鋰電池充電電路原理及應用

鋰離子電(dian)池以其優良的特性，被(bei)廣泛應用于: 手機、攝錄像機、筆記本電(dian)腦、無繩電(dian)話(hua)、電(dian)動工具(ju)、遙(yao)控或電(dian)動玩具(ju)、照(zhao)相機等便攜式電(dian)子設備中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)(li)(li)離子(zi)電(dian)(dian)池(chi)的負極為(wei)石(shi)(shi)墨晶(jing)體，正(zheng)極通常為(wei)二(er)氧化鋰(li)(li)(li)。充電(dian)(dian)時(shi)鋰(li)(li)(li)離子(zi)由正(zheng)極向負極運動(dong)而嵌入石(shi)(shi)墨層中。放電(dian)(dian)時(shi)，鋰(li)(li)(li)離子(zi)從(cong)石(shi)(shi)墨晶(jing)體內負極表面脫(tuo)離移向正(zheng)極。所以，在該電(dian)(dian)池(chi)充放電(dian)(dian)過(guo)程中鋰(li)(li)(li)總是(shi)以鋰(li)(li)(li)離子(zi)形態(tai)出現(xian)，而不(bu)是(shi)以金屬鋰(li)(li)(li)的形態(tai)出現(xian)。因而這種(zhong)電(dian)(dian)池(chi)叫做鋰(li)(li)(li)離子(zi)電(dian)(dian)池(chi)，簡稱(cheng)鋰(li)(li)(li)電(dian)(dian)池(chi)。

鋰電(dian)池具(ju)有：體(ti)積小、容量(liang)大、重量(liang)輕、無(wu)污(wu)染(ran)、單(dan)節電(dian)壓高(gao)、自(zi)放電(dian)率低、電(dian)池循(xun)環次數多等優(you)點，但價格(ge)較貴。鎳鎘電(dian)池因(yin)(yin)容量(liang)低，自(zi)放電(dian)嚴重，且對環境有污(wu)染(ran)，正逐步被淘汰。鎳氫電(dian)池具(ju)有較高(gao)的(de)性能(neng)價格(ge)比，且不污(wu)染(ran)環境，但單(dan)體(ti)電(dian)壓只有1.2V，因(yin)(yin)而(er)在使(shi)用(yong)范圍上受(shou)到限制。

二、鋰電池的特點：

1、具有(you)更(geng)高的重量(liang)能量(liang)比、體積能量(liang)比；

2、電(dian)壓高，單節鋰電(dian)池(chi)電(dian)壓為3.6V，等(deng)于3只鎳(nie)鎘或(huo)鎳(nie)氫(qing)充電(dian)電(dian)池(chi)的串(chuan)聯電(dian)壓；

3、自放(fang)電小(xiao)可長(chang)時間存放(fang)，這是該電池最突出的優越性；

4、無記(ji)憶效應(ying)。鋰(li)電(dian)池(chi)不存在(zai)鎳鎘電(dian)池(chi)的所謂記(ji)憶效應(ying)，所以鋰(li)電(dian)池(chi)充電(dian)前無需放電(dian)；

5、壽命長(chang)。正常工(gong)作(zuo)條(tiao)件下，鋰(li)電(dian)池充/放電(dian)循(xun)環次(ci)數(shu)遠(yuan)大于500次(ci)；

6、可以快(kuai)速充電(dian)。鋰電(dian)池通(tong)常可以采用0.5～1倍容(rong)量的電(dian)流充電(dian)，使充電(dian)時間縮短至(zhi)1～2小時；

7、可(ke)以隨意(yi)并聯使用；

8、由于電池中不含鎘(ge)、鉛、汞等重(zhong)金屬元素，對環境無污染(ran)，是當(dang)代最先進的綠色電池；

9、成本(ben)高。與(yu)其它可充電池相比，鋰電池價格較貴。

三、鋰電池的內部結構：

鋰電池通常有兩種外型：圓柱(zhu)型和長方(fang)型。

電池(chi)(chi)內(nei)部采用(yong)螺旋繞制結構(gou)，用(yong)一(yi)種(zhong)非(fei)常精細而(er)滲透性很(hen)強的(de)聚乙烯薄膜隔離(li)材料(liao)在(zai)正、負極(ji)間間隔而(er)成。正極(ji)包括由鋰(li)(li)和(he)二氧化鈷組(zu)成的(de)鋰(li)(li)離(li)子收集(ji)(ji)(ji)極(ji)及(ji)由鋁(lv)薄膜組(zu)成的(de)電流(liu)收集(ji)(ji)(ji)極(ji)。負極(ji)由片狀碳材料(liao)組(zu)成的(de)鋰(li)(li)離(li)子收集(ji)(ji)(ji)極(ji)和(he)銅薄膜組(zu)成的(de)電流(liu)收集(ji)(ji)(ji)極(ji)組(zu)成。電池(chi)(chi)內(nei)充有(you)有(you)機電解質溶液。另外還裝有(you)安(an)全閥和(he)PTC元件，以便電池(chi)(chi)在(zai)不正常狀態及(ji)輸出短路時保護(hu)電池(chi)(chi)不受損壞。

單(dan)節(jie)鋰電(dian)池的電(dian)壓為3.6V，容量也(ye)不可(ke)能無限大，因此，常常將單(dan)節(jie)鋰電(dian)池進行串(chuan)、并聯處理，以滿(man)足不同場合(he)的要求(qiu)。

四、鋰電池的充放電要求：

1、鋰電(dian)(dian)池的(de)充(chong)(chong)電(dian)(dian)：根(gen)據鋰電(dian)(dian)池的(de)結構特(te)性，最(zui)高(gao)充(chong)(chong)電(dian)(dian)終止(zhi)電(dian)(dian)壓(ya)(ya)應(ying)為4.2V，不能(neng)過(guo)充(chong)(chong)，否則會(hui)因(yin)正(zheng)極的(de)鋰離(li)子拿走太多，而使電(dian)(dian)池報廢(fei)。其(qi)充(chong)(chong)放電(dian)(dian)要(yao)求較(jiao)高(gao)，可采(cai)用(yong)專(zhuan)用(yong)的(de)恒(heng)(heng)流(liu)、恒(heng)(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)器進行充(chong)(chong)電(dian)(dian)。通常恒(heng)(heng)流(liu)充(chong)(chong)電(dian)(dian)至4.2V/節后轉(zhuan)入恒(heng)(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)，當恒(heng)(heng)壓(ya)(ya)充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)降至100mA以內時(shi)，應(ying)停止(zhi)充(chong)(chong)電(dian)(dian)。

充(chong)電(dian)(dian)電(dian)(dian)流(liu)（mA）=0.1～1.5倍(bei)(bei)電(dian)(dian)池容(rong)量（如1350mAh的電(dian)(dian)池，其充(chong)電(dian)(dian)電(dian)(dian)流(liu)可控(kong)制(zhi)在135～2025mA之(zhi)間）。常規充(chong)電(dian)(dian)電(dian)(dian)流(liu)可選擇在0.5倍(bei)(bei)電(dian)(dian)池容(rong)量左右，充(chong)電(dian)(dian)時間約為2～3小時。

2、鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：因(yin)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)內部結(jie)構所致，放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)離(li)子不(bu)能全部移向正(zheng)極，必須保(bao)(bao)留一(yi)部分鋰(li)離(li)子在(zai)負極，以(yi)保(bao)(bao)證在(zai)下(xia)次(ci)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)鋰(li)離(li)子能夠暢通地(di)嵌(qian)入(ru)通道(dao)。否則，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)壽命就(jiu)(jiu)相應縮短。為了保(bao)(bao)證石墨層中放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)后留有部分鋰(li)離(li)子，就(jiu)(jiu)要嚴(yan)格(ge)(ge)限制放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終止(zhi)最低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，也就(jiu)(jiu)是說鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)不(bu)能過放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓通常為3.0V/節(jie)，最低不(bu)能低于2.5V/節(jie)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)長短與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容(rong)量(liang)、放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流大(da)小有關。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)（小時(shi)）=電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容(rong)量(liang)/放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流。鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(mA)不(bu)應超過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)容(rong)量(liang)的(de)3倍。（如1000mAH電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)，則放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流應嚴(yan)格(ge)(ge)控制在(zai)3A以(yi)內）否則會(hui)使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)損壞。

目(mu)前市場上所(suo)售鋰電(dian)池組內(nei)部均封有(you)配套的(de)充放電(dian)保護板。只(zhi)要控制(zhi)好(hao)外(wai)部的(de)充放電(dian)電(dian)流即(ji)可(ke)。

五、鋰電池的保護電路：

兩節鋰電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)如圖一(yi)所示(shi)。由兩個場(chang)效應管(guan)(guan)和專用保(bao)護(hu)集(ji)成(cheng)塊S--8232組成(cheng)，過(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)(zhi)(zhi)管(guan)(guan)FET2和過(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)(zhi)(zhi)管(guan)(guan)FET1串聯于電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，由保(bao)護(hu)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)(zhi)(zhi)，當電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上升至4.2V時(shi)(shi)，過(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)保(bao)護(hu)管(guan)(guan)FET1截(jie)止(zhi)(zhi)，停(ting)止(zhi)(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。為(wei)防止(zhi)(zhi)誤(wu)動作(zuo)，一(yi)般在(zai)(zai)外電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)加有延(yan)時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)容。當電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)處于放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)狀態下，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)至2.55V時(shi)(shi)，過(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)(zhi)(zhi)管(guan)(guan)FET1截(jie)止(zhi)(zhi)，停(ting)止(zhi)(zhi)向(xiang)負(fu)載供電(dian)(dian)(dian)(dian)(dian)(dian)。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流保(bao)護(hu)是(shi)在(zai)(zai)當負(fu)載上有較大電(dian)(dian)(dian)(dian)(dian)(dian)流流過(guo)時(shi)(shi)，控制(zhi)(zhi)(zhi)FET1使(shi)其(qi)截(jie)止(zhi)(zhi)，停(ting)止(zhi)(zhi)向(xiang)負(fu)載放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，目的是(shi)為(wei)了(le)保(bao)護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和場(chang)效應管(guan)(guan)。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流檢測是(shi)利(li)用場(chang)效應管(guan)(guan)的導通電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)作(zuo)為(wei)檢測電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，監(jian)視它的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)，當電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)超(chao)過(guo)設定值(zhi)時(shi)(shi)就停(ting)止(zhi)(zhi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)中一(yi)般還(huan)加有延(yan)時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，以區分浪(lang)涌電(dian)(dian)(dian)(dian)(dian)(dian)流和短路(lu)(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)流。該電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)功能完善，性能可靠，但專業(ye)性強，且專用集(ji)成(cheng)塊不易購買，業(ye)余愛好(hao)者不易仿制(zhi)(zhi)(zhi)。

六、簡易充電電路：

現在(zai)有不少商家出售不帶充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)板的(de)單節鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。其(qi)性能優越，價格低廉，可(ke)(ke)用于(yu)自制(zhi)產品及鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組的(de)維(wei)修代換，因而(er)深受(shou)廣大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子愛好者喜愛。有興趣的(de)讀(du)者可(ke)(ke)參(can)照圖(tu)(tu)二制(zhi)作(zuo)一塊充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)板。其(qi)原理是(shi)：采用恒定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，確保不會過(guo)充(chong)(chong)(chong)(chong)。輸入(ru)直流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)高于(yu)所充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)3伏即可(ke)(ke)。R1、Q1、W1、TL431組成精密可(ke)(ke)調穩壓(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，Q2、W2、R2構成可(ke)(ke)調恒流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，Q3、R3、R4、R5、LED為充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)指(zhi)(zhi)示電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)。隨著被充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)上(shang)升，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流將(jiang)逐漸減小(xiao)，待電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)滿后R4上(shang)的(de)壓(ya)(ya)降將(jiang)降低，從而(er)使Q3截止(zhi)， LED將(jiang)熄滅，為保證電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)能夠充(chong)(chong)(chong)(chong)足，請(qing)在(zai)指(zhi)(zhi)示燈熄滅后繼續充(chong)(chong)(chong)(chong)1—2小(xiao)時。使用時請(qing)給Q2、Q3裝上(shang)合適的(de)散熱器。本電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)優點(dian)是(shi)：制(zhi)作(zuo)簡單，元器件易購，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)安全，顯示直觀，并且(qie)不會損壞電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)．通過(guo)改變W1可(ke)(ke)以對(dui)多(duo)節串聯鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，改變W２可(ke)(ke)以對(dui)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流進行大范圍調節。缺點(dian)是(shi)：無過(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)。圖(tu)(tu)三是(shi)該充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)板的(de)印制(zhi)板圖(tu)(tu)（從元件面(mian)看的(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

有許多電池(chi)組：如筆記本電腦上用的那(nei)種，經維修(xiu)發現，此電池(chi)組損(sun)壞時僅(jin)是(shi)個別(bie)電池(chi)有問題。可以選(xuan)用合適的單(dan)節鋰電池(chi)進行更換。

2、 制作高亮微型電筒

筆(bi)者曾用單節3.6V1.6AH鋰電(dian)池(chi)配(pei)合一(yi)個(ge)白色超高亮(liang)度發光(guang)管做成一(yi)只(zhi)微型電(dian)筒，使(shi)用方便，小巧(qiao)美(mei)觀。而且由于電(dian)池(chi)容量大，平均(jun)每晚使(shi)用半小時，至今已用兩個(ge)多月(yue)仍無(wu)需(xu)充電(dian)。電(dian)路如圖四所示。

3、代替3V電源

由(you)于單節(jie)鋰電(dian)池(chi)電(dian)壓為3.6V。因此僅需一節(jie)鋰電(dian)池(chi)便(bian)可代(dai)替兩節(jie)普通電(dian)池(chi)，給收音機(ji)、隨身聽、照相機(ji)等小家電(dian)產品供電(dian)，不僅重量輕(qing)，而且連續(xu)使用時間長(chang)。

八、鋰電池的保存：

鋰(li)電(dian)池需充足電(dian)后保(bao)存。在20℃下可(ke)儲存半年以上，可(ke)見(jian)鋰(li)電(dian)池適宜在低溫下保(bao)存。曾有人建(jian)議將充電(dian)電(dian)池放入冰箱冷藏(zang)室內保(bao)存，的確是(shi)個好注(zhu)意(yi)。

九、使用注意事項：

鋰(li)電池絕對不(bu)(bu)可(ke)(ke)解(jie)體、鉆(zhan)孔(kong)、穿刺、鋸割、加壓、加熱，否則有(you)可(ke)(ke)能(neng)造成嚴(yan)重后果。沒有(you)充電保護板(ban)的鋰(li)電池不(bu)(bu)可(ke)(ke)短路，不(bu)(bu)可(ke)(ke)供小孩玩耍(shua)。不(bu)(bu)能(neng)靠近易燃(ran)物品、化(hua)學物品。報廢的鋰(li)電池要妥善處(chu)理。