鋰電池充電電路原理及應用

鋰離子(zi)電池以其優(you)良的特性，被廣泛(fan)應用(yong)于: 手機(ji)(ji)、攝錄像(xiang)機(ji)(ji)、筆記本(ben)電腦、無繩電話、電動(dong)工具、遙控或電動(dong)玩具、照相機(ji)(ji)等便攜式電子(zi)設備中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)離(li)(li)子(zi)電(dian)(dian)池(chi)(chi)的(de)(de)負極(ji)為石墨晶體，正(zheng)極(ji)通常為二氧化鋰(li)。充(chong)電(dian)(dian)時鋰(li)離(li)(li)子(zi)由正(zheng)極(ji)向負極(ji)運動而(er)(er)嵌入石墨層中。放電(dian)(dian)時，鋰(li)離(li)(li)子(zi)從(cong)石墨晶體內負極(ji)表面脫離(li)(li)移向正(zheng)極(ji)。所以(yi)，在該電(dian)(dian)池(chi)(chi)充(chong)放電(dian)(dian)過程中鋰(li)總(zong)是(shi)以(yi)鋰(li)離(li)(li)子(zi)形(xing)態(tai)(tai)出現(xian)，而(er)(er)不是(shi)以(yi)金屬鋰(li)的(de)(de)形(xing)態(tai)(tai)出現(xian)。因而(er)(er)這種電(dian)(dian)池(chi)(chi)叫做鋰(li)離(li)(li)子(zi)電(dian)(dian)池(chi)(chi)，簡稱鋰(li)電(dian)(dian)池(chi)(chi)。

鋰電(dian)池具(ju)有(you)(you)：體(ti)積(ji)小、容(rong)量(liang)大(da)、重量(liang)輕、無污(wu)染、單節電(dian)壓高、自放電(dian)率(lv)低、電(dian)池循環次數多(duo)等優點，但價格(ge)較貴。鎳(nie)鎘電(dian)池因(yin)容(rong)量(liang)低，自放電(dian)嚴重，且(qie)(qie)對環境有(you)(you)污(wu)染，正逐步被淘(tao)汰(tai)。鎳(nie)氫(qing)電(dian)池具(ju)有(you)(you)較高的性能價格(ge)比，且(qie)(qie)不污(wu)染環境，但單體(ti)電(dian)壓只有(you)(you)1.2V，因(yin)而在使(shi)用范圍上受到限制。

二、鋰電池的特點：

1、具有(you)更高的重(zhong)量(liang)能(neng)量(liang)比、體積(ji)能(neng)量(liang)比；

2、電(dian)壓高，單(dan)節(jie)鋰(li)電(dian)池電(dian)壓為3.6V，等(deng)于3只(zhi)鎳鎘或鎳氫充電(dian)電(dian)池的(de)串聯電(dian)壓；

3、自放電小(xiao)可長時間存(cun)放，這是該電池(chi)最突出的優越性；

4、無(wu)(wu)記憶效(xiao)應。鋰電池不存在鎳鎘電池的所謂記憶效(xiao)應，所以(yi)鋰電池充電前無(wu)(wu)需放(fang)電；

5、壽命(ming)長。正常工作條件下，鋰電池充/放(fang)電循環次數遠大于500次；

6、可以快速充(chong)電(dian)。鋰電(dian)池通常可以采用0.5～1倍容(rong)量的電(dian)流充(chong)電(dian)，使充(chong)電(dian)時(shi)間縮(suo)短至1～2小時(shi)；

7、可以(yi)隨意(yi)并(bing)聯使用；

8、由于(yu)電(dian)池中不(bu)含(han)鎘、鉛、汞等重金屬(shu)元素，對環境無污染，是(shi)當代最先進(jin)的綠色(se)電(dian)池；

9、成本高。與其它(ta)可充電(dian)池相比，鋰電(dian)池價格較貴。

三、鋰電池的內部結構：

鋰(li)電池通常(chang)有兩種外型(xing)：圓柱型(xing)和長(chang)方型(xing)。

電(dian)池內(nei)(nei)部采用螺旋繞制(zhi)結構，用一種(zhong)非常精(jing)細而滲(shen)透性很強的(de)聚乙烯薄(bo)(bo)膜隔離材料在正、負(fu)極(ji)(ji)間(jian)間(jian)隔而成(cheng)(cheng)。正極(ji)(ji)包括由鋰和二氧化鈷組(zu)成(cheng)(cheng)的(de)鋰離子收集極(ji)(ji)及(ji)由鋁薄(bo)(bo)膜組(zu)成(cheng)(cheng)的(de)電(dian)流(liu)收集極(ji)(ji)。負(fu)極(ji)(ji)由片(pian)狀碳(tan)材料組(zu)成(cheng)(cheng)的(de)鋰離子收集極(ji)(ji)和銅薄(bo)(bo)膜組(zu)成(cheng)(cheng)的(de)電(dian)流(liu)收集極(ji)(ji)組(zu)成(cheng)(cheng)。電(dian)池內(nei)(nei)充有有機電(dian)解質溶液。另外還(huan)裝有安全閥和PTC元件，以(yi)便電(dian)池在不正常狀態及(ji)輸(shu)出短路(lu)時(shi)保護電(dian)池不受損壞(huai)。

單節鋰(li)(li)電(dian)池的電(dian)壓為(wei)3.6V，容量(liang)也不可(ke)能無(wu)限大，因此(ci)，常(chang)常(chang)將單節鋰(li)(li)電(dian)池進行串、并聯處理，以滿(man)足不同場(chang)合的要求。

四、鋰電池的充放電要求：

1、鋰(li)電(dian)(dian)(dian)池的充(chong)(chong)(chong)電(dian)(dian)(dian)：根據鋰(li)電(dian)(dian)(dian)池的結構特性(xing)，最高充(chong)(chong)(chong)電(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)壓(ya)應為4.2V，不能過充(chong)(chong)(chong)，否則會因正(zheng)極的鋰(li)離子拿(na)走太多，而(er)使電(dian)(dian)(dian)池報(bao)廢。其充(chong)(chong)(chong)放電(dian)(dian)(dian)要求較高，可采用專用的恒(heng)流(liu)、恒(heng)壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)器進行充(chong)(chong)(chong)電(dian)(dian)(dian)。通常恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)至4.2V/節后轉入恒(heng)壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)，當(dang)恒(heng)壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)降至100mA以內時(shi)，應停止(zhi)充(chong)(chong)(chong)電(dian)(dian)(dian)。

充電(dian)(dian)(dian)電(dian)(dian)(dian)流（mA）=0.1～1.5倍(bei)電(dian)(dian)(dian)池(chi)(chi)容量(liang)（如(ru)1350mAh的電(dian)(dian)(dian)池(chi)(chi)，其充電(dian)(dian)(dian)電(dian)(dian)(dian)流可控(kong)制在(zai)135～2025mA之間(jian)）。常規充電(dian)(dian)(dian)電(dian)(dian)(dian)流可選擇在(zai)0.5倍(bei)電(dian)(dian)(dian)池(chi)(chi)容量(liang)左右，充電(dian)(dian)(dian)時間(jian)約為2～3小時。

2、鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的(de)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)：因鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的(de)內部(bu)結構(gou)所致，放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)鋰(li)離(li)子(zi)(zi)不(bu)能(neng)(neng)(neng)全部(bu)移向正極(ji)，必須保(bao)(bao)留一部(bu)分鋰(li)離(li)子(zi)(zi)在負極(ji)，以保(bao)(bao)證在下(xia)次(ci)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)鋰(li)離(li)子(zi)(zi)能(neng)(neng)(neng)夠暢通(tong)地嵌入通(tong)道。否(fou)則，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池壽命就相應(ying)縮短。為(wei)了(le)保(bao)(bao)證石墨層中放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)后留有(you)部(bu)分鋰(li)離(li)子(zi)(zi)，就要(yao)嚴格限制放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終止(zhi)最低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，也就是說(shuo)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池不(bu)能(neng)(neng)(neng)過放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓通(tong)常為(wei)3.0V/節(jie)，最低不(bu)能(neng)(neng)(neng)低于(yu)2.5V/節(jie)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)間長短與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池容量(liang)、放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)大小有(you)關。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)間（小時(shi)(shi)）=電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池容量(liang)/放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(mA)不(bu)應(ying)超過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池容量(liang)的(de)3倍(bei)。（如1000mAH電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池，則放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)應(ying)嚴格控制在3A以內）否(fou)則會使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池損壞。

目前市(shi)場上所售鋰(li)電池組內部(bu)(bu)均封有配套的充放電保護板。只要控制好外部(bu)(bu)的充放電電流即可。

五、鋰電池的保護電路：

兩節鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池的(de)充放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)保護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)如(ru)圖一所示。由兩個場效(xiao)(xiao)應(ying)管(guan)(guan)和(he)(he)專用保護(hu)集(ji)成(cheng)(cheng)塊S--8232組成(cheng)(cheng)，過充電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)(kong)制(zhi)管(guan)(guan)FET2和(he)(he)過放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)(kong)制(zhi)管(guan)(guan)FET1串聯于電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，由保護(hu)IC監(jian)視電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)并進行控(kong)(kong)(kong)制(zhi)，當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)(shang)升至4.2V時，過充電(dian)(dian)(dian)(dian)(dian)(dian)保護(hu)管(guan)(guan)FET1截止(zhi)，停止(zhi)充電(dian)(dian)(dian)(dian)(dian)(dian)。為防止(zhi)誤動作，一般在(zai)外電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)加有(you)延時電(dian)(dian)(dian)(dian)(dian)(dian)容。當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)池處于放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)狀態下，電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降至2.55V時，過放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)(kong)制(zhi)管(guan)(guan)FET1截止(zhi)，停止(zhi)向負載供電(dian)(dian)(dian)(dian)(dian)(dian)。過電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)保護(hu)是(shi)在(zai)當(dang)(dang)負載上(shang)(shang)有(you)較(jiao)大電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過時，控(kong)(kong)(kong)制(zhi)FET1使其截止(zhi)，停止(zhi)向負載放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，目的(de)是(shi)為了保護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)池和(he)(he)場效(xiao)(xiao)應(ying)管(guan)(guan)。過電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢測是(shi)利用場效(xiao)(xiao)應(ying)管(guan)(guan)的(de)導通電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)作為檢測電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)，監(jian)視它(ta)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降，當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降超(chao)過設定值時就停止(zhi)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)。在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)中一般還加有(you)延時電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，以區分(fen)浪涌電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和(he)(he)短(duan)路(lu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)功能完善，性能可靠(kao)，但專業性強，且(qie)專用集(ji)成(cheng)(cheng)塊不易購買，業余(yu)愛(ai)好者不易仿(fang)制(zhi)。

六、簡易充電電路：

現在有不少商家出售不帶充電(dian)(dian)(dian)(dian)(dian)(dian)板的(de)(de)(de)單節(jie)鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。其性能優越，價(jia)格低廉(lian)，可(ke)(ke)用(yong)于(yu)自制產品及鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)(zu)的(de)(de)(de)維修代換，因(yin)而(er)深受廣大(da)電(dian)(dian)(dian)(dian)(dian)(dian)子愛(ai)好者(zhe)喜愛(ai)。有興(xing)趣的(de)(de)(de)讀者(zhe)可(ke)(ke)參照圖(tu)二制作一塊充電(dian)(dian)(dian)(dian)(dian)(dian)板。其原理是(shi)：采(cai)用(yong)恒定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)給(gei)(gei)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)，確保不會(hui)過(guo)充。輸入直流電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高于(yu)所充電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(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)穩壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，Q2、W2、R2構成可(ke)(ke)調(diao)恒流電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，Q3、R3、R4、R5、LED為充電(dian)(dian)(dian)(dian)(dian)(dian)指示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。隨著(zhu)被充電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)上升，充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流將逐漸減小，待電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充滿后R4上的(de)(de)(de)壓(ya)降將降低，從(cong)而(er)使Q3截止， LED將熄(xi)滅，為保證電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)能夠充足，請(qing)在指示(shi)(shi)燈熄(xi)滅后繼(ji)續充1—2小時。使用(yong)時請(qing)給(gei)(gei)Q2、Q3裝上合適的(de)(de)(de)散熱(re)器。本電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)優點(dian)(dian)是(shi)：制作簡單，元器件易購，充電(dian)(dian)(dian)(dian)(dian)(dian)安全，顯示(shi)(shi)直觀，并且不會(hui)損壞電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)．通過(guo)改變W1可(ke)(ke)以對多節(jie)串聯鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)，改變W２可(ke)(ke)以對充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流進行大(da)范圍調(diao)節(jie)。缺點(dian)(dian)是(shi)：無過(guo)放電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。圖(tu)三是(shi)該充電(dian)(dian)(dian)(dian)(dian)(dian)板的(de)(de)(de)印制板圖(tu)（從(cong)元件面看的(de)(de)(de)透視圖(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(duo)電池組：如筆記本電腦(nao)上用的那種，經維修發現，此電池組損壞時僅是(shi)個別電池有問題。可以選用合適的單節鋰(li)電池進行更(geng)換。

2、 制作高亮微型電筒

筆(bi)者曾用單節(jie)3.6V1.6AH鋰電池(chi)配合一個白色(se)超高亮度發光管做成一只微(wei)型(xing)電筒，使(shi)用方便，小巧美(mei)觀。而且由(you)于(yu)電池(chi)容量大，平均(jun)每晚使(shi)用半小時，至今已用兩個多(duo)月仍無需(xu)充電。電路(lu)如圖四所示。

3、代替3V電源

由于單節(jie)鋰電(dian)池(chi)電(dian)壓為3.6V。因此(ci)僅需一節(jie)鋰電(dian)池(chi)便可代替兩節(jie)普通電(dian)池(chi)，給收音機、隨身聽(ting)、照相機等小家電(dian)產品供電(dian)，不僅重(zhong)量輕，而且連(lian)續(xu)使用時間長。

八、鋰電池的保存：

鋰電(dian)(dian)(dian)池(chi)需充足電(dian)(dian)(dian)后保存。在(zai)20℃下可(ke)儲存半年以(yi)上，可(ke)見鋰電(dian)(dian)(dian)池(chi)適(shi)宜在(zai)低溫下保存。曾(ceng)有(you)人建(jian)議(yi)將充電(dian)(dian)(dian)電(dian)(dian)(dian)池(chi)放(fang)入冰(bing)箱冷藏室(shi)內保存，的確是個好注意(yi)。

九、使用注意事項：

鋰電池(chi)絕對不(bu)可解體、鉆孔、穿刺、鋸割、加壓(ya)、加熱，否(fou)則有可能造成嚴重后果。沒有充(chong)電保護板的(de)鋰電池(chi)不(bu)可短(duan)路(lu)，不(bu)可供小孩玩耍。不(bu)能靠近易燃物(wu)品、化(hua)學(xue)物(wu)品。報廢的(de)鋰電池(chi)要妥(tuo)善處理。