鋰電池充電電路原理及應用

鋰離子(zi)電(dian)池以其優良的特性，被廣(guang)泛應用于: 手機(ji)、攝錄像機(ji)、筆記本電(dian)腦、無繩(sheng)電(dian)話、電(dian)動(dong)工(gong)具(ju)、遙(yao)控或電(dian)動(dong)玩具(ju)、照相機(ji)等便攜(xie)式電(dian)子(zi)設(she)備中(zhong)。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)(li)離(li)(li)子電(dian)池(chi)(chi)的負極(ji)(ji)為石墨晶體，正(zheng)極(ji)(ji)通(tong)常為二氧(yang)化鋰(li)(li)。充電(dian)時(shi)鋰(li)(li)離(li)(li)子由正(zheng)極(ji)(ji)向負極(ji)(ji)運(yun)動(dong)而(er)嵌入石墨層中。放電(dian)時(shi)，鋰(li)(li)離(li)(li)子從石墨晶體內負極(ji)(ji)表面(mian)脫離(li)(li)移向正(zheng)極(ji)(ji)。所以，在(zai)該(gai)電(dian)池(chi)(chi)充放電(dian)過(guo)程中鋰(li)(li)總是以鋰(li)(li)離(li)(li)子形(xing)態(tai)出現(xian)(xian)，而(er)不是以金屬鋰(li)(li)的形(xing)態(tai)出現(xian)(xian)。因而(er)這種電(dian)池(chi)(chi)叫做鋰(li)(li)離(li)(li)子電(dian)池(chi)(chi)，簡稱鋰(li)(li)電(dian)池(chi)(chi)。

鋰電池具有：體(ti)積(ji)小、容量(liang)大、重量(liang)輕(qing)、無污(wu)染、單(dan)節電壓(ya)高(gao)、自放電率(lv)低、電池循環次數(shu)多等優點，但價(jia)格較(jiao)貴。鎳鎘電池因(yin)容量(liang)低，自放電嚴重，且(qie)對(dui)環境(jing)有污(wu)染，正逐步被淘汰。鎳氫電池具有較(jiao)高(gao)的性(xing)能價(jia)格比，且(qie)不污(wu)染環境(jing)，但單(dan)體(ti)電壓(ya)只(zhi)有1.2V，因(yin)而(er)在使用范(fan)圍(wei)上受到限制(zhi)。

二、鋰電池的特點：

1、具有更高的重量能量比、體(ti)積能量比；

2、電(dian)(dian)壓(ya)高，單節(jie)鋰電(dian)(dian)池(chi)電(dian)(dian)壓(ya)為3.6V，等于(yu)3只鎳(nie)鎘或(huo)鎳(nie)氫充(chong)電(dian)(dian)電(dian)(dian)池(chi)的(de)串(chuan)聯電(dian)(dian)壓(ya)；

3、自放(fang)電小可長時(shi)間存放(fang)，這是該電池最突出的優越性；

4、無(wu)記憶(yi)效(xiao)應(ying)(ying)。鋰電(dian)池不存(cun)在鎳(nie)鎘電(dian)池的所(suo)謂記憶(yi)效(xiao)應(ying)(ying)，所(suo)以鋰電(dian)池充電(dian)前無(wu)需放電(dian)；

5、壽(shou)命(ming)長。正常工(gong)作(zuo)條(tiao)件(jian)下，鋰(li)電(dian)池充/放電(dian)循環(huan)次(ci)數遠大于500次(ci)；

6、可以快速充電。鋰電池通常可以采用(yong)0.5～1倍容量(liang)的(de)電流充電，使充電時間縮短至1～2小(xiao)時；

7、可以隨意并聯使用；

8、由(you)于電池中不含鎘、鉛、汞等重金屬元(yuan)素，對(dui)環境無污染，是當代最先進的綠色電池；

9、成本高。與其它可充(chong)電池相比，鋰電池價格較(jiao)貴(gui)。

三、鋰電池的內部結構：

鋰(li)電(dian)池通常有兩種(zhong)外型：圓柱(zhu)型和(he)長方型。

電(dian)(dian)(dian)池(chi)內部采用螺旋(xuan)繞(rao)制結構，用一種非常精細而滲透(tou)性很強(qiang)的(de)聚(ju)乙烯(xi)薄膜隔離材料在正(zheng)、負極(ji)(ji)(ji)(ji)間間隔而成。正(zheng)極(ji)(ji)(ji)(ji)包括由鋰(li)和二氧(yang)化鈷組(zu)(zu)成的(de)鋰(li)離子(zi)收(shou)集極(ji)(ji)(ji)(ji)及(ji)由鋁(lv)薄膜組(zu)(zu)成的(de)電(dian)(dian)(dian)流收(shou)集極(ji)(ji)(ji)(ji)。負極(ji)(ji)(ji)(ji)由片狀碳材料組(zu)(zu)成的(de)鋰(li)離子(zi)收(shou)集極(ji)(ji)(ji)(ji)和銅(tong)薄膜組(zu)(zu)成的(de)電(dian)(dian)(dian)流收(shou)集極(ji)(ji)(ji)(ji)組(zu)(zu)成。電(dian)(dian)(dian)池(chi)內充有有機電(dian)(dian)(dian)解質溶液。另外還裝有安全(quan)閥和PTC元件(jian)，以便電(dian)(dian)(dian)池(chi)在不(bu)正(zheng)常狀態及(ji)輸出短路時保(bao)護電(dian)(dian)(dian)池(chi)不(bu)受損壞。

單(dan)節鋰電池的(de)電壓為3.6V，容(rong)量也不(bu)可(ke)能無限大(da)，因此，常(chang)常(chang)將單(dan)節鋰電池進行串、并(bing)聯(lian)處理(li)，以滿足不(bu)同場合的(de)要求(qiu)。

四、鋰電池的充放電要求：

1、鋰電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)：根(gen)據鋰電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)結構特性(xing)，最高(gao)充(chong)電(dian)(dian)(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)應(ying)為4.2V，不(bu)能過(guo)充(chong)，否則會(hui)因正極的(de)鋰離子拿走太多，而(er)使電(dian)(dian)(dian)(dian)(dian)池(chi)報(bao)廢。其充(chong)放電(dian)(dian)(dian)(dian)(dian)要求(qiu)較高(gao)，可采用(yong)專用(yong)的(de)恒(heng)流、恒(heng)壓(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)進行充(chong)電(dian)(dian)(dian)(dian)(dian)。通(tong)常(chang)恒(heng)流充(chong)電(dian)(dian)(dian)(dian)(dian)至(zhi)4.2V/節后轉入恒(heng)壓(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)(dian)，當恒(heng)壓(ya)(ya)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流降至(zhi)100mA以內時，應(ying)停(ting)止(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)。

充(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)（mA）=0.1～1.5倍(bei)電(dian)(dian)池容量（如1350mAh的電(dian)(dian)池，其充(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)可控制在135～2025mA之(zhi)間）。常規充(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)可選擇(ze)在0.5倍(bei)電(dian)(dian)池容量左右(you)，充(chong)電(dian)(dian)時間約為2～3小(xiao)時。

2、鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)：因(yin)鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的內部結(jie)構所致，放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)時鋰(li)離(li)子(zi)不能(neng)全部移向(xiang)正極，必須(xu)保留一部分(fen)鋰(li)離(li)子(zi)在(zai)(zai)負(fu)極，以保證(zheng)在(zai)(zai)下次(ci)充電(dian)(dian)(dian)(dian)(dian)時鋰(li)離(li)子(zi)能(neng)夠暢(chang)通地嵌入通道(dao)。否則，電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)壽命(ming)就相(xiang)應(ying)縮短。為了保證(zheng)石墨(mo)層中(zhong)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)后留有(you)部分(fen)鋰(li)離(li)子(zi)，就要嚴格(ge)限制(zhi)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)終止(zhi)(zhi)最低(di)電(dian)(dian)(dian)(dian)(dian)壓，也就是說(shuo)鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)不能(neng)過(guo)(guo)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)。放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)終止(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)壓通常為3.0V/節，最低(di)不能(neng)低(di)于(yu)2.5V/節。電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)時間長短與電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容量(liang)(liang)、放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流大小(xiao)有(you)關。電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)時間（小(xiao)時）=電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容量(liang)(liang)/放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流。鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(mA)不應(ying)超(chao)過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容量(liang)(liang)的3倍(bei)。（如(ru)1000mAH電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)，則放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流應(ying)嚴格(ge)控制(zhi)在(zai)(zai)3A以內）否則會使電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)損壞。

目(mu)前市場上所售鋰電池組內(nei)部(bu)均封有配套的(de)充(chong)放電保(bao)護板。只要控(kong)制(zhi)好外部(bu)的(de)充(chong)放電電流即可(ke)。

五、鋰電池的保護電路：

兩(liang)節(jie)鋰電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的充(chong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)如圖(tu)一所示。由(you)兩(liang)個場效(xiao)應管(guan)和(he)專用(yong)保(bao)護集成塊S--8232組成，過(guo)(guo)(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)管(guan)FET2和(he)過(guo)(guo)(guo)(guo)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)管(guan)FET1串聯于電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，由(you)保(bao)護IC監(jian)視電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)并進行控制(zhi)，當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上升至(zhi)4.2V時，過(guo)(guo)(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護管(guan)FET1截止(zhi)，停(ting)止(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。為(wei)防止(zhi)誤動作，一般(ban)在(zai)外電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)加(jia)有(you)延時電(dian)(dian)(dian)(dian)(dian)(dian)容。當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)處于放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)狀態下(xia)，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降至(zhi)2.55V時，過(guo)(guo)(guo)(guo)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)管(guan)FET1截止(zhi)，停(ting)止(zhi)向負(fu)載供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)。過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)保(bao)護是(shi)在(zai)當(dang)負(fu)載上有(you)較大(da)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)過(guo)(guo)(guo)(guo)時，控制(zhi)FET1使其截止(zhi)，停(ting)止(zhi)向負(fu)載放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，目(mu)的是(shi)為(wei)了保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和(he)場效(xiao)應管(guan)。過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)檢(jian)測是(shi)利用(yong)場效(xiao)應管(guan)的導通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)阻作為(wei)檢(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)阻，監(jian)視它的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降，當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降超(chao)過(guo)(guo)(guo)(guo)設(she)定(ding)值時就停(ting)止(zhi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)中(zhong)一般(ban)還加(jia)有(you)延時電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，以區分(fen)浪涌電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)和(he)短(duan)路(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。該電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)功(gong)能完善，性(xing)能可靠，但專業性(xing)強，且專用(yong)集成塊不易購買，業余(yu)愛好者(zhe)不易仿(fang)制(zhi)。

六、簡易充電電路：

現(xian)在有(you)不(bu)少商家(jia)出(chu)售不(bu)帶(dai)充(chong)電(dian)(dian)(dian)(dian)(dian)板的(de)(de)單節鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)。其性能(neng)優越，價格低廉，可(ke)用于(yu)自制(zhi)產(chan)品及鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組的(de)(de)維修代換，因而(er)深受廣大電(dian)(dian)(dian)(dian)(dian)子愛(ai)好者(zhe)(zhe)喜愛(ai)。有(you)興(xing)趣的(de)(de)讀者(zhe)(zhe)可(ke)參(can)照圖(tu)二制(zhi)作一塊(kuai)充(chong)電(dian)(dian)(dian)(dian)(dian)板。其原理是(shi)：采用恒定電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)給電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)，確保(bao)不(bu)會(hui)過(guo)充(chong)。輸入直(zhi)流電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高于(yu)所充(chong)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)3伏即可(ke)。R1、Q1、W1、TL431組成精密可(ke)調(diao)穩壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，Q2、W2、R2構成可(ke)調(diao)恒流電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，Q3、R3、R4、R5、LED為充(chong)電(dian)(dian)(dian)(dian)(dian)指示電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。隨著(zhu)被(bei)充(chong)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)上升，充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流將逐漸減(jian)小(xiao)，待電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)滿(man)后R4上的(de)(de)壓(ya)(ya)降(jiang)將降(jiang)低，從(cong)(cong)而(er)使(shi)Q3截止(zhi)， LED將熄(xi)滅(mie)，為保(bao)證電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)能(neng)夠充(chong)足(zu)，請在指示燈(deng)熄(xi)滅(mie)后繼續充(chong)1—2小(xiao)時。使(shi)用時請給Q2、Q3裝上合適的(de)(de)散熱(re)器(qi)(qi)。本電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)(de)優點(dian)是(shi)：制(zhi)作簡單，元器(qi)(qi)件易購(gou)，充(chong)電(dian)(dian)(dian)(dian)(dian)安全，顯(xian)示直(zhi)觀，并且不(bu)會(hui)損壞電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)．通過(guo)改(gai)變W1可(ke)以對多(duo)節串聯(lian)鋰電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)，改(gai)變W２可(ke)以對充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流進行(xing)大范圍調(diao)節。缺點(dian)是(shi)：無(wu)過(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。圖(tu)三是(shi)該充(chong)電(dian)(dian)(dian)(dian)(dian)板的(de)(de)印制(zhi)板圖(tu)（從(cong)(cong)元件面看的(de)(de)透(tou)視圖(tu)）。

七、單節鋰電池的應用舉例

1、 作電池組維修代換品

有許多電(dian)(dian)池組(zu)：如(ru)筆(bi)記(ji)本電(dian)(dian)腦上(shang)用(yong)的那種，經維(wei)修發現(xian)，此電(dian)(dian)池組(zu)損(sun)壞時僅是個別(bie)電(dian)(dian)池有問題。可以選用(yong)合適的單節(jie)鋰電(dian)(dian)池進(jin)行更(geng)換。

2、 制作高亮微型電筒

筆(bi)者曾用(yong)單節3.6V1.6AH鋰電(dian)池(chi)(chi)配合一(yi)個白色超(chao)高亮度發光管做成一(yi)只(zhi)微型電(dian)筒，使用(yong)方便(bian)，小(xiao)(xiao)巧美觀。而(er)且由于電(dian)池(chi)(chi)容量大，平(ping)均(jun)每(mei)晚使用(yong)半小(xiao)(xiao)時，至(zhi)今已用(yong)兩個多月仍無(wu)需充電(dian)。電(dian)路如(ru)圖四(si)所(suo)示(shi)。

3、代替3V電源

由于單節鋰(li)電(dian)(dian)池電(dian)(dian)壓為3.6V。因(yin)此僅(jin)需一(yi)節鋰(li)電(dian)(dian)池便可(ke)代替(ti)兩節普通(tong)電(dian)(dian)池，給收音機、隨身聽、照相機等小家電(dian)(dian)產品供電(dian)(dian)，不僅(jin)重量輕，而且連續使用時(shi)間長。

八、鋰電池的保存：

鋰電池(chi)需充(chong)足電后保存。在20℃下可(ke)儲存半(ban)年以上(shang)，可(ke)見鋰電池(chi)適宜在低(di)溫下保存。曾有人建(jian)議將充(chong)電電池(chi)放入(ru)冰箱冷藏(zang)室內保存，的確是個好(hao)注意。

九、使用注意事項：

鋰電池絕對不可解(jie)體、鉆(zhan)孔、穿刺(ci)、鋸割、加壓、加熱，否則有(you)可能(neng)造成嚴重后果。沒有(you)充電保護板的鋰電池不可短路，不可供小孩玩(wan)耍。不能(neng)靠近易燃(ran)物(wu)品、化(hua)學物(wu)品。報廢的鋰電池要妥善處理。