鋰電池充電電路原理及應用

鋰離(li)子(zi)電(dian)池以其優良的特(te)性(xing)，被廣(guang)泛應用于(yu): 手機(ji)、攝錄像機(ji)、筆(bi)記本電(dian)腦、無繩電(dian)話、電(dian)動工具(ju)、遙控或電(dian)動玩(wan)具(ju)、照相(xiang)機(ji)等便攜式(shi)電(dian)子(zi)設備中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)(li)離(li)(li)子電(dian)(dian)池(chi)(chi)(chi)的負極為(wei)石墨晶(jing)體，正極通(tong)常為(wei)二氧化鋰(li)(li)。充電(dian)(dian)時鋰(li)(li)離(li)(li)子由正極向(xiang)負極運動而(er)嵌(qian)入石墨層中。放(fang)電(dian)(dian)時，鋰(li)(li)離(li)(li)子從(cong)石墨晶(jing)體內負極表面(mian)脫離(li)(li)移(yi)向(xiang)正極。所以，在該電(dian)(dian)池(chi)(chi)(chi)充放(fang)電(dian)(dian)過程(cheng)中鋰(li)(li)總是以鋰(li)(li)離(li)(li)子形(xing)態出現，而(er)不是以金屬鋰(li)(li)的形(xing)態出現。因而(er)這種電(dian)(dian)池(chi)(chi)(chi)叫做鋰(li)(li)離(li)(li)子電(dian)(dian)池(chi)(chi)(chi)，簡稱鋰(li)(li)電(dian)(dian)池(chi)(chi)(chi)。

鋰電(dian)池(chi)具(ju)有：體積小、容量大、重(zhong)量輕、無污染、單節電(dian)壓(ya)高、自放電(dian)率低、電(dian)池(chi)循環次數多等(deng)優(you)點，但價格較貴。鎳鎘電(dian)池(chi)因容量低，自放電(dian)嚴重(zhong)，且對環境有污染，正逐(zhu)步被淘(tao)汰。鎳氫電(dian)池(chi)具(ju)有較高的(de)性能價格比，且不污染環境，但單體電(dian)壓(ya)只有1.2V，因而在使用范圍上受到限制。

二、鋰電池的特點：

1、具有更高的重量(liang)能(neng)量(liang)比(bi)、體積能(neng)量(liang)比(bi)；

2、電(dian)壓高，單節鋰電(dian)池電(dian)壓為(wei)3.6V，等于3只鎳鎘或鎳氫充電(dian)電(dian)池的(de)串聯電(dian)壓；

3、自放(fang)電(dian)小可(ke)長時間存放(fang)，這(zhe)是該電(dian)池最突(tu)出的優越性；

4、無記憶效(xiao)應。鋰(li)電(dian)池不存(cun)在鎳(nie)鎘電(dian)池的所(suo)謂(wei)記憶效(xiao)應，所(suo)以鋰(li)電(dian)池充電(dian)前無需放電(dian)；

5、壽命(ming)長。正(zheng)常工作條件下，鋰(li)電(dian)池充/放電(dian)循環(huan)次數遠大于500次；

6、可以快速充電。鋰電池通常可以采(cai)用0.5～1倍容(rong)量的電流充電，使充電時(shi)間縮短至1～2小(xiao)時(shi)；

7、可以(yi)隨意并聯(lian)使用；

8、由于電(dian)池中不含(han)鎘、鉛、汞(gong)等(deng)重金屬(shu)元素(su)，對(dui)環(huan)境無污染，是(shi)當代最先進的(de)綠色電(dian)池；

9、成本高。與(yu)其它可充電池(chi)相比，鋰電池(chi)價(jia)格較貴。

三、鋰電池的內部結構：

鋰電(dian)池(chi)通常有(you)兩種(zhong)外型：圓柱型和長方型。

電(dian)(dian)池(chi)(chi)內(nei)(nei)部采用螺旋繞制結構，用一種非常精細而滲透性很強(qiang)的聚乙烯薄(bo)膜隔離(li)材料在正、負極(ji)(ji)間(jian)間(jian)隔而成(cheng)。正極(ji)(ji)包括由鋰和(he)二氧化鈷組成(cheng)的鋰離(li)子收集(ji)極(ji)(ji)及由鋁薄(bo)膜組成(cheng)的電(dian)(dian)流收集(ji)極(ji)(ji)。負極(ji)(ji)由片狀碳材料組成(cheng)的鋰離(li)子收集(ji)極(ji)(ji)和(he)銅薄(bo)膜組成(cheng)的電(dian)(dian)流收集(ji)極(ji)(ji)組成(cheng)。電(dian)(dian)池(chi)(chi)內(nei)(nei)充有(you)有(you)機電(dian)(dian)解質(zhi)溶液。另外(wai)還裝有(you)安(an)全閥和(he)PTC元(yuan)件，以便電(dian)(dian)池(chi)(chi)在不正常狀態及輸出(chu)短路時保護(hu)電(dian)(dian)池(chi)(chi)不受(shou)損(sun)壞。

單節鋰(li)電(dian)(dian)池(chi)的電(dian)(dian)壓(ya)為3.6V，容量也(ye)不(bu)可能無限大，因此(ci)，常常將單節鋰(li)電(dian)(dian)池(chi)進(jin)行串(chuan)、并(bing)聯處理(li)，以(yi)滿(man)足不(bu)同場合的要求。

四、鋰電池的充放電要求：

1、鋰(li)電(dian)(dian)池(chi)的(de)充(chong)(chong)電(dian)(dian)：根據鋰(li)電(dian)(dian)池(chi)的(de)結構特性，最高充(chong)(chong)電(dian)(dian)終止電(dian)(dian)壓(ya)(ya)應為4.2V，不能過充(chong)(chong)，否則會(hui)因正極的(de)鋰(li)離子(zi)拿走太多，而使電(dian)(dian)池(chi)報廢(fei)。其(qi)充(chong)(chong)放電(dian)(dian)要(yao)求較高，可采用專用的(de)恒(heng)流、恒(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)器(qi)進行充(chong)(chong)電(dian)(dian)。通(tong)常恒(heng)流充(chong)(chong)電(dian)(dian)至(zhi)4.2V/節后轉(zhuan)入恒(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)，當恒(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)電(dian)(dian)流降(jiang)至(zhi)100mA以內時，應停止充(chong)(chong)電(dian)(dian)。

充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)（mA）=0.1～1.5倍電(dian)(dian)(dian)池容量(liang)（如1350mAh的電(dian)(dian)(dian)池，其充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)可控制在135～2025mA之間(jian)）。常規充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)可選擇在0.5倍電(dian)(dian)(dian)池容量(liang)左右，充電(dian)(dian)(dian)時間(jian)約為2～3小(xiao)時。

2、鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)：因鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的內部(bu)(bu)結(jie)構所(suo)致，放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)(li)離(li)子不能全部(bu)(bu)移向(xiang)正極，必須保留一部(bu)(bu)分鋰(li)(li)離(li)子在負極，以保證(zheng)在下次充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)(li)離(li)子能夠暢(chang)通地嵌(qian)入通道。否則，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)壽(shou)命(ming)就(jiu)相(xiang)應縮短。為了保證(zheng)石墨層中放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)后留有部(bu)(bu)分鋰(li)(li)離(li)子，就(jiu)要嚴格(ge)(ge)限制(zhi)(zhi)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止最低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，也就(jiu)是說鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)不能過(guo)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓通常為3.0V/節，最低不能低于2.5V/節。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)長短與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量、放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)大小(xiao)有關。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)（小(xiao)時(shi)）=電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量/放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(mA)不應超(chao)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)容量的3倍(bei)。（如1000mAH電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，則放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)應嚴格(ge)(ge)控(kong)制(zhi)(zhi)在3A以內）否則會使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)損壞。

目前市(shi)場上所(suo)售鋰電(dian)池組(zu)內(nei)部均封有(you)配套的(de)充放電(dian)保護板。只(zhi)要控制好外(wai)部的(de)充放電(dian)電(dian)流即可。

五、鋰電池的保護電路：

兩節鋰電(dian)(dian)(dian)池(chi)的充放(fang)(fang)電(dian)(dian)(dian)保(bao)護(hu)電(dian)(dian)(dian)路(lu)(lu)如圖一(yi)所示。由(you)兩個場效應管(guan)(guan)和(he)(he)專用保(bao)護(hu)集成塊(kuai)S--8232組成，過(guo)(guo)充電(dian)(dian)(dian)控制(zhi)管(guan)(guan)FET2和(he)(he)過(guo)(guo)放(fang)(fang)電(dian)(dian)(dian)控制(zhi)管(guan)(guan)FET1串聯于(yu)電(dian)(dian)(dian)路(lu)(lu)，由(you)保(bao)護(hu)IC監(jian)視(shi)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)(ya)并進(jin)行控制(zhi)，當(dang)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)(ya)上升至4.2V時，過(guo)(guo)充電(dian)(dian)(dian)保(bao)護(hu)管(guan)(guan)FET1截(jie)(jie)止(zhi)(zhi)(zhi)(zhi)(zhi)，停止(zhi)(zhi)(zhi)(zhi)(zhi)充電(dian)(dian)(dian)。為防止(zhi)(zhi)(zhi)(zhi)(zhi)誤動作(zuo)，一(yi)般在(zai)外電(dian)(dian)(dian)路(lu)(lu)加(jia)有(you)延時電(dian)(dian)(dian)容。當(dang)電(dian)(dian)(dian)池(chi)處于(yu)放(fang)(fang)電(dian)(dian)(dian)狀態下，電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)(ya)降至2.55V時，過(guo)(guo)放(fang)(fang)電(dian)(dian)(dian)控制(zhi)管(guan)(guan)FET1截(jie)(jie)止(zhi)(zhi)(zhi)(zhi)(zhi)，停止(zhi)(zhi)(zhi)(zhi)(zhi)向負載供(gong)電(dian)(dian)(dian)。過(guo)(guo)電(dian)(dian)(dian)流(liu)(liu)保(bao)護(hu)是在(zai)當(dang)負載上有(you)較大電(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)過(guo)(guo)時，控制(zhi)FET1使其(qi)截(jie)(jie)止(zhi)(zhi)(zhi)(zhi)(zhi)，停止(zhi)(zhi)(zhi)(zhi)(zhi)向負載放(fang)(fang)電(dian)(dian)(dian)，目的是為了(le)保(bao)護(hu)電(dian)(dian)(dian)池(chi)和(he)(he)場效應管(guan)(guan)。過(guo)(guo)電(dian)(dian)(dian)流(liu)(liu)檢(jian)測是利用場效應管(guan)(guan)的導通電(dian)(dian)(dian)阻(zu)作(zuo)為檢(jian)測電(dian)(dian)(dian)阻(zu)，監(jian)視(shi)它的電(dian)(dian)(dian)壓(ya)(ya)(ya)降，當(dang)電(dian)(dian)(dian)壓(ya)(ya)(ya)降超過(guo)(guo)設定值(zhi)時就停止(zhi)(zhi)(zhi)(zhi)(zhi)放(fang)(fang)電(dian)(dian)(dian)。在(zai)電(dian)(dian)(dian)路(lu)(lu)中一(yi)般還加(jia)有(you)延時電(dian)(dian)(dian)路(lu)(lu)，以區分浪涌電(dian)(dian)(dian)流(liu)(liu)和(he)(he)短(duan)路(lu)(lu)電(dian)(dian)(dian)流(liu)(liu)。該電(dian)(dian)(dian)路(lu)(lu)功能完善，性能可靠，但(dan)專業(ye)性強，且專用集成塊(kuai)不易購買，業(ye)余愛好(hao)者不易仿制(zhi)。

六、簡易充電電路：

現在有(you)不少商家出售不帶充(chong)(chong)(chong)電(dian)(dian)(dian)板(ban)(ban)的(de)(de)單(dan)節(jie)鋰(li)電(dian)(dian)(dian)池(chi)。其性能優越，價格低廉，可(ke)用(yong)(yong)于(yu)自制(zhi)產品及(ji)鋰(li)電(dian)(dian)(dian)池(chi)組(zu)的(de)(de)維修代換，因而深(shen)受廣(guang)大電(dian)(dian)(dian)子愛好者喜愛。有(you)興(xing)趣的(de)(de)讀者可(ke)參(can)照圖(tu)(tu)二制(zhi)作(zuo)一(yi)塊(kuai)充(chong)(chong)(chong)電(dian)(dian)(dian)板(ban)(ban)。其原理(li)是(shi)(shi)：采(cai)用(yong)(yong)恒(heng)定電(dian)(dian)(dian)壓(ya)(ya)給電(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)，確保(bao)不會過充(chong)(chong)(chong)。輸入直流(liu)電(dian)(dian)(dian)壓(ya)(ya)高于(yu)所充(chong)(chong)(chong)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)3伏即可(ke)。R1、Q1、W1、TL431組(zu)成(cheng)(cheng)精密可(ke)調穩壓(ya)(ya)電(dian)(dian)(dian)路，Q2、W2、R2構成(cheng)(cheng)可(ke)調恒(heng)流(liu)電(dian)(dian)(dian)路，Q3、R3、R4、R5、LED為(wei)充(chong)(chong)(chong)電(dian)(dian)(dian)指示電(dian)(dian)(dian)路。隨著被充(chong)(chong)(chong)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓(ya)(ya)的(de)(de)上升，充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)將(jiang)逐漸(jian)減小(xiao)(xiao)，待電(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)滿后R4上的(de)(de)壓(ya)(ya)降將(jiang)降低，從而使Q3截止(zhi)， LED將(jiang)熄(xi)滅(mie)，為(wei)保(bao)證電(dian)(dian)(dian)池(chi)能夠充(chong)(chong)(chong)足，請在指示燈熄(xi)滅(mie)后繼續充(chong)(chong)(chong)1—2小(xiao)(xiao)時。使用(yong)(yong)時請給Q2、Q3裝(zhuang)上合適的(de)(de)散熱器(qi)。本電(dian)(dian)(dian)路的(de)(de)優點是(shi)(shi)：制(zhi)作(zuo)簡單(dan)，元器(qi)件易購(gou)，充(chong)(chong)(chong)電(dian)(dian)(dian)安(an)全，顯示直觀，并且(qie)不會損壞電(dian)(dian)(dian)池(chi)．通(tong)過改變W1可(ke)以對(dui)多(duo)節(jie)串(chuan)聯鋰(li)電(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)，改變W２可(ke)以對(dui)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)進(jin)行大范圍調節(jie)。缺點是(shi)(shi)：無過放電(dian)(dian)(dian)控制(zhi)電(dian)(dian)(dian)路。圖(tu)(tu)三(san)是(shi)(shi)該充(chong)(chong)(chong)電(dian)(dian)(dian)板(ban)(ban)的(de)(de)印(yin)制(zhi)板(ban)(ban)圖(tu)(tu)（從元件面看的(de)(de)透視圖(tu)(tu)）。

七、單節鋰電池的應用舉例

1、 作電池組維修代換品

有許(xu)多電(dian)池(chi)(chi)組：如筆記本電(dian)腦上用的那種，經維修(xiu)發現，此電(dian)池(chi)(chi)組損壞時僅是(shi)個別電(dian)池(chi)(chi)有問題。可以選用合(he)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)者曾用(yong)單節3.6V1.6AH鋰電池配合一(yi)個白色(se)超高亮度發光管做(zuo)成一(yi)只微型電筒，使用(yong)方便，小巧美(mei)觀。而且由于電池容量大，平均(jun)每(mei)晚使用(yong)半小時，至今已用(yong)兩個多月仍無需充電。電路如(ru)圖(tu)四所示。

3、代替3V電源

由于單節鋰電池電壓為(wei)3.6V。因此(ci)僅需一節鋰電池便可(ke)代(dai)替(ti)兩節普通電池，給收音機(ji)、隨身聽(ting)、照相(xiang)機(ji)等(deng)小(xiao)家電產品供電，不僅重量輕(qing)，而且(qie)連續使(shi)用(yong)時間(jian)長。

八、鋰電池的保存：

鋰(li)電(dian)池(chi)需充(chong)足電(dian)后保存(cun)。在(zai)20℃下可儲(chu)存(cun)半年以上，可見鋰(li)電(dian)池(chi)適(shi)宜在(zai)低溫下保存(cun)。曾有人建議將(jiang)充(chong)電(dian)電(dian)池(chi)放入(ru)冰箱冷藏室內保存(cun)，的確是個好注意。

九、使用注意事項：

鋰電池(chi)絕對不(bu)(bu)可解體(ti)、鉆孔(kong)、穿刺、鋸割(ge)、加壓(ya)、加熱(re)，否則有可能造成(cheng)嚴重后果。沒有充電保護板的鋰電池(chi)不(bu)(bu)可短路，不(bu)(bu)可供小孩玩耍。不(bu)(bu)能靠(kao)近易燃(ran)物品、化學物品。報廢的鋰電池(chi)要妥善(shan)處(chu)理(li)。