鉛酸蓄電池充電機充電原理示意圖
鉛酸(suan)蓄電(dian)池(chi)由(you)于(yu)其制造成本低(di)，容量大(da)，價格(ge)低(di)廉(lian)而得到了廣泛的(de)使用。但是(shi)，若(ruo)使用不當，其壽命(ming)將大(da)大(da)縮(suo)短。影響鉛酸(suan)蓄電(dian)池(chi)壽命(ming)的(de)因素(su)很多，而采用正確的(de)充電(dian)方式，能有效延長蓄電(dian)池(chi)的(de)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(chi)的(de)使用(yong)壽命具有(you)舉(ju)足輕重的(de)作用(yong)。
1 蓄(xu)電池充(chong)電理(li)論基(ji)礎
上世紀60年代中(zhong)期，美國科學家(jia)馬斯對開(kai)口蓄電池(chi)的(de)充電過程作了大(da)量的(de)試驗(yan)研究，并提出(chu)了以最低出(chu)氣率為前提的(de)，蓄電池(chi)可接(jie)受的(de)充電曲(qu)線(xian)，如(ru)圖1所示。實(shi)驗(yan)表明，如(ru)果充電電流(liu)按這條(tiao)(tiao)曲(qu)線(xian)變(bian)化(hua)，就可以大(da)大(da)縮短(duan)充電時(shi)間，并且對電池(chi)的(de)容量和壽命也沒有影響。原(yuan)則上把這條(tiao)(tiao)曲(qu)線(xian)稱為最佳充電曲(qu)線(xian)，從而奠定了快速充電方法的(de)研究方向(xiang)[1，2]。
圖1最(zui)佳(jia)充(chong)電(dian)曲線(xian)
由圖(tu)1可以看出：初(chu)始充(chong)(chong)電(dian)電(dian)流很大(da)，但(dan)是(shi)衰減很快。主要原因是(shi)充(chong)(chong)電(dian)過(guo)程(cheng)中產(chan)生了(le)(le)極(ji)化現(xian)象(xiang)。在密封式蓄電(dian)池充(chong)(chong)電(dian)過(guo)程(cheng)中，內(nei)(nei)部(bu)產(chan)生氧氣(qi)和氫氣(qi)，當氧氣(qi)不(bu)能被及(ji)時(shi)(shi)吸收時(shi)(shi)，便堆積(ji)(ji)在正(zheng)(zheng)極(ji)板(ban)（正(zheng)(zheng)極(ji)板(ban)產(chan)生氧氣(qi)），使電(dian)池內(nei)(nei)部(bu)壓力(li)加大(da)，電(dian)池溫度上(shang)升(sheng)，同(tong)時(shi)(shi)縮小了(le)(le)正(zheng)(zheng)極(ji)板(ban)的(de)面(mian)積(ji)(ji)，表現(xian)為內(nei)(nei)阻上(shang)升(sheng)，出現(xian)所(suo)謂的(de)極(ji)化現(xian)象(xiang)。
蓄電池是可逆的(de)。其放電及充電的(de)化學反(fan)應式(shi)如(ru)下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很顯然(ran)，充(chong)電(dian)(dian)(dian)過(guo)(guo)程(cheng)和放電(dian)(dian)(dian)過(guo)(guo)程(cheng)互為(wei)逆(ni)反(fan)應。可逆(ni)過(guo)(guo)程(cheng)就(jiu)是熱力學(xue)(xue)的(de)(de)平(ping)衡(heng)過(guo)(guo)程(cheng)，為(wei)保障電(dian)(dian)(dian)池能(neng)夠始終維(wei)持在平(ping)衡(heng)狀態之(zhi)下充(chong)電(dian)(dian)(dian)，必(bi)須盡(jin)量使通過(guo)(guo)電(dian)(dian)(dian)池的(de)(de)電(dian)(dian)(dian)流(liu)小一些。理(li)想條件是外(wai)加電(dian)(dian)(dian)壓等于(yu)電(dian)(dian)(dian)池本身的(de)(de)電(dian)(dian)(dian)動(dong)勢(shi)。但是，實踐表明(ming)，蓄(xu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)時，外(wai)加電(dian)(dian)(dian)壓必(bi)須增(zeng)大到(dao)一定數(shu)值(zhi)(zhi)才行,而這(zhe)個數(shu)值(zhi)(zhi)又因為(wei)電(dian)(dian)(dian)極(ji)材(cai)料，溶(rong)液濃度等各種因素的(de)(de)差別而在不同程(cheng)度上超過(guo)(guo)了蓄(xu)電(dian)(dian)(dian)池的(de)(de)平(ping)衡(heng)電(dian)(dian)(dian)動(dong)勢(shi)值(zhi)(zhi)。在化學(xue)(xue)反(fan)應中(zhong)，這(zhe)種電(dian)(dian)(dian)動(dong)勢(shi)超過(guo)(guo)熱力學(xue)(xue)平(ping)衡(heng)值(zhi)(zhi)的(de)(de)現象(xiang)，就(jiu)是極(ji)化現象(xiang)。
一般來說，產(chan)生極化現象有3個方(fang)面的原因。
1）歐(ou)姆(mu)極(ji)(ji)化 充(chong)電(dian)過(guo)(guo)程中，正負(fu)離子向兩極(ji)(ji)遷移(yi)(yi)。在離子遷移(yi)(yi)過(guo)(guo)程中不可避免地(di)受到一定的(de)阻力，稱為歐(ou)姆(mu)內阻。為了克服這個內阻，外(wai)加(jia)電(dian)壓(ya)(ya)就必須額外(wai)施加(jia)一定的(de)電(dian)壓(ya)(ya)，以克服阻力推動離子遷移(yi)(yi)。該電(dian)壓(ya)(ya)以熱(re)的(de)方式轉化給環境，出(chu)現所(suo)謂(wei)的(de)歐(ou)姆(mu)極(ji)(ji)化。隨著(zhu)充(chong)電(dian)電(dian)流(liu)急劇加(jia)大，歐(ou)姆(mu)極(ji)(ji)化將造成(cheng)蓄電(dian)池在充(chong)電(dian)過(guo)(guo)程中的(de)高溫。
2）濃(nong)度(du)極化(hua) 電(dian)(dian)(dian)(dian)流流過蓄電(dian)(dian)(dian)(dian)池時，為維持(chi)正常(chang)的反(fan)應，最理想的情(qing)況是電(dian)(dian)(dian)(dian)極表面(mian)的反(fan)應物(wu)(wu)能及時得到(dao)補充，生成(cheng)物(wu)(wu)能及時離去。實際上(shang)，生成(cheng)物(wu)(wu)和(he)反(fan)應物(wu)(wu)的擴散速度(du)遠遠比不(bu)上(shang)化(hua)學反(fan)應速度(du)，從而造成(cheng)極板附近電(dian)(dian)(dian)(dian)解(jie)質溶液濃(nong)度(du)發生變化(hua)。也就是說(shuo)，從電(dian)(dian)(dian)(dian)極表面(mian)到(dao)中(zhong)部(bu)溶液，電(dian)(dian)(dian)(dian)解(jie)液濃(nong)度(du)分布不(bu)均(jun)勻。這種現象稱為濃(nong)度(du)極化(hua)。
3）電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)學(xue)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua) 這種極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua)是由(you)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)上進(jin)行(xing)(xing)(xing)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)學(xue)反應(ying)的速(su)度(du)，落后于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)上電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子運動(dong)的速(su)度(du)造(zao)成的。例如：電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的負(fu)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)帶(dai)(dai)有(you)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷，其附近溶液(ye)帶(dai)(dai)有(you)正電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷，兩(liang)者處于平衡(heng)狀(zhuang)態。放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，立即有(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子釋(shi)放(fang)給外(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷減(jian)少(shao)，而(er)金(jin)屬(shu)溶解的氧化(hua)(hua)(hua)反應(ying)進(jin)行(xing)(xing)(xing)緩慢Me－e→Me＋，不(bu)能及(ji)時補(bu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子的減(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)帶(dai)(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態發生變(bian)(bian)化(hua)(hua)(hua)。這種表(biao)面(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷減(jian)少(shao)的狀(zhuang)態促進(jin)金(jin)屬(shu)中電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子離開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)，金(jin)屬(shu)離子Me＋轉入溶液(ye)，加(jia)速(su)Me－e→Me＋反應(ying)進(jin)行(xing)(xing)(xing)。總有(you)一個時刻(ke)，達(da)到(dao)新的動(dong)態平衡(heng)。但與放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)前相比，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)所帶(dai)(dai)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷數目(mu)減(jian)少(shao)了，與此對(dui)應(ying)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)變(bian)(bian)正。也(ye)就是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)(hua)學(xue)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)化(hua)(hua)(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓變(bian)(bian)高(gao)，從而(er)嚴重阻礙了正常的充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。同理，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池正極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)表(biao)面(mian)所帶(dai)(dai)正電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷數目(mu)減(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)變(bian)(bian)負(fu)。
這3種極化現象都是隨著充(chong)電電流(liu)的增大而嚴重。
2 充電方法的研究
2.1 常規充電法
常規充(chong)(chong)電(dian)制度是依(yi)據1940年前國際公認(ren)的經驗法則(ze)設計的。其中最著名的就是“安培小時(shi)規則(ze)”：充(chong)(chong)電(dian)電(dian)流安培數(shu)，不應超(chao)過蓄電(dian)池待(dai)充(chong)(chong)電(dian)的安時(shi)數(shu)。實際上，常規充(chong)(chong)電(dian)的速度被蓄電(dian)池在充(chong)(chong)電(dian)過程中的溫升(sheng)和(he)氣體的產生所限(xian)制。這(zhe)個現象對蓄電(dian)池充(chong)(chong)電(dian)所必須的最短時(shi)間具有重要意義。
一般來說，常規充電(dian)有以下3種。
2.1.1 恒(heng)流(liu)充電法
恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)法(fa)是用(yong)(yong)調整充(chong)(chong)(chong)電(dian)(dian)(dian)裝置輸出電(dian)(dian)(dian)壓或改變(bian)與蓄電(dian)(dian)(dian)池(chi)串聯電(dian)(dian)(dian)阻(zu)的(de)(de)方法(fa)，保持充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)強度(du)不變(bian)的(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)方法(fa)，如圖2所(suo)示(shi)。控制方法(fa)簡(jian)單，但由于(yu)電(dian)(dian)(dian)池(chi)的(de)(de)可接(jie)受電(dian)(dian)(dian)流(liu)能(neng)力是隨著(zhu)充(chong)(chong)(chong)電(dian)(dian)(dian)過程的(de)(de)進行而逐漸下降的(de)(de)，到充(chong)(chong)(chong)電(dian)(dian)(dian)后(hou)期(qi)，充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)多用(yong)(yong)于(yu)電(dian)(dian)(dian)解水(shui)，產生(sheng)氣(qi)(qi)體，使出氣(qi)(qi)過甚，因此，常選用(yong)(yong)階段(duan)充(chong)(chong)(chong)電(dian)(dian)(dian)法(fa)。
圖2 恒流充電(dian)曲線
2.1.2 階段充電法
此方法包括二階段充(chong)電法和三階段充(chong)電法。
1）二(er)(er)階(jie)(jie)段(duan)(duan)法 采用恒(heng)電(dian)(dian)流(liu)和恒(heng)電(dian)(dian)壓相結合的(de)(de)快速充電(dian)(dian)方法，如圖3所示。首先(xian)，以(yi)恒(heng)電(dian)(dian)流(liu)充電(dian)(dian)至預定的(de)(de)電(dian)(dian)壓值，然后(hou)，改為(wei)恒(heng)電(dian)(dian)壓完成(cheng)剩余的(de)(de)充電(dian)(dian)。一般兩階(jie)(jie)段(duan)(duan)之間(jian)的(de)(de)轉(zhuan)換(huan)電(dian)(dian)壓就是第二(er)(er)階(jie)(jie)段(duan)(duan)的(de)(de)恒(heng)電(dian)(dian)壓。
圖3 二階段法曲線(xian)
2）三階段充電(dian)(dian)(dian)法 在充電(dian)(dian)(dian)開始和(he)結(jie)束時采用恒電(dian)(dian)(dian)流充電(dian)(dian)(dian)，中間用恒電(dian)(dian)(dian)壓充電(dian)(dian)(dian)。當電(dian)(dian)(dian)流衰(shuai)減到預(yu)定值時，由第(di)二(er)階段轉換到第(di)三階段。這種方法可以將出氣量減到最少(shao)，但作(zuo)為(wei)一種快速充電(dian)(dian)(dian)方法使用，受(shou)到一定的限(xian)制。
2.1.3 恒壓充電法(fa)
充(chong)(chong)電(dian)(dian)電(dian)(dian)源的(de)(de)電(dian)(dian)壓(ya)在全部充(chong)(chong)電(dian)(dian)時間里保持(chi)恒(heng)定的(de)(de)數值，隨著蓄電(dian)(dian)池端電(dian)(dian)壓(ya)的(de)(de)逐漸(jian)升(sheng)高(gao)，電(dian)(dian)流(liu)逐漸(jian)減(jian)少。與恒(heng)流(liu)充(chong)(chong)電(dian)(dian)法相比，其(qi)充(chong)(chong)電(dian)(dian)過(guo)程更接近于最(zui)佳充(chong)(chong)電(dian)(dian)曲線。用恒(heng)定電(dian)(dian)壓(ya)快速充(chong)(chong)電(dian)(dian)，如圖4所示。由(you)于充(chong)(chong)電(dian)(dian)初期(qi)蓄電(dian)(dian)池電(dian)(dian)動勢較低(di)，充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)很大，隨著充(chong)(chong)電(dian)(dian)的(de)(de)進行(xing)，電(dian)(dian)流(liu)將(jiang)逐漸(jian)減(jian)少，因此，只需簡(jian)易(yi)控(kong)制系統。
圖4 恒壓充電法曲線(xian)
這種充(chong)(chong)電(dian)方(fang)法電(dian)解水(shui)很少，避免了蓄電(dian)池(chi)過(guo)(guo)充(chong)(chong)。但在充(chong)(chong)電(dian)初期電(dian)流過(guo)(guo)大(da)，對蓄電(dian)池(chi)壽命造成很大(da)影響，且容(rong)易使蓄電(dian)池(chi)極板彎曲，造成電(dian)池(chi)報廢(fei)。
鑒于這種缺點，恒壓(ya)充(chong)電很少使用(yong)，只有在充(chong)電電源電壓(ya)低而(er)電流(liu)大時采用(yong)。例(li)如，汽車運行過程中，蓄電池(chi)就是以恒壓(ya)充(chong)電法(fa)充(chong)電的。
2.2 快速充(chong)電技(ji)術
為了(le)能夠最大限度(du)地(di)(di)加(jia)快(kuai)蓄電池的(de)化學反應(ying)速(su)度(du)，縮短蓄電池達到滿充狀態的(de)時(shi)間(jian)，同時(shi)，保證蓄電池正(zheng)負極板的(de)極化現象盡量地(di)(di)少(shao)或輕，提高蓄電池使用效率。快(kuai)速(su)充電技術近年來得到了(le)迅速(su)發展。
下面介(jie)紹目前比較流行的(de)幾種快速充(chong)電方法(fa)。這些方法(fa)都是圍(wei)繞著最佳充(chong)電曲線進行設計的(de)，目的(de)就是使(shi)其充(chong)電曲線盡可能地逼(bi)進最佳充(chong)電曲線。
2.2.1 脈沖式(shi)充電法
這種充電(dian)(dian)法不僅遵循蓄(xu)電(dian)(dian)池(chi)固(gu)有(you)的充電(dian)(dian)接受率，而且(qie)能夠提高蓄(xu)電(dian)(dian)池(chi)充電(dian)(dian)接受率，從(cong)而打(da)破了蓄(xu)電(dian)(dian)池(chi)指(zhi)數(shu)充電(dian)(dian)接受曲(qu)線(xian)的限制，這也(ye)是蓄(xu)電(dian)(dian)池(chi)充電(dian)(dian)理論(lun)的新(xin)發(fa)展。
脈(mo)沖(chong)(chong)(chong)充(chong)(chong)電(dian)(dian)(dian)方式首先(xian)是用(yong)脈(mo)沖(chong)(chong)(chong)電(dian)(dian)(dian)流(liu)(liu)對(dui)電(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)，然(ran)后讓電(dian)(dian)(dian)池(chi)(chi)停充(chong)(chong)一段(duan)時間(jian)，如(ru)此循環，如(ru)圖5所示。充(chong)(chong)電(dian)(dian)(dian)脈(mo)沖(chong)(chong)(chong)使蓄(xu)電(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)滿(man)電(dian)(dian)(dian)量，而(er)間(jian)歇(xie)期使蓄(xu)電(dian)(dian)(dian)池(chi)(chi)經化(hua)(hua)學反(fan)應產生的(de)氧氣和氫氣有時間(jian)重新化(hua)(hua)合而(er)被吸(xi)收掉，使濃(nong)差極(ji)化(hua)(hua)和歐姆(mu)極(ji)化(hua)(hua)自然(ran)而(er)然(ran)地得到(dao)消(xiao)除，從而(er)減(jian)輕了(le)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)的(de)內壓(ya)，使下(xia)一輪的(de)恒流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)能夠更(geng)加(jia)順利地進行，使蓄(xu)電(dian)(dian)(dian)池(chi)(chi)可以吸(xi)收更(geng)多(duo)的(de)電(dian)(dian)(dian)量。間(jian)歇(xie)脈(mo)沖(chong)(chong)(chong)使蓄(xu)電(dian)(dian)(dian)池(chi)(chi)有較充(chong)(chong)分的(de)反(fan)應時間(jian)，減(jian)少了(le)析氣量，提高(gao)了(le)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)的(de)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)接(jie)受率[5]。
圖5 脈沖式充電曲線
2.2.2 ReflexTM快(kuai)速充電(dian)法
這種技(ji)術(shu)是美國的(de)一(yi)項專利技(ji)術(shu)，它主(zhu)要面對(dui)(dui)的(de)充電(dian)(dian)(dian)對(dui)(dui)象是鎳鎘電(dian)(dian)(dian)池。由(you)于它采用了新型的(de)充電(dian)(dian)(dian)方法，解決(jue)了鎳鎘電(dian)(dian)(dian)池的(de)記(ji)憶效(xiao)應，因此，大大降低了蓄電(dian)(dian)(dian)池的(de)快(kuai)速(su)充電(dian)(dian)(dian)的(de)時(shi)間(jian)。鉛(qian)酸蓄電(dian)(dian)(dian)池的(de)充電(dian)(dian)(dian)方法和對(dui)(dui)充電(dian)(dian)(dian)狀態的(de)檢測方法與(yu)鎳鎘電(dian)(dian)(dian)池有很大的(de)不同，但它們之間(jian)可以相互借鑒(jian)[3]。
如圖6所示(shi)，ReflexTM充電(dian)法的一(yi)個(ge)工作(zuo)周期包括正向充電(dian)脈(mo)沖，反向瞬(shun)間放電(dian)脈(mo)沖，停(ting)充維持(chi)3個(ge)階(jie)段(duan)[3]。
圖6 ReflexTM快速充電法
2.2.3 變電(dian)(dian)流間歇充電(dian)(dian)法
這種充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)方法(fa)(fa)建立在恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)和脈(mo)沖充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)的基礎上，如圖7所示。其(qi)特點是將恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)改為限壓變電(dian)(dian)(dian)(dian)流(liu)(liu)間歇充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)。充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)前期(qi)的各段(duan)采(cai)用變電(dian)(dian)(dian)(dian)流(liu)(liu)間歇充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)的方法(fa)(fa)，保證加大充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)，獲(huo)得絕大部分(fen)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)量。充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)后期(qi)采(cai)用定電(dian)(dian)(dian)(dian)壓充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)，獲(huo)得過充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)量，將電(dian)(dian)(dian)(dian)池恢復至完全充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)態。通過間歇停(ting)充(chong)(chong)(chong)(chong)，使(shi)蓄電(dian)(dian)(dian)(dian)池經(jing)化(hua)學反應(ying)產(chan)生的氧(yang)氣和氫氣有時間重新(xin)化(hua)合而被吸(xi)收(shou)掉(diao)，使(shi)濃差極(ji)化(hua)和歐姆極(ji)化(hua)自(zi)然(ran)而然(ran)地(di)得到消除，從而減輕了蓄電(dian)(dian)(dian)(dian)池的內(nei)壓，使(shi)下一輪的恒(heng)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)能夠更加順利地(di)進行，使(shi)蓄電(dian)(dian)(dian)(dian)池可(ke)以吸(xi)收(shou)更多的電(dian)(dian)(dian)(dian)量[4]。
圖7 變(bian)電流(liu)間歇充(chong)電曲線
2.2.4 變電壓(ya)間(jian)歇充電法
在(zai)變(bian)電(dian)流(liu)間(jian)(jian)歇(xie)充電(dian)法(fa)的基礎上(shang)又有人提出了變(bian)電(dian)壓(ya)(ya)間(jian)(jian)歇(xie)充電(dian)法(fa)，如圖(tu)8所(suo)示。與變(bian)電(dian)流(liu)間(jian)(jian)歇(xie)充電(dian)方法(fa)不同之處在(zai)于(yu)第一階段(duan)的不是間(jian)(jian)歇(xie)恒流(liu)，而是間(jian)(jian)歇(xie)恒壓(ya)(ya)。
圖8 變電(dian)壓間歇(xie)充(chong)電(dian)曲線
比較(jiao)圖(tu)7和圖(tu)8，可以看出：圖(tu)8更(geng)加符(fu)合(he)最佳(jia)充(chong)電(dian)的充(chong)電(dian)曲線(xian)。在每(mei)個恒(heng)電(dian)壓(ya)充(chong)電(dian)階段，由(you)于是恒(heng)壓(ya)充(chong)電(dian)，充(chong)電(dian)電(dian)流(liu)自然(ran)按照指(zhi)數(shu)規律下降(jiang)，符(fu)合(he)電(dian)池電(dian)流(liu)可接(jie)受率(lv)隨著充(chong)電(dian)的進行逐漸下降(jiang)的特點(dian)[4]。
2.2.5 變電(dian)(dian)壓變電(dian)(dian)流(liu)波浪式間歇正負零脈沖快速充電(dian)(dian)法
綜合脈(mo)沖充(chong)(chong)電法(fa)(fa)(fa)、ReflexTM快速充(chong)(chong)電法(fa)(fa)(fa)、變(bian)電流(liu)間(jian)歇充(chong)(chong)電法(fa)(fa)(fa)及變(bian)電壓(ya)間(jian)歇充(chong)(chong)電法(fa)(fa)(fa)的優點(dian)，變(bian)電壓(ya)變(bian)電流(liu)波浪式正負零脈(mo)沖間(jian)歇快速充(chong)(chong)電法(fa)(fa)(fa)得到發展應用。脈(mo)沖充(chong)(chong)電法(fa)(fa)(fa)充(chong)(chong)電電路的控制一般有兩種：
1）脈沖電流的幅值可變，而(er)PWM（驅動充放(fang)電開關管）信號的頻率是(shi)固定的；
2）脈沖電流幅值固定不(bu)變，PWM信號的頻率可調。
圖(tu)9采用了(le)一種不(bu)同(tong)于這兩者的(de)(de)控制模式，脈沖(chong)電流幅值和PWM信號的(de)(de)頻率均固定(ding)，PWM占空比(bi)可調，在(zai)此基(ji)礎上加入間(jian)歇停充階(jie)段，能夠在(zai)較(jiao)短的(de)(de)時(shi)間(jian)內充進更多(duo)的(de)(de)電量，提高蓄電池的(de)(de)充電接受能力。
圖9 波浪式(shi)間歇正負零脈沖快速充電
3 結(jie)語
鉛酸蓄(xu)電(dian)(dian)(dian)池是(shi)目前(qian)世界上(shang)廣(guang)(guang)泛使(shi)用(yong)的(de)一(yi)種化學電(dian)(dian)(dian)源，該產品(pin)具(ju)有(you)良好的(de)可(ke)逆性，電(dian)(dian)(dian)壓(ya)特(te)性平穩(wen)，使(shi)用(yong)壽命(ming)長，適用(yong)范圍廣(guang)(guang)，原材(cai)料豐(feng)富（且可(ke)再(zai)生使(shi)用(yong)）及造價低廉等優點。主要應用(yong)在交通運輸，通信，電(dian)(dian)(dian)力，鐵(tie)路，礦(kuang)山(shan)，港口等國民(min)經濟(ji)各個(ge)部門，是(shi)社會生產經營活動中不(bu)可(ke)缺少的(de)產品(pin)，具(ju)有(you)廣(guang)(guang)闊的(de)發(fa)展前(qian)景。