汽車(che)常用的(de)12V的(de)蓄(xu)(xu)電池由(you)6個單格(ge)蓄(xu)(xu)電池串聯而成(cheng)，每個單格(ge)蓄(xu)(xu)電池的(de)標稱電壓為2V，充滿(man)電時為2.1V。它由(you)極板與(yu)極板組(zu)、隔板、電解液和殼體組(zu)成(cheng)。蓄(xu)(xu)電池是(shi)一個化學電源，其充電與(yu)放電過程是(shi)一種可逆的(de)化學反應。它的(de)工作原理(li)如下：

電(dian)(dian)瓶(ping)在充(chong)電(dian)(dian)時(shi)(shi)，是把極(ji)板上的(de)(de)(de)硫(liu)酸(suan)(suan)(suan)鉛(qian)(qian)還原成氧(yang)化鉛(qian)(qian)、金(jin)屬(shu)(shu)鉛(qian)(qian)和(he)硫(liu)酸(suan)(suan)(suan)，其(qi)中的(de)(de)(de)氧(yang)化鉛(qian)(qian)和(he)金(jin)屬(shu)(shu)鉛(qian)(qian)沉(chen)積在極(ji)板上；在放電(dian)(dian)時(shi)(shi)，是把硫(liu)酸(suan)(suan)(suan)和(he)鉛(qian)(qian)、氧(yang)化鉛(qian)(qian)反應生成硫(liu)酸(suan)(suan)(suan)鉛(qian)(qian)附著在極(ji)板上。所(suo)以，當電(dian)(dian)瓶(ping)充(chong)滿電(dian)(dian)的(de)(de)(de)時(shi)(shi)候，就是把電(dian)(dian)瓶(ping)中的(de)(de)(de)硫(liu)酸(suan)(suan)(suan)鉛(qian)(qian)全部還原成了氧(yang)化鉛(qian)(qian)、金(jin)屬(shu)(shu)鉛(qian)(qian)和(he)硫(liu)酸(suan)(suan)(suan)，此時(shi)(shi)電(dian)(dian)解液的(de)(de)(de)密度也達到了最大。假如此時(shi)(shi)我們還繼續充(chong)電(dian)(dian)，會發生什(shen)么呢？

大家了解(jie)，電(dian)(dian)(dian)是(shi)可以電(dian)(dian)(dian)解(jie)水(shui)并生成(cheng)氫氣和(he)氧(yang)氣的(de)。在鉛酸(suan)電(dian)(dian)(dian)瓶(ping)中(zhong)也是(shi)這(zhe)樣(yang)，當硫酸(suan)鉛不再吸收外(wai)界電(dian)(dian)(dian)量(liang)時(shi)，繼(ji)續充(chong)進來(lai)的(de)電(dian)(dian)(dian)能(neng)無事可做(zuo)，就玩起了電(dian)(dian)(dian)解(jie)水(shui)的(de)游戲，把電(dian)(dian)(dian)解(jie)液中(zhong)的(de)水(shui)分解(jie)成(cheng)了氫氣和(he)氧(yang)氣，并逸出電(dian)(dian)(dian)瓶(ping)外(wai)面(mian)。這(zhe)樣(yang)電(dian)(dian)(dian)解(jie)液中(zhong)的(de)水(shui)就會(hui)越(yue)來(lai)越(yue)少(shao)，電(dian)(dian)(dian)解(jie)液的(de)密度會(hui)繼(ji)續升高，同時(shi)電(dian)(dian)(dian)瓶(ping)的(de)溫度也會(hui)上升。

假如(ru)電(dian)(dian)(dian)(dian)解(jie)(jie)液的(de)密度過高，它的(de)流(liu)動性就會(hui)變差，這樣電(dian)(dian)(dian)(dian)瓶(ping)在充(chong)放(fang)電(dian)(dian)(dian)(dian)時(shi)，電(dian)(dian)(dian)(dian)流(liu)就會(hui)受(shou)到(dao)很大(da)的(de)影響。比如(ru)正常放(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)可以(yi)達到(dao)100安，過充(chong)電(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)瓶(ping)放(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)可能(neng)(neng)就只能(neng)(neng)達到(dao)70安了。另外由于水分的(de)減(jian)(jian)少，電(dian)(dian)(dian)(dian)解(jie)(jie)液數量(liang)也減(jian)(jian)少了，這會(hui)導致電(dian)(dian)(dian)(dian)瓶(ping)容電(dian)(dian)(dian)(dian)量(liang)的(de)下降，電(dian)(dian)(dian)(dian)瓶(ping)的(de)充(chong)電(dian)(dian)(dian)(dian)速度也會(hui)下降。對外的(de)故障表現就是起動機運轉無力，啟(qi)動困難(nan)。所(suo)以(yi)說，電(dian)(dian)(dian)(dian)瓶(ping)過充(chong)電(dian)(dian)(dian)(dian)也是會(hui)損壞的(de)。

那么這(zhe)樣的(de)電(dian)(dian)瓶該(gai)如何修復(fu)呢？其實很簡單，只要向(xiang)里面補充蒸餾水就(jiu)可以了(le)（千萬不要補充電(dian)(dian)解(jie)液）。水稀釋了(le)電(dian)(dian)解(jie)液，恢復(fu)了(le)流(liu)動性，同時電(dian)(dian)解(jie)液的(de)數量也(ye)新增(zeng)了(le)，這(zhe)樣它的(de)放電(dian)(dian)速度得(de)到了(le)提(ti)升，容電(dian)(dian)量也(ye)提(ti)高了(le)，電(dian)(dian)瓶就(jiu)恢復(fu)正(zheng)常了(le)。假如此時再(zai)做一次補充充電(dian)(dian)，效果會(hui)更好。

現在很(hen)(hen)多車型都使用(yong)免維護蓄(xu)電(dian)(dian)池(chi)，這(zhe)種(zhong)蓄(xu)電(dian)(dian)池(chi)的(de)(de)特點是采用(yong)了(le)安全(quan)通(tong)氣孔，在通(tong)氣室中設置了(le)氧化(hua)鋁過濾器(qi)和鈀催化(hua)劑(ji)，阻止內部硫酸蒸(zheng)氣的(de)(de)排出，減少了(le)腐(fu)蝕(shi)用(yong)途，并使化(hua)學反應中出現的(de)(de)氫氣和氧氣再結合，生(sheng)成水返回(hui)電(dian)(dian)解(jie)液中，這(zhe)樣就能基本維持電(dian)(dian)解(jie)液的(de)(de)密度不(bu)變。這(zhe)樣的(de)(de)電(dian)(dian)瓶一(yi)般(ban)不(bu)要補充(chong)充(chong)電(dian)(dian)，假如充(chong)電(dian)(dian)時間(jian)過長(chang)，還會(hui)造成電(dian)(dian)瓶鼓包甚至漲(zhang)裂(lie)等故(gu)障。不(bu)過現在的(de)(de)充(chong)電(dian)(dian)機一(yi)般(ban)都有過充(chong)保護裝置，當電(dian)(dian)壓過高時會(hui)自動斷電(dian)(dian)的(de)(de)，一(yi)般(ban)很(hen)(hen)少發(fa)生(sheng)過充(chong)電(dian)(dian)的(de)(de)故(gu)障。