鎳氫電池充足電后，如果不及時停止快速充電，電池的溫度和內部壓力將迅速上升。內部壓力過大時，密封電池將打開放氣孔，從而使電解液逸散，造成電解液的粘稠性增大，電池的內阻增大，容量下降。因此，為了既保證電池充足電，又不過充電，必須控制充電的終點，一般采用定時控制，電壓控制和溫度控制等多種方法。

第一階段

當恒定電(dian)流剛充入(ru)放完電(dian)的(de)(de)鎳氫電(dian)池(chi)時，由(you)于電(dian)池(chi)內(nei)阻產生壓降，所以電(dian)池(chi)電(dian)壓很快上升（A點）。此后，電(dian)池(chi)開始接受電(dian)荷(he)，電(dian)池(chi)電(dian)壓以較(jiao)低(di)的(de)(de)速(su)率(lv)持(chi)續上升。在這個范圍內(nei)（AB之間），電(dian)化學反應以一(yi)定的(de)(de)速(su)率(lv)產生氧氣，同(tong)時氧氣也以同(tong)樣的(de)(de)速(su)率(lv)與(yu)氫氣化合，因(yin)此，電(dian)池(chi)內(nei)部的(de)(de)溫度和氣體(ti)壓力都很低(di)。

第二階(jie)段

經(jing)過(guo)一(yi)定時間后，電(dian)(dian)解液中開始產生氣(qi)泡，這(zhe)些氣(qi)泡聚(ju)集在極(ji)板(ban)表面，使極(ji)板(ban)的有效面積減小，所以電(dian)(dian)池的內阻抗增加，電(dian)(dian)池電(dian)(dian)壓開始較快上升。這(zhe)是接近充足電(dian)(dian)的信(xin)號。

第三階段

充足電(dian)后，充入電(dian)池(chi)的電(dian)流不是轉換為電(dian)池(chi)的貯能，而(er)是在正(zheng)極板(ban)上(shang)產生(sheng)氧(yang)(yang)(yang)氣(qi)。氧(yang)(yang)(yang)氣(qi)是由(you)于(yu)電(dian)解(jie)液電(dian)解(jie)而(er)產生(sheng)的。在氫(qing)氧(yang)(yang)(yang)化鉀(jia)和水組成(cheng)的電(dian)解(jie)液中，氫(qing)氧(yang)(yang)(yang)離(li)子變成(cheng)氧(yang)(yang)(yang)、水和自由(you)電(dian)子，反應式為40H-→O21+2H0+4e-

雖然電(dian)(dian)解液(ye)產生的(de)氧氣能(neng)很快在(zai)負極板(ban)表面的(de)電(dian)(dian)解液(ye)中復合，但(dan)是電(dian)(dian)池的(de)溫(wen)度仍(reng)顯著升高。此外由(you)于充電(dian)(dian)電(dian)(dian)流用來產生氧氣，所以(yi)電(dian)(dian)池內的(de)壓力(li)也(ye)升高。

由于從(cong)大量(liang)的(de)(de)氫氧離子中很容易分(fen)解(jie)出(chu)氧氣，所(suo)以電池內的(de)(de)溫度(du)急劇(ju)上升，這樣就(jiu)使電池電壓(ya)(ya)下降。因此電池電壓(ya)(ya)曲線出(chu)現峰值。

鎳氫電池充(chong)電過程

電(dian)池的充(chong)(chong)電(dian)過程通常(chang)可分為預充(chong)(chong)電(dian)、快速充(chong)(chong)電(dian)、補足(zu)充(chong)(chong)電(dian)、涓(juan)流充(chong)(chong)電(dian)四個階(jie)段。

預(yu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)：對長期不用的(de)或新(xin)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時，一開始就采用快速充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，會影響電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)壽(shou)命(ming)。因此，這種電(dian)(dian)(dian)(dian)(dian)池(chi)應(ying)先用小電(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，使其滿足一定的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)條件，這個階(jie)段(duan)稱為預(yu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。

快(kuai)速(su)充電(dian)(dian)：就是用(yong)大電(dian)(dian)流充電(dian)(dian)，迅速(su)恢復電(dian)(dian)池(chi)電(dian)(dian)能。快(kuai)速(su)充電(dian)(dian)速(su)率(lv)一般在1C以上，快(kuai)速(su)充時間由電(dian)(dian)池(chi)容量和充電(dian)(dian)速(su)率(lv)決定(ding)。

鎳氫電池電池充電過程

補(bu)足(zu)充(chong)(chong)電(dian)：采用某些快速(su)充(chong)(chong)電(dian)止法(fa)時，快速(su)充(chong)(chong)電(dian)終止后，電(dian)池并未(wei)充(chong)(chong)足(zu)電(dian)。為了保證充(chong)(chong)入(ru)100%的電(dian)量，還應加入(ru)補(bu)足(zu)充(chong)(chong)電(dian)過程(cheng)。補(bu)足(zu)充(chong)(chong)電(dian)速(su)率(lv)一般不超過0.3C。

涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)：也(ye)稱為維(wei)護(hu)充(chong)(chong)(chong)電(dian)(dian)(dian)。根據電(dian)(dian)(dian)池的自放(fang)電(dian)(dian)(dian)特性，涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)速(su)率一般都(dou)很低。只要電(dian)(dian)(dian)池接(jie)(jie)在充(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)上并且(qie)充(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)接(jie)(jie)通電(dian)(dian)(dian)源，在維(wei)護(hu)充(chong)(chong)(chong)電(dian)(dian)(dian)狀態下，充(chong)(chong)(chong)電(dian)(dian)(dian)器(qi)將以某一充(chong)(chong)(chong)電(dian)(dian)(dian)速(su)率給(gei)電(dian)(dian)(dian)池補充(chong)(chong)(chong)電(dian)(dian)(dian)荷，這樣可使電(dian)(dian)(dian)池總(zong)處于充(chong)(chong)(chong)足電(dian)(dian)(dian)狀態。

充電終制方(fang)法

定時控制

根據電(dian)(dian)池的(de)容量(liang)和充(chong)電(dian)(dian)電(dian)(dian)流(liu)，很容易確定(ding)所需的(de)充(chong)電(dian)(dian)時間。這(zhe)種控制方法最簡單，但是由(you)于(yu)電(dian)(dian)池的(de)起(qi)始充(chong)電(dian)(dian)狀態不(bu)完全相同，有(you)的(de)電(dian)(dian)池充(chong)不(bu)足(zu)，有(you)的(de)電(dian)(dian)池過(guo)充(chong)電(dian)(dian)，因(yin)此，只有(you)充(chong)電(dian)(dian)速率(lv)小(xiao)于(yu)0.3C時，才(cai)允(yun)許采用這(zhe)種方法。

電壓控制

最高電(dian)(dian)壓(ya)（V）：從充(chong)(chong)(chong)電(dian)(dian)特性(xing)曲(qu)線可(ke)以看出，電(dian)(dian)池(chi)電(dian)(dian)壓(ya)達(da)到(dao)最大值(zhi)時，電(dian)(dian)池(chi)即充(chong)(chong)(chong)足(zu)電(dian)(dian)。充(chong)(chong)(chong)電(dian)(dian)過(guo)程(cheng)中，當電(dian)(dian)池(chi)電(dian)(dian)壓(ya)達(da)到(dao)規定值(zhi)后，應立即停止(zhi)快速(su)(su)充(chong)(chong)(chong)電(dian)(dian)。這種(zhong)控制(zhi)方法的缺點是：電(dian)(dian)池(chi)充(chong)(chong)(chong)足(zu)電(dian)(dian)的最高電(dian)(dian)壓(ya)隨環境溫度、充(chong)(chong)(chong)電(dian)(dian)速(su)(su)率(lv)而(er)變，而(er)且電(dian)(dian)池(chi)組中各單體電(dian)(dian)池(chi)的最高充(chong)(chong)(chong)電(dian)(dian)壓(ya)也有(you)差別(bie)，因此采用(yong)這種(zhong)方法不可(ke)能非常準確(que)地(di)判斷電(dian)(dian)池(chi)已(yi)足(zu)充(chong)(chong)(chong)電(dian)(dian)。

電(dian)(dian)壓(ya)負(fu)增量(liang)（-AV）：由(you)于電(dian)(dian)池(chi)電(dian)(dian)壓(ya)的負(fu)增量(liang)與(yu)電(dian)(dian)池(chi)組的絕對(dui)電(dian)(dian)壓(ya)無關(guan)，而且不受環境溫度和充(chong)(chong)電(dian)(dian)速率(lv)等(deng)因(yin)素(su)影響，因(yin)此可以比較(jiao)準確(que)地判(pan)斷電(dian)(dian)池(chi)已(yi)充(chong)(chong)足電(dian)(dian)。這種控(kong)制方法的缺(que)點是：電(dian)(dian)池(chi)電(dian)(dian)壓(ya)出現負(fu)增量(liang)后(hou)，電(dian)(dian)池(chi)已(yi)經(jing)過充(chong)(chong)電(dian)(dian)，因(yin)此電(dian)(dian)池(chi)的溫度較(jiao)高(gao)。此外鎳(nie)氫電(dian)(dian)池(chi)充(chong)(chong)足電(dian)(dian)后(hou)，電(dian)(dian)池(chi)電(dian)(dian)壓(ya)要經(jing)過較(jiao)長時間，才出現負(fu)增量(liang)，過充(chong)(chong)電(dian)(dian)較(jiao)嚴重。

電(dian)(dian)(dian)壓(ya)(ya)零(ling)增量（0AV）：鎳氫電(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)器中，為(wei)了避免等待出現電(dian)(dian)(dian)壓(ya)(ya)負增量的時間(jian)過(guo)久而(er)損壞電(dian)(dian)(dian)池(chi)，通常采(cai)用0AV控制法。這(zhe)種方法的缺點是：充(chong)(chong)足電(dian)(dian)(dian)以前(qian)(qian)，電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)在(zai)某(mou)一段(duan)時間(jian)內可能變(bian)化(hua)很小，從而(er)造成過(guo)早地停(ting)止快速(su)充(chong)(chong)電(dian)(dian)(dian)。為(wei)此(ci)，目(mu)前(qian)(qian)大多數(shu)鎳氫電(dian)(dian)(dian)池(chi)快速(su)充(chong)(chong)電(dian)(dian)(dian)器都(dou)采(cai)用高靈(ling)敏-0AV檢(jian)測，當(dang)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)略有降低(di)時（一般約為(wei)10mV），立即(ji)停(ting)止快速(su)充(chong)(chong)電(dian)(dian)(dian)。

溫度控制

最(zui)高溫度(du)（Tm）：充電(dian)(dian)(dian)過程中，通常當電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)溫度(du)達到(dao)45℃時，應立(li)即停止快速(su)充電(dian)(dian)(dian)。電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的溫度(du)可通過與電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)裝(zhuang)在一(yi)起的熱敏電(dian)(dian)(dian)阻來檢測。這種(zhong)方法的缺點是熱敏電(dian)(dian)(dian)阻的響應時間較長，溫度(du)檢測有(you)一(yi)定滯后，同(tong)時，電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的最(zui)高工作溫度(du)與環境(jing)溫度(du)有(you)關(guan)。當環境(jing)溫度(du)過低時，充足(zu)電(dian)(dian)(dian)后，電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的溫度(du)也達不到(dao)45℃。

溫升（AT）：為(wei)了消除環境(jing)影(ying)響(xiang)，可采用(yong)溫升控(kong)制法(fa)。當電(dian)池的溫升達(da)到(dao)規定(ding)值后，立(li)即停止快速(su)充電(dian)。為(wei)了實(shi)現(xian)溫升控(kong)制，必(bi)須用(yong)兩只熱敏電(dian)阻，分別檢測電(dian)池溫度和環境(jing)溫度。

溫(wen)度(du)變(bian)化率（AT/At）：鎳氫電(dian)池(chi)(chi)充足電(dian)后，電(dian)池(chi)(chi)溫(wen)度(du)迅速上(shang)升(sheng)，當(dang)電(dian)池(chi)(chi)溫(wen)度(du)每分鐘上(shang)升(sheng)1℃時，應(ying)(ying)當(dang)立即終止快(kuai)速充電(dian)，這種充電(dian)控制方(fang)法(fa)，近年來被(bei)普遍采用。應(ying)(ying)當(dang)說明，由于熱(re)敏電(dian)阻(zu)的(de)阻(zu)值(zhi)與溫(wen)度(du)關(guan)系是非線(xian)性的(de)，因(yin)此，為了提(ti)高(gao)檢測精(jing)度(du)應(ying)(ying)設法(fa)減小熱(re)敏電(dian)阻(zu)非線(xian)性的(de)影響。