“雙(shuang)極(ji)硫(liu)酸(suan)鹽(yan)化(hua)理(li)論(lun)”可(ke)以(yi)描(miao)述(shu)為(wei):鉛(qian)蓄(xu)電(dian)池(chi)在(zai)放(fang)電(dian)時(shi),正(zheng)負(fu)極(ji)的(di)活(huo)性(xing)物(wu)質(zhi)均(jun)變(bian)成(cheng)硫(liu)酸(suan)鉛(qian)( PbSO4 ),充(chong)電(dian)後(hou)又(you)恢(hui)複(fu)到(dao)原(yuan)來(lai)的(di)狀(zhuang)態(tai),即(ji)正(zheng)極(ji)轉(zhuan)變(bian)成(cheng)二(er)氧(yang)化(hua)鉛(qian)( PbO2) , 負(fu)極(ji)轉(zhuan)變(bian)成(cheng)海(hai)綿(mian)狀(zhuang)鉛(qian)(Pb)。
( 1 )電(dian)動(dong)勢(shi)的(di)產(chan)生(sheng)
鉛(qian)蓄(xu)電(dian)池(chi)正(zheng)極(ji)板(pan)上(shang)的(di)活(huo)性(xing)物(wu)質(zhi)是(shi)二(er)氧(yang)化(hua)鉛(qian),負(fu)極(ji)板(pan)上(shang)的(di)活(huo)性(xing)物(wu)質(zhi)是(shi)海(hai)綿(mian)狀(zhuang)鉛(qian)。在(zai)稀(xi)硫(liu)酸(suan)溶(rong)液(ye)中(zhong),由(you)於(yu)電(dian)化(hua)學(xue)作(zuo)用(yong),正(zheng)、負(fu)極(ji)板(pan)與(yu)電(dian)解(xie)液(ye)之(zhi)間(jian)分(fen)別(bie)產(chan)生(sheng)了(liao)電(dian)極(ji)電(dian)位(wei),正(zheng)、負(fu)兩(liang)極(ji)間(jian)電(dian)位(wei)差(chai)就(jiu)是(shi)蓄(xu)電(dian)池(chi)的(di)電(dian)動(dong)勢(shi)。負(fu)極(ji)板(pan).上(shang)的(di)海(hai)綿(mian)狀(zhuang)金(jin)屬(zhu)鉛(qian)是(shi)由(you)二(er)價(jia)鉛(qian)離(li)子(zi)( Pb2+ )和(hu)電(dian)子(zi)組(zu)成(cheng)的(di)。稀(xi)硫(liu)酸(suan)在(zai)水(shui)中(zhong)被(bei)電(dian)離(li)為(wei)氫(qing)離(li)子(zi)( H+)和(hu)硫(liu)酸(suan)根(gen)離(li)子(zi)( S04 )。負(fu)極(ji)板(pan)浸(jin)入(ru)稀(xi)硫(liu)酸(suan)溶(rong)液(ye)後(hou),二(er)價(jia)鉛(qian)離(li)子(zi)進(jin)入(ru)溶(rong)液(ye),在(zai)極(ji)板(pan)上(shang)留(liu)下(xia)能(neng)自(zi)由(you)移(yi)動(dong)的(di)電(dian)子(zi),因(yin)而(er)負(fu)極(ji)板(pan)帶(dai)負(fu)電(dian),即(ji)產(chan)生(sheng)了(liao)電(dian)極(ji)電(dian)位(wei)。同(tong)樣(yang),正(zheng)極(ji)板(pan).上(shang)的(di)二(er)氧(yang)化(hua)鉛(qian)也(ye)與(yu)這(zhe)樣(yang),在(zai)電(dian)池(chi)的(di)正(zheng)、負(fu)兩(liang)極(ji)上(shang)便(pian)產(chan)生(sheng)了(liao)電(dian)動(dong)勢(shi)。稀(xi)硫(liu)酸(suan)作(zuo)用(yong)，產(chan)生(sheng)的(di)四(si)價(jia)鉛(qian)正(zheng)離(li)子(zi)( Pb4+)留(liu)在(zai)極(ji)板(pan)上(shang)，使(shi)正(zheng)極(ji)板(pan)帶(dai)正(zheng)電(dian)，也(ye)產(chan)生(sheng)了(liao)電(dian)極(ji)電(dian)位(wei)。
( 2 )放(fang)電(dian)過(guo)程(cheng)中(zhong)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)
①負(fu)極(ji)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)在(zai)放(fang)電(dian)過(guo)程(cheng)中(zhong) ,負(fu)極(ji)上(shang)的(di)鉛(qian)原(yuan)子(zi)失(shi)去(qu)兩(liang)個(ge)電(dian)子(zi),變(bian)成(cheng)二(er)價(jia)鉛(qian)正(zheng)離(li)子(zi)( Pb2+ )。電(dian)解(xie)液(ye)中(zhong)的(di)硫(liu)酸(suan)分(fen)子(zi)( H2SO4 )離(li)解(xie)為(wei)兩(liang)個(ge)氫(qing)離(li)子(zi)(H+)和(hu)一(yi)個(ge)硫(liu)酸(suan)根(gen)離(li)子(zi)( S04 )。此(ci)時(shi)二(er)價(jia)鉛(qian)正(zheng)離(li)子(zi)( Pb2+ )與(yu)一(yi)個(ge)硫(liu)酸(suan)根(gen)離(li)子(zi)結(jie)合(ge)成(cheng)硫(liu)酸(suan)鉛(qian)( PbSO4 )分(fen)子(zi)，附(fu)著(zhuo)在(zai)負(fu)極(ji)板(pan)上(shang)。兩(liang)個(ge)氫(qing)離(li)子(zi)( H+ )留(liu)在(zai)電(dian)解(xie)液(ye)中(zhong),參(shen)加(jia)正(zheng)極(ji)化(hua)學(xue)反(fan)應(ying)。負(fu)極(ji)板(pan)失(shi)去(qu)的(di)電(dian)子(zi)將(qiang)通(tong)過(guo)外(wai)電(dian)路(lu)流(liu)入(ru)正(zheng)極(ji)。化(hua)學(xue)反(fan)應(ying)方(fang)程(cheng)式(shi)如(ru)下(xia):
②正(zheng)極(ji)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)放(fang)電(dian)開(kai)始(shi)後(hou) ,正(zheng)極(ji)上(shang)的(di)PbO2與(yu)電(dian)解(xie)液(ye)中(zhong)的(di)水(shui)分(fen)子(zi)作(zuo)用(yong),生(sheng)成(cheng)四(si)價(jia)鉛(qian)離(li)子(zi)( Pb4+ )和(hu)四(si)個(ge)氫(qing)氧(yang)根(gen)離(li)子(zi)(OH )。每(mei)個(ge)四(si)價(jia)鉛(qian)離(li)子(zi)接(jie)受(shou)負(fu)極(ji)傳(zhuan)來(lai)的(di)兩(liang)個(ge)電(dian)子(zi)後(hou)生(sheng)成(cheng)Pb2+,再(zai)進(jin)入(ru)溶(rong)液(ye)與(yu)硫(liu)酸(suan)根(gen)(SO4 )結(jie)合(ge)成(cheng)硫(liu)酸(suan)鉛(qian)分(fen)子(zi)( PbSO4 )附(fu)在(zai)正(zheng)極(ji)上(shang),氫(qing)氧(yang)根(gen)離(li)子(zi)(OH- )與(yu)溶(rong)液(ye)中(zhong)氫(qing)離(li)子(zi)( H+ )反(fan)應(ying)生(sheng)成(cheng)水(shui)分(fen)子(zi)。反(fan)應(ying)式(shi)如(ru)下(xia):
③鉛(qian)蓄(xu)電(dian)池(chi)放(fang)電(dian)過(guo)程(cheng)中(zhong)總(zong)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)將(qiang)負(fu)極(ji)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)與(yu)正(zheng)極(ji)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)兩(liang)式(shi)相(xiang)加(jia),就(jiu)得(dei)到(dao)鉛(qian)蓄(xu)電(dian)池(chi)放(fang)電(dian)過(guo)程(cheng)中(zhong)的(di)總(zong)反(fan)應(ying)方(fang)程(cheng)式(shi)。鉛(qian)蓄(xu)電(dian)池(chi)放(fang)電(dian)過(guo)程(cheng)中(zhong)的(di)電(dian)化(hua)學(xue)反(fan)應(ying)示(shi)意(yi)圖(tu)如(ru)圖(tu)5 -3所(suo)示(shi)。
不(bu)斷(duan)生(sheng)成(cheng),電(dian)解(xie)液(ye)密(mi)度(duo)不(bu)斷(duan)升(sheng)高(gao)。因(yin)此(ci),電(dian)解(xie)液(ye)密(mi)度(duo)可(ke)以(yi)作(zuo)為(wei)電(dian)池(chi)充(chong)電(dian)終(zhong)了(liao)的(di)標(biao)誌(zhi),如(ru)啟(qi)動(dong)用(yong)鉛(qian)蓄(xu)電(dian)池(chi)的(di)充(chong)電(dian)終(zhong)了(liao)密(mi)度(duo)是(shi)ds=1.28 ~ 1.30kg/L ,固(gu)定(ding)用(yong)防(fang)酸(suan)隔(ge)爆(bao)式(shi)鉛(qian)蓄(xu)電(dian)池(chi)的(di)充(chong)電(dian)終(zhong)了(liao)密(mi)度(duo)是(shi)d15=1.20~ 1.22kg/L。
④充(chong)電(dian)後(hou)期(qi)分(fen)解(xie)水(shui)的(di)反(fan)應(ying)鉛(qian)蓄(xu)電(dian)池(chi)在(zai)充(chong)電(dian)過(guo)程(cheng)中(zhong)還(huan)伴(ban)隨(sui)有(you)電(dian)解(xie)水(shui)的(di)反(fan)應(ying),這(zhe)種(zhong)反(fan)應(ying)在(zai)充(chong)電(dian)初(chu)期(qi)很(hen)微(wei)弱(ruo),但(dan)當(dang)單(shan)體(ti)電(dian)池(chi)的(di)端(duan)電(dian)壓(ya)達(da)到(dao)2.3V/隻(zhi)時(shi),水(shui)的(di)電(dian)解(xie)開(kai)始(shi)逐(zhu)漸(jian)成(cheng)為(wei)主(zhu)要(yao)反(fan)應(ying)。這(zhe)是(shi)因(yin)為(wei)端(duan)電(dian)壓(ya)達(da)2.3V/隻(zhi)時(shi),正(zheng)負(fu)極(ji)板(pan)上(shang)的(di)活(huo)性(xing)物(wu)質(zhi)已(yi)大(dai)部(bu)分(fen)恢(hui)複(fu),硫(liu)酸(suan)鉛(qian)的(di)量(liang)逐(zhu)漸(jian)減(jian)少(shao),使(shi)充(chong)電(dian)電(dian)流(liu)用(yong)於(yu)活(huo)性(xing)物(wu)質(zhi)恢(hui)複(fu)的(di)部(bu)分(fen)越(yue)來(lai)越(yue)少(shao),而(er)用(yong)於(yu)電(dian)解(xie)水(shui)的(di)部(bu)分(fen)越(yue)來(lai)越(yue)多(duo)。此(ci)時(shi),負(fu)極(ji)板(pan).上(shang)有(you)大(dai)量(liang)氫(qing)氣(qi)冒(mao)出(chu),正(zheng)極(ji)板(pan)上(shang)有(you)大(dai)量(liang)氧(yang)氣(qi)冒(mao)出(chu)。其(qi)化(hua)學(xue)反(fan)應(ying)方(fang)程(cheng)式(shi)如(ru)下(xia):
對(dui)於(yu)富(fu)液(ye)式(shi)鉛(qian)蓄(xu)電(dian)池(chi)來(lai)說(shui),此(ci)時(shi)可(ke)觀(guan)察(cha)到(dao)有(you)大(dai)量(liang)氣(qi)泡(pao)逸(yi)出(chu),並(bing)且(qie)冒(mao)氣(qi)越(yue)來(lai)越(yue)激(ji)烈(lie),因(yin)此(ci)可(ke)用(yong)充(chong)電(dian)末(mo)期(qi)電(dian)池(chi)冒(mao)氣(qi)的(di)程(cheng)度(duo)作(zuo)為(wei)充(chong)電(dian)終(zhong)了(liao)標(biao)誌(zhi)之(zhi)一(yi)。但(dan)對(dui)於(yu)閥(fa)控(kong)式(shi)密(mi)封(feng)鉛(qian)蓄(xu)電(dian)池(chi)來(lai)說(shui),因(yin)為(wei)是(shi)密(mi)封(feng)結(jie)構(gou)，其(qi)充(chong)電(dian)後(hou)期(qi)為(wei)恒(heng)壓(ya)充(chong)電(dian)( 2.3V/隻(zhi)左(zuo)右(you)) , 充(chong)電(dian)電(dian)流(liu)很(hen)小(xiao),而(er)且(qie)正(zheng)極(ji)析(xi)出(chu)的(di)氧(yang)氣(qi)能(neng)在(zai)負(fu)極(ji)被(bei)吸(xi)收(shou),所(suo)以(yi)不(bu)能(neng)觀(guan)察(cha)到(dao)冒(mao)氣(qi)的(di)現(xian)象(xiang)。水(shui)的(di)分(fen)解(xie)不(bu)僅(jin)使(shi)電(dian)解(xie)液(ye)減(jian)少(shao),而(er)且(qie)浪(lang)費(fei)電(dian)能(neng)，同(tong)時(shi)激(ji)烈(lie)氣(qi)泡(pao)的(di)衝(chong)擊(ji)能(neng)加(jia)速(su)活(huo)性(xing)物(wu)質(zhi)脫(tuo)落(la),使(shi)蓄(xu)電(dian)池(chi)壽(shou)命(ming)縮(suo)短(duan)。因(yin)此(ci),充(chong)電(dian)後(hou)期(qi)須(xu)減(jian)小(xiao)充(chong)電(dian)電(dian)流(liu),減(jian)緩(huan)冒(mao)氣(qi)的(di)劇(ju)烈(lie)程(cheng)度(duo),以(yi)延(yan)長(zhang)電(dian)池(chi)壽(shou)命(ming)。
