鉛酸蓄電池充電機充電原理示意圖
鉛(qian)酸蓄電池由于其制造成本(ben)低，容量大(da)，價(jia)格(ge)低廉而得到了廣泛的(de)使用(yong)。但是，若使用(yong)不當，其壽(shou)(shou)命將大(da)大(da)縮短。影(ying)響鉛(qian)酸蓄電池壽(shou)(shou)命的(de)因素很多，而采用(yong)正確(que)的(de)充電方(fang)式，能有(you)效延長蓄電池的(de)使用(yong)壽(shou)(shou)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(shi)用(yong)(yong)壽命(ming)具有舉足輕重的作用(yong)(yong)。
1 蓄電池充電理(li)論基礎
上(shang)世紀60年代中期(qi)，美國科學家馬斯對開(kai)口(kou)蓄電(dian)(dian)池的(de)充(chong)(chong)電(dian)(dian)過程作了大(da)量的(de)試驗研究，并(bing)提出了以(yi)最低出氣(qi)率為前提的(de)，蓄電(dian)(dian)池可(ke)接受的(de)充(chong)(chong)電(dian)(dian)曲(qu)(qu)線(xian)，如圖1所示。實驗表明(ming)，如果充(chong)(chong)電(dian)(dian)電(dian)(dian)流按這條曲(qu)(qu)線(xian)變化，就可(ke)以(yi)大(da)大(da)縮短充(chong)(chong)電(dian)(dian)時間，并(bing)且對電(dian)(dian)池的(de)容(rong)量和(he)壽(shou)命也沒有(you)影(ying)響。原則上(shang)把這條曲(qu)(qu)線(xian)稱為最佳充(chong)(chong)電(dian)(dian)曲(qu)(qu)線(xian)，從而(er)奠定了快速充(chong)(chong)電(dian)(dian)方(fang)法(fa)的(de)研究方(fang)向(xiang)[1，2]。
圖1最(zui)佳充電曲線
由(you)圖1可(ke)以看出(chu)：初始(shi)充(chong)電(dian)電(dian)流(liu)很(hen)大，但是衰減很(hen)快。主(zhu)要原因是充(chong)電(dian)過(guo)(guo)程中(zhong)產(chan)(chan)生了(le)極(ji)化現象。在密封(feng)式(shi)蓄電(dian)池充(chong)電(dian)過(guo)(guo)程中(zhong)，內(nei)部產(chan)(chan)生氧氣(qi)和氫(qing)氣(qi)，當(dang)氧氣(qi)不能被及時吸收時，便堆積在正極(ji)板(ban)（正極(ji)板(ban)產(chan)(chan)生氧氣(qi)），使(shi)電(dian)池內(nei)部壓(ya)力加大，電(dian)池溫度上升，同時縮小了(le)正極(ji)板(ban)的面積，表現為(wei)內(nei)阻(zu)上升，出(chu)現所謂(wei)的極(ji)化現象。
蓄(xu)電(dian)池是可逆的。其(qi)放電(dian)及充電(dian)的化學反應式如下：
PbO2＋Pb＋2H2SO42PbSO4＋2H2O （1）
很顯然，充電(dian)(dian)(dian)(dian)過(guo)程(cheng)(cheng)和放(fang)電(dian)(dian)(dian)(dian)過(guo)程(cheng)(cheng)互為逆反應(ying)。可逆過(guo)程(cheng)(cheng)就是(shi)熱(re)力(li)學(xue)的(de)(de)平(ping)衡(heng)過(guo)程(cheng)(cheng)，為保障電(dian)(dian)(dian)(dian)池能夠(gou)始終維持在平(ping)衡(heng)狀態(tai)之下充電(dian)(dian)(dian)(dian)，必須盡量使(shi)通過(guo)電(dian)(dian)(dian)(dian)池的(de)(de)電(dian)(dian)(dian)(dian)流(liu)小一(yi)些。理想(xiang)條件是(shi)外(wai)加電(dian)(dian)(dian)(dian)壓等于電(dian)(dian)(dian)(dian)池本(ben)身(shen)的(de)(de)電(dian)(dian)(dian)(dian)動勢(shi)。但(dan)是(shi)，實(shi)踐表(biao)明(ming)，蓄電(dian)(dian)(dian)(dian)池充電(dian)(dian)(dian)(dian)時，外(wai)加電(dian)(dian)(dian)(dian)壓必須增大到一(yi)定數值才行,而(er)這個數值又(you)因(yin)為電(dian)(dian)(dian)(dian)極(ji)材(cai)料，溶液濃度等各種因(yin)素的(de)(de)差別(bie)而(er)在不(bu)同程(cheng)(cheng)度上超(chao)過(guo)了蓄電(dian)(dian)(dian)(dian)池的(de)(de)平(ping)衡(heng)電(dian)(dian)(dian)(dian)動勢(shi)值。在化學(xue)反應(ying)中(zhong)，這種電(dian)(dian)(dian)(dian)動勢(shi)超(chao)過(guo)熱(re)力(li)學(xue)平(ping)衡(heng)值的(de)(de)現象，就是(shi)極(ji)化現象。
一(yi)般來說，產生極化現象有3個方(fang)面的(de)原(yuan)因。
1）歐(ou)(ou)姆極(ji)化(hua)(hua)(hua) 充電(dian)(dian)過程(cheng)中(zhong)，正(zheng)負離子(zi)(zi)向兩極(ji)遷(qian)移(yi)。在離子(zi)(zi)遷(qian)移(yi)過程(cheng)中(zhong)不(bu)可避(bi)免地受到一定的(de)(de)阻力，稱為歐(ou)(ou)姆內阻。為了克服(fu)這個(ge)內阻，外加電(dian)(dian)壓(ya)就必(bi)須額外施加一定的(de)(de)電(dian)(dian)壓(ya)，以克服(fu)阻力推動離子(zi)(zi)遷(qian)移(yi)。該電(dian)(dian)壓(ya)以熱(re)的(de)(de)方(fang)式轉化(hua)(hua)(hua)給環境，出現所謂(wei)的(de)(de)歐(ou)(ou)姆極(ji)化(hua)(hua)(hua)。隨(sui)著充電(dian)(dian)電(dian)(dian)流急劇加大，歐(ou)(ou)姆極(ji)化(hua)(hua)(hua)將造成蓄電(dian)(dian)池在充電(dian)(dian)過程(cheng)中(zhong)的(de)(de)高溫。
2）濃(nong)度(du)極(ji)化(hua)(hua) 電流(liu)流(liu)過蓄電池時，為(wei)維持正常(chang)的(de)反應，最理(li)想的(de)情況是電極(ji)表(biao)(biao)面的(de)反應物(wu)(wu)能及時得(de)到補充(chong)，生(sheng)成(cheng)物(wu)(wu)能及時離(li)去。實際上(shang)(shang)，生(sheng)成(cheng)物(wu)(wu)和(he)反應物(wu)(wu)的(de)擴散速(su)度(du)遠遠比不上(shang)(shang)化(hua)(hua)學反應速(su)度(du)，從(cong)而造成(cheng)極(ji)板附近(jin)電解質溶液濃(nong)度(du)發生(sheng)變化(hua)(hua)。也(ye)就是說，從(cong)電極(ji)表(biao)(biao)面到中部溶液，電解液濃(nong)度(du)分布不均勻。這(zhe)種(zhong)現(xian)象稱為(wei)濃(nong)度(du)極(ji)化(hua)(hua)。
3）電(dian)(dian)(dian)(dian)(dian)(dian)(dian)化學(xue)極(ji)(ji)化 這種(zhong)(zhong)極(ji)(ji)化是由于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)上(shang)進(jin)(jin)行(xing)(xing)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)化學(xue)反應(ying)的(de)(de)(de)速(su)度(du)，落后(hou)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子運動的(de)(de)(de)速(su)度(du)造(zao)成的(de)(de)(de)。例如(ru)：電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)負(fu)極(ji)(ji)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)帶(dai)有負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)，其附近溶(rong)液帶(dai)有正電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)，兩者處于平衡(heng)狀態。放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，立即有電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子釋(shi)放給外電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)減(jian)少(shao)，而金屬(shu)溶(rong)解的(de)(de)(de)氧化反應(ying)進(jin)(jin)行(xing)(xing)緩慢Me－e→Me＋，不能及時(shi)補充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子的(de)(de)(de)減(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)帶(dai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態發生變(bian)化。這種(zhong)(zhong)表面(mian)(mian)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)減(jian)少(shao)的(de)(de)(de)狀態促進(jin)(jin)金屬(shu)中電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子離(li)開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)，金屬(shu)離(li)子Me＋轉(zhuan)入溶(rong)液，加速(su)Me－e→Me＋反應(ying)進(jin)(jin)行(xing)(xing)。總有一個時(shi)刻，達到新(xin)的(de)(de)(de)動態平衡(heng)。但與(yu)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)前(qian)相比，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)所帶(dai)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)數(shu)目減(jian)少(shao)了，與(yu)此對(dui)應(ying)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)變(bian)正。也就(jiu)是電(dian)(dian)(dian)(dian)(dian)(dian)(dian)化學(xue)極(ji)(ji)化電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓變(bian)高，從而嚴重阻(zu)礙了正常(chang)的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流。同(tong)理，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池正極(ji)(ji)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)表面(mian)(mian)所帶(dai)正電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)(he)(he)數(shu)目減(jian)少(shao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)變(bian)負(fu)。
這(zhe)3種極化現象都是隨著充電電流(liu)的增大而嚴(yan)重。
2 充電方法的研究
2.1 常規充電(dian)法
常規充(chong)電(dian)制度是依據1940年(nian)前國際(ji)公認(ren)的(de)經驗(yan)法(fa)則(ze)設計的(de)。其中最(zui)(zui)著名的(de)就是“安培(pei)小時規則(ze)”：充(chong)電(dian)電(dian)流安培(pei)數，不應(ying)超過(guo)(guo)蓄(xu)電(dian)池待充(chong)電(dian)的(de)安時數。實際(ji)上，常規充(chong)電(dian)的(de)速度被蓄(xu)電(dian)池在充(chong)電(dian)過(guo)(guo)程中的(de)溫升和氣(qi)體的(de)產生所(suo)限制。這(zhe)個現象對蓄(xu)電(dian)池充(chong)電(dian)所(suo)必須的(de)最(zui)(zui)短時間具有重要意義。
一般來說，常規充電有以下3種。
2.1.1 恒流充電(dian)法
恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)法是用(yong)調整充(chong)電(dian)(dian)(dian)(dian)(dian)裝置輸出電(dian)(dian)(dian)(dian)(dian)壓或改變(bian)與蓄電(dian)(dian)(dian)(dian)(dian)池串(chuan)聯電(dian)(dian)(dian)(dian)(dian)阻的(de)(de)方(fang)法，保(bao)持充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)強度不變(bian)的(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法，如圖2所示。控(kong)制(zhi)方(fang)法簡單，但由于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)池的(de)(de)可(ke)接(jie)受(shou)電(dian)(dian)(dian)(dian)(dian)流(liu)能力是隨著充(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程的(de)(de)進行而(er)逐漸(jian)下降的(de)(de)，到充(chong)電(dian)(dian)(dian)(dian)(dian)后期，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)多用(yong)于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)解(jie)水，產生氣體，使出氣過(guo)甚，因此，常選(xuan)用(yong)階段充(chong)電(dian)(dian)(dian)(dian)(dian)法。
圖2 恒流充電(dian)曲線
2.1.2 階段(duan)充(chong)電法(fa)
此方法(fa)(fa)包括(kuo)二(er)階段充(chong)電(dian)法(fa)(fa)和三階段充(chong)電(dian)法(fa)(fa)。
1）二階段(duan)法 采用(yong)恒(heng)電(dian)(dian)(dian)流(liu)和恒(heng)電(dian)(dian)(dian)壓(ya)相(xiang)結合的(de)(de)快速(su)充電(dian)(dian)(dian)方法，如(ru)圖3所示。首先(xian)，以(yi)恒(heng)電(dian)(dian)(dian)流(liu)充電(dian)(dian)(dian)至預定的(de)(de)電(dian)(dian)(dian)壓(ya)值(zhi)，然后，改為恒(heng)電(dian)(dian)(dian)壓(ya)完(wan)成剩余(yu)的(de)(de)充電(dian)(dian)(dian)。一般(ban)兩(liang)階段(duan)之間的(de)(de)轉(zhuan)換電(dian)(dian)(dian)壓(ya)就是(shi)第二階段(duan)的(de)(de)恒(heng)電(dian)(dian)(dian)壓(ya)。
圖3 二階段(duan)法曲(qu)線
2）三階(jie)段充(chong)(chong)電(dian)(dian)法 在充(chong)(chong)電(dian)(dian)開始和結束時采用恒電(dian)(dian)流充(chong)(chong)電(dian)(dian)，中(zhong)間用恒電(dian)(dian)壓充(chong)(chong)電(dian)(dian)。當(dang)電(dian)(dian)流衰減到預定值時，由第二階(jie)段轉(zhuan)換到第三階(jie)段。這種(zhong)方法可以(yi)將出氣量減到最少，但作(zuo)為一(yi)種(zhong)快(kuai)速充(chong)(chong)電(dian)(dian)方法使(shi)用，受到一(yi)定的限制。
2.1.3 恒(heng)壓充(chong)電法
充(chong)(chong)電(dian)(dian)電(dian)(dian)源(yuan)的電(dian)(dian)壓在全部充(chong)(chong)電(dian)(dian)時間里保(bao)持恒定的數值，隨著蓄電(dian)(dian)池端(duan)電(dian)(dian)壓的逐(zhu)漸(jian)升高，電(dian)(dian)流逐(zhu)漸(jian)減(jian)少。與恒流充(chong)(chong)電(dian)(dian)法相比，其充(chong)(chong)電(dian)(dian)過程更接近于最佳充(chong)(chong)電(dian)(dian)曲(qu)線。用恒定電(dian)(dian)壓快速充(chong)(chong)電(dian)(dian)，如圖4所示(shi)。由(you)于充(chong)(chong)電(dian)(dian)初期蓄電(dian)(dian)池電(dian)(dian)動(dong)勢較低，充(chong)(chong)電(dian)(dian)電(dian)(dian)流很(hen)大，隨著充(chong)(chong)電(dian)(dian)的進(jin)行(xing)，電(dian)(dian)流將(jiang)逐(zhu)漸(jian)減(jian)少，因此，只需簡易控制系統。
圖4 恒壓充電法曲(qu)線
這種充電(dian)方法(fa)電(dian)解水很少，避免了蓄(xu)(xu)電(dian)池過(guo)充。但在(zai)充電(dian)初期電(dian)流過(guo)大(da)，對蓄(xu)(xu)電(dian)池壽命造成(cheng)很大(da)影響，且容易使(shi)蓄(xu)(xu)電(dian)池極板(ban)彎曲，造成(cheng)電(dian)池報廢(fei)。
鑒于這(zhe)種缺點(dian)，恒(heng)壓充(chong)(chong)電(dian)(dian)很少(shao)使(shi)用，只有在充(chong)(chong)電(dian)(dian)電(dian)(dian)源(yuan)電(dian)(dian)壓低而電(dian)(dian)流大時采用。例(li)如，汽(qi)車運行過程中，蓄電(dian)(dian)池就(jiu)是以(yi)恒(heng)壓充(chong)(chong)電(dian)(dian)法充(chong)(chong)電(dian)(dian)的。
2.2 快速(su)充電技(ji)術
為了能夠最大限度(du)地加快(kuai)蓄(xu)電池的(de)化學反應(ying)速(su)(su)度(du)，縮(suo)短蓄(xu)電池達到滿(man)充狀態的(de)時間(jian)，同(tong)時，保證蓄(xu)電池正負(fu)極板的(de)極化現象盡量地少或輕，提高蓄(xu)電池使(shi)用效率(lv)。快(kuai)速(su)(su)充電技術近(jin)年(nian)來得到了迅(xun)速(su)(su)發展。
下面介(jie)紹(shao)目(mu)前比較流行的幾(ji)種快速充(chong)電方法。這些方法都是(shi)圍繞著最(zui)佳充(chong)電曲線進行設計的，目(mu)的就是(shi)使(shi)其(qi)充(chong)電曲線盡可能地逼(bi)進最(zui)佳充(chong)電曲線。
2.2.1 脈沖(chong)式(shi)充電法(fa)
這種充(chong)電(dian)(dian)(dian)(dian)法(fa)不僅遵(zun)循(xun)蓄(xu)電(dian)(dian)(dian)(dian)池(chi)固有的(de)充(chong)電(dian)(dian)(dian)(dian)接受(shou)(shou)率，而且(qie)能夠提高蓄(xu)電(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)接受(shou)(shou)率，從而打(da)破了蓄(xu)電(dian)(dian)(dian)(dian)池(chi)指數充(chong)電(dian)(dian)(dian)(dian)接受(shou)(shou)曲線的(de)限制(zhi)，這也是蓄(xu)電(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)理論的(de)新(xin)發展。
脈沖(chong)充(chong)電(dian)方式首先是用脈沖(chong)電(dian)流(liu)對電(dian)池充(chong)電(dian)，然后讓電(dian)池停充(chong)一(yi)段時間(jian)，如此循環，如圖5所(suo)示。充(chong)電(dian)脈沖(chong)使(shi)蓄(xu)(xu)電(dian)池充(chong)滿電(dian)量，而間(jian)歇期(qi)使(shi)蓄(xu)(xu)電(dian)池經化學反應(ying)(ying)產生的(de)氧氣和氫氣有(you)時間(jian)重新化合(he)而被(bei)吸(xi)收(shou)掉，使(shi)濃(nong)差(cha)極(ji)化和歐姆(mu)極(ji)化自然而然地(di)得(de)到消除，從(cong)而減(jian)輕了蓄(xu)(xu)電(dian)池的(de)內壓，使(shi)下一(yi)輪的(de)恒流(liu)充(chong)電(dian)能夠更加(jia)順利地(di)進行，使(shi)蓄(xu)(xu)電(dian)池可以(yi)吸(xi)收(shou)更多的(de)電(dian)量。間(jian)歇脈沖(chong)使(shi)蓄(xu)(xu)電(dian)池有(you)較(jiao)充(chong)分的(de)反應(ying)(ying)時間(jian)，減(jian)少了析(xi)氣量，提高了蓄(xu)(xu)電(dian)池的(de)充(chong)電(dian)電(dian)流(liu)接受率[5]。
圖5 脈沖式(shi)充電(dian)曲線
2.2.2 ReflexTM快速(su)充電法
這種技術是(shi)美國的(de)(de)一項專利技術，它主要面對的(de)(de)充(chong)(chong)電對象是(shi)鎳鎘(ge)電池(chi)(chi)。由于它采用(yong)了(le)新型的(de)(de)充(chong)(chong)電方法，解決了(le)鎳鎘(ge)電池(chi)(chi)的(de)(de)記憶效(xiao)應，因此，大大降低(di)了(le)蓄電池(chi)(chi)的(de)(de)快速充(chong)(chong)電的(de)(de)時間。鉛酸蓄電池(chi)(chi)的(de)(de)充(chong)(chong)電方法和對充(chong)(chong)電狀態(tai)的(de)(de)檢測方法與鎳鎘(ge)電池(chi)(chi)有很大的(de)(de)不同，但它們之間可以相互借鑒[3]。
如圖6所(suo)示，ReflexTM充電法的一個工作周(zhou)期包括正向充電脈沖，反向瞬間放電脈沖，停充維持3個階段[3]。
圖6 ReflexTM快速充電法
2.2.3 變電(dian)流間歇充電(dian)法
這種充(chong)(chong)電(dian)(dian)(dian)(dian)方法(fa)建立在恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)和(he)脈沖充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)基(ji)礎上，如圖7所示(shi)。其特點(dian)是將(jiang)恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)(duan)(duan)(duan)改(gai)為限壓(ya)(ya)變電(dian)(dian)(dian)(dian)流(liu)間歇(xie)充(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)(duan)(duan)(duan)。充(chong)(chong)電(dian)(dian)(dian)(dian)前期的(de)各段(duan)(duan)(duan)(duan)采(cai)用變電(dian)(dian)(dian)(dian)流(liu)間歇(xie)充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)方法(fa)，保證(zheng)加(jia)大充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)，獲得絕大部分充(chong)(chong)電(dian)(dian)(dian)(dian)量。充(chong)(chong)電(dian)(dian)(dian)(dian)后期采(cai)用定電(dian)(dian)(dian)(dian)壓(ya)(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)段(duan)(duan)(duan)(duan)，獲得過充(chong)(chong)電(dian)(dian)(dian)(dian)量，將(jiang)電(dian)(dian)(dian)(dian)池(chi)恢復至完全充(chong)(chong)電(dian)(dian)(dian)(dian)態。通過間歇(xie)停(ting)充(chong)(chong)，使(shi)蓄電(dian)(dian)(dian)(dian)池(chi)經化學(xue)反(fan)應產生的(de)氧氣和(he)氫(qing)氣有時(shi)間重(zhong)新(xin)化合而被吸(xi)收(shou)掉，使(shi)濃差(cha)極(ji)化和(he)歐姆極(ji)化自然而然地得到消(xiao)除，從(cong)而減輕(qing)了蓄電(dian)(dian)(dian)(dian)池(chi)的(de)內壓(ya)(ya)，使(shi)下一(yi)輪的(de)恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)能夠(gou)更加(jia)順利地進行，使(shi)蓄電(dian)(dian)(dian)(dian)池(chi)可以吸(xi)收(shou)更多的(de)電(dian)(dian)(dian)(dian)量[4]。
圖7 變電流(liu)間歇充(chong)電曲線
2.2.4 變(bian)電壓間歇(xie)充電法
在(zai)(zai)變(bian)電(dian)(dian)流間(jian)(jian)歇充(chong)電(dian)(dian)法(fa)的基礎上又(you)有人(ren)提出了(le)變(bian)電(dian)(dian)壓(ya)間(jian)(jian)歇充(chong)電(dian)(dian)法(fa)，如圖8所(suo)示(shi)。與變(bian)電(dian)(dian)流間(jian)(jian)歇充(chong)電(dian)(dian)方法(fa)不同之處(chu)在(zai)(zai)于第一階段的不是(shi)間(jian)(jian)歇恒(heng)(heng)流，而是(shi)間(jian)(jian)歇恒(heng)(heng)壓(ya)。
圖8 變電(dian)壓間歇充電(dian)曲(qu)線
比較圖(tu)7和圖(tu)8，可(ke)以看出：圖(tu)8更加符(fu)合(he)最佳充(chong)(chong)電(dian)(dian)(dian)的充(chong)(chong)電(dian)(dian)(dian)曲線。在每個恒電(dian)(dian)(dian)壓(ya)充(chong)(chong)電(dian)(dian)(dian)階段，由于是恒壓(ya)充(chong)(chong)電(dian)(dian)(dian)，充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)自然按照指數規律(lv)下降，符(fu)合(he)電(dian)(dian)(dian)池電(dian)(dian)(dian)流(liu)可(ke)接受率隨(sui)著充(chong)(chong)電(dian)(dian)(dian)的進(jin)行逐漸下降的特點(dian)[4]。
2.2.5 變電(dian)壓變電(dian)流波浪(lang)式間(jian)歇正負(fu)零脈沖快速充電(dian)法
綜合脈(mo)(mo)沖(chong)充(chong)電(dian)法、ReflexTM快(kuai)速充(chong)電(dian)法、變(bian)電(dian)流間歇(xie)充(chong)電(dian)法及(ji)變(bian)電(dian)壓間歇(xie)充(chong)電(dian)法的優(you)點，變(bian)電(dian)壓變(bian)電(dian)流波浪(lang)式正負零(ling)脈(mo)(mo)沖(chong)間歇(xie)快(kuai)速充(chong)電(dian)法得到發展應用(yong)。脈(mo)(mo)沖(chong)充(chong)電(dian)法充(chong)電(dian)電(dian)路的控制一般有兩種：
1）脈沖電流的幅值可變，而(er)PWM（驅動(dong)充放電開關管）信號(hao)的頻率(lv)是固定的；
2）脈沖電流幅值固定(ding)不(bu)變，PWM信號的頻率(lv)可調。
圖9采用(yong)了一種不(bu)同于這兩者的(de)(de)(de)(de)(de)控制模式，脈沖電流幅(fu)值和PWM信號的(de)(de)(de)(de)(de)頻率均固定，PWM占空比可調，在此基礎上加(jia)入間(jian)歇(xie)停充階段，能(neng)夠在較短的(de)(de)(de)(de)(de)時間(jian)內充進更多的(de)(de)(de)(de)(de)電量，提高蓄(xu)電池的(de)(de)(de)(de)(de)充電接受能(neng)力。
圖9 波浪式間(jian)歇(xie)正(zheng)負零脈沖快速充電
3 結(jie)語
鉛酸蓄電(dian)池是目前世界上(shang)廣(guang)泛(fan)使用的(de)一(yi)種化學電(dian)源，該產(chan)品具(ju)(ju)有良(liang)好的(de)可逆性(xing)，電(dian)壓特性(xing)平穩，使用壽命長，適用范圍(wei)廣(guang)，原材料豐富(fu)（且可再生使用）及(ji)造(zao)價低廉等(deng)優(you)點。主要(yao)應用在交通(tong)運輸，通(tong)信(xin)，電(dian)力，鐵路，礦山，港口等(deng)國民經(jing)濟各個部門，是社會生產(chan)經(jing)營(ying)活動中不可缺少的(de)產(chan)品，具(ju)(ju)有廣(guang)闊的(de)發展前景。