鋰電池充電電路原理及應用

鋰(li)離子(zi)電(dian)池(chi)以其(qi)優良的(de)特性(xing)，被廣泛應用于(yu): 手(shou)機、攝錄像機、筆記(ji)本電(dian)腦、無繩電(dian)話、電(dian)動(dong)工具、遙控(kong)或電(dian)動(dong)玩(wan)具、照(zhao)相(xiang)機等便攜式電(dian)子(zi)設(she)備(bei)中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)離(li)(li)子電(dian)池(chi)的(de)負(fu)極(ji)為(wei)石墨(mo)晶(jing)體，正(zheng)(zheng)極(ji)通常(chang)為(wei)二氧化鋰(li)。充(chong)電(dian)時鋰(li)離(li)(li)子由正(zheng)(zheng)極(ji)向負(fu)極(ji)運動而嵌入(ru)石墨(mo)層(ceng)中。放電(dian)時，鋰(li)離(li)(li)子從(cong)石墨(mo)晶(jing)體內負(fu)極(ji)表面脫(tuo)離(li)(li)移(yi)向正(zheng)(zheng)極(ji)。所以，在該(gai)電(dian)池(chi)充(chong)放電(dian)過(guo)程中鋰(li)總是(shi)以鋰(li)離(li)(li)子形態出現，而不(bu)是(shi)以金屬(shu)鋰(li)的(de)形態出現。因而這(zhe)種電(dian)池(chi)叫做鋰(li)離(li)(li)子電(dian)池(chi)，簡(jian)稱(cheng)鋰(li)電(dian)池(chi)。

鋰電(dian)(dian)池具(ju)有(you)(you)：體(ti)(ti)積小、容量大、重量輕(qing)、無污染(ran)、單(dan)節電(dian)(dian)壓高(gao)、自(zi)放(fang)(fang)電(dian)(dian)率低、電(dian)(dian)池循環(huan)次數多等優點，但價格較貴。鎳鎘電(dian)(dian)池因容量低，自(zi)放(fang)(fang)電(dian)(dian)嚴重，且對(dui)環(huan)境有(you)(you)污染(ran)，正逐步被淘汰(tai)。鎳氫電(dian)(dian)池具(ju)有(you)(you)較高(gao)的性能價格比，且不污染(ran)環(huan)境，但單(dan)體(ti)(ti)電(dian)(dian)壓只(zhi)有(you)(you)1.2V，因而在使(shi)用范圍上受到限(xian)制。

二、鋰電池的特點：

1、具有更高的重量能量比、體積能量比；

2、電(dian)壓高，單(dan)節鋰(li)電(dian)池電(dian)壓為3.6V，等于3只鎳鎘或(huo)鎳氫充電(dian)電(dian)池的串聯(lian)電(dian)壓；

3、自放電(dian)小可長時間存放，這是該電(dian)池(chi)最突出的優(you)越性；

4、無記憶效應。鋰(li)電池(chi)不存在鎳(nie)鎘(ge)電池(chi)的所謂(wei)記憶效應，所以鋰(li)電池(chi)充(chong)電前無需放電；

5、壽命長。正常(chang)工作(zuo)條(tiao)件(jian)下，鋰電池充/放電循環次數(shu)遠(yuan)大于500次；

6、可以(yi)快(kuai)速充電。鋰電池通常可以(yi)采(cai)用0.5～1倍容量的電流充電，使充電時(shi)間縮短至1～2小時(shi)；

7、可以隨意(yi)并聯(lian)使用；

8、由于電(dian)池中不含鎘、鉛、汞等重金(jin)屬元(yuan)素，對(dui)環境(jing)無污染，是當代最先進的綠(lv)色電(dian)池；

9、成本高(gao)。與其(qi)它可充電池相比，鋰電池價格(ge)較貴。

三、鋰電池的內部結構：

鋰(li)電(dian)池通常有兩種外型(xing)：圓柱型(xing)和(he)長方型(xing)。

電(dian)(dian)(dian)池(chi)內(nei)(nei)部(bu)采用螺旋繞(rao)制(zhi)結構，用一種非(fei)常(chang)精細而滲(shen)透性很強的(de)聚乙(yi)烯(xi)薄(bo)(bo)(bo)膜隔離材料(liao)在正、負極(ji)間(jian)間(jian)隔而成。正極(ji)包括由鋰和二氧化(hua)鈷(gu)組(zu)成的(de)鋰離子收集極(ji)及由鋁薄(bo)(bo)(bo)膜組(zu)成的(de)電(dian)(dian)(dian)流(liu)收集極(ji)。負極(ji)由片(pian)狀碳(tan)材料(liao)組(zu)成的(de)鋰離子收集極(ji)和銅薄(bo)(bo)(bo)膜組(zu)成的(de)電(dian)(dian)(dian)流(liu)收集極(ji)組(zu)成。電(dian)(dian)(dian)池(chi)內(nei)(nei)充有有機電(dian)(dian)(dian)解質(zhi)溶液(ye)。另外還裝有安全閥和PTC元件(jian)，以便電(dian)(dian)(dian)池(chi)在不(bu)正常(chang)狀態及輸出短路時保護電(dian)(dian)(dian)池(chi)不(bu)受損壞。

單(dan)節鋰(li)(li)電池的電壓為3.6V，容量也(ye)不可能無限(xian)大(da)，因此，常常將單(dan)節鋰(li)(li)電池進行串、并聯處理，以滿足(zu)不同場合(he)的要(yao)求。

四、鋰電池的充放電要求：

1、鋰電(dian)(dian)(dian)(dian)(dian)(dian)池的充電(dian)(dian)(dian)(dian)(dian)(dian)：根(gen)據鋰電(dian)(dian)(dian)(dian)(dian)(dian)池的結構特(te)性，最(zui)高(gao)充電(dian)(dian)(dian)(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓應(ying)(ying)為4.2V，不能過充，否(fou)則會因正極的鋰離(li)子拿走太(tai)多，而使電(dian)(dian)(dian)(dian)(dian)(dian)池報廢。其充放電(dian)(dian)(dian)(dian)(dian)(dian)要(yao)求較高(gao)，可采用(yong)(yong)專用(yong)(yong)的恒(heng)流(liu)、恒(heng)壓充電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)進行充電(dian)(dian)(dian)(dian)(dian)(dian)。通常恒(heng)流(liu)充電(dian)(dian)(dian)(dian)(dian)(dian)至4.2V/節后轉入恒(heng)壓充電(dian)(dian)(dian)(dian)(dian)(dian)，當恒(heng)壓充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)降至100mA以內時，應(ying)(ying)停止(zhi)充電(dian)(dian)(dian)(dian)(dian)(dian)。

充(chong)電(dian)電(dian)流（mA）=0.1～1.5倍(bei)電(dian)池容量（如(ru)1350mAh的電(dian)池，其充(chong)電(dian)電(dian)流可控制在135～2025mA之間(jian)）。常(chang)規充(chong)電(dian)電(dian)流可選擇在0.5倍(bei)電(dian)池容量左右(you)，充(chong)電(dian)時間(jian)約為2～3小時。

2、鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：因鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)內(nei)部(bu)(bu)(bu)結構所致，放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時鋰(li)(li)離子(zi)不能全部(bu)(bu)(bu)移(yi)向正極，必(bi)須保留(liu)一部(bu)(bu)(bu)分(fen)鋰(li)(li)離子(zi)在負極，以保證(zheng)在下次(ci)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時鋰(li)(li)離子(zi)能夠暢通地嵌入通道。否則，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)壽命就(jiu)相應(ying)縮短。為了保證(zheng)石墨層(ceng)中放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)后留(liu)有部(bu)(bu)(bu)分(fen)鋰(li)(li)離子(zi)，就(jiu)要(yao)嚴(yan)格限制放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止最(zui)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，也就(jiu)是說(shuo)鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)不能過放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終(zhong)止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓通常為3.0V/節，最(zui)低(di)不能低(di)于2.5V/節。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時間(jian)長短與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量、放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流大小(xiao)有關。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時間(jian)（小(xiao)時）=電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量/放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流。鋰(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(mA)不應(ying)超(chao)過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量的(de)(de)3倍。（如1000mAH電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)，則放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流應(ying)嚴(yan)格控(kong)制在3A以內(nei)）否則會使(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)損壞。

目前(qian)市場上所售鋰電池組內部(bu)均封(feng)有(you)配套(tao)的充(chong)放(fang)電保護(hu)板(ban)。只要(yao)控制(zhi)好(hao)外部(bu)的充(chong)放(fang)電電流即可。

五、鋰電池的保護電路：

兩節鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的(de)充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)如圖一所示。由兩個場效應管(guan)(guan)(guan)和專(zhuan)用保(bao)護集成(cheng)塊S--8232組成(cheng)，過(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管(guan)(guan)(guan)FET2和過(guo)(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管(guan)(guan)(guan)FET1串聯于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，由保(bao)護IC監(jian)視(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)并(bing)進行控(kong)(kong)制，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)上升至4.2V時(shi)，過(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護管(guan)(guan)(guan)FET1截(jie)止(zhi)，停止(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為防止(zhi)誤(wu)動作，一般在外電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)加有(you)延(yan)時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池處于放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態下，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降至2.55V時(shi)，過(guo)(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制管(guan)(guan)(guan)FET1截(jie)止(zhi)，停止(zhi)向負載供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)保(bao)護是在當負載上有(you)較大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過(guo)(guo)時(shi)，控(kong)(kong)制FET1使其截(jie)止(zhi)，停止(zhi)向負載放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，目的(de)是為了保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池和場效應管(guan)(guan)(guan)。過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢測是利用場效應管(guan)(guan)(guan)的(de)導通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻作為檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，監(jian)視(shi)它的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降超過(guo)(guo)設定(ding)值時(shi)就停止(zhi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中一般還(huan)加有(you)延(yan)時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，以區分(fen)浪涌電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和短(duan)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)功能完(wan)善(shan)，性能可靠(kao)，但專(zhuan)業(ye)性強，且(qie)專(zhuan)用集成(cheng)塊不易(yi)(yi)購買(mai)，業(ye)余愛好(hao)者不易(yi)(yi)仿制。

六、簡易充電電路：

現在有不(bu)少商家出售不(bu)帶充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)板(ban)(ban)的(de)(de)單節鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)。其(qi)性能優越，價(jia)格低(di)廉(lian)，可(ke)用(yong)于自制(zhi)產(chan)品及鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)組的(de)(de)維(wei)修代(dai)換(huan)，因(yin)而深受廣大電(dian)(dian)(dian)(dian)(dian)子愛好者喜愛。有興趣的(de)(de)讀者可(ke)參照圖二制(zhi)作(zuo)一(yi)塊充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)板(ban)(ban)。其(qi)原理是：采用(yong)恒定電(dian)(dian)(dian)(dian)(dian)壓(ya)給(gei)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，確保不(bu)會(hui)過(guo)充(chong)(chong)(chong)(chong)。輸入直流(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)高于所充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)3伏(fu)即可(ke)。R1、Q1、W1、TL431組成精(jing)密可(ke)調(diao)穩壓(ya)電(dian)(dian)(dian)(dian)(dian)路(lu)，Q2、W2、R2構成可(ke)調(diao)恒流(liu)電(dian)(dian)(dian)(dian)(dian)路(lu)，Q3、R3、R4、R5、LED為(wei)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)指示(shi)電(dian)(dian)(dian)(dian)(dian)路(lu)。隨著(zhu)被充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)上升，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)將(jiang)逐漸減小，待電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)滿后R4上的(de)(de)壓(ya)降將(jiang)降低(di)，從(cong)而使(shi)Q3截(jie)止(zhi)， LED將(jiang)熄滅，為(wei)保證電(dian)(dian)(dian)(dian)(dian)池(chi)能夠充(chong)(chong)(chong)(chong)足(zu)，請(qing)在指示(shi)燈熄滅后繼續(xu)充(chong)(chong)(chong)(chong)1—2小時。使(shi)用(yong)時請(qing)給(gei)Q2、Q3裝(zhuang)上合適的(de)(de)散(san)熱器(qi)。本電(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)優點是：制(zhi)作(zuo)簡單，元(yuan)器(qi)件(jian)易購，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)安(an)全，顯示(shi)直觀，并且不(bu)會(hui)損(sun)壞電(dian)(dian)(dian)(dian)(dian)池(chi)．通過(guo)改(gai)變W1可(ke)以對(dui)多節串聯鋰(li)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，改(gai)變W２可(ke)以對(dui)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)進行大范圍調(diao)節。缺點是：無過(guo)放電(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)電(dian)(dian)(dian)(dian)(dian)路(lu)。圖三是該充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)板(ban)(ban)的(de)(de)印制(zhi)板(ban)(ban)圖（從(cong)元(yuan)件(jian)面看的(de)(de)透視圖）。

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(duo)電(dian)(dian)池組：如筆記(ji)本電(dian)(dian)腦上用的那種(zhong)，經(jing)維修發現，此電(dian)(dian)池組損壞(huai)時(shi)僅是(shi)個別電(dian)(dian)池有(you)問題。可以選用合適(shi)的單節鋰電(dian)(dian)池進行更換。

2、 制作高亮微型電筒

筆(bi)者曾用(yong)(yong)單節3.6V1.6AH鋰電池配合一(yi)個白色超高(gao)亮度(du)發光(guang)管(guan)做成(cheng)一(yi)只微型電筒，使用(yong)(yong)方便，小(xiao)巧(qiao)美觀。而且由于電池容量大，平(ping)均每晚使用(yong)(yong)半小(xiao)時，至今(jin)已(yi)用(yong)(yong)兩(liang)個多月仍無需充(chong)電。電路(lu)如圖四所示。

3、代替3V電源

由于單(dan)節鋰電(dian)(dian)池電(dian)(dian)壓(ya)為(wei)3.6V。因此僅(jin)(jin)需(xu)一節鋰電(dian)(dian)池便可代替兩節普通電(dian)(dian)池，給(gei)收音(yin)機、隨身聽、照(zhao)相機等小家電(dian)(dian)產(chan)品供電(dian)(dian)，不僅(jin)(jin)重量輕，而(er)且連續使(shi)用(yong)時間(jian)長(chang)。

八、鋰電池的保存：

鋰電(dian)池(chi)需充足電(dian)后(hou)保存。在(zai)20℃下可儲(chu)存半年以上，可見鋰電(dian)池(chi)適(shi)宜在(zai)低溫下保存。曾有人建議將充電(dian)電(dian)池(chi)放入冰箱冷藏室內保存，的確是個好注意。

九、使用注意事項：

鋰(li)電(dian)(dian)池(chi)(chi)絕對不(bu)可(ke)解體(ti)、鉆(zhan)孔、穿刺、鋸割、加(jia)壓(ya)、加(jia)熱，否(fou)則有可(ke)能造成嚴重(zhong)后果(guo)。沒(mei)有充電(dian)(dian)保護板的鋰(li)電(dian)(dian)池(chi)(chi)不(bu)可(ke)短路(lu)，不(bu)可(ke)供(gong)小孩玩耍。不(bu)能靠(kao)近易燃物品(pin)、化學物品(pin)。報(bao)廢的鋰(li)電(dian)(dian)池(chi)(chi)要妥善(shan)處理。