鉛酸蓄電池充電機充電原理示意圖
鉛酸(suan)蓄電(dian)池由于(yu)其制造成本(ben)低，容量(liang)大(da)，價格低廉而(er)得到了(le)廣泛的(de)(de)使(shi)用(yong)(yong)。但是，若使(shi)用(yong)(yong)不當，其壽命將大(da)大(da)縮短。影(ying)響鉛酸(suan)蓄電(dian)池壽命的(de)(de)因(yin)素(su)很多，而(er)采用(yong)(yong)正確的(de)(de)充電(dian)方式(shi)，能有效延長蓄電(dian)池的(de)(de)使(shi)用(yong)(yong)壽命。
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(shou)命具有舉足輕重的作用。
1 蓄電池充電理(li)論基礎
上(shang)世紀60年代中期(qi)，美國(guo)科學家(jia)馬斯(si)對(dui)開口蓄(xu)電(dian)池(chi)(chi)的充(chong)電(dian)過(guo)程作了(le)大(da)(da)量的試驗研(yan)究，并提(ti)出了(le)以最低出氣(qi)率為前提(ti)的，蓄(xu)電(dian)池(chi)(chi)可(ke)接受(shou)的充(chong)電(dian)曲(qu)(qu)線(xian)(xian)，如(ru)圖(tu)1所(suo)示。實驗表明，如(ru)果充(chong)電(dian)電(dian)流按(an)這條(tiao)曲(qu)(qu)線(xian)(xian)變化，就可(ke)以大(da)(da)大(da)(da)縮短充(chong)電(dian)時(shi)間，并且對(dui)電(dian)池(chi)(chi)的容量和(he)壽命也沒有(you)影(ying)響。原則上(shang)把這條(tiao)曲(qu)(qu)線(xian)(xian)稱為最佳充(chong)電(dian)曲(qu)(qu)線(xian)(xian)，從而奠定了(le)快速充(chong)電(dian)方法的研(yan)究方向[1，2]。
圖1最佳充電(dian)曲線
由(you)圖1可以看出：初始充(chong)電(dian)電(dian)流很(hen)大(da)，但是(shi)衰減很(hen)快(kuai)。主要原因是(shi)充(chong)電(dian)過(guo)程中產(chan)生(sheng)(sheng)了(le)極(ji)(ji)化現(xian)(xian)(xian)象。在密(mi)封式蓄(xu)電(dian)池充(chong)電(dian)過(guo)程中，內(nei)部產(chan)生(sheng)(sheng)氧氣(qi)和氫(qing)氣(qi)，當氧氣(qi)不能被及時吸收(shou)時，便堆積在正極(ji)(ji)板（正極(ji)(ji)板產(chan)生(sheng)(sheng)氧氣(qi)），使電(dian)池內(nei)部壓力加大(da)，電(dian)池溫度上升，同時縮小(xiao)了(le)正極(ji)(ji)板的(de)面(mian)積，表現(xian)(xian)(xian)為內(nei)阻上升，出現(xian)(xian)(xian)所(suo)謂的(de)極(ji)(ji)化現(xian)(xian)(xian)象。
蓄電池是可逆的。其放電及(ji)充電的化學反(fan)應式如(ru)下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很(hen)顯(xian)然，充電(dian)(dian)(dian)(dian)過(guo)(guo)程和放(fang)電(dian)(dian)(dian)(dian)過(guo)(guo)程互為逆(ni)反應。可逆(ni)過(guo)(guo)程就是(shi)熱(re)力(li)學的(de)平(ping)衡(heng)(heng)過(guo)(guo)程，為保障電(dian)(dian)(dian)(dian)池(chi)(chi)能夠始終維持在平(ping)衡(heng)(heng)狀(zhuang)態之下充電(dian)(dian)(dian)(dian)，必須盡量使通(tong)過(guo)(guo)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)電(dian)(dian)(dian)(dian)流小(xiao)一些。理想條件是(shi)外加電(dian)(dian)(dian)(dian)壓(ya)等于電(dian)(dian)(dian)(dian)池(chi)(chi)本(ben)身的(de)電(dian)(dian)(dian)(dian)動(dong)勢。但(dan)是(shi)，實踐表明，蓄電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)時，外加電(dian)(dian)(dian)(dian)壓(ya)必須增大到(dao)一定(ding)數值才行(xing),而這個數值又因為電(dian)(dian)(dian)(dian)極材料(liao)，溶液濃度等各種(zhong)因素的(de)差別而在不同程度上超過(guo)(guo)了蓄電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)平(ping)衡(heng)(heng)電(dian)(dian)(dian)(dian)動(dong)勢值。在化學反應中，這種(zhong)電(dian)(dian)(dian)(dian)動(dong)勢超過(guo)(guo)熱(re)力(li)學平(ping)衡(heng)(heng)值的(de)現象(xiang)，就是(shi)極化現象(xiang)。
一(yi)般(ban)來說(shuo)，產生極化現象(xiang)有3個方(fang)面的原因。
1）歐姆極化(hua) 充電(dian)過程中，正(zheng)負離(li)子向(xiang)兩(liang)極遷移(yi)。在離(li)子遷移(yi)過程中不可避免地受到(dao)一(yi)定(ding)的(de)(de)阻力，稱為歐姆內阻。為了克服這個內阻，外加(jia)電(dian)壓就必須額外施加(jia)一(yi)定(ding)的(de)(de)電(dian)壓，以克服阻力推動離(li)子遷移(yi)。該電(dian)壓以熱的(de)(de)方(fang)式轉化(hua)給環(huan)境，出現所謂(wei)的(de)(de)歐姆極化(hua)。隨(sui)著充電(dian)電(dian)流急劇(ju)加(jia)大，歐姆極化(hua)將造成蓄電(dian)池在充電(dian)過程中的(de)(de)高溫(wen)。
2）濃(nong)度(du)極(ji)(ji)化 電(dian)流流過蓄電(dian)池(chi)時(shi)，為維持正常的(de)反應，最理想的(de)情況(kuang)是電(dian)極(ji)(ji)表面的(de)反應物(wu)能(neng)及時(shi)得到補充，生(sheng)成物(wu)能(neng)及時(shi)離去(qu)。實際(ji)上，生(sheng)成物(wu)和反應物(wu)的(de)擴散速(su)度(du)遠(yuan)遠(yuan)比不上化學(xue)反應速(su)度(du)，從而造(zao)成極(ji)(ji)板(ban)附近電(dian)解質溶液(ye)濃(nong)度(du)發生(sheng)變化。也就是說，從電(dian)極(ji)(ji)表面到中部(bu)溶液(ye)，電(dian)解液(ye)濃(nong)度(du)分布不均勻(yun)。這種現象稱為濃(nong)度(du)極(ji)(ji)化。
3）電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學極(ji)(ji)化(hua)(hua) 這種極(ji)(ji)化(hua)(hua)是(shi)由于電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)上(shang)進(jin)行(xing)的(de)電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學反(fan)應(ying)的(de)速(su)度(du)，落后于電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)上(shang)電(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)運動的(de)速(su)度(du)造成的(de)。例如：電(dian)(dian)(dian)(dian)(dian)池的(de)負極(ji)(ji)放電(dian)(dian)(dian)(dian)(dian)前，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)帶有負電(dian)(dian)(dian)(dian)(dian)荷(he)，其(qi)附近(jin)溶液帶有正電(dian)(dian)(dian)(dian)(dian)荷(he)，兩者處于平衡(heng)狀(zhuang)態(tai)。放電(dian)(dian)(dian)(dian)(dian)時(shi)，立即有電(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)釋放給外電(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)負電(dian)(dian)(dian)(dian)(dian)荷(he)減少(shao)，而金(jin)屬(shu)溶解的(de)氧化(hua)(hua)反(fan)應(ying)進(jin)行(xing)緩慢Me－e→Me＋，不能及(ji)時(shi)補(bu)充電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)電(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)的(de)減少(shao)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)帶電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態(tai)發生(sheng)變(bian)化(hua)(hua)。這種表(biao)(biao)(biao)(biao)面(mian)負電(dian)(dian)(dian)(dian)(dian)荷(he)減少(shao)的(de)狀(zhuang)態(tai)促進(jin)金(jin)屬(shu)中(zhong)電(dian)(dian)(dian)(dian)(dian)子(zi)(zi)(zi)離開(kai)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)，金(jin)屬(shu)離子(zi)(zi)(zi)Me＋轉入溶液，加(jia)速(su)Me－e→Me＋反(fan)應(ying)進(jin)行(xing)。總(zong)有一個時(shi)刻，達到新的(de)動態(tai)平衡(heng)。但(dan)與放電(dian)(dian)(dian)(dian)(dian)前相比，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)所(suo)帶負電(dian)(dian)(dian)(dian)(dian)荷(he)數目(mu)減少(shao)了，與此對應(ying)的(de)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢(shi)(shi)變(bian)正。也就是(shi)電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學極(ji)(ji)化(hua)(hua)電(dian)(dian)(dian)(dian)(dian)壓變(bian)高，從而嚴重(zhong)阻礙了正常的(de)充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流。同理，電(dian)(dian)(dian)(dian)(dian)池正極(ji)(ji)放電(dian)(dian)(dian)(dian)(dian)時(shi)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表(biao)(biao)(biao)(biao)面(mian)所(suo)帶正電(dian)(dian)(dian)(dian)(dian)荷(he)數目(mu)減少(shao)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢(shi)(shi)變(bian)負。
這3種極化現象都(dou)是隨(sui)著充電電流(liu)的增大而嚴(yan)重。
2 充電(dian)方法的(de)研(yan)究(jiu)
2.1 常規(gui)充電法
常(chang)規(gui)充電(dian)(dian)制度是(shi)依(yi)據1940年(nian)前(qian)國際公認的經驗法則設計的。其中(zhong)最著名的就是(shi)“安(an)培(pei)小時規(gui)則”：充電(dian)(dian)電(dian)(dian)流安(an)培(pei)數，不應超過蓄電(dian)(dian)池待充電(dian)(dian)的安(an)時數。實際上，常(chang)規(gui)充電(dian)(dian)的速度被蓄電(dian)(dian)池在充電(dian)(dian)過程(cheng)中(zhong)的溫升和氣體的產生(sheng)所(suo)限制。這個現象對(dui)蓄電(dian)(dian)池充電(dian)(dian)所(suo)必須的最短(duan)時間具(ju)有重要意(yi)義(yi)。
一般來說，常規(gui)充(chong)電有以下(xia)3種。
2.1.1 恒流充電法
恒流充(chong)(chong)電(dian)(dian)法(fa)是(shi)用(yong)調整充(chong)(chong)電(dian)(dian)裝置輸出電(dian)(dian)壓或改變(bian)與蓄電(dian)(dian)池串聯電(dian)(dian)阻的方(fang)法(fa)，保(bao)持充(chong)(chong)電(dian)(dian)電(dian)(dian)流強度不變(bian)的充(chong)(chong)電(dian)(dian)方(fang)法(fa)，如圖2所示。控制(zhi)方(fang)法(fa)簡單，但(dan)由于電(dian)(dian)池的可接受電(dian)(dian)流能力是(shi)隨著充(chong)(chong)電(dian)(dian)過程的進行而(er)逐(zhu)漸下降的，到充(chong)(chong)電(dian)(dian)后期，充(chong)(chong)電(dian)(dian)電(dian)(dian)流多用(yong)于電(dian)(dian)解(jie)水，產生(sheng)氣體，使(shi)出氣過甚(shen)，因此，常選用(yong)階段充(chong)(chong)電(dian)(dian)法(fa)。
圖2 恒(heng)流充電曲線
2.1.2 階段充電法
此方法包括二階段(duan)充電(dian)法和(he)三階段(duan)充電(dian)法。
1）二(er)(er)階段法 采(cai)用恒(heng)電(dian)流和恒(heng)電(dian)壓相結合的(de)(de)快速充電(dian)方法，如圖3所示。首先，以恒(heng)電(dian)流充電(dian)至預定的(de)(de)電(dian)壓值，然后，改(gai)為恒(heng)電(dian)壓完成剩余(yu)的(de)(de)充電(dian)。一般兩階段之間的(de)(de)轉換電(dian)壓就是(shi)第二(er)(er)階段的(de)(de)恒(heng)電(dian)壓。
圖3 二(er)階段法曲線
2）三(san)階(jie)段(duan)充(chong)(chong)電法(fa)(fa) 在充(chong)(chong)電開始和結束時采用(yong)恒電流充(chong)(chong)電，中(zhong)間用(yong)恒電壓充(chong)(chong)電。當電流衰減到預定值時，由(you)第(di)二階(jie)段(duan)轉(zhuan)換到第(di)三(san)階(jie)段(duan)。這(zhe)種(zhong)方(fang)法(fa)(fa)可以將(jiang)出氣量減到最(zui)少，但作(zuo)為一(yi)種(zhong)快速(su)充(chong)(chong)電方(fang)法(fa)(fa)使(shi)用(yong)，受到一(yi)定的限制。
2.1.3 恒壓充(chong)電法(fa)
充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)在全部充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時(shi)間里保持恒定的(de)(de)(de)數值(zhi)，隨(sui)著蓄電(dian)(dian)(dian)(dian)(dian)池端電(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)逐漸升高，電(dian)(dian)(dian)(dian)(dian)流(liu)逐漸減(jian)少。與恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)法相比，其(qi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程(cheng)更接近于(yu)最佳(jia)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)曲(qu)線。用(yong)恒定電(dian)(dian)(dian)(dian)(dian)壓(ya)快(kuai)速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，如圖4所示。由于(yu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)初期蓄電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)動勢(shi)較(jiao)低，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)很(hen)大(da)，隨(sui)著充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)進行，電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)逐漸減(jian)少，因此，只(zhi)需簡易控制系統。
圖4 恒壓充電法曲(qu)線
這(zhe)種(zhong)充(chong)電(dian)(dian)方(fang)法電(dian)(dian)解水很少，避免了(le)蓄電(dian)(dian)池過(guo)充(chong)。但在充(chong)電(dian)(dian)初期(qi)電(dian)(dian)流過(guo)大，對蓄電(dian)(dian)池壽命造成很大影響，且容易(yi)使蓄電(dian)(dian)池極板彎曲(qu)，造成電(dian)(dian)池報廢(fei)。
鑒于這種缺點(dian)，恒(heng)壓(ya)充電很少(shao)使用，只有在充電電源電壓(ya)低(di)而電流大時采用。例如，汽車(che)運行過程中，蓄電池(chi)就(jiu)是以恒(heng)壓(ya)充電法(fa)充電的(de)。
2.2 快速充電技術(shu)
為了能夠最(zui)大限度(du)地加(jia)快蓄電(dian)池(chi)(chi)的化學反(fan)應速度(du)，縮(suo)短(duan)蓄電(dian)池(chi)(chi)達(da)到(dao)滿充狀態的時間，同(tong)時，保證蓄電(dian)池(chi)(chi)正負極(ji)板的極(ji)化現象盡量地少或輕，提(ti)高蓄電(dian)池(chi)(chi)使用效(xiao)率。快速充電(dian)技術近(jin)年來得到(dao)了迅速發(fa)展。
下面介(jie)紹目(mu)前(qian)比較(jiao)流行的幾種快速充(chong)電(dian)方(fang)法。這些方(fang)法都是(shi)圍繞(rao)著最(zui)(zui)佳充(chong)電(dian)曲線進行設計的，目(mu)的就是(shi)使其(qi)充(chong)電(dian)曲線盡可能(neng)地逼進最(zui)(zui)佳充(chong)電(dian)曲線。
2.2.1 脈沖式充電法
這種充(chong)(chong)電法不僅(jin)遵(zun)循蓄(xu)電池(chi)固(gu)有的(de)充(chong)(chong)電接受率(lv)，而(er)且能夠提(ti)高蓄(xu)電池(chi)充(chong)(chong)電接受率(lv)，從而(er)打破了(le)蓄(xu)電池(chi)指數充(chong)(chong)電接受曲線的(de)限制，這也是(shi)蓄(xu)電池(chi)充(chong)(chong)電理論的(de)新發展。
脈沖充(chong)(chong)(chong)電(dian)(dian)(dian)方式首先是用脈沖電(dian)(dian)(dian)流(liu)對電(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)，然后讓電(dian)(dian)(dian)池(chi)(chi)(chi)停(ting)充(chong)(chong)(chong)一(yi)段時(shi)間(jian)，如(ru)此循環，如(ru)圖5所示。充(chong)(chong)(chong)電(dian)(dian)(dian)脈沖使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)滿電(dian)(dian)(dian)量(liang)，而(er)(er)間(jian)歇期使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)經(jing)化學(xue)反應(ying)產生的(de)(de)氧氣(qi)和氫氣(qi)有時(shi)間(jian)重新化合而(er)(er)被(bei)吸收掉(diao)，使(shi)(shi)濃差極(ji)(ji)化和歐姆極(ji)(ji)化自然而(er)(er)然地得到消(xiao)除，從而(er)(er)減輕了(le)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)內壓，使(shi)(shi)下一(yi)輪的(de)(de)恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)能夠(gou)更(geng)加順利地進行，使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)可以吸收更(geng)多的(de)(de)電(dian)(dian)(dian)量(liang)。間(jian)歇脈沖使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)有較(jiao)充(chong)(chong)(chong)分(fen)的(de)(de)反應(ying)時(shi)間(jian)，減少了(le)析氣(qi)量(liang)，提高(gao)了(le)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)接受率[5]。
圖5 脈沖式充電曲(qu)線(xian)
2.2.2 ReflexTM快速充(chong)電法(fa)
這種技術是(shi)美國的(de)一(yi)項專利技術，它(ta)主要面對(dui)的(de)充(chong)電(dian)對(dui)象是(shi)鎳(nie)鎘(ge)(ge)電(dian)池(chi)(chi)。由于它(ta)采用了(le)新型的(de)充(chong)電(dian)方(fang)法，解決了(le)鎳(nie)鎘(ge)(ge)電(dian)池(chi)(chi)的(de)記憶效應，因(yin)此，大大降(jiang)低了(le)蓄(xu)電(dian)池(chi)(chi)的(de)快速充(chong)電(dian)的(de)時間。鉛酸(suan)蓄(xu)電(dian)池(chi)(chi)的(de)充(chong)電(dian)方(fang)法和(he)對(dui)充(chong)電(dian)狀態的(de)檢測方(fang)法與鎳(nie)鎘(ge)(ge)電(dian)池(chi)(chi)有很(hen)大的(de)不同，但它(ta)們之間可以(yi)相互借鑒(jian)[3]。
如(ru)圖6所示，ReflexTM充電(dian)法(fa)的一個工作(zuo)周期包括正向(xiang)(xiang)充電(dian)脈(mo)沖，反向(xiang)(xiang)瞬間放電(dian)脈(mo)沖，停充維(wei)持(chi)3個階段(duan)[3]。
圖6 ReflexTM快速充電法
2.2.3 變(bian)電流間歇充電法
這種充(chong)電(dian)(dian)方(fang)法(fa)建(jian)立在恒(heng)(heng)流(liu)充(chong)電(dian)(dian)和(he)脈沖充(chong)電(dian)(dian)的(de)基礎上，如圖7所示。其特點是將恒(heng)(heng)流(liu)充(chong)電(dian)(dian)段(duan)(duan)改為限壓變電(dian)(dian)流(liu)間(jian)(jian)歇充(chong)電(dian)(dian)段(duan)(duan)。充(chong)電(dian)(dian)前期的(de)各段(duan)(duan)采(cai)用變電(dian)(dian)流(liu)間(jian)(jian)歇充(chong)電(dian)(dian)的(de)方(fang)法(fa)，保證加大充(chong)電(dian)(dian)電(dian)(dian)流(liu)，獲(huo)得絕大部分充(chong)電(dian)(dian)量(liang)。充(chong)電(dian)(dian)后(hou)期采(cai)用定電(dian)(dian)壓充(chong)電(dian)(dian)段(duan)(duan)，獲(huo)得過(guo)(guo)充(chong)電(dian)(dian)量(liang)，將電(dian)(dian)池恢復(fu)至完全充(chong)電(dian)(dian)態(tai)。通過(guo)(guo)間(jian)(jian)歇停充(chong)，使(shi)蓄電(dian)(dian)池經化(hua)(hua)學反應(ying)產生(sheng)的(de)氧氣和(he)氫(qing)氣有時間(jian)(jian)重新化(hua)(hua)合(he)而被吸收掉，使(shi)濃差(cha)極(ji)化(hua)(hua)和(he)歐姆極(ji)化(hua)(hua)自然(ran)而然(ran)地得到消(xiao)除，從而減輕(qing)了(le)蓄電(dian)(dian)池的(de)內壓，使(shi)下一輪的(de)恒(heng)(heng)流(liu)充(chong)電(dian)(dian)能夠更加順利地進行，使(shi)蓄電(dian)(dian)池可以吸收更多的(de)電(dian)(dian)量(liang)[4]。
圖7 變電流間歇充(chong)電曲線(xian)
2.2.4 變電(dian)壓(ya)間歇充電(dian)法(fa)
在(zai)變(bian)電流間歇(xie)充(chong)電法的基(ji)礎上(shang)又有(you)人(ren)提出了變(bian)電壓間歇(xie)充(chong)電法，如(ru)圖8所(suo)示。與變(bian)電流間歇(xie)充(chong)電方法不同之處在(zai)于第(di)一階段的不是間歇(xie)恒(heng)流，而是間歇(xie)恒(heng)壓。
圖8 變電壓間歇充電曲線
比較圖7和圖8，可(ke)(ke)以看出：圖8更加(jia)符合最(zui)佳充(chong)(chong)電(dian)(dian)(dian)的(de)充(chong)(chong)電(dian)(dian)(dian)曲線。在(zai)每(mei)個恒(heng)電(dian)(dian)(dian)壓充(chong)(chong)電(dian)(dian)(dian)階段，由于是恒(heng)壓充(chong)(chong)電(dian)(dian)(dian)，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流自然按照指數規律下(xia)降，符合電(dian)(dian)(dian)池電(dian)(dian)(dian)流可(ke)(ke)接受率隨著充(chong)(chong)電(dian)(dian)(dian)的(de)進(jin)行(xing)逐(zhu)漸(jian)下(xia)降的(de)特點[4]。
2.2.5 變(bian)電(dian)(dian)壓變(bian)電(dian)(dian)流波浪式間歇正負(fu)零(ling)脈沖快速充(chong)電(dian)(dian)法
綜合脈(mo)沖(chong)充(chong)(chong)(chong)電法(fa)、ReflexTM快速(su)充(chong)(chong)(chong)電法(fa)、變(bian)(bian)電流間歇(xie)充(chong)(chong)(chong)電法(fa)及(ji)變(bian)(bian)電壓間歇(xie)充(chong)(chong)(chong)電法(fa)的(de)(de)優點，變(bian)(bian)電壓變(bian)(bian)電流波浪式正負零脈(mo)沖(chong)間歇(xie)快速(su)充(chong)(chong)(chong)電法(fa)得(de)到發展應用。脈(mo)沖(chong)充(chong)(chong)(chong)電法(fa)充(chong)(chong)(chong)電電路(lu)的(de)(de)控制一(yi)般有兩種(zhong)：
1）脈沖電流的幅值(zhi)可(ke)變，而(er)PWM（驅(qu)動充放電開關(guan)管）信號的頻(pin)率是固定的；
2）脈沖電(dian)流幅(fu)值固定不變，PWM信號的頻(pin)率可調。
圖9采(cai)用了一種不同于這兩者的(de)(de)(de)控制(zhi)模(mo)式，脈沖電流幅值和PWM信號的(de)(de)(de)頻率均固定，PWM占(zhan)空比可(ke)調，在(zai)(zai)此基礎(chu)上加入間(jian)歇(xie)停充階段，能夠在(zai)(zai)較(jiao)短的(de)(de)(de)時(shi)間(jian)內(nei)充進更(geng)多(duo)的(de)(de)(de)電量，提(ti)高蓄電池(chi)的(de)(de)(de)充電接受能力。
圖9 波(bo)浪(lang)式間歇正(zheng)負零脈(mo)沖快速(su)充電(dian)
3 結(jie)語(yu)
鉛酸蓄電(dian)池是(shi)目前世界上廣泛使(shi)用的(de)(de)(de)一(yi)種化學電(dian)源，該產品具有(you)良好的(de)(de)(de)可逆性(xing)，電(dian)壓特性(xing)平穩，使(shi)用壽命長(chang)，適用范圍廣，原材料豐(feng)富（且可再生使(shi)用）及造價低廉(lian)等(deng)優點(dian)。主要應用在交通運輸，通信(xin)，電(dian)力，鐵路，礦山(shan)，港口等(deng)國民經(jing)濟各個部(bu)門，是(shi)社(she)會(hui)生產經(jing)營活(huo)動中(zhong)不可缺少的(de)(de)(de)產品，具有(you)廣闊的(de)(de)(de)發展前景。