鋰電池充電電路原理及應用

鋰離子(zi)電池以其優良的特(te)性，被廣泛應用(yong)于: 手機(ji)、攝錄像(xiang)機(ji)、筆記本電腦、無繩電話、電動(dong)工具、遙控或(huo)電動(dong)玩(wan)具、照相(xiang)機(ji)等(deng)便(bian)攜式電子(zi)設備中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)(li)離(li)子(zi)電(dian)池(chi)(chi)(chi)的(de)負(fu)(fu)極為石(shi)(shi)墨晶(jing)體，正(zheng)極通常為二氧(yang)化鋰(li)(li)。充(chong)電(dian)時(shi)鋰(li)(li)離(li)子(zi)由(you)正(zheng)極向負(fu)(fu)極運動而嵌入(ru)石(shi)(shi)墨層中(zhong)。放電(dian)時(shi)，鋰(li)(li)離(li)子(zi)從石(shi)(shi)墨晶(jing)體內(nei)負(fu)(fu)極表面脫離(li)移向正(zheng)極。所以，在該(gai)電(dian)池(chi)(chi)(chi)充(chong)放電(dian)過程中(zhong)鋰(li)(li)總是以鋰(li)(li)離(li)子(zi)形(xing)態出現，而不是以金屬鋰(li)(li)的(de)形(xing)態出現。因(yin)而這種電(dian)池(chi)(chi)(chi)叫做鋰(li)(li)離(li)子(zi)電(dian)池(chi)(chi)(chi)，簡稱(cheng)鋰(li)(li)電(dian)池(chi)(chi)(chi)。

鋰電(dian)(dian)(dian)池(chi)具有(you)：體積小、容量大(da)、重(zhong)量輕、無污(wu)染(ran)、單(dan)節電(dian)(dian)(dian)壓高、自(zi)放(fang)電(dian)(dian)(dian)率(lv)低、電(dian)(dian)(dian)池(chi)循(xun)環次數多等優點，但(dan)價(jia)格較貴。鎳(nie)鎘電(dian)(dian)(dian)池(chi)因容量低，自(zi)放(fang)電(dian)(dian)(dian)嚴重(zhong)，且對環境(jing)有(you)污(wu)染(ran)，正逐步(bu)被淘(tao)汰。鎳(nie)氫電(dian)(dian)(dian)池(chi)具有(you)較高的性(xing)能價(jia)格比，且不污(wu)染(ran)環境(jing)，但(dan)單(dan)體電(dian)(dian)(dian)壓只有(you)1.2V，因而(er)在使用范圍上受(shou)到(dao)限制。

二、鋰電池的特點：

1、具有更(geng)高(gao)的重量(liang)(liang)能(neng)(neng)量(liang)(liang)比(bi)、體積能(neng)(neng)量(liang)(liang)比(bi)；

2、電(dian)壓(ya)(ya)高，單節鋰電(dian)池(chi)電(dian)壓(ya)(ya)為3.6V，等于3只鎳(nie)鎘或鎳(nie)氫充(chong)電(dian)電(dian)池(chi)的串聯(lian)電(dian)壓(ya)(ya)；

3、自放電(dian)小可長(chang)時間存放，這是該(gai)電(dian)池最突出的優(you)越性；

4、無(wu)記憶效應。鋰(li)電(dian)(dian)池不存在鎳(nie)鎘電(dian)(dian)池的所(suo)謂記憶效應，所(suo)以鋰(li)電(dian)(dian)池充電(dian)(dian)前無(wu)需放電(dian)(dian)；

5、壽命長。正常工作條件下，鋰(li)電池充/放電循(xun)環次(ci)數遠(yuan)大于500次(ci)；

6、可以快速充(chong)電(dian)(dian)。鋰電(dian)(dian)池通常可以采用0.5～1倍(bei)容量的(de)電(dian)(dian)流(liu)充(chong)電(dian)(dian)，使充(chong)電(dian)(dian)時(shi)間(jian)縮短至1～2小(xiao)時(shi)；

7、可(ke)以隨意并聯使用；

8、由(you)于電池中不(bu)含鎘、鉛、汞等重金屬(shu)元素，對環境無污染(ran)，是當代最先進(jin)的綠色電池；

9、成(cheng)本(ben)高。與其它可充電(dian)池相比，鋰電(dian)池價(jia)格較(jiao)貴。

三、鋰電池的內部結構：

鋰電池通常有兩種外型(xing)(xing)(xing)：圓柱(zhu)型(xing)(xing)(xing)和長方型(xing)(xing)(xing)。

電(dian)(dian)池(chi)(chi)內部(bu)采用螺旋繞(rao)制(zhi)結構，用一(yi)種(zhong)非常精(jing)細而滲(shen)透性很強的(de)(de)聚乙烯薄膜(mo)隔(ge)離材料在(zai)正(zheng)(zheng)、負極(ji)間(jian)間(jian)隔(ge)而成。正(zheng)(zheng)極(ji)包(bao)括(kuo)由鋰(li)和(he)(he)二氧化鈷組成的(de)(de)鋰(li)離子(zi)收集極(ji)及(ji)由鋁薄膜(mo)組成的(de)(de)電(dian)(dian)流收集極(ji)。負極(ji)由片狀碳材料組成的(de)(de)鋰(li)離子(zi)收集極(ji)和(he)(he)銅薄膜(mo)組成的(de)(de)電(dian)(dian)流收集極(ji)組成。電(dian)(dian)池(chi)(chi)內充有有機電(dian)(dian)解質溶(rong)液。另外還裝有安全(quan)閥和(he)(he)PTC元件，以便電(dian)(dian)池(chi)(chi)在(zai)不正(zheng)(zheng)常狀態及(ji)輸出(chu)短路時保護電(dian)(dian)池(chi)(chi)不受損(sun)壞。

單(dan)節(jie)鋰電池(chi)的電壓為3.6V，容量也不可能無限大，因此(ci)，常(chang)常(chang)將單(dan)節(jie)鋰電池(chi)進行串、并聯處(chu)理，以(yi)滿足不同場(chang)合的要求。

四、鋰電池的充放電要求：

1、鋰電(dian)(dian)(dian)池的(de)(de)充(chong)(chong)電(dian)(dian)(dian)：根(gen)據鋰電(dian)(dian)(dian)池的(de)(de)結構特性(xing)，最高充(chong)(chong)電(dian)(dian)(dian)終(zhong)止電(dian)(dian)(dian)壓(ya)應為4.2V，不能過充(chong)(chong)，否則(ze)會因(yin)正極(ji)的(de)(de)鋰離(li)子拿走太多，而使電(dian)(dian)(dian)池報廢。其充(chong)(chong)放電(dian)(dian)(dian)要求(qiu)較高，可采用專(zhuan)用的(de)(de)恒(heng)流(liu)、恒(heng)壓(ya)充(chong)(chong)電(dian)(dian)(dian)器進行充(chong)(chong)電(dian)(dian)(dian)。通(tong)常恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)至4.2V/節后轉入(ru)恒(heng)壓(ya)充(chong)(chong)電(dian)(dian)(dian)，當(dang)恒(heng)壓(ya)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)降至100mA以(yi)內時，應停(ting)止充(chong)(chong)電(dian)(dian)(dian)。

充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)（mA）=0.1～1.5倍電(dian)(dian)(dian)池容量（如1350mAh的電(dian)(dian)(dian)池，其充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)可控(kong)制在135～2025mA之間）。常規充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)可選擇在0.5倍電(dian)(dian)(dian)池容量左右，充(chong)(chong)電(dian)(dian)(dian)時(shi)間約為2～3小時(shi)。

2、鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)：因(yin)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的內部結(jie)構所致，放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)(li)離(li)子不能(neng)全部移向正極(ji)，必須保(bao)留一(yi)部分鋰(li)(li)離(li)子在(zai)負極(ji)，以保(bao)證在(zai)下次(ci)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)(li)離(li)子能(neng)夠暢通地(di)嵌入(ru)通道。否則，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)壽(shou)命就相(xiang)應(ying)縮短。為了保(bao)證石(shi)墨層中放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)后留有(you)部分鋰(li)(li)離(li)子，就要(yao)嚴格(ge)限制放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止最低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，也就是說鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)不能(neng)過放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓通常為3.0V/節，最低(di)不能(neng)低(di)于2.5V/節。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)(jian)長(chang)短與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)、放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)大(da)小有(you)關。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)(jian)（小時(shi)）=電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)/放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(mA)不應(ying)超過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量(liang)的3倍。（如1000mAH電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，則放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)應(ying)嚴格(ge)控(kong)制在(zai)3A以內）否則會使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)損壞。

目前市(shi)場(chang)上所售鋰電池組內部均封有配套的充放電保護板。只(zhi)要(yao)控制好外部的充放電電流即可。

五、鋰電池的保護電路：

兩節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)(hu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)如圖一所示。由兩個場(chang)(chang)效(xiao)應管和(he)專用保(bao)護(hu)(hu)集(ji)成塊S--8232組成，過(guo)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管FET2和(he)過(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管FET1串聯于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，由保(bao)護(hu)(hu)IC監(jian)視電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓并進行(xing)控(kong)(kong)制，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓上升至(zhi)4.2V時(shi)，過(guo)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)(hu)管FET1截止(zhi)，停止(zhi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為(wei)防止(zhi)誤動作，一般在(zai)(zai)外(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)加(jia)有延時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)處(chu)于放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態下(xia)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降至(zhi)2.55V時(shi)，過(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管FET1截止(zhi)，停止(zhi)向負(fu)載供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)保(bao)護(hu)(hu)是在(zai)(zai)當負(fu)載上有較大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過(guo)時(shi)，控(kong)(kong)制FET1使其(qi)截止(zhi)，停止(zhi)向負(fu)載放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，目的(de)是為(wei)了保(bao)護(hu)(hu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)和(he)場(chang)(chang)效(xiao)應管。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢測是利用場(chang)(chang)效(xiao)應管的(de)導通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻作為(wei)檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，監(jian)視它(ta)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降超(chao)過(guo)設定值時(shi)就停止(zhi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)中(zhong)一般還加(jia)有延時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，以區分浪涌電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和(he)短路(lu)(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)功能完善，性(xing)(xing)能可靠(kao)，但專業性(xing)(xing)強(qiang)，且專用集(ji)成塊不易(yi)購買(mai)，業余愛好者不易(yi)仿制。

六、簡易充電電路：

現在有不少商家出售不帶充電(dian)(dian)(dian)(dian)板(ban)的(de)(de)單節鋰電(dian)(dian)(dian)(dian)池(chi)(chi)。其性能(neng)優越，價(jia)格低廉，可(ke)(ke)用(yong)于自制產品及(ji)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)(zu)的(de)(de)維修代換，因而深受(shou)廣(guang)大(da)電(dian)(dian)(dian)(dian)子愛(ai)好者(zhe)(zhe)喜(xi)愛(ai)。有興趣的(de)(de)讀者(zhe)(zhe)可(ke)(ke)參(can)照圖二制作(zuo)一塊充電(dian)(dian)(dian)(dian)板(ban)。其原理是：采用(yong)恒(heng)定電(dian)(dian)(dian)(dian)壓(ya)給電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)，確保不會過(guo)充。輸入(ru)直(zhi)流(liu)電(dian)(dian)(dian)(dian)壓(ya)高于所充電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)3伏即可(ke)(ke)。R1、Q1、W1、TL431組(zu)(zu)成精密可(ke)(ke)調(diao)(diao)穩壓(ya)電(dian)(dian)(dian)(dian)路，Q2、W2、R2構成可(ke)(ke)調(diao)(diao)恒(heng)流(liu)電(dian)(dian)(dian)(dian)路，Q3、R3、R4、R5、LED為充電(dian)(dian)(dian)(dian)指示電(dian)(dian)(dian)(dian)路。隨著被充電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)的(de)(de)上(shang)升，充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)將(jiang)逐漸(jian)減小(xiao)，待電(dian)(dian)(dian)(dian)池(chi)(chi)充滿后(hou)R4上(shang)的(de)(de)壓(ya)降將(jiang)降低，從而使Q3截(jie)止， LED將(jiang)熄(xi)滅，為保證電(dian)(dian)(dian)(dian)池(chi)(chi)能(neng)夠充足，請在指示燈熄(xi)滅后(hou)繼續充1—2小(xiao)時。使用(yong)時請給Q2、Q3裝上(shang)合適的(de)(de)散熱器(qi)。本電(dian)(dian)(dian)(dian)路的(de)(de)優點是：制作(zuo)簡(jian)單，元器(qi)件易購(gou)，充電(dian)(dian)(dian)(dian)安全，顯示直(zhi)觀，并且不會損壞電(dian)(dian)(dian)(dian)池(chi)(chi)．通過(guo)改變W1可(ke)(ke)以(yi)對(dui)(dui)多節串聯(lian)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)，改變W２可(ke)(ke)以(yi)對(dui)(dui)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)進行大(da)范圍(wei)調(diao)(diao)節。缺點是：無過(guo)放電(dian)(dian)(dian)(dian)控制電(dian)(dian)(dian)(dian)路。圖三是該充電(dian)(dian)(dian)(dian)板(ban)的(de)(de)印(yin)制板(ban)圖（從元件面看的(de)(de)透(tou)視(shi)圖）。

七、單節鋰電池的應用舉例

1、 作電池組維修代換品

有(you)許多電(dian)池(chi)(chi)組：如(ru)筆(bi)記本電(dian)腦上(shang)用的那種(zhong)，經維(wei)修發現(xian)，此(ci)電(dian)池(chi)(chi)組損壞時僅是個別(bie)電(dian)池(chi)(chi)有(you)問題。可(ke)以(yi)選用合適的單節鋰(li)電(dian)池(chi)(chi)進行更(geng)換。

2、 制作高亮微型電筒

筆(bi)者(zhe)曾(ceng)用單節3.6V1.6AH鋰電(dian)池配合一個(ge)白色超高亮度發光管做成一只微(wei)型電(dian)筒，使用方便，小巧(qiao)美觀。而(er)且由(you)于電(dian)池容量大，平(ping)均每(mei)晚(wan)使用半(ban)小時，至今已用兩個(ge)多月仍(reng)無需充(chong)電(dian)。電(dian)路如圖(tu)四所示。

3、代替3V電源

由于單節(jie)鋰電(dian)池(chi)電(dian)壓為3.6V。因此僅需(xu)一節(jie)鋰電(dian)池(chi)便(bian)可代替兩節(jie)普通電(dian)池(chi)，給收(shou)音機、隨身聽、照(zhao)相(xiang)機等小家(jia)電(dian)產品供電(dian)，不僅重量輕，而且連(lian)續使用時間長。

八、鋰電池的保存：

鋰(li)電(dian)(dian)(dian)池(chi)需(xu)充(chong)足(zu)電(dian)(dian)(dian)后保存。在20℃下可(ke)儲存半年以上(shang)，可(ke)見鋰(li)電(dian)(dian)(dian)池(chi)適宜在低溫下保存。曾(ceng)有人建議將充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)池(chi)放(fang)入冰箱冷藏室內保存，的確是個好注意。

九、使用注意事項：

鋰電池絕對不(bu)可(ke)(ke)解體、鉆孔、穿刺、鋸割、加壓(ya)、加熱，否則有(you)可(ke)(ke)能造成(cheng)嚴重后果。沒有(you)充電保(bao)護板(ban)的鋰電池不(bu)可(ke)(ke)短路，不(bu)可(ke)(ke)供小孩玩耍。不(bu)能靠(kao)近易燃物(wu)品、化學物(wu)品。報廢的鋰電池要妥善處理。