鉛酸蓄電池充電機充電原理示意圖
鉛酸蓄(xu)電(dian)(dian)(dian)池(chi)由(you)于(yu)其(qi)制造成本(ben)低，容量大(da)，價格低廉而得(de)到了廣泛的(de)(de)使(shi)用(yong)。但是，若使(shi)用(yong)不當，其(qi)壽命(ming)將大(da)大(da)縮短。影響鉛酸蓄(xu)電(dian)(dian)(dian)池(chi)壽命(ming)的(de)(de)因(yin)素很多(duo)，而采(cai)用(yong)正(zheng)確的(de)(de)充電(dian)(dian)(dian)方式，能有效延長(chang)蓄(xu)電(dian)(dian)(dian)池(chi)的(de)(de)使(shi)用(yong)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(xu)電池的(de)使用(yong)壽命具有(you)舉(ju)足輕重的(de)作用(yong)。
1 蓄(xu)電池充電理論基礎
上世紀60年代中期(qi)，美國(guo)科學家馬斯對(dui)開(kai)口蓄(xu)電(dian)池的(de)充電(dian)過程作了(le)(le)大量(liang)的(de)試(shi)驗(yan)研究，并(bing)提出了(le)(le)以最(zui)低出氣率為前提的(de)，蓄(xu)電(dian)池可接受的(de)充電(dian)曲(qu)線，如圖1所示(shi)。實(shi)驗(yan)表明，如果(guo)充電(dian)電(dian)流按這條(tiao)(tiao)曲(qu)線變化(hua)，就(jiu)可以大大縮短充電(dian)時間，并(bing)且對(dui)電(dian)池的(de)容量(liang)和(he)壽命也沒有(you)影響。原(yuan)則上把這條(tiao)(tiao)曲(qu)線稱(cheng)為最(zui)佳充電(dian)曲(qu)線，從而奠定了(le)(le)快速充電(dian)方法的(de)研究方向[1，2]。
圖1最佳充電(dian)曲線
由(you)圖(tu)1可以看出：初始充電(dian)電(dian)流很大，但是(shi)衰減很快。主(zhu)要原因是(shi)充電(dian)過程中(zhong)產生了(le)(le)極(ji)化現(xian)象(xiang)。在(zai)密(mi)封式蓄電(dian)池(chi)充電(dian)過程中(zhong)，內(nei)部產生氧(yang)氣(qi)(qi)和氫氣(qi)(qi)，當氧(yang)氣(qi)(qi)不能被及時吸收時，便堆積在(zai)正極(ji)板（正極(ji)板產生氧(yang)氣(qi)(qi)），使電(dian)池(chi)內(nei)部壓力加(jia)大，電(dian)池(chi)溫度上升(sheng)，同時縮小了(le)(le)正極(ji)板的(de)面積，表現(xian)為內(nei)阻上升(sheng)，出現(xian)所謂的(de)極(ji)化現(xian)象(xiang)。
蓄電(dian)池(chi)是可逆(ni)的。其放電(dian)及充電(dian)的化學反應式如下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很顯然，充(chong)電(dian)(dian)過(guo)(guo)(guo)程(cheng)和放電(dian)(dian)過(guo)(guo)(guo)程(cheng)互(hu)為逆(ni)反應。可逆(ni)過(guo)(guo)(guo)程(cheng)就是(shi)熱力(li)學(xue)的(de)平(ping)衡(heng)過(guo)(guo)(guo)程(cheng)，為保障電(dian)(dian)池(chi)(chi)能夠始終維持(chi)在(zai)(zai)平(ping)衡(heng)狀態之下充(chong)電(dian)(dian)，必(bi)(bi)須盡量使通過(guo)(guo)(guo)電(dian)(dian)池(chi)(chi)的(de)電(dian)(dian)流小一(yi)些(xie)。理想條件是(shi)外加電(dian)(dian)壓等(deng)于(yu)電(dian)(dian)池(chi)(chi)本身(shen)的(de)電(dian)(dian)動(dong)勢。但是(shi)，實踐表明(ming)，蓄電(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)時(shi)，外加電(dian)(dian)壓必(bi)(bi)須增(zeng)大(da)到一(yi)定數值(zhi)才(cai)行,而這(zhe)個數值(zhi)又因為電(dian)(dian)極材(cai)料，溶(rong)液濃度等(deng)各種因素的(de)差(cha)別而在(zai)(zai)不同程(cheng)度上(shang)超過(guo)(guo)(guo)了(le)蓄電(dian)(dian)池(chi)(chi)的(de)平(ping)衡(heng)電(dian)(dian)動(dong)勢值(zhi)。在(zai)(zai)化(hua)學(xue)反應中(zhong)，這(zhe)種電(dian)(dian)動(dong)勢超過(guo)(guo)(guo)熱力(li)學(xue)平(ping)衡(heng)值(zhi)的(de)現象，就是(shi)極化(hua)現象。
一般來說，產生極化現(xian)象有3個(ge)方面(mian)的原因。
1）歐姆(mu)極(ji)化(hua) 充電(dian)(dian)過程(cheng)中(zhong)，正(zheng)負離(li)子(zi)向兩極(ji)遷移(yi)。在離(li)子(zi)遷移(yi)過程(cheng)中(zhong)不可(ke)避(bi)免地(di)受(shou)到一定的(de)阻力，稱(cheng)為(wei)歐姆(mu)內阻。為(wei)了克服這個內阻，外加(jia)(jia)電(dian)(dian)壓(ya)就必須額外施加(jia)(jia)一定的(de)電(dian)(dian)壓(ya)，以克服阻力推(tui)動離(li)子(zi)遷移(yi)。該電(dian)(dian)壓(ya)以熱的(de)方式轉化(hua)給環境，出現所謂的(de)歐姆(mu)極(ji)化(hua)。隨(sui)著充電(dian)(dian)電(dian)(dian)流急劇(ju)加(jia)(jia)大(da)，歐姆(mu)極(ji)化(hua)將(jiang)造成蓄電(dian)(dian)池在充電(dian)(dian)過程(cheng)中(zhong)的(de)高溫。
2）濃度(du)極(ji)化 電流流過蓄電池時，為維持正(zheng)常的反應(ying)，最理想的情況是(shi)電極(ji)表面(mian)的反應(ying)物能及時得到(dao)補充，生成(cheng)物能及時離去。實際上，生成(cheng)物和反應(ying)物的擴散速度(du)遠(yuan)遠(yuan)比(bi)不上化學(xue)反應(ying)速度(du)，從(cong)而造成(cheng)極(ji)板附近電解質(zhi)溶(rong)液(ye)(ye)濃度(du)發生變化。也就是(shi)說，從(cong)電極(ji)表面(mian)到(dao)中部溶(rong)液(ye)(ye)，電解液(ye)(ye)濃度(du)分布不均勻。這種現(xian)象(xiang)稱為濃度(du)極(ji)化。
3）電(dian)(dian)(dian)(dian)(dian)化學極(ji)(ji)(ji)化 這種極(ji)(ji)(ji)化是(shi)(shi)由于(yu)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)上(shang)進行(xing)的(de)(de)電(dian)(dian)(dian)(dian)(dian)化學反應的(de)(de)速(su)度，落后于(yu)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)上(shang)電(dian)(dian)(dian)(dian)(dian)子運動(dong)的(de)(de)速(su)度造成(cheng)的(de)(de)。例如：電(dian)(dian)(dian)(dian)(dian)池的(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)表面帶(dai)有負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)，其附近溶(rong)液(ye)帶(dai)有正電(dian)(dian)(dian)(dian)(dian)荷(he)，兩者處于(yu)平衡狀態(tai)。放(fang)電(dian)(dian)(dian)(dian)(dian)時，立即有電(dian)(dian)(dian)(dian)(dian)子釋放(fang)給外電(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)減(jian)少，而(er)金屬(shu)(shu)溶(rong)解的(de)(de)氧化反應進行(xing)緩慢Me－e→Me＋，不能(neng)及(ji)時補充(chong)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面電(dian)(dian)(dian)(dian)(dian)子的(de)(de)減(jian)少，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面帶(dai)電(dian)(dian)(dian)(dian)(dian)狀態(tai)發生變化。這種表面負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)減(jian)少的(de)(de)狀態(tai)促進金屬(shu)(shu)中(zhong)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(su)Me－e→Me＋反應進行(xing)。總有一(yi)個(ge)時刻，達到新的(de)(de)動(dong)態(tai)平衡。但與放(fang)電(dian)(dian)(dian)(dian)(dian)前相比(bi)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面所帶(dai)負(fu)電(dian)(dian)(dian)(dian)(dian)荷(he)數目減(jian)少了(le)，與此對應的(de)(de)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢變正。也就是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)化學極(ji)(ji)(ji)化電(dian)(dian)(dian)(dian)(dian)壓變高，從而(er)嚴重阻(zu)礙了(le)正常的(de)(de)充(chong)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)(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)時，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)表面所帶(dai)正電(dian)(dian)(dian)(dian)(dian)荷(he)數目減(jian)少，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)勢變負(fu)。
這3種極化現象都是隨著充電電流(liu)的增大而嚴重。
2 充電(dian)方法的研究(jiu)
2.1 常規充電(dian)法
常(chang)規(gui)充(chong)(chong)電(dian)(dian)制度是(shi)依據(ju)1940年(nian)前國際(ji)公認的經驗法則(ze)設計的。其(qi)中最著名的就是(shi)“安(an)(an)培小時(shi)規(gui)則(ze)”：充(chong)(chong)電(dian)(dian)電(dian)(dian)流安(an)(an)培數(shu)，不應超過(guo)蓄(xu)(xu)電(dian)(dian)池(chi)待(dai)充(chong)(chong)電(dian)(dian)的安(an)(an)時(shi)數(shu)。實際(ji)上，常(chang)規(gui)充(chong)(chong)電(dian)(dian)的速度被(bei)蓄(xu)(xu)電(dian)(dian)池(chi)在充(chong)(chong)電(dian)(dian)過(guo)程(cheng)中的溫升(sheng)和(he)氣體的產生(sheng)所限制。這個現象對(dui)蓄(xu)(xu)電(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)所必須的最短(duan)時(shi)間具(ju)有重要意義(yi)。
一般來說，常規充電有以下(xia)3種。
2.1.1 恒流充電法
恒流充電(dian)(dian)(dian)法(fa)(fa)是用(yong)調整充電(dian)(dian)(dian)裝(zhuang)置輸出(chu)(chu)電(dian)(dian)(dian)壓或改變(bian)與蓄電(dian)(dian)(dian)池串聯(lian)電(dian)(dian)(dian)阻的(de)(de)方(fang)法(fa)(fa)，保持充電(dian)(dian)(dian)電(dian)(dian)(dian)流強度不變(bian)的(de)(de)充電(dian)(dian)(dian)方(fang)法(fa)(fa)，如圖2所(suo)示。控制方(fang)法(fa)(fa)簡單，但由于電(dian)(dian)(dian)池的(de)(de)可接(jie)受(shou)電(dian)(dian)(dian)流能(neng)力是隨著充電(dian)(dian)(dian)過程的(de)(de)進行而(er)逐漸下降的(de)(de)，到充電(dian)(dian)(dian)后(hou)期(qi)，充電(dian)(dian)(dian)電(dian)(dian)(dian)流多(duo)用(yong)于電(dian)(dian)(dian)解水，產生氣體(ti)，使(shi)出(chu)(chu)氣過甚(shen)，因此，常選用(yong)階(jie)段充電(dian)(dian)(dian)法(fa)(fa)。
圖2 恒流充電曲線
2.1.2 階(jie)段充電法
此方(fang)法(fa)包(bao)括二階(jie)段充(chong)電法(fa)和三階(jie)段充(chong)電法(fa)。
1）二階段(duan)法(fa) 采用恒(heng)電(dian)流和恒(heng)電(dian)壓(ya)(ya)(ya)相結合的快速充(chong)電(dian)方(fang)法(fa)，如圖3所示。首先，以恒(heng)電(dian)流充(chong)電(dian)至(zhi)預定(ding)的電(dian)壓(ya)(ya)(ya)值(zhi)，然后，改為(wei)恒(heng)電(dian)壓(ya)(ya)(ya)完成(cheng)剩余的充(chong)電(dian)。一般兩(liang)階段(duan)之間(jian)的轉換電(dian)壓(ya)(ya)(ya)就是第二階段(duan)的恒(heng)電(dian)壓(ya)(ya)(ya)。
圖3 二階段法(fa)曲線
2）三(san)階段(duan)(duan)(duan)充電(dian)(dian)法(fa)(fa) 在(zai)充電(dian)(dian)開始和(he)結(jie)束(shu)時采用恒電(dian)(dian)流(liu)充電(dian)(dian)，中間用恒電(dian)(dian)壓充電(dian)(dian)。當電(dian)(dian)流(liu)衰減(jian)到(dao)(dao)(dao)預定(ding)值(zhi)時，由(you)第二階段(duan)(duan)(duan)轉換到(dao)(dao)(dao)第三(san)階段(duan)(duan)(duan)。這種方(fang)法(fa)(fa)可以將出氣量減(jian)到(dao)(dao)(dao)最少(shao)，但作(zuo)為一種快(kuai)速(su)充電(dian)(dian)方(fang)法(fa)(fa)使用，受(shou)到(dao)(dao)(dao)一定(ding)的限制。
2.1.3 恒壓充電法
充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)電(dian)(dian)(dian)(dian)(dian)壓在全部充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時(shi)間里(li)保(bao)持(chi)恒定的(de)數(shu)值，隨(sui)(sui)著蓄電(dian)(dian)(dian)(dian)(dian)池端電(dian)(dian)(dian)(dian)(dian)壓的(de)逐漸升高，電(dian)(dian)(dian)(dian)(dian)流(liu)逐漸減少。與恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)法相比，其充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程更(geng)接近于(yu)(yu)最佳充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)曲線。用恒定電(dian)(dian)(dian)(dian)(dian)壓快速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，如圖(tu)4所示。由于(yu)(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)動勢較低，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)很大(da)，隨(sui)(sui)著充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)進行，電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)逐漸減少，因此，只需簡易控制系統。
圖4 恒壓(ya)充電法曲線
這種充電(dian)(dian)方法(fa)電(dian)(dian)解(jie)水很(hen)少(shao)，避免(mian)了蓄電(dian)(dian)池(chi)過(guo)充。但在(zai)充電(dian)(dian)初期(qi)電(dian)(dian)流過(guo)大(da)，對蓄電(dian)(dian)池(chi)壽命造成很(hen)大(da)影響，且容易使蓄電(dian)(dian)池(chi)極板(ban)彎曲，造成電(dian)(dian)池(chi)報(bao)廢。
鑒于這種缺點(dian)，恒壓(ya)充電(dian)(dian)很少使用(yong)，只(zhi)有在充電(dian)(dian)電(dian)(dian)源電(dian)(dian)壓(ya)低(di)而(er)電(dian)(dian)流大時采用(yong)。例如，汽(qi)車運行過程(cheng)中，蓄電(dian)(dian)池就是以恒壓(ya)充電(dian)(dian)法(fa)充電(dian)(dian)的。
2.2 快速充電技術
為(wei)了能夠最大限度(du)地(di)加快蓄(xu)(xu)(xu)電(dian)池的(de)化學反應(ying)速(su)(su)度(du)，縮短(duan)蓄(xu)(xu)(xu)電(dian)池達到滿充狀態的(de)時間，同(tong)時，保證(zheng)蓄(xu)(xu)(xu)電(dian)池正負極板的(de)極化現象盡(jin)量地(di)少或輕，提(ti)高蓄(xu)(xu)(xu)電(dian)池使用(yong)效(xiao)率。快速(su)(su)充電(dian)技(ji)術近(jin)年來(lai)得(de)到了迅速(su)(su)發展。
下(xia)面介(jie)紹目前比(bi)較流行的(de)幾(ji)種(zhong)快速充(chong)電(dian)(dian)方法。這些方法都是圍繞(rao)著最(zui)佳充(chong)電(dian)(dian)曲(qu)線(xian)進(jin)行設計的(de)，目的(de)就是使其充(chong)電(dian)(dian)曲(qu)線(xian)盡可能(neng)地逼進(jin)最(zui)佳充(chong)電(dian)(dian)曲(qu)線(xian)。
2.2.1 脈沖式充(chong)電法
這種充電(dian)(dian)法不僅(jin)遵循蓄電(dian)(dian)池固有的充電(dian)(dian)接(jie)受(shou)(shou)率，而(er)(er)且(qie)能夠提(ti)高蓄電(dian)(dian)池充電(dian)(dian)接(jie)受(shou)(shou)率，從而(er)(er)打破了蓄電(dian)(dian)池指數充電(dian)(dian)接(jie)受(shou)(shou)曲線(xian)的限制，這也是蓄電(dian)(dian)池充電(dian)(dian)理論的新發(fa)展。
脈(mo)沖(chong)充(chong)電(dian)(dian)(dian)(dian)方式首(shou)先是用脈(mo)沖(chong)電(dian)(dian)(dian)(dian)流(liu)(liu)對電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)，然后讓電(dian)(dian)(dian)(dian)池(chi)(chi)停充(chong)一段時間(jian)，如(ru)此循環，如(ru)圖5所(suo)示。充(chong)電(dian)(dian)(dian)(dian)脈(mo)沖(chong)使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)滿電(dian)(dian)(dian)(dian)量(liang)，而(er)間(jian)歇期(qi)使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)經化學(xue)反(fan)應(ying)產生的氧氣(qi)(qi)和氫(qing)氣(qi)(qi)有時間(jian)重新化合而(er)被吸(xi)收(shou)掉，使(shi)(shi)濃差極化和歐姆極化自(zi)然而(er)然地(di)得到消除，從而(er)減(jian)輕了(le)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)的內壓(ya)，使(shi)(shi)下一輪的恒流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)能夠(gou)更加順利地(di)進行，使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)可以吸(xi)收(shou)更多的電(dian)(dian)(dian)(dian)量(liang)。間(jian)歇脈(mo)沖(chong)使(shi)(shi)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)有較充(chong)分的反(fan)應(ying)時間(jian)，減(jian)少了(le)析(xi)氣(qi)(qi)量(liang)，提高(gao)了(le)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)的充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)接受(shou)率[5]。
圖(tu)5 脈沖式充(chong)電(dian)曲線
2.2.2 ReflexTM快速充電(dian)法
這(zhe)種技(ji)術是美國的(de)(de)(de)一項(xiang)專利技(ji)術，它(ta)主要面對的(de)(de)(de)充(chong)電(dian)(dian)對象是鎳(nie)鎘(ge)電(dian)(dian)池。由于它(ta)采用(yong)了新(xin)型的(de)(de)(de)充(chong)電(dian)(dian)方(fang)法(fa)，解決了鎳(nie)鎘(ge)電(dian)(dian)池的(de)(de)(de)記憶效(xiao)應(ying)，因此(ci)，大大降低了蓄電(dian)(dian)池的(de)(de)(de)快速充(chong)電(dian)(dian)的(de)(de)(de)時間(jian)。鉛(qian)酸蓄電(dian)(dian)池的(de)(de)(de)充(chong)電(dian)(dian)方(fang)法(fa)和對充(chong)電(dian)(dian)狀態的(de)(de)(de)檢(jian)測方(fang)法(fa)與(yu)鎳(nie)鎘(ge)電(dian)(dian)池有很大的(de)(de)(de)不同，但(dan)它(ta)們之間(jian)可以相互借鑒[3]。
如圖6所示(shi)，ReflexTM充(chong)電(dian)法的一個工作周期包(bao)括正向充(chong)電(dian)脈沖，反向瞬間(jian)放電(dian)脈沖，停(ting)充(chong)維(wei)持3個階段[3]。
圖6 ReflexTM快速充電法
2.2.3 變電流(liu)間歇充電法
這種充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方法(fa)建立在恒(heng)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)和(he)脈(mo)沖(chong)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)基礎上，如(ru)圖7所示。其特點是將(jiang)恒(heng)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)段(duan)(duan)改為限壓(ya)變電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)間(jian)(jian)歇充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)段(duan)(duan)。充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)前期(qi)(qi)的(de)(de)各段(duan)(duan)采(cai)(cai)用變電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)間(jian)(jian)歇充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)方法(fa)，保證加大充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，獲(huo)得絕大部分充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)量。充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)后期(qi)(qi)采(cai)(cai)用定電(dian)(dian)(dian)(dian)(dian)壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)段(duan)(duan)，獲(huo)得過充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)量，將(jiang)電(dian)(dian)(dian)(dian)(dian)池恢復至(zhi)完全充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)態。通過間(jian)(jian)歇停充(chong)(chong)，使(shi)(shi)(shi)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池經化學反(fan)應產生的(de)(de)氧氣(qi)和(he)氫氣(qi)有時(shi)間(jian)(jian)重新化合而(er)被(bei)吸(xi)(xi)收掉，使(shi)(shi)(shi)濃差極(ji)(ji)化和(he)歐姆極(ji)(ji)化自然而(er)然地(di)得到消(xiao)除，從而(er)減輕了蓄(xu)電(dian)(dian)(dian)(dian)(dian)池的(de)(de)內(nei)壓(ya)，使(shi)(shi)(shi)下一輪的(de)(de)恒(heng)流(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)能夠更加順利地(di)進(jin)行，使(shi)(shi)(shi)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池可以(yi)吸(xi)(xi)收更多的(de)(de)電(dian)(dian)(dian)(dian)(dian)量[4]。
圖7 變電(dian)流間歇充電(dian)曲(qu)線
2.2.4 變(bian)電(dian)壓間(jian)歇充電(dian)法
在變(bian)電流間歇(xie)(xie)充電法(fa)的基(ji)礎上(shang)又有(you)人提出了變(bian)電壓間歇(xie)(xie)充電法(fa)，如圖8所(suo)示。與(yu)變(bian)電流間歇(xie)(xie)充電方法(fa)不同(tong)之處在于第(di)一階段的不是間歇(xie)(xie)恒流，而是間歇(xie)(xie)恒壓。
圖8 變(bian)電壓間(jian)歇充電曲線
比較圖7和圖8，可以(yi)看出(chu)：圖8更加符合(he)最佳充電(dian)的(de)充電(dian)曲線。在每個恒電(dian)壓充電(dian)階(jie)段，由于是恒壓充電(dian)，充電(dian)電(dian)流自(zi)然(ran)按照指(zhi)數規律下降(jiang)，符合(he)電(dian)池電(dian)流可接受(shou)率隨著充電(dian)的(de)進行逐漸下降(jiang)的(de)特點[4]。
2.2.5 變電(dian)壓(ya)變電(dian)流波浪式間(jian)歇正負零脈沖(chong)快(kuai)速(su)充電(dian)法
綜合脈(mo)沖充(chong)(chong)(chong)電(dian)法(fa)、ReflexTM快速充(chong)(chong)(chong)電(dian)法(fa)、變(bian)(bian)電(dian)流間歇(xie)(xie)充(chong)(chong)(chong)電(dian)法(fa)及變(bian)(bian)電(dian)壓間歇(xie)(xie)充(chong)(chong)(chong)電(dian)法(fa)的優點(dian)，變(bian)(bian)電(dian)壓變(bian)(bian)電(dian)流波浪式(shi)正負零脈(mo)沖間歇(xie)(xie)快速充(chong)(chong)(chong)電(dian)法(fa)得到發展應用。脈(mo)沖充(chong)(chong)(chong)電(dian)法(fa)充(chong)(chong)(chong)電(dian)電(dian)路(lu)的控制一(yi)般(ban)有兩種(zhong)：
1）脈沖電(dian)流的幅值可變，而PWM（驅動充放(fang)電(dian)開關(guan)管(guan)）信號(hao)的頻率是(shi)固定的；
2）脈沖(chong)電(dian)流幅值(zhi)固定不變，PWM信(xin)號的(de)頻(pin)率可調。
圖9采用了一種(zhong)不同(tong)于這(zhe)兩者的控制模式(shi)，脈沖(chong)電(dian)(dian)流(liu)幅值和PWM信號的頻(pin)率均固定(ding)，PWM占空比(bi)可調(diao)，在此(ci)基礎(chu)上加入間歇停充階段(duan)，能(neng)夠在較短的時間內充進更多的電(dian)(dian)量(liang)，提高蓄(xu)電(dian)(dian)池的充電(dian)(dian)接受能(neng)力。
圖9 波(bo)浪(lang)式間歇(xie)正負零脈(mo)沖快速充電
3 結語
鉛酸蓄電池(chi)是目前世界上廣(guang)泛使(shi)用(yong)的(de)(de)一種(zhong)化學電源，該產品具有良好的(de)(de)可逆性，電壓特性平(ping)穩，使(shi)用(yong)壽命長，適用(yong)范(fan)圍(wei)廣(guang)，原(yuan)材料(liao)豐(feng)富（且可再生使(shi)用(yong)）及(ji)造價低廉等優點。主(zhu)要應用(yong)在交通運輸，通信，電力，鐵(tie)路，礦山，港(gang)口等國(guo)民(min)經濟各個(ge)部門，是社會(hui)生產經營活動中(zhong)不可缺少的(de)(de)產品，具有廣(guang)闊(kuo)的(de)(de)發展前景。