鋰電池充電電路原理及應用

鋰(li)離子電(dian)(dian)池以其優良(liang)的特性，被廣(guang)泛應用于: 手機(ji)(ji)、攝錄像機(ji)(ji)、筆記(ji)本電(dian)(dian)腦、無繩電(dian)(dian)話、電(dian)(dian)動(dong)工具(ju)、遙控(kong)或(huo)電(dian)(dian)動(dong)玩具(ju)、照相機(ji)(ji)等便攜(xie)式電(dian)(dian)子設(she)備中。

一、鋰電池與鎳鎘、鎳氫可充電池：

鋰(li)(li)(li)(li)離(li)子(zi)(zi)電(dian)池的負(fu)極為石墨(mo)晶(jing)體(ti)，正(zheng)極通常(chang)為二氧化鋰(li)(li)(li)(li)。充電(dian)時(shi)鋰(li)(li)(li)(li)離(li)子(zi)(zi)由(you)正(zheng)極向負(fu)極運動而嵌入石墨(mo)層中。放電(dian)時(shi)，鋰(li)(li)(li)(li)離(li)子(zi)(zi)從石墨(mo)晶(jing)體(ti)內負(fu)極表面脫離(li)移(yi)向正(zheng)極。所(suo)以(yi)，在該電(dian)池充放電(dian)過程中鋰(li)(li)(li)(li)總是以(yi)鋰(li)(li)(li)(li)離(li)子(zi)(zi)形態出(chu)現，而不(bu)是以(yi)金屬(shu)鋰(li)(li)(li)(li)的形態出(chu)現。因而這種電(dian)池叫做(zuo)鋰(li)(li)(li)(li)離(li)子(zi)(zi)電(dian)池，簡稱鋰(li)(li)(li)(li)電(dian)池。

鋰電(dian)(dian)池具有(you)：體積小、容量大、重量輕、無污(wu)染(ran)、單節電(dian)(dian)壓高、自(zi)放(fang)電(dian)(dian)率低、電(dian)(dian)池循環次數多等優(you)點，但價格較貴。鎳(nie)(nie)鎘電(dian)(dian)池因容量低，自(zi)放(fang)電(dian)(dian)嚴重，且對環境(jing)有(you)污(wu)染(ran)，正逐(zhu)步(bu)被淘汰。鎳(nie)(nie)氫(qing)電(dian)(dian)池具有(you)較高的性能價格比，且不污(wu)染(ran)環境(jing)，但單體電(dian)(dian)壓只有(you)1.2V，因而在使用(yong)范(fan)圍上受(shou)到限制。

二、鋰電池的特點：

1、具有更高的(de)重(zhong)量(liang)(liang)能量(liang)(liang)比、體積能量(liang)(liang)比；

2、電(dian)壓高，單節鋰(li)電(dian)池電(dian)壓為(wei)3.6V，等于3只(zhi)鎳(nie)鎘或鎳(nie)氫充(chong)電(dian)電(dian)池的串聯(lian)電(dian)壓；

3、自放電小可長時間存放，這是該電池最突出的優越性(xing)；

4、無(wu)記憶效(xiao)應。鋰電(dian)池(chi)不存在鎳鎘(ge)電(dian)池(chi)的所謂記憶效(xiao)應，所以鋰電(dian)池(chi)充電(dian)前(qian)無(wu)需(xu)放(fang)電(dian)；

5、壽命長(chang)。正常工作條(tiao)件下，鋰電池充/放電循環次數遠大(da)于500次；

6、可以快(kuai)速充(chong)電。鋰(li)電池通常可以采用(yong)0.5～1倍(bei)容量(liang)的電流(liu)充(chong)電，使充(chong)電時(shi)間縮短至1～2小時(shi)；

7、可以(yi)隨(sui)意并(bing)聯(lian)使用；

8、由于電(dian)(dian)池中(zhong)不含鎘(ge)、鉛、汞等重金屬元素，對環境(jing)無污染，是當代最先(xian)進的綠色電(dian)(dian)池；

9、成本高。與其它可(ke)充電池相(xiang)比(bi)，鋰電池價格較貴(gui)。

三、鋰電池的內部結構：

鋰(li)電池(chi)通常有兩種外型：圓(yuan)柱(zhu)型和長方(fang)型。

電(dian)(dian)(dian)池(chi)(chi)內部采用(yong)螺旋(xuan)繞制結(jie)構，用(yong)一種非常(chang)精(jing)細(xi)而(er)滲透性很強的聚(ju)乙烯薄(bo)(bo)膜(mo)隔離材(cai)料(liao)在正、負(fu)極(ji)間間隔而(er)成(cheng)(cheng)。正極(ji)包括由(you)鋰和二氧化鈷(gu)組成(cheng)(cheng)的鋰離子收(shou)集(ji)(ji)極(ji)及由(you)鋁薄(bo)(bo)膜(mo)組成(cheng)(cheng)的電(dian)(dian)(dian)流收(shou)集(ji)(ji)極(ji)。負(fu)極(ji)由(you)片(pian)狀碳材(cai)料(liao)組成(cheng)(cheng)的鋰離子收(shou)集(ji)(ji)極(ji)和銅薄(bo)(bo)膜(mo)組成(cheng)(cheng)的電(dian)(dian)(dian)流收(shou)集(ji)(ji)極(ji)組成(cheng)(cheng)。電(dian)(dian)(dian)池(chi)(chi)內充有(you)有(you)機電(dian)(dian)(dian)解質溶液(ye)。另外(wai)還裝有(you)安全閥和PTC元件，以便電(dian)(dian)(dian)池(chi)(chi)在不正常(chang)狀態及輸出(chu)短路(lu)時(shi)保護(hu)電(dian)(dian)(dian)池(chi)(chi)不受損(sun)壞。

單(dan)節鋰(li)電(dian)池的電(dian)壓為3.6V，容量也不(bu)可(ke)能無(wu)限大，因此，常常將(jiang)單(dan)節鋰(li)電(dian)池進行串、并聯處理，以(yi)滿足不(bu)同(tong)場合的要求。

四、鋰電池的充放電要求：

1、鋰電(dian)(dian)(dian)(dian)池的(de)充電(dian)(dian)(dian)(dian)：根據鋰電(dian)(dian)(dian)(dian)池的(de)結構特性，最高(gao)充電(dian)(dian)(dian)(dian)終止(zhi)電(dian)(dian)(dian)(dian)壓(ya)應為(wei)4.2V，不能過充，否則會因(yin)正(zheng)極的(de)鋰離子拿走太(tai)多，而使電(dian)(dian)(dian)(dian)池報廢。其充放電(dian)(dian)(dian)(dian)要求較(jiao)高(gao)，可采用(yong)專用(yong)的(de)恒(heng)(heng)流、恒(heng)(heng)壓(ya)充電(dian)(dian)(dian)(dian)器(qi)進行充電(dian)(dian)(dian)(dian)。通(tong)常(chang)恒(heng)(heng)流充電(dian)(dian)(dian)(dian)至(zhi)(zhi)4.2V/節后轉(zhuan)入(ru)恒(heng)(heng)壓(ya)充電(dian)(dian)(dian)(dian)，當恒(heng)(heng)壓(ya)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流降至(zhi)(zhi)100mA以內時，應停止(zhi)充電(dian)(dian)(dian)(dian)。

充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)（mA）=0.1～1.5倍電(dian)(dian)池容量(liang)(liang)（如(ru)1350mAh的電(dian)(dian)池，其充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)可(ke)控制(zhi)在(zai)135～2025mA之(zhi)間(jian)）。常規(gui)充(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)可(ke)選擇在(zai)0.5倍電(dian)(dian)池容量(liang)(liang)左右，充(chong)(chong)電(dian)(dian)時間(jian)約為2～3小(xiao)時。

2、鋰(li)(li)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的放(fang)(fang)電(dian)(dian)(dian)：因(yin)鋰(li)(li)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的內(nei)部結構所致，放(fang)(fang)電(dian)(dian)(dian)時鋰(li)(li)離(li)子(zi)不(bu)能全(quan)部移向正極(ji)，必須(xu)保(bao)留一部分鋰(li)(li)離(li)子(zi)在(zai)負極(ji)，以保(bao)證在(zai)下(xia)次充(chong)電(dian)(dian)(dian)時鋰(li)(li)離(li)子(zi)能夠暢通地(di)嵌(qian)入通道。否則(ze)(ze)，電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)壽命(ming)就相應(ying)縮短。為(wei)了保(bao)證石墨層中(zhong)放(fang)(fang)電(dian)(dian)(dian)后(hou)留有部分鋰(li)(li)離(li)子(zi)，就要嚴(yan)格(ge)限制放(fang)(fang)電(dian)(dian)(dian)終止最(zui)低電(dian)(dian)(dian)壓(ya)，也就是說鋰(li)(li)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)不(bu)能過(guo)放(fang)(fang)電(dian)(dian)(dian)。放(fang)(fang)電(dian)(dian)(dian)終止電(dian)(dian)(dian)壓(ya)通常(chang)為(wei)3.0V/節(jie)(jie)，最(zui)低不(bu)能低于2.5V/節(jie)(jie)。電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)時間(jian)長短與電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量、放(fang)(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)大(da)小有關。電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)時間(jian)（小時）=電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量/放(fang)(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)。鋰(li)(li)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)(mA)不(bu)應(ying)超過(guo)電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)容(rong)量的3倍。（如1000mAH電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)，則(ze)(ze)放(fang)(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)(liu)應(ying)嚴(yan)格(ge)控制在(zai)3A以內(nei)）否則(ze)(ze)會使電(dian)(dian)(dian)池(chi)(chi)(chi)(chi)損壞(huai)。

目前市場(chang)上(shang)所(suo)售鋰電池組內部均封有配套的(de)充放電保護板。只要控(kong)制好外部的(de)充放電電流即可。

五、鋰電池的保護電路：

兩(liang)節鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路如圖(tu)一所示。由兩(liang)個場效應管(guan)(guan)和專(zhuan)用保(bao)(bao)護集成(cheng)塊S--8232組(zu)成(cheng)，過(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)(zhi)管(guan)(guan)FET2和過(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)(zhi)管(guan)(guan)FET1串聯于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路，由保(bao)(bao)護IC監視電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓并進行控(kong)制(zhi)(zhi)，當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓上(shang)升至(zhi)4.2V時(shi)，過(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護管(guan)(guan)FET1截止(zhi)，停(ting)止(zhi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為防止(zhi)誤動作，一般(ban)在外(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路加(jia)有(you)延時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容。當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池處于(yu)放(fang)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)壓降(jiang)至(zhi)2.55V時(shi)，過(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)(zhi)管(guan)(guan)FET1截止(zhi)，停(ting)止(zhi)向負載供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)保(bao)(bao)護是在當(dang)(dang)負載上(shang)有(you)較大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)流(liu)過(guo)時(shi)，控(kong)制(zhi)(zhi)FET1使其截止(zhi)，停(ting)止(zhi)向負載放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，目的是為了保(bao)(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池和場效應管(guan)(guan)。過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢(jian)測是利用場效應管(guan)(guan)的導通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻作為檢(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，監視它的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降(jiang)，當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓降(jiang)超過(guo)設(she)定(ding)值時(shi)就停(ting)止(zhi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)一般(ban)還(huan)加(jia)有(you)延時(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路，以(yi)區分浪(lang)涌電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和短路電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路功能(neng)完善，性能(neng)可靠(kao)，但專(zhuan)業(ye)(ye)性強，且(qie)專(zhuan)用集成(cheng)塊不(bu)易購買，業(ye)(ye)余愛好者(zhe)不(bu)易仿制(zhi)(zhi)。

六、簡易充電電路：

現(xian)在有(you)不(bu)少商家(jia)出售不(bu)帶充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)板(ban)(ban)的(de)(de)單節鋰電(dian)(dian)(dian)(dian)池(chi)(chi)。其(qi)性能優(you)越，價格低廉，可(ke)用(yong)于自制產品(pin)及鋰電(dian)(dian)(dian)(dian)池(chi)(chi)組的(de)(de)維修代換，因而(er)深受廣大電(dian)(dian)(dian)(dian)子(zi)愛(ai)好(hao)者(zhe)(zhe)喜(xi)愛(ai)。有(you)興趣的(de)(de)讀者(zhe)(zhe)可(ke)參照(zhao)圖二制作一塊充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)板(ban)(ban)。其(qi)原理(li)是：采(cai)用(yong)恒(heng)定電(dian)(dian)(dian)(dian)壓(ya)給電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，確保不(bu)會(hui)過(guo)充(chong)(chong)(chong)(chong)(chong)(chong)。輸入直流(liu)電(dian)(dian)(dian)(dian)壓(ya)高于所充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)3伏即(ji)可(ke)。R1、Q1、W1、TL431組成精(jing)密可(ke)調(diao)(diao)穩(wen)壓(ya)電(dian)(dian)(dian)(dian)路，Q2、W2、R2構成可(ke)調(diao)(diao)恒(heng)流(liu)電(dian)(dian)(dian)(dian)路，Q3、R3、R4、R5、LED為充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)指(zhi)示電(dian)(dian)(dian)(dian)路。隨著被(bei)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)的(de)(de)上升，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)將逐(zhu)漸(jian)減小，待電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)(chong)(chong)滿后(hou)R4上的(de)(de)壓(ya)降(jiang)將降(jiang)低，從(cong)(cong)而(er)使Q3截止， LED將熄(xi)滅，為保證電(dian)(dian)(dian)(dian)池(chi)(chi)能夠(gou)充(chong)(chong)(chong)(chong)(chong)(chong)足，請在指(zhi)示燈熄(xi)滅后(hou)繼續充(chong)(chong)(chong)(chong)(chong)(chong)1—2小時。使用(yong)時請給Q2、Q3裝(zhuang)上合適的(de)(de)散熱器。本電(dian)(dian)(dian)(dian)路的(de)(de)優(you)點是：制作簡單，元(yuan)器件(jian)易購，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)安(an)全，顯(xian)示直觀(guan)，并(bing)且不(bu)會(hui)損壞電(dian)(dian)(dian)(dian)池(chi)(chi)．通過(guo)改(gai)變W1可(ke)以對(dui)多(duo)節串聯(lian)鋰電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，改(gai)變W２可(ke)以對(dui)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)進行(xing)大范圍(wei)調(diao)(diao)節。缺點是：無(wu)過(guo)放電(dian)(dian)(dian)(dian)控制電(dian)(dian)(dian)(dian)路。圖三是該充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)板(ban)(ban)的(de)(de)印制板(ban)(ban)圖（從(cong)(cong)元(yuan)件(jian)面看(kan)的(de)(de)透(tou)視圖）。

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)(dian)(dian)池(chi)組：如筆記本電(dian)(dian)(dian)腦上用(yong)的那種，經(jing)維(wei)修發現，此電(dian)(dian)(dian)池(chi)組損壞(huai)時(shi)僅是個別電(dian)(dian)(dian)池(chi)有問題。可以選用(yong)合適(shi)的單節鋰電(dian)(dian)(dian)池(chi)進行更(geng)換。

2、 制作高亮微型電筒

筆者曾用(yong)單節3.6V1.6AH鋰電(dian)(dian)池配合一(yi)個(ge)白色超高亮(liang)度發光管做(zuo)成一(yi)只微型電(dian)(dian)筒(tong)，使(shi)用(yong)方便(bian)，小巧美(mei)觀(guan)。而且由于(yu)電(dian)(dian)池容量大(da)，平均每晚(wan)使(shi)用(yong)半小時，至今已用(yong)兩個(ge)多(duo)月仍無需充電(dian)(dian)。電(dian)(dian)路如圖四所示。

3、代替3V電源

由于單(dan)節(jie)(jie)(jie)鋰電池電壓為3.6V。因此僅需一節(jie)(jie)(jie)鋰電池便可(ke)代替(ti)兩(liang)節(jie)(jie)(jie)普通電池，給收(shou)音機(ji)、隨身聽、照相機(ji)等小(xiao)家電產品供(gong)電，不僅重量輕，而(er)且連續使用時(shi)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℃下可儲存半年(nian)以(yi)上，可見鋰電(dian)(dian)(dian)池(chi)適宜在(zai)低溫下保存。曾有人建議將充電(dian)(dian)(dian)電(dian)(dian)(dian)池(chi)放(fang)入(ru)冰箱冷藏室(shi)內(nei)保存，的(de)確是個(ge)好注意(yi)。

九、使用注意事項：

鋰(li)電池絕對不(bu)可解體、鉆(zhan)孔(kong)、穿刺、鋸割、加壓、加熱(re)，否則有可能造成嚴(yan)重后果(guo)。沒有充電保護板的鋰(li)電池不(bu)可短路，不(bu)可供小(xiao)孩玩耍。不(bu)能靠近易燃物品、化學物品。報廢的鋰(li)電池要妥善處理。