鉛酸蓄電池充電機充電原理示意圖
鉛酸蓄電(dian)池由于其制造成本低(di)，容量大(da)，價格低(di)廉而(er)得(de)到了廣泛的(de)使(shi)用(yong)。但是，若使(shi)用(yong)不當，其壽命將大(da)大(da)縮短。影響(xiang)鉛酸蓄電(dian)池壽命的(de)因素很(hen)多，而(er)采用(yong)正(zheng)確的(de)充電(dian)方式，能(neng)有(you)效(xiao)延長蓄電(dian)池的(de)使(shi)用(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(de)使(shi)用(yong)壽命具有舉足(zu)輕重的(de)作用(yong)。
1 蓄(xu)電(dian)池充(chong)電(dian)理論基礎
上(shang)世(shi)紀60年代(dai)中期，美國科學家馬斯對開口蓄電(dian)池的(de)(de)充電(dian)過程(cheng)作了(le)大(da)量的(de)(de)試驗研究，并(bing)提出了(le)以最低出氣率(lv)為(wei)(wei)前(qian)提的(de)(de)，蓄電(dian)池可接受的(de)(de)充電(dian)曲(qu)(qu)線(xian)，如圖(tu)1所示。實驗表明，如果充電(dian)電(dian)流按這(zhe)條曲(qu)(qu)線(xian)變化(hua)，就可以大(da)大(da)縮短充電(dian)時間(jian)，并(bing)且對電(dian)池的(de)(de)容量和壽命也沒有(you)影響(xiang)。原則上(shang)把這(zhe)條曲(qu)(qu)線(xian)稱為(wei)(wei)最佳充電(dian)曲(qu)(qu)線(xian)，從(cong)而(er)奠(dian)定了(le)快速(su)充電(dian)方(fang)法的(de)(de)研究方(fang)向(xiang)[1，2]。
圖1最佳充電曲線(xian)
由(you)圖(tu)1可以看出：初始充(chong)(chong)電(dian)(dian)電(dian)(dian)流很大(da)，但是衰(shuai)減很快。主要原(yuan)因是充(chong)(chong)電(dian)(dian)過程(cheng)中(zhong)產生了極(ji)(ji)化現(xian)(xian)象(xiang)。在密封式(shi)蓄電(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)過程(cheng)中(zhong)，內部(bu)產生氧(yang)氣(qi)(qi)(qi)和氫(qing)氣(qi)(qi)(qi)，當氧(yang)氣(qi)(qi)(qi)不能被及時(shi)吸收時(shi)，便(bian)堆積在正(zheng)極(ji)(ji)板（正(zheng)極(ji)(ji)板產生氧(yang)氣(qi)(qi)(qi)），使(shi)電(dian)(dian)池(chi)內部(bu)壓(ya)力加(jia)大(da)，電(dian)(dian)池(chi)溫度(du)上(shang)升，同時(shi)縮小了正(zheng)極(ji)(ji)板的(de)(de)面積，表現(xian)(xian)為內阻(zu)上(shang)升，出現(xian)(xian)所謂(wei)的(de)(de)極(ji)(ji)化現(xian)(xian)象(xiang)。
蓄(xu)電(dian)(dian)池是可逆(ni)的。其放電(dian)(dian)及充(chong)電(dian)(dian)的化學反應式如下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很顯然，充(chong)電(dian)(dian)(dian)過(guo)程和放電(dian)(dian)(dian)過(guo)程互為逆反(fan)應。可逆過(guo)程就是熱(re)力學的平(ping)衡過(guo)程，為保障電(dian)(dian)(dian)池(chi)能夠始終維(wei)持在平(ping)衡狀態(tai)之(zhi)下充(chong)電(dian)(dian)(dian)，必(bi)須(xu)盡量(liang)使通過(guo)電(dian)(dian)(dian)池(chi)的電(dian)(dian)(dian)流小一些。理想條件是外加電(dian)(dian)(dian)壓(ya)等于(yu)電(dian)(dian)(dian)池(chi)本(ben)身的電(dian)(dian)(dian)動(dong)勢。但是，實(shi)踐表明，蓄電(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)時，外加電(dian)(dian)(dian)壓(ya)必(bi)須(xu)增大到一定數值才行,而這(zhe)個數值又因為電(dian)(dian)(dian)極材料，溶液濃度(du)(du)等各種(zhong)因素的差別而在不(bu)同(tong)程度(du)(du)上超過(guo)了蓄電(dian)(dian)(dian)池(chi)的平(ping)衡電(dian)(dian)(dian)動(dong)勢值。在化(hua)學反(fan)應中，這(zhe)種(zhong)電(dian)(dian)(dian)動(dong)勢超過(guo)熱(re)力學平(ping)衡值的現象，就是極化(hua)現象。
一般來說，產生極化現象(xiang)有3個方(fang)面(mian)的原因(yin)。
1）歐姆(mu)極化 充電過程(cheng)中，正負離(li)子(zi)向兩極遷(qian)(qian)移(yi)。在離(li)子(zi)遷(qian)(qian)移(yi)過程(cheng)中不可避(bi)免地受(shou)到一定的(de)(de)阻(zu)(zu)力，稱為歐姆(mu)內阻(zu)(zu)。為了克(ke)服這(zhe)個內阻(zu)(zu)，外(wai)加(jia)電壓(ya)(ya)就必須(xu)額外(wai)施加(jia)一定的(de)(de)電壓(ya)(ya)，以克(ke)服阻(zu)(zu)力推動離(li)子(zi)遷(qian)(qian)移(yi)。該電壓(ya)(ya)以熱的(de)(de)方(fang)式(shi)轉(zhuan)化給環境，出(chu)現所謂的(de)(de)歐姆(mu)極化。隨著充電電流急劇加(jia)大，歐姆(mu)極化將造(zao)成蓄電池(chi)在充電過程(cheng)中的(de)(de)高溫。
2）濃度極(ji)(ji)化(hua) 電(dian)流流過(guo)蓄電(dian)池(chi)時(shi)，為(wei)(wei)維持正常的(de)反應，最理想的(de)情(qing)況是電(dian)極(ji)(ji)表面(mian)(mian)的(de)反應物(wu)能(neng)及(ji)時(shi)得到(dao)補(bu)充，生(sheng)成(cheng)物(wu)能(neng)及(ji)時(shi)離去。實際上，生(sheng)成(cheng)物(wu)和反應物(wu)的(de)擴散速度遠遠比不上化(hua)學反應速度，從而造成(cheng)極(ji)(ji)板附近(jin)電(dian)解質溶(rong)液濃度發生(sheng)變化(hua)。也就(jiu)是說，從電(dian)極(ji)(ji)表面(mian)(mian)到(dao)中部(bu)溶(rong)液，電(dian)解液濃度分布不均勻。這種現象稱為(wei)(wei)濃度極(ji)(ji)化(hua)。
3）電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學極(ji)(ji)(ji)化(hua)(hua) 這種極(ji)(ji)(ji)化(hua)(hua)是由于電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)上進行的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學反應的(de)(de)(de)(de)速度，落(luo)后于電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)上電(dian)(dian)(dian)(dian)(dian)子運動的(de)(de)(de)(de)速度造成的(de)(de)(de)(de)。例如：電(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)(de)負(fu)極(ji)(ji)(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)前，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)帶(dai)有負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)，其(qi)附近溶(rong)液(ye)帶(dai)有正(zheng)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)，兩者處于平衡狀(zhuang)態。放(fang)電(dian)(dian)(dian)(dian)(dian)時，立即有電(dian)(dian)(dian)(dian)(dian)子釋放(fang)給外(wai)電(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)減(jian)(jian)少(shao)，而(er)金屬(shu)(shu)溶(rong)解的(de)(de)(de)(de)氧化(hua)(hua)反應進行緩慢Me－e→Me＋，不(bu)能及時補充(chong)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)電(dian)(dian)(dian)(dian)(dian)子的(de)(de)(de)(de)減(jian)(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)帶(dai)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態發生變(bian)化(hua)(hua)。這種表(biao)面(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)減(jian)(jian)少(shao)的(de)(de)(de)(de)狀(zhuang)態促進金屬(shu)(shu)中電(dian)(dian)(dian)(dian)(dian)子離開電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)，金屬(shu)(shu)離子Me＋轉入溶(rong)液(ye)，加速Me－e→Me＋反應進行。總有一個(ge)時刻，達(da)到新的(de)(de)(de)(de)動態平衡。但與放(fang)電(dian)(dian)(dian)(dian)(dian)前相比，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)所(suo)帶(dai)負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)數目減(jian)(jian)少(shao)了，與此對應的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢變(bian)正(zheng)。也就(jiu)是電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學極(ji)(ji)(ji)化(hua)(hua)電(dian)(dian)(dian)(dian)(dian)壓變(bian)高，從而(er)嚴重阻礙了正(zheng)常的(de)(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流。同理(li)，電(dian)(dian)(dian)(dian)(dian)池正(zheng)極(ji)(ji)(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)時，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表(biao)面(mian)所(suo)帶(dai)正(zheng)電(dian)(dian)(dian)(dian)(dian)荷(he)(he)數目減(jian)(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢變(bian)負(fu)。
這3種極(ji)化現象都是隨著(zhu)充電(dian)電(dian)流(liu)的增大而嚴重。
2 充電方法的(de)研(yan)究
2.1 常規充電(dian)法
常規充電(dian)(dian)制度是(shi)依據1940年前國(guo)際公認的(de)(de)經(jing)驗法則(ze)設(she)計的(de)(de)。其中(zhong)(zhong)最著名的(de)(de)就是(shi)“安(an)培(pei)小時規則(ze)”：充電(dian)(dian)電(dian)(dian)流安(an)培(pei)數，不應超(chao)過(guo)蓄(xu)電(dian)(dian)池待充電(dian)(dian)的(de)(de)安(an)時數。實際上(shang)，常規充電(dian)(dian)的(de)(de)速(su)度被(bei)蓄(xu)電(dian)(dian)池在充電(dian)(dian)過(guo)程中(zhong)(zhong)的(de)(de)溫升(sheng)和氣(qi)體的(de)(de)產(chan)生所(suo)限制。這個現象對蓄(xu)電(dian)(dian)池充電(dian)(dian)所(suo)必須的(de)(de)最短(duan)時間具有重要意義(yi)。
一(yi)般來說，常規充電有以下(xia)3種。
2.1.1 恒流充(chong)電法
恒(heng)流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)法是(shi)用(yong)(yong)調整充(chong)電(dian)(dian)(dian)(dian)(dian)裝(zhuang)置輸出電(dian)(dian)(dian)(dian)(dian)壓或改變與蓄電(dian)(dian)(dian)(dian)(dian)池串聯電(dian)(dian)(dian)(dian)(dian)阻(zu)的(de)方(fang)法，保持充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)強度不變的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法，如圖2所示。控制方(fang)法簡(jian)單(dan)，但由于(yu)電(dian)(dian)(dian)(dian)(dian)池的(de)可接受(shou)電(dian)(dian)(dian)(dian)(dian)流(liu)能力是(shi)隨著充(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)(guo)程的(de)進行而逐漸下降的(de)，到充(chong)電(dian)(dian)(dian)(dian)(dian)后期(qi)，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)多(duo)用(yong)(yong)于(yu)電(dian)(dian)(dian)(dian)(dian)解水，產生氣(qi)體，使(shi)出氣(qi)過(guo)(guo)甚，因此，常(chang)選用(yong)(yong)階段充(chong)電(dian)(dian)(dian)(dian)(dian)法。
圖2 恒流充電曲線
2.1.2 階段充電(dian)法
此方法(fa)包括(kuo)二階(jie)段(duan)充電法(fa)和三(san)階(jie)段(duan)充電法(fa)。
1）二階段(duan)法 采(cai)用恒(heng)電(dian)(dian)流(liu)和恒(heng)電(dian)(dian)壓相結合的(de)快速充(chong)電(dian)(dian)方法，如圖3所示。首(shou)先，以(yi)恒(heng)電(dian)(dian)流(liu)充(chong)電(dian)(dian)至預定的(de)電(dian)(dian)壓值，然后，改為恒(heng)電(dian)(dian)壓完成剩余的(de)充(chong)電(dian)(dian)。一般兩(liang)階段(duan)之間(jian)的(de)轉換電(dian)(dian)壓就是第(di)二階段(duan)的(de)恒(heng)電(dian)(dian)壓。
圖3 二階段法曲線
2）三(san)階(jie)(jie)段充電(dian)(dian)法 在充電(dian)(dian)開始和結束(shu)時采用恒電(dian)(dian)流(liu)充電(dian)(dian)，中間(jian)用恒電(dian)(dian)壓(ya)充電(dian)(dian)。當電(dian)(dian)流(liu)衰減到預定(ding)值時，由第二階(jie)(jie)段轉換到第三(san)階(jie)(jie)段。這種(zhong)(zhong)方法可(ke)以將(jiang)出氣量減到最少，但作(zuo)為一(yi)種(zhong)(zhong)快速充電(dian)(dian)方法使用，受到一(yi)定(ding)的限制。
2.1.3 恒壓充(chong)電(dian)法
充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源的電(dian)(dian)(dian)(dian)(dian)壓在(zai)全(quan)部(bu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)里保持恒定(ding)的數值(zhi)，隨(sui)著蓄電(dian)(dian)(dian)(dian)(dian)池端電(dian)(dian)(dian)(dian)(dian)壓的逐漸升高(gao)，電(dian)(dian)(dian)(dian)(dian)流(liu)逐漸減少(shao)。與恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)相比，其充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程(cheng)更接(jie)近(jin)于最佳充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)曲線(xian)。用恒定(ding)電(dian)(dian)(dian)(dian)(dian)壓快速(su)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，如圖4所示。由于充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)初期蓄電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)動勢較(jiao)低，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)很大(da)，隨(sui)著充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的進行，電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)逐漸減少(shao)，因此，只需簡易控制系統。
圖4 恒壓充電法曲(qu)線
這(zhe)種充(chong)電(dian)方法電(dian)解水很(hen)少，避免了(le)蓄(xu)電(dian)池(chi)(chi)過(guo)充(chong)。但在充(chong)電(dian)初期(qi)電(dian)流過(guo)大，對蓄(xu)電(dian)池(chi)(chi)壽命造(zao)成很(hen)大影(ying)響，且容(rong)易使(shi)蓄(xu)電(dian)池(chi)(chi)極(ji)板彎曲，造(zao)成電(dian)池(chi)(chi)報廢。
鑒于這種(zhong)缺點，恒壓充電(dian)很少使(shi)用(yong)，只有在充電(dian)電(dian)源電(dian)壓低(di)而(er)電(dian)流(liu)大時采用(yong)。例如，汽車運行過程中(zhong)，蓄電(dian)池就(jiu)是(shi)以恒壓充電(dian)法充電(dian)的。
2.2 快速充(chong)電技(ji)術(shu)
為了能夠(gou)最(zui)大限度(du)地加快(kuai)蓄電(dian)池的(de)化學(xue)反應速度(du)，縮短(duan)蓄電(dian)池達到滿充(chong)狀態的(de)時間，同時，保(bao)證(zheng)蓄電(dian)池正(zheng)負極板的(de)極化現(xian)象盡量地少(shao)或輕，提(ti)高蓄電(dian)池使用效率。快(kuai)速充(chong)電(dian)技(ji)術近年(nian)來得到了迅速發(fa)展。
下面介紹(shao)目前(qian)比較(jiao)流行的(de)幾(ji)種(zhong)快速(su)充電(dian)方法。這些方法都是圍繞著最佳充電(dian)曲線進行設計的(de)，目的(de)就是使其充電(dian)曲線盡可能地逼進最佳充電(dian)曲線。
2.2.1 脈沖式充電法
這種充(chong)電(dian)(dian)(dian)法不(bu)僅遵循蓄(xu)電(dian)(dian)(dian)池固有的充(chong)電(dian)(dian)(dian)接受(shou)(shou)率，而且能夠提高蓄(xu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)接受(shou)(shou)率，從(cong)而打(da)破(po)了(le)蓄(xu)電(dian)(dian)(dian)池指(zhi)數(shu)充(chong)電(dian)(dian)(dian)接受(shou)(shou)曲線的限(xian)制(zhi)，這也是蓄(xu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)理論的新發展。
脈(mo)沖(chong)充電(dian)(dian)(dian)方式首(shou)先是用脈(mo)沖(chong)電(dian)(dian)(dian)流(liu)對電(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)，然后讓電(dian)(dian)(dian)池(chi)(chi)停(ting)充一(yi)(yi)段(duan)時間(jian)，如此循環(huan)，如圖5所示。充電(dian)(dian)(dian)脈(mo)沖(chong)使(shi)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)充滿電(dian)(dian)(dian)量(liang)，而(er)間(jian)歇(xie)(xie)期使(shi)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)經化學反(fan)應產生的(de)氧氣(qi)(qi)和氫氣(qi)(qi)有時間(jian)重新化合而(er)被吸收掉，使(shi)濃差(cha)極(ji)化和歐(ou)姆(mu)極(ji)化自(zi)然而(er)然地得(de)到消除(chu)，從而(er)減(jian)輕了(le)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)的(de)內(nei)壓，使(shi)下一(yi)(yi)輪的(de)恒(heng)流(liu)充電(dian)(dian)(dian)能夠(gou)更加順利地進行，使(shi)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)可以吸收更多(duo)的(de)電(dian)(dian)(dian)量(liang)。間(jian)歇(xie)(xie)脈(mo)沖(chong)使(shi)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)有較充分的(de)反(fan)應時間(jian)，減(jian)少了(le)析氣(qi)(qi)量(liang)，提(ti)高了(le)蓄(xu)電(dian)(dian)(dian)池(chi)(chi)的(de)充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)接受(shou)率(lv)[5]。
圖5 脈(mo)沖式充電(dian)曲線
2.2.2 ReflexTM快速充電法
這(zhe)種技(ji)術是(shi)美(mei)國的(de)(de)(de)一項專利技(ji)術，它主要面(mian)對的(de)(de)(de)充電(dian)對象是(shi)鎳鎘(ge)電(dian)池。由于它采用了(le)新型(xing)的(de)(de)(de)充電(dian)方法，解(jie)決了(le)鎳鎘(ge)電(dian)池的(de)(de)(de)記憶效應(ying)，因(yin)此(ci)，大(da)(da)大(da)(da)降低了(le)蓄(xu)電(dian)池的(de)(de)(de)快速(su)充電(dian)的(de)(de)(de)時(shi)間(jian)。鉛酸蓄(xu)電(dian)池的(de)(de)(de)充電(dian)方法和對充電(dian)狀態(tai)的(de)(de)(de)檢測方法與鎳鎘(ge)電(dian)池有很大(da)(da)的(de)(de)(de)不同，但(dan)它們之間(jian)可以(yi)相互借鑒[3]。
如圖6所示，ReflexTM充(chong)電(dian)法(fa)的(de)一個(ge)工(gong)作(zuo)周期包括正向充(chong)電(dian)脈沖(chong)，反向瞬間放電(dian)脈沖(chong)，停充(chong)維持3個(ge)階段[3]。
圖6 ReflexTM快速充電法
2.2.3 變電流間(jian)歇充電法
這種充(chong)(chong)電(dian)(dian)(dian)方法建立在恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)和脈沖(chong)充(chong)(chong)電(dian)(dian)(dian)的基礎(chu)上，如圖7所(suo)示。其特點是將恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)段改為限(xian)壓變電(dian)(dian)(dian)流(liu)間(jian)歇充(chong)(chong)電(dian)(dian)(dian)段。充(chong)(chong)電(dian)(dian)(dian)前期的各段采用變電(dian)(dian)(dian)流(liu)間(jian)歇充(chong)(chong)電(dian)(dian)(dian)的方法，保證加大充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)，獲得(de)(de)絕大部分充(chong)(chong)電(dian)(dian)(dian)量。充(chong)(chong)電(dian)(dian)(dian)后期采用定電(dian)(dian)(dian)壓充(chong)(chong)電(dian)(dian)(dian)段，獲得(de)(de)過(guo)充(chong)(chong)電(dian)(dian)(dian)量，將電(dian)(dian)(dian)池(chi)恢復至(zhi)完全充(chong)(chong)電(dian)(dian)(dian)態。通過(guo)間(jian)歇停充(chong)(chong)，使蓄電(dian)(dian)(dian)池(chi)經(jing)化(hua)學反應產生的氧氣和氫氣有(you)時間(jian)重新化(hua)合而被吸收(shou)(shou)掉，使濃(nong)差極化(hua)和歐姆(mu)極化(hua)自然而然地得(de)(de)到消除，從而減輕了(le)蓄電(dian)(dian)(dian)池(chi)的內壓，使下一輪的恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)能夠更加順利地進行，使蓄電(dian)(dian)(dian)池(chi)可以吸收(shou)(shou)更多的電(dian)(dian)(dian)量[4]。
圖7 變電(dian)流間歇充電(dian)曲線
2.2.4 變電壓(ya)間歇(xie)充電法
在變電(dian)流(liu)間(jian)歇(xie)充電(dian)法(fa)的基礎上(shang)又有人(ren)提出(chu)了變電(dian)壓間(jian)歇(xie)充電(dian)法(fa)，如(ru)圖8所示。與變電(dian)流(liu)間(jian)歇(xie)充電(dian)方法(fa)不(bu)同(tong)之處在于第一階段的不(bu)是(shi)間(jian)歇(xie)恒(heng)流(liu)，而是(shi)間(jian)歇(xie)恒(heng)壓。
圖8 變電(dian)壓間歇充電(dian)曲線
比較圖(tu)7和圖(tu)8，可以看(kan)出(chu)：圖(tu)8更加符合最佳充(chong)電的(de)充(chong)電曲線(xian)。在每個恒電壓充(chong)電階(jie)段(duan)，由于是恒壓充(chong)電，充(chong)電電流(liu)自(zi)然按照指(zhi)數規律下降(jiang)(jiang)，符合電池電流(liu)可接(jie)受(shou)率隨著充(chong)電的(de)進行逐漸下降(jiang)(jiang)的(de)特點[4]。
2.2.5 變電壓(ya)變電流波浪(lang)式間歇正負零脈沖快速充電法
綜合脈沖充電(dian)(dian)法(fa)、ReflexTM快(kuai)速充電(dian)(dian)法(fa)、變電(dian)(dian)流(liu)間歇(xie)充電(dian)(dian)法(fa)及變電(dian)(dian)壓間歇(xie)充電(dian)(dian)法(fa)的優點，變電(dian)(dian)壓變電(dian)(dian)流(liu)波浪(lang)式正負零(ling)脈沖間歇(xie)快(kuai)速充電(dian)(dian)法(fa)得到發(fa)展應用。脈沖充電(dian)(dian)法(fa)充電(dian)(dian)電(dian)(dian)路(lu)的控制一般(ban)有兩種：
1）脈沖電(dian)流的(de)幅值可(ke)變，而(er)PWM（驅動充放電(dian)開(kai)關管）信號(hao)的(de)頻率是固定(ding)的(de)；
2）脈(mo)沖電流幅(fu)值(zhi)固(gu)定(ding)不變，PWM信號(hao)的頻率可調。
圖9采用(yong)了一種不同于這兩(liang)者(zhe)的控制(zhi)模式，脈沖電流幅(fu)值和PWM信號(hao)的頻(pin)率均固定，PWM占空比可調(diao)，在(zai)(zai)此基礎(chu)上加入(ru)間(jian)歇停充階段，能夠在(zai)(zai)較短的時間(jian)內(nei)充進更多的電量(liang)，提高蓄電池的充電接受能力(li)。
圖9 波(bo)浪式間歇正(zheng)負零脈沖快速充電(dian)
3 結語
鉛酸蓄電(dian)(dian)(dian)池是目前世界上(shang)廣(guang)(guang)泛使(shi)(shi)用(yong)的(de)一種化(hua)學(xue)電(dian)(dian)(dian)源，該產品(pin)具有良好的(de)可逆性，電(dian)(dian)(dian)壓特性平穩(wen)，使(shi)(shi)用(yong)壽命長，適(shi)用(yong)范圍廣(guang)(guang)，原材料豐富（且可再(zai)生使(shi)(shi)用(yong)）及造價低廉等優點。主要應(ying)用(yong)在交通(tong)運輸，通(tong)信，電(dian)(dian)(dian)力(li)，鐵路，礦山，港口等國民經(jing)濟各個部門，是社(she)會生產經(jing)營(ying)活動中不可缺少的(de)產品(pin)，具有廣(guang)(guang)闊(kuo)的(de)發展(zhan)前景(jing)。