另(ling)外,充(chong)(chong)電(dian)關斷狀態在低(di)于C\8電(dian)流(liu)充(chong)(chong)電(dian)時很(hen)難監測(ce)到(dao)數(shu)據,這(zhe)是(shi)因(yin)為與其他系統數(shu)據比較, 電(dian)壓和溫度曲(qu)線(xian)(xian)[V/t和T/t]斜率很(hen)小所(suo)致.為快速充(chong)(chong)電(dian)的(de)(de)安(an)全起見,這(zhe)些系統中的(de)(de)硬軟件(jian)配置(zhi)總是(shi)會造成充(chong)(chong)電(dian)器提(ti) 前關斷的(de)(de)誤操作(zuo)動作(zuo).

 

鋰離子電池

鋰(li)離(li)子蓄電(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)曲線(xian)和鎳離(li)子蓄電(dian)(dian)(dian)(dian)(dian)池相比很不一(yi)樣.充(chong)電(dian)(dian)(dian)(dian)(dian)關斷要確定到最大安全值之后才(cai)會動作.鋰(li)電(dian)(dian)(dian)(dian)(dian)充(chong)電(dian)(dian)(dian)(dian)(dian)器要將充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓控(kong)制(zhi) 在小于0.75%的精確范(fan)圍內,并且其最大充(chong)電(dian)(dian)(dian)(dian)(dian)效率用充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流限定控(kong)制(zhi),非常類似(si)臺式桌面型直流電(dian)(dian)(dian)(dian)(dian)源. 當(dang)快充(chong)開始(shi)時,電(dian)(dian)(dian)(dian)(dian)池端口電(dian)(dian)(dian)(dian)(dian)壓相 對較低(di),充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流就等(deng)同于其限定電(dian)(dian)(dian)(dian)(dian)流值.

在(zai)充(chong)電(dian)過(guo)程(cheng)中,電(dian)池電(dian)壓緩慢上升.最(zui)后,充(chong)電(dian)電(dian)流(liu)到(dao)達設(she)定(ding)峰值,充(chong)電(dian)電(dian)壓上升到(dao)每(mei)節 4.2V的浮充(chong)電(dian)壓水(shui)平(ping)[見(jian)圖4]

圖4.鋰離子蓄電池充電簡圖.

當電(dian)池充(chong)電(dian)到浮充(chong)電(dian)壓(ya)水平,充(chong)電(dian)器(qi)就可以終止充(chong)電(dian)了,但(dan)這種(zhong)方式忽略了充(chong)電(dian)峰頂值(zhi)關(guan)斷(duan)操作(zuo)(zuo).如在浮充(chong)電(dian)壓(ya)階(jie)段(duan),充(chong)電(dian)器(qi)會開始 定(ding)(ding)(ding)時器(qi)的操作(zuo)(zuo),在一(yi)(yi)段(duan)設定(ding)(ding)(ding)緩(huan)沖期后(hou),自(zi)動終止充(chong)電(dian).另一(yi)(yi)方式,也可監測充(chong)電(dian)電(dian)流(liu),在一(yi)(yi)個較低電(dian)流(liu)水平關(guan)斷(duan)[典型地用0.05的限定(ding)(ding)(ding)值(zhi), 一(yi)(yi)些制造商建議使用相對較高的100mA電(dian)流(liu)最小值(zhi)].充(chong)電(dian)峰值(zhi)關(guan)斷(duan)環路往往也依靠(kao)這種(zhong)技術.

最近幾年,在鋰(li)離子電(dian)池(chi)和其充電(dian)器,以及對這種新型電(dian)池(chi)的了解方面,都取得(de)了相當的進展.最早期的鋰(li)離子電(dian)池(chi)在用(yong)戶的使用(yong)方 面都有(you)一些安全層面的缺點,而(er)這些問題已(yi)不(bu)會(hui)(hui)出現在當今設計成(cheng)功的系統上了.制(zhi)造商們的建議既不(bu)會(hui)(hui)一成(cheng)不(bu)變(bian),也不(bu)會(hui)(hui)完全一致, 而(er)鋰(li)離子電(dian)池(chi)技術會(hui)(hui)繼(ji)續向前發(fa)展.

鋰(li)聚(ju)合物電(dian)池(chi)的(de)充(chong)電(dian)要求和鋰(li)離子電(dian)池(chi)的(de)要求是一樣的(de)，可(ke)以(yi)按同類(lei)對(dui)待。

最新出(chu)現的磷(lin)酸鐵鋰(li)(li)電(dian)池的電(dian)壓(ya)比鋰(li)(li)離子電(dian)池的額(e)度(du)電(dian)壓(ya)要低(di)0.4V左右，充(chong)電(dian)的恒壓(ya)電(dian)壓(ya)設定值為3.7V/節(jie)為宜。充(chong)電(dian)的方式與 鋰(li)(li)離子電(dian)池基(ji)本相同（注意只是(shi)電(dian)壓(ya)要低(di)一些！）

 

鉛酸電池.

鉛酸[PbSO4]蓄電(dian)池既可以用限(xian)流充(chong)電(dian),也可以用較(jiao)通用簡單的限(xian)壓充(chong)電(dian).限(xian)壓充(chong)電(dian)與(yu)前者具有(you)類似的作用功能,而高精確性并(bing)非是 其關鍵.這需要(yao)設(she)置一個高于電(dian)池浮充(chong)電(dian)壓的限(xian)流電(dian)壓源[大約2.45V左右].

經過預設狀態操作,充(chong)電器確認開始快(kuai)充(chong),一直(zhi)延續到最小(xiao)充(chong)電電流[這個過程類似(si)鋰(li)離子電池(chi)充(chong)電器],然(ran)后快(kuai)充(chong)終(zhong)止.這時充(chong)電器 需要一段Vf浮充(chong)電壓(ya)進行維護[通常(chang)用(yong)2.25V左(zuo)右(you)電壓(ya)].鉛酸(suan)[PbSO4]蓄電池(chi)允許在非(fei)確定階段用(yong)此浮充(chong)電壓(ya)進行維護[見圖5].

圖5.鉛酸[PbSO4]蓄電池充電簡圖.

 

在高溫(wen)環境下,對(dui)鉛酸[PbSO4]蓄(xu)電(dian)(dian)池進行快充(chong)的電(dian)(dian)流要(yao)根據每攝氏(shi)度(du)0.3百分比的標準溫(wen)度(du)系數進行調低.快充(chong)時(shi)設定最大電(dian)(dian)池溫(wen)度(du) 建議在50’C左右,但(dan)浮充(chong)一般可以超(chao)過(guo)這個溫(wen)度(du).

 

可選擇的涓流充電[適合除鋰離子電池外的其它蓄電池]

除鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)外,其(qi)它蓄電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)器(qi)經常設置(zhi)有(you)一個可供(gong)選擇的(de)涓(juan)流(liu)充(chong)電(dian)(dian)(dian)階段.這(zhe)個階段的(de)設置(zhi)可以用來補償(chang)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)滿(man)后本體的(de)自放(fang)電(dian)(dian)(dian) 現象.鉛酸[PbSO4]電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)自放(fang)電(dian)(dian)(dian)率(lv)最大[每天呈數個百分點],而(er)鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)最低(di).鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)自放(fang)電(dian)(dian)(dian)率(lv)有(you)時(shi)低(di)到已無需涓(juan)充(chong)來維護.然而(er), 鎳鎘(ge)[NiCds]蓄電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)卻經常,不定地需要C/16的(de)涓(juan)充(chong)電(dian)(dian)(dian)流(liu)以進行(xing)維護.對鎳氫[NiMH]蓄電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)而(er)言,安全的(de)持續(xu)放(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)經常在C/50左右,而(er)涓(juan) 流(liu)充(chong)電(dian)(dian)(dian)一般不被(bei)建議.

續(xu)放電(dian)電(dian)流經常在C/50左右,而涓 流充電(dian)一般(ban)不被(bei)建議.