鉛酸蓄電池充電機充電原理示意圖
鉛(qian)酸蓄(xu)電池由(you)于其制造(zao)成本(ben)低，容量大，價格低廉而(er)得到了(le)廣泛(fan)的使用。但是，若使用不當，其壽命(ming)將(jiang)大大縮短(duan)。影(ying)響鉛(qian)酸蓄(xu)電池壽命(ming)的因(yin)素很多，而(er)采用正(zheng)確的充電方(fang)式，能(neng)有效延長蓄(xu)電池的使用壽命(ming)。
研究發現：電池充電過程對電池壽命影響最大，放電過程的影響較少。也就是說，絕大多數的蓄電池不是用壞的，而是“充壞”的。由此可見，一個好的充電器對蓄電池的使用壽命(ming)具(ju)有舉(ju)足輕重的作用。
1 蓄電(dian)池充電(dian)理論基礎
上世紀60年代中(zhong)期(qi)，美國科學家馬斯對(dui)開(kai)口蓄(xu)電(dian)(dian)池的(de)(de)充(chong)電(dian)(dian)過(guo)程作了(le)(le)大量的(de)(de)試驗(yan)研(yan)究，并提出了(le)(le)以(yi)(yi)最(zui)低(di)出氣率為(wei)前提的(de)(de)，蓄(xu)電(dian)(dian)池可(ke)接受的(de)(de)充(chong)電(dian)(dian)曲線，如圖1所示。實驗(yan)表(biao)明(ming)，如果(guo)充(chong)電(dian)(dian)電(dian)(dian)流(liu)按這條曲線變化，就可(ke)以(yi)(yi)大大縮(suo)短充(chong)電(dian)(dian)時(shi)間，并且對(dui)電(dian)(dian)池的(de)(de)容量和壽命也沒有影(ying)響。原則(ze)上把這條曲線稱為(wei)最(zui)佳充(chong)電(dian)(dian)曲線，從(cong)而奠(dian)定了(le)(le)快速充(chong)電(dian)(dian)方法的(de)(de)研(yan)究方向[1，2]。
圖1最佳充電曲線
由圖1可以看出：初始充(chong)電(dian)電(dian)流很(hen)大，但是衰減很(hen)快。主(zhu)要原(yuan)因是充(chong)電(dian)過(guo)(guo)程中產生(sheng)了極(ji)化現象。在密封(feng)式(shi)蓄電(dian)池(chi)充(chong)電(dian)過(guo)(guo)程中，內部產生(sheng)氧氣(qi)和(he)氫氣(qi)，當(dang)氧氣(qi)不能被及時吸(xi)收(shou)時，便堆積在正極(ji)板(ban)（正極(ji)板(ban)產生(sheng)氧氣(qi)），使(shi)電(dian)池(chi)內部壓力加大，電(dian)池(chi)溫度上(shang)升，同(tong)時縮小了正極(ji)板(ban)的面積，表現為內阻上(shang)升，出現所謂的極(ji)化現象。
蓄電(dian)池(chi)是(shi)可逆(ni)的(de)。其放電(dian)及(ji)充(chong)電(dian)的(de)化(hua)學(xue)反應式如下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很顯(xian)然，充(chong)電過(guo)(guo)程(cheng)(cheng)和(he)放電過(guo)(guo)程(cheng)(cheng)互為逆反應(ying)。可逆過(guo)(guo)程(cheng)(cheng)就是熱力(li)學的(de)平衡過(guo)(guo)程(cheng)(cheng)，為保障(zhang)電池(chi)能夠(gou)始終維(wei)持在(zai)平衡狀態之下充(chong)電，必(bi)須(xu)盡量使通過(guo)(guo)電池(chi)的(de)電流小一(yi)些。理想條件(jian)是外加(jia)電壓等(deng)于電池(chi)本身(shen)的(de)電動(dong)(dong)勢(shi)。但是，實踐表明，蓄(xu)電池(chi)充(chong)電時，外加(jia)電壓必(bi)須(xu)增大到(dao)一(yi)定(ding)數值才行(xing),而這(zhe)個數值又因(yin)為電極材料，溶液濃(nong)度等(deng)各種因(yin)素的(de)差別而在(zai)不同(tong)程(cheng)(cheng)度上(shang)超(chao)過(guo)(guo)了蓄(xu)電池(chi)的(de)平衡電動(dong)(dong)勢(shi)值。在(zai)化學反應(ying)中，這(zhe)種電動(dong)(dong)勢(shi)超(chao)過(guo)(guo)熱力(li)學平衡值的(de)現象，就是極化現象。
一(yi)般(ban)來說，產生(sheng)極化(hua)現(xian)象有(you)3個方(fang)面的(de)原因。
1）歐(ou)姆極(ji)(ji)化(hua) 充電過(guo)程中(zhong)，正負離(li)子(zi)向兩極(ji)(ji)遷移。在離(li)子(zi)遷移過(guo)程中(zhong)不可避免地受到一(yi)定(ding)(ding)的(de)阻(zu)(zu)(zu)力(li)，稱為(wei)歐(ou)姆內阻(zu)(zu)(zu)。為(wei)了克(ke)服這個內阻(zu)(zu)(zu)，外(wai)加電壓(ya)(ya)就必(bi)須額外(wai)施加一(yi)定(ding)(ding)的(de)電壓(ya)(ya)，以克(ke)服阻(zu)(zu)(zu)力(li)推動離(li)子(zi)遷移。該(gai)電壓(ya)(ya)以熱的(de)方式轉化(hua)給環境，出(chu)現所(suo)謂的(de)歐(ou)姆極(ji)(ji)化(hua)。隨著充電電流急劇加大，歐(ou)姆極(ji)(ji)化(hua)將造(zao)成蓄電池在充電過(guo)程中(zhong)的(de)高溫。
2）濃(nong)度(du)(du)(du)極(ji)化 電(dian)流(liu)流(liu)過(guo)蓄電(dian)池(chi)時(shi)，為(wei)維持正(zheng)常的反(fan)應，最(zui)理想的情況是電(dian)極(ji)表面(mian)的反(fan)應物(wu)能(neng)(neng)及時(shi)得到(dao)補充(chong)，生成物(wu)能(neng)(neng)及時(shi)離(li)去。實際上(shang)，生成物(wu)和(he)反(fan)應物(wu)的擴散(san)速度(du)(du)(du)遠(yuan)遠(yuan)比不(bu)上(shang)化學反(fan)應速度(du)(du)(du)，從(cong)而(er)造成極(ji)板附近電(dian)解質(zhi)溶(rong)(rong)液(ye)(ye)濃(nong)度(du)(du)(du)發生變化。也就是說(shuo)，從(cong)電(dian)極(ji)表面(mian)到(dao)中部溶(rong)(rong)液(ye)(ye)，電(dian)解液(ye)(ye)濃(nong)度(du)(du)(du)分布(bu)不(bu)均勻。這種現(xian)象稱為(wei)濃(nong)度(du)(du)(du)極(ji)化。
3）電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)(hua)學(xue)極(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua)(hua) 這種極(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua)(hua)是由于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)上(shang)進行的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)(hua)學(xue)反應(ying)的速度(du)，落后(hou)于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子運動的速度(du)造成(cheng)的。例如：電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的負(fu)(fu)極(ji)(ji)(ji)(ji)(ji)(ji)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)帶(dai)有負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)，其附(fu)近(jin)溶液帶(dai)有正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)，兩者處于(yu)平衡(heng)狀(zhuang)態(tai)(tai)。放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，立即有電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子釋放(fang)(fang)給外電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)減(jian)少，而(er)金(jin)屬溶解的氧化(hua)(hua)(hua)(hua)反應(ying)進行緩慢(man)Me－e→Me＋，不能(neng)及時(shi)補充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子的減(jian)少，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)帶(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態(tai)(tai)發(fa)生變(bian)(bian)化(hua)(hua)(hua)(hua)。這種表(biao)面(mian)(mian)負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)減(jian)少的狀(zhuang)態(tai)(tai)促(cu)進金(jin)屬中電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子離(li)開(kai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)，金(jin)屬離(li)子Me＋轉入(ru)溶液，加(jia)速Me－e→Me＋反應(ying)進行。總有一個(ge)時(shi)刻，達(da)到新(xin)的動態(tai)(tai)平衡(heng)。但與放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)相(xiang)比，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)所(suo)(suo)帶(dai)負(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)數(shu)目減(jian)少了(le)，與此對(dui)應(ying)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢變(bian)(bian)正(zheng)。也就是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)(hua)學(xue)極(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)變(bian)(bian)高(gao)，從而(er)嚴重(zhong)阻礙了(le)正(zheng)常的充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流。同理，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池正(zheng)極(ji)(ji)(ji)(ji)(ji)(ji)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)(mian)所(suo)(suo)帶(dai)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)數(shu)目減(jian)少，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢變(bian)(bian)負(fu)(fu)。
這(zhe)3種(zhong)極化現(xian)象(xiang)都(dou)是隨著(zhu)充電電流(liu)的增大而(er)嚴(yan)重。
2 充電方法(fa)的(de)研究
2.1 常規充電(dian)法(fa)
常(chang)規(gui)充(chong)(chong)(chong)(chong)電(dian)制度(du)是(shi)(shi)依據1940年前國際公認的(de)經驗法(fa)則(ze)設計的(de)。其中最(zui)著(zhu)名的(de)就(jiu)是(shi)(shi)“安(an)培小時規(gui)則(ze)”：充(chong)(chong)(chong)(chong)電(dian)電(dian)流(liu)安(an)培數，不應超過(guo)蓄電(dian)池待充(chong)(chong)(chong)(chong)電(dian)的(de)安(an)時數。實際上，常(chang)規(gui)充(chong)(chong)(chong)(chong)電(dian)的(de)速(su)度(du)被蓄電(dian)池在充(chong)(chong)(chong)(chong)電(dian)過(guo)程中的(de)溫升和氣體(ti)的(de)產生所(suo)限制。這個現(xian)象對(dui)蓄電(dian)池充(chong)(chong)(chong)(chong)電(dian)所(suo)必須的(de)最(zui)短(duan)時間具有重要意義(yi)。
一(yi)般來說，常規充電有(you)以下3種。
2.1.1 恒流充(chong)電法
恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)是(shi)用調整充(chong)電(dian)(dian)(dian)(dian)(dian)裝置輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓或(huo)改變與蓄電(dian)(dian)(dian)(dian)(dian)池(chi)串聯電(dian)(dian)(dian)(dian)(dian)阻的方(fang)法(fa)，保持充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)強度不變的充(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法(fa)，如圖2所示。控制方(fang)法(fa)簡單，但由于電(dian)(dian)(dian)(dian)(dian)池(chi)的可(ke)接受電(dian)(dian)(dian)(dian)(dian)流(liu)能(neng)力是(shi)隨著(zhu)充(chong)電(dian)(dian)(dian)(dian)(dian)過程(cheng)的進行而逐(zhu)漸下降的，到充(chong)電(dian)(dian)(dian)(dian)(dian)后(hou)期，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)多(duo)用于電(dian)(dian)(dian)(dian)(dian)解(jie)水，產生氣體，使(shi)出(chu)氣過甚，因此，常選用階段充(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)。
圖2 恒流充電(dian)曲線(xian)
2.1.2 階段(duan)充電法
此方法(fa)包(bao)括二(er)階段充電法(fa)和三階段充電法(fa)。
1）二階(jie)段法 采(cai)用恒(heng)(heng)電流(liu)和(he)恒(heng)(heng)電壓(ya)(ya)相結合的(de)快速(su)充電方法，如圖3所示。首先，以恒(heng)(heng)電流(liu)充電至預(yu)定的(de)電壓(ya)(ya)值(zhi)，然后(hou)，改為恒(heng)(heng)電壓(ya)(ya)完成剩(sheng)余(yu)的(de)充電。一般兩階(jie)段之間的(de)轉(zhuan)換(huan)電壓(ya)(ya)就是第二階(jie)段的(de)恒(heng)(heng)電壓(ya)(ya)。
圖3 二階段法曲線(xian)
2）三(san)階段(duan)充電(dian)(dian)(dian)法(fa) 在充電(dian)(dian)(dian)開始和結束(shu)時采用恒電(dian)(dian)(dian)流(liu)充電(dian)(dian)(dian)，中間用恒電(dian)(dian)(dian)壓充電(dian)(dian)(dian)。當電(dian)(dian)(dian)流(liu)衰減(jian)(jian)到(dao)(dao)(dao)預定值時，由第二階段(duan)轉換到(dao)(dao)(dao)第三(san)階段(duan)。這種(zhong)方(fang)法(fa)可以將(jiang)出氣量減(jian)(jian)到(dao)(dao)(dao)最少(shao)，但(dan)作為一(yi)種(zhong)快速充電(dian)(dian)(dian)方(fang)法(fa)使用，受到(dao)(dao)(dao)一(yi)定的限制(zhi)。
2.1.3 恒壓充電法
充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓在全部充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時間里保持恒(heng)定的(de)數值，隨(sui)著蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池端電(dian)(dian)(dian)(dian)(dian)(dian)壓的(de)逐(zhu)漸(jian)升(sheng)高(gao)，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)逐(zhu)漸(jian)減少(shao)。與恒(heng)流(liu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)法相比，其充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程更(geng)接(jie)近于最佳充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)曲線。用恒(heng)定電(dian)(dian)(dian)(dian)(dian)(dian)壓快速充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，如圖4所示(shi)。由于充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)初期(qi)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)動勢較低，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)很大(da)，隨(sui)著充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)進行，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)將逐(zhu)漸(jian)減少(shao)，因此，只需(xu)簡(jian)易(yi)控制系統。
圖4 恒壓(ya)充(chong)電法曲線
這種充(chong)電(dian)方(fang)法(fa)電(dian)解(jie)水(shui)很(hen)少(shao)，避(bi)免了蓄電(dian)池(chi)(chi)過充(chong)。但在充(chong)電(dian)初期電(dian)流過大，對蓄電(dian)池(chi)(chi)壽(shou)命造成很(hen)大影響，且容易使蓄電(dian)池(chi)(chi)極板彎曲(qu)，造成電(dian)池(chi)(chi)報廢。
鑒于這種缺點，恒壓充(chong)電(dian)很(hen)少使用，只有(you)在充(chong)電(dian)電(dian)源電(dian)壓低而電(dian)流大(da)時采(cai)用。例如，汽車運行過程中，蓄電(dian)池就是以恒壓充(chong)電(dian)法充(chong)電(dian)的(de)。
2.2 快速充(chong)電技術
為(wei)了能夠最大限度地加(jia)快蓄(xu)電池(chi)(chi)的化(hua)學(xue)反應速度，縮短蓄(xu)電池(chi)(chi)達到滿充(chong)狀態的時(shi)間，同(tong)時(shi)，保證蓄(xu)電池(chi)(chi)正負極板的極化(hua)現象盡量(liang)地少(shao)或輕，提高(gao)蓄(xu)電池(chi)(chi)使(shi)用效率。快速充(chong)電技術近年來得(de)到了迅(xun)速發展。
下面介(jie)紹目前(qian)比較(jiao)流行的幾種(zhong)快速充(chong)電(dian)方法(fa)(fa)。這些方法(fa)(fa)都(dou)是(shi)圍繞著(zhu)最(zui)佳充(chong)電(dian)曲(qu)線進行設計的，目的就是(shi)使其充(chong)電(dian)曲(qu)線盡可(ke)能地逼(bi)進最(zui)佳充(chong)電(dian)曲(qu)線。
2.2.1 脈沖(chong)式充電法
這種(zhong)充電(dian)(dian)法不僅遵循蓄(xu)電(dian)(dian)池固有的(de)充電(dian)(dian)接(jie)受率，而且能夠提高蓄(xu)電(dian)(dian)池充電(dian)(dian)接(jie)受率，從而打(da)破了蓄(xu)電(dian)(dian)池指(zhi)數充電(dian)(dian)接(jie)受曲線(xian)的(de)限制，這也是(shi)蓄(xu)電(dian)(dian)池充電(dian)(dian)理論的(de)新發展。
脈(mo)(mo)沖(chong)充(chong)電(dian)(dian)方式首先是用脈(mo)(mo)沖(chong)電(dian)(dian)流(liu)對(dui)電(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)，然后讓電(dian)(dian)池(chi)(chi)停(ting)充(chong)一(yi)段時(shi)(shi)間(jian)(jian)(jian)，如此循(xun)環，如圖5所示。充(chong)電(dian)(dian)脈(mo)(mo)沖(chong)使(shi)(shi)(shi)蓄(xu)電(dian)(dian)池(chi)(chi)充(chong)滿電(dian)(dian)量(liang)，而(er)間(jian)(jian)(jian)歇期使(shi)(shi)(shi)蓄(xu)電(dian)(dian)池(chi)(chi)經化學反應(ying)產生的氧氣和氫氣有時(shi)(shi)間(jian)(jian)(jian)重新化合而(er)被吸收掉(diao)，使(shi)(shi)(shi)濃(nong)差極(ji)化和歐姆(mu)極(ji)化自然而(er)然地(di)得到消除(chu)，從而(er)減輕(qing)了蓄(xu)電(dian)(dian)池(chi)(chi)的內壓，使(shi)(shi)(shi)下一(yi)輪的恒流(liu)充(chong)電(dian)(dian)能夠更加順(shun)利地(di)進行(xing)，使(shi)(shi)(shi)蓄(xu)電(dian)(dian)池(chi)(chi)可以吸收更多的電(dian)(dian)量(liang)。間(jian)(jian)(jian)歇脈(mo)(mo)沖(chong)使(shi)(shi)(shi)蓄(xu)電(dian)(dian)池(chi)(chi)有較充(chong)分的反應(ying)時(shi)(shi)間(jian)(jian)(jian)，減少了析氣量(liang)，提高了蓄(xu)電(dian)(dian)池(chi)(chi)的充(chong)電(dian)(dian)電(dian)(dian)流(liu)接受率(lv)[5]。
圖5 脈沖式充電曲線
2.2.2 ReflexTM快速充(chong)電法
這種技術是美國的(de)一項專利技術，它(ta)主要(yao)面對(dui)(dui)的(de)充(chong)電(dian)(dian)對(dui)(dui)象是鎳鎘(ge)電(dian)(dian)池。由于它(ta)采(cai)用了新型的(de)充(chong)電(dian)(dian)方法，解(jie)決(jue)了鎳鎘(ge)電(dian)(dian)池的(de)記憶效應，因此，大大降低了蓄電(dian)(dian)池的(de)快速充(chong)電(dian)(dian)的(de)時間(jian)。鉛(qian)酸蓄電(dian)(dian)池的(de)充(chong)電(dian)(dian)方法和對(dui)(dui)充(chong)電(dian)(dian)狀(zhuang)態的(de)檢測方法與鎳鎘(ge)電(dian)(dian)池有很(hen)大的(de)不同，但它(ta)們(men)之間(jian)可(ke)以相互借鑒[3]。
如圖6所示，ReflexTM充(chong)(chong)(chong)電法的(de)一個工(gong)作周期包括(kuo)正(zheng)向充(chong)(chong)(chong)電脈(mo)沖，反向瞬間放電脈(mo)沖，停充(chong)(chong)(chong)維持3個階段[3]。
圖6 ReflexTM快速充電法
2.2.3 變電(dian)流間歇(xie)充(chong)電(dian)法
這種(zhong)充(chong)(chong)電(dian)(dian)(dian)(dian)方(fang)法建立在恒流充(chong)(chong)電(dian)(dian)(dian)(dian)和脈沖充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)(de)(de)基礎(chu)上，如圖7所示。其特點是將恒流充(chong)(chong)電(dian)(dian)(dian)(dian)段改為限壓變電(dian)(dian)(dian)(dian)流間歇(xie)(xie)充(chong)(chong)電(dian)(dian)(dian)(dian)段。充(chong)(chong)電(dian)(dian)(dian)(dian)前期的(de)(de)(de)各段采用變電(dian)(dian)(dian)(dian)流間歇(xie)(xie)充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)(de)(de)方(fang)法，保證加大充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流，獲得絕大部分充(chong)(chong)電(dian)(dian)(dian)(dian)量(liang)。充(chong)(chong)電(dian)(dian)(dian)(dian)后期采用定電(dian)(dian)(dian)(dian)壓充(chong)(chong)電(dian)(dian)(dian)(dian)段，獲得過充(chong)(chong)電(dian)(dian)(dian)(dian)量(liang)，將電(dian)(dian)(dian)(dian)池(chi)恢復(fu)至完全充(chong)(chong)電(dian)(dian)(dian)(dian)態。通過間歇(xie)(xie)停(ting)充(chong)(chong)，使(shi)(shi)蓄(xu)電(dian)(dian)(dian)(dian)池(chi)經(jing)化(hua)學反(fan)應產生的(de)(de)(de)氧氣和氫氣有時間重新化(hua)合(he)而被吸收掉，使(shi)(shi)濃差極化(hua)和歐(ou)姆極化(hua)自然而然地得到消除，從而減輕了蓄(xu)電(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)內壓，使(shi)(shi)下一輪的(de)(de)(de)恒流充(chong)(chong)電(dian)(dian)(dian)(dian)能夠更(geng)加順利地進行，使(shi)(shi)蓄(xu)電(dian)(dian)(dian)(dian)池(chi)可以吸收更(geng)多的(de)(de)(de)電(dian)(dian)(dian)(dian)量(liang)[4]。
圖(tu)7 變(bian)電(dian)流間歇充(chong)電(dian)曲線
2.2.4 變電(dian)壓間歇充電(dian)法
在變電(dian)流間(jian)歇充電(dian)法的(de)基礎上又有人提出(chu)了變電(dian)壓間(jian)歇充電(dian)法，如(ru)圖8所示(shi)。與變電(dian)流間(jian)歇充電(dian)方法不同之(zhi)處(chu)在于第一(yi)階段的(de)不是(shi)間(jian)歇恒流，而(er)是(shi)間(jian)歇恒壓。
圖8 變電壓間歇充(chong)電曲線
比較圖(tu)7和(he)圖(tu)8，可(ke)(ke)以看出：圖(tu)8更加(jia)符合(he)最佳充(chong)電(dian)(dian)的(de)充(chong)電(dian)(dian)曲線。在每個(ge)恒(heng)電(dian)(dian)壓充(chong)電(dian)(dian)階段，由于是(shi)恒(heng)壓充(chong)電(dian)(dian)，充(chong)電(dian)(dian)電(dian)(dian)流(liu)自然按照指數規律下降(jiang)，符合(he)電(dian)(dian)池(chi)電(dian)(dian)流(liu)可(ke)(ke)接受(shou)率隨著充(chong)電(dian)(dian)的(de)進行逐漸下降(jiang)的(de)特點[4]。
2.2.5 變(bian)電壓變(bian)電流波浪式間歇(xie)正負零(ling)脈沖(chong)快速(su)充電法
綜(zong)合脈沖充(chong)(chong)(chong)電(dian)法、ReflexTM快速充(chong)(chong)(chong)電(dian)法、變電(dian)流間(jian)歇(xie)充(chong)(chong)(chong)電(dian)法及變電(dian)壓間(jian)歇(xie)充(chong)(chong)(chong)電(dian)法的優(you)點，變電(dian)壓變電(dian)流波浪式正負零(ling)脈沖間(jian)歇(xie)快速充(chong)(chong)(chong)電(dian)法得到(dao)發(fa)展應(ying)用。脈沖充(chong)(chong)(chong)電(dian)法充(chong)(chong)(chong)電(dian)電(dian)路的控制一般(ban)有(you)兩(liang)種(zhong)：
1）脈沖電(dian)流的幅(fu)值可變(bian)，而PWM（驅動充放(fang)電(dian)開關管）信號的頻(pin)率(lv)是固(gu)定的；
2）脈(mo)沖電(dian)流幅值固(gu)定不(bu)變，PWM信(xin)號(hao)的頻率可調。
圖9采用了一種不同于這兩者的控制模式，脈沖(chong)電流幅值(zhi)和PWM信號的頻率(lv)均固(gu)定(ding)，PWM占空比可調，在此基礎上(shang)加入間歇停充階段，能夠(gou)在較短的時(shi)間內充進更多的電量(liang)，提高蓄(xu)電池(chi)的充電接(jie)受能力。
圖9 波浪式間歇正負零脈沖快速充電
3 結語
鉛(qian)酸(suan)蓄電(dian)池是目前世界上廣(guang)泛使(shi)(shi)用(yong)的(de)(de)(de)一種化學電(dian)源(yuan)，該產(chan)(chan)品(pin)具有(you)良好的(de)(de)(de)可(ke)逆性(xing)，電(dian)壓(ya)特性(xing)平穩，使(shi)(shi)用(yong)壽命長，適用(yong)范(fan)圍廣(guang)，原材料豐富（且可(ke)再生使(shi)(shi)用(yong)）及造價低廉等(deng)優點(dian)。主要應用(yong)在交(jiao)通運輸(shu)，通信，電(dian)力，鐵路(lu)，礦山(shan)，港口等(deng)國民(min)經濟各個部門(men)，是社(she)會生產(chan)(chan)經營活動中不(bu)可(ke)缺少的(de)(de)(de)產(chan)(chan)品(pin)，具有(you)廣(guang)闊的(de)(de)(de)發展前景(jing)。