【鎳(nie)氫充電電池】鎳氫充電電池壽命 如何延長鎳氫充電電池壽命

鎳氫電池是鎳(nie)鎘(ge)電(dian)池的后代產(chan)品，各方面(mian)性能都優于(yu)鎳(nie)鎘(ge)電(dian)池。鎳(nie)氫(qing)電(dian)池采用(yong)(yong)鎳(nie)氧化物作為正(zheng)極(ji)，儲(chu)氫(qing)金屬(shu)作為負(fu)極(ji)，堿液(ye)（主要為氫(qing)氧化鉀）作為電(dian)解液(ye)。額定電(dian)壓為1.2V，滿(man)充電(dian)時的最大電(dian)壓可達1.6V～1.8V。正(zheng)常放電(dian)終止電(dian)壓為1.0V，實際上可使用(yong)(yong)到(dao)0.9V。重復(fu)充電(dian)次(ci)數大于(yu)500次(ci)，自放電(dian)率20％/月。

鎳氫電(dian)池(chi)(chi)的(de)最大(da)放(fang)(fang)電(dian)電(dian)流可(ke)(ke)達3C（放(fang)(fang)電(dian)率C是(shi)指一(yi)小時放(fang)(fang)完全部容量的(de)電(dian)流值。如500mAh電(dian)池(chi)(chi)的(de)C為500mA）。能(neng)量重量比(bi)60～80Wh／kg，能(neng)量體積比(bi)遠高(gao)于鎳鎘(ge)(ge)電(dian)池(chi)(chi)，其(qi)單節5號(hao)電(dian)池(chi)(chi)的(de)最大(da)容量可(ke)(ke)達2300mAh，為鎳鎘(ge)(ge)電(dian)池(chi)(chi)的(de)近四倍多(duo)。鎳氫電(dian)池(chi)(chi)成本低，無鎘(ge)(ge)污染，溫度(du)使用范圍廣。具有良好的(de)快充電(dian)性能(neng)，無記憶效應，可(ke)(ke)以隨充隨用。故在采用通用電(dian)池(chi)(chi)的(de)設備(bei)中，鎳氫電(dian)池(chi)(chi)的(de)市場愈(yu)來愈(yu)大(da)。

但(dan)(dan)在實用中，人們發現鎳氫(qing)(qing)電(dian)池(chi)的(de)重復充電(dian)次數反而不(bu)及鎳鎘(ge)電(dian)池(chi)多(duo)，故有(you)鎳氫(qing)(qing)電(dian)池(chi)壽命不(bu)長之說。其(qi)實在理論上，鎳氫(qing)(qing)電(dian)池(chi)的(de)壽命比鎳鎘(ge)電(dian)池(chi)略長，但(dan)(dan)鎳氫(qing)(qing)電(dian)池(chi)過充電(dian)時，對電(dian)池(chi)的(de)不(bu)良影響比鎳鎘(ge)電(dian)池(chi)要大。

如果長期充電不當就(jiu)會損傷電池。

目前(qian)市場上(shang)的(de)(de)(de)幾十元錢的(de)(de)(de)鎳(nie)鎘／鎳(nie)氫電池(chi)充(chong)電器都過于簡單，很(hen)容易造成(cheng)鎳(nie)氫電池(chi)的(de)(de)(de)過充(chong)電。而帶(dai)充(chong)電控制芯片的(de)(de)(de)充(chong)電器售價高達(da)幾百(bai)元，使用(yong)者(zhe)不多。

因此，造(zao)成(cheng)鎳氫(qing)電池(chi)不能全面發揮(hui)優良性能。

所(suo)以，了解鎳氫電(dian)池的充電(dian)機理，正確選(xuan)購(gou)和使用充電(dian)器，對延長使用壽命至(zhi)關重要。

所(suo)謂正確的充電(dian)，就是要使充電(dian)電(dian)池(chi)的容(rong)(rong)量(liang)100％地發(fa)揮出(chu)(chu)來(lai)，而且又不損傷電(dian)池(chi)。充電(dian)不正確有二個結(jie)果，容(rong)(rong)量(liang)不能100％地發(fa)揮出(chu)(chu)來(lai)，或電(dian)池(chi)嚴重受損，在充電(dian)過程(cheng)中(zhong)異(yi)常發(fa)熱(re)、破裂，甚至起火。

下圖是鎳(nie)氫充電電池(chi)(chi)充電時(shi)的(de)充電電流和電池(chi)(chi)電壓的(de)特(te)性(xing)關(guan)系。

圖中可見在大(da)電(dian)(dian)(dian)流充(chong)電(dian)(dian)(dian)時，電(dian)(dian)(dian)壓(ya)(ya)上升(sheng)(sheng)到100％后，電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)(ya)不升(sheng)(sheng)反(fan)降。充(chong)電(dian)(dian)(dian)fC控(kong)制芯片就能利(li)用電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)(ya)從(cong)上升(sheng)(sheng)轉為下(xia)降的特征來結束充(chong)電(dian)(dian)(dian)，這種結束充(chong)電(dian)(dian)(dian)的判據(ju)稱為-△V檢測。

利(li)用(yong)(yong)-△V檢(jian)測結束充電(dian)(dian)必(bi)須(xu)恒(heng)流(liu)充電(dian)(dian)，因為電(dian)(dian)流(liu)的變(bian)(bian)動也會引(yin)起電(dian)(dian)池電(dian)(dian)壓(ya)的變(bian)(bian)動。簡(jian)單(dan)的充電(dian)(dian)器(qi)一(yi)(yi)般為恒(heng)壓(ya)限流(liu)充電(dian)(dian)，充電(dian)(dian)后期電(dian)(dian)流(liu)越(yue)來越(yue)小，-△V的檢(jian)測就變(bian)(bian)得困難。所以，利(li)用(yong)(yong)這一(yi)(yi)特性結束鎳氫電(dian)(dian)池充電(dian)(dian)時，充電(dian)(dian)電(dian)(dian)流(liu)必(bi)須(xu)保(bao)持恒(heng)定，而且必(bi)須(xu)用(yong)(yong)1C以上的大電(dian)(dian)流(liu)充電(dian)(dian)。

充電(dian)電(dian)池(chi)充滿電(dian)后，再繼續充電(dian)，電(dian)能變(bian)成電(dian)池(chi)的熱能，電(dian)池(chi)開始發(fa)熱。

充(chong)(chong)電(dian)IC控制芯片的(de)(de)另一個控制就是(shi)利用(yong)溫度的(de)(de)上升率的(de)(de)增(zeng)長來結束充(chong)(chong)電(dian)，稱為(wei)△T／△t檢(jian)測。一般達2℃／分鐘時(shi)，充(chong)(chong)電(dian)停止。

△T／△t檢(jian)測時，也要求充(chong)電(dian)(dian)電(dian)(dian)流(liu)必須保持(chi)恒流(liu)。而且也是(shi)充(chong)電(dian)(dian)電(dian)(dian)流(liu)較大（0.3C以上）時，檢(jian)測較為正確。當充(chong)電(dian)(dian)電(dian)(dian)流(liu)小或環境溫度低、散熱很好(hao)時，也會無法檢(jian)出，形成過充(chong)電(dian)(dian)。

這兩種正規(gui)的(de)(de)檢測方(fang)法都要求(qiu)大電(dian)(dian)流(liu)恒流(liu)充(chong)電(dian)(dian)。用(yong)分(fen)立元件(jian)構成，控制電(dian)(dian)路(lu)復雜(za)。用(yong)IC芯片較(jiao)方(fang)便，但溫度傳感器還(huan)必(bi)須外接。關鍵是充(chong)電(dian)(dian)器的(de)(de)電(dian)(dian)源部份要求(qiu)較(jiao)高，恒定電(dian)(dian)流(liu)較(jiao)大用(yong)簡單(dan)的(de)(de)變壓(ya)器整流(liu)己不合適，必(bi)須用(yong)開(kai)關電(dian)(dian)源。故正規(gui)的(de)(de)鎳氫電(dian)(dian)池充(chong)電(dian)(dian)器的(de)(de)售價較(jiao)高。

最為簡單的控制方式是用(yong)最大時(shi)間控制。按充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流和電(dian)(dian)(dian)池容量及充(chong)(chong)電(dian)(dian)(dian)效率決定最大充(chong)(chong)電(dian)(dian)(dian)時(shi)間，超過(guo)這個時(shi)間就無條(tiao)件(jian)停止充(chong)(chong)電(dian)(dian)(dian)。例如(ru)，用(yong)0.1C率充(chong)(chong)電(dian)(dian)(dian)，考慮(lv)充(chong)(chong)電(dian)(dian)(dian)效率，定時(shi)在12左(zuo)右小時(shi)結束充(chong)(chong)電(dian)(dian)(dian)。但這樣(yang)充(chong)(chong)電(dian)(dian)(dian)，若開(kai)始時(shi)電(dian)(dian)(dian)池內有(you)殘留量，就會有(you)事實上的過(guo)充(chong)(chong)電(dian)(dian)(dian)。

所以，定(ding)時充電(dian)(dian)電(dian)(dian)流(liu)必須小于(yu)0.3C率(lv)，大(da)多數采用(yong)0.1C率(lv)充電(dian)(dian)。由于(yu)充電(dian)(dian)電(dian)(dian)流(liu)小，過充電(dian)(dian)在電(dian)(dian)池上產生的熱量(liang)能較(jiao)快地散發(fa)出(chu)去，對電(dian)(dian)池的影響不大(da)。

最(zui)大(da)時(shi)間(jian)控制的充(chong)(chong)電(dian)器安全性(xing)能(neng)較好，最(zui)適宜充(chong)(chong)足(zu)用空的場合采用。對需隨用隨充(chong)(chong)的電(dian)器不太(tai)合適，常會存在(zai)不嚴重(zhong)的過充(chong)(chong)電(dian)。如果開(kai)始充(chong)(chong)電(dian)時(shi)能(neng)估測(ce)出(chu)電(dian)池的殘留量，就可(ke)(ke)(ke)用可(ke)(ke)(ke)變時(shi)間(jian)充(chong)(chong)電(dian)方(fang)法充(chong)(chong)足(zu)。還(huan)可(ke)(ke)(ke)在(zai)必要時(shi)進行(xing)人工干(gan)預(yu)，到達(da)估計時(shi)間(jian)或(huo)手(shou)觸電(dian)池外殼溫度明顯(xian)高(gao)于室溫時(shi)，停止充(chong)(chong)電(dian)。

好(hao)(hao)了，有了這些基礎知(zhi)識后就能正確選擇充電(dian)(dian)電(dian)(dian)池和充電(dian)(dian)器(qi)(qi)了。如(ru)果你喜歡用容量(liang)較大(da)(da)的(de)鎳氫電(dian)(dian)池，如(ru)1600mAh以(yi)上(shang)的(de)品種，那么最好(hao)(hao)還是買一只大(da)(da)電(dian)(dian)流、帶IC控制器(qi)(qi)的(de)充電(dian)(dian)器(qi)(qi)。這不但可(ke)以(yi)大(da)(da)大(da)(da)縮短充電(dian)(dian)時(shi)間，還能有效(xiao)地保護較為(wei)昂貴的(de)大(da)(da)容量(liang)充電(dian)(dian)電(dian)(dian)池。

簡易型充電器使用(yong)(yong)方便(bian)、小巧易(yi)帶(dai)。但一般都(dou)是與鎳鎘電池通用(yong)(yong)的品種。為恒(heng)壓限流型充電，電路(lu)非常簡單。只在半波整流后，串一只電阻充電。

這種(zhong)充(chong)(chong)電(dian)(dian)方法一開(kai)始電(dian)(dian)流(liu)較(jiao)大，后來電(dian)(dian)流(liu)就被限(xian)制在0.1C的小電(dian)(dian)流(liu)上，即50mA上。有的有快充(chong)(chong)電(dian)(dian)檔，也(ye)就100mA，相當(dang)500mAh鎳鎘電(dian)(dian)池的0.2C充(chong)(chong)電(dian)(dian)。好(hao)處是(shi)，用戶即使(shi)過充(chong)(chong)電(dian)(dian)，對(dui)電(dian)(dian)池的影響也(ye)不(bu)大。這種(zhong)充(chong)(chong)電(dian)(dian)器充(chong)(chong)500mAh電(dian)(dian)池，差不(bu)多一個晚上。下班充(chong)(chong)電(dian)(dian)，上班使(shi)用正(zheng)合適。

若要充1600mAh的電(dian)(dian)池就要30～40小時，實用上幾乎不(bu)可能被充足了(le)。用戶也會象對(dui)待用手機電(dian)(dian)池充電(dian)(dian)那(nei)樣，有空就充。使這類鎳氫電(dian)(dian)池長期工作在不(bu)飽不(bu)餓的狀態，對(dui)壽命和實際(ji)最大(da)可用容量都有影響。

所以。選購(gou)鎳(nie)(nie)氫電池(chi)(chi)若沒有(you)好鞍，也不必(bi)用好馬。容(rong)(rong)量適(shi)中即可(ke)，核(he)算一下以8～1 2小時(shi)能把電池(chi)(chi)充(chong)足為宜，且(qie)充(chong)電器小于O.3C。順便提一句，大容(rong)(rong)量鎳(nie)(nie)氫電池(chi)(chi)應(ying)該較重(zhong)。如果兩節(jie)鎳(nie)(nie)氫電池(chi)(chi)重(zhong)量差(cha)不多，標稱(cheng)容(rong)(rong)量大的有(you)可(ke)能是(shi)假貨。

鎳氫電(dian)(dian)(dian)池(chi)(chi)的放(fang)電(dian)(dian)(dian)也有(you)講(jiang)究(jiu)。由于鎳氫電(dian)(dian)(dian)池(chi)(chi)放(fang)電(dian)(dian)(dian)終(zhong)止電(dian)(dian)(dian)壓在(zai)1.0V為正常，但在(zai)1.O～0.9伏(fu)(fu)時(shi)也還能(neng)放(fang)電(dian)(dian)(dian)。這時(shi)就(jiu)是過(guo)放(fang)電(dian)(dian)(dian)，對(dui)電(dian)(dian)(dian)池(chi)(chi)壽命(ming)有(you)損。而一(yi)般設備(bei)，如收音機、隨身聽(ting)、電(dian)(dian)(dian)須刀等等都不具備(bei)1.0伏(fu)(fu)自動終(zhong)止放(fang)電(dian)(dian)(dian)的電(dian)(dian)(dian)路(lu)，容易使鎳氫電(dian)(dian)(dian)池(chi)(chi)過(guo)放(fang)電(dian)(dian)(dian)。在(zai)這類設備(bei)上使用(yong)，用(yong)到差不多感覺沒電(dian)(dian)(dian)時(shi)，就(jiu)該(gai)充電(dian)(dian)(dian)，不能(neng)用(yong)到完全走不動再充。在(zai)數碼相(xiang)機、MP3等內部有(you)電(dian)(dian)(dian)源管理(li)系(xi)統(tong)的設備(bei)上沒此問題。

后期放電(dian)因內(nei)阻(zu)增高，電(dian)池(chi)(chi)(chi)溫(wen)度也會(hui)上升。而鎳(nie)(nie)氫電(dian)池(chi)(chi)(chi)的(de)(de)內(nei)阻(zu)雖比鋰離子電(dian)池(chi)(chi)(chi)低幾倍(bei)，但為(wei)鎳(nie)(nie)鎘(ge)電(dian)池(chi)(chi)(chi)內(nei)阻(zu)的(de)(de)2倍(bei)。故(gu)鎳(nie)(nie)氫電(dian)池(chi)(chi)(chi)后期使用發熱會(hui)比鎳(nie)(nie)鎘(ge)電(dian)池(chi)(chi)(chi)大。

鎳(nie)氫電(dian)(dian)池雖然一開始認為沒有記憶(yi)效應(ying)，但與后來出現(xian)(xian)的(de)鋰離子電(dian)(dian)池相比(bi)，仍有一定的(de)容量下降現(xian)(xian)象。鎳(nie)氫電(dian)(dian)池若長期不用，就(jiu)會(hui)出現(xian)(xian)休眠現(xian)(xian)象。

容量大(da)大(da)降(jiang)低。故對(dui)于新買來的(de)或擱置了一段時間沒(mei)用的(de)鎳氫電(dian)(dian)池，要(yao)先以涓(juan)流充足(zu)電(dian)(dian)量（寧過勿缺），然后(hou)以0.2C率(lv)放電(dian)(dian)到(dao)1.0V，此反(fan)復幾次，以此激活。