單體鋰離子電池的額定電壓為3.6V，不能滿足高電壓供電場合的需要，因此就需要多節鋰離子電池串聯(lian)使用。為此，各有關電(dian)(dian)源(yuan)管理控制集成電(dian)(dian)路生產(chan)廠商(shang)紛紛推出了自己的(de)(de)多節(jie)鋰離(li)子(zi)電(dian)(dian)池（電(dian)(dian)池組）保護集成電(dian)(dian)路芯(xin)片，如(ru)精工技術有限公(gong)司（SII）的(de)(de)S-8204B(S-8204B隸屬于S-8204系列(lie)，該系列(lie)的(de)(de)另(ling)一(yi)個產(chan)品是(shi)S-8204A。兩者(zhe)的(de)(de)區別是(shi)S-8204A配合(he)P溝(gou)(gou)道(dao)MOSFET工作，S-8204B則配合(he)N溝(gou)(gou)道(dao)MOSFET工作)。這(zhe)類(lei)產(chan)品的(de)(de)特點是(shi)監(jian)控3、4節(jie)鋰離(li)子(zi)電(dian)(dian)池的(de)(de)充(chong)放電(dian)(dian)狀態，可實現過(guo)充(chong)、過(guo)放和過(guo)電(dian)(dian)流保護。

以S-8204B為例，它(ta)能(neng)對(dui)各(ge)節鋰離子電(dian)(dian)(dian)(dian)(dian)池的電(dian)(dian)(dian)(dian)(dian)壓進(jin)行(xing)高精(jing)度檢(jian)測(ce)，具有3段過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流檢(jian)測(ce)功能(neng)，通(tong)(tong)過(guo)(guo)外接電(dian)(dian)(dian)(dian)(dian)容可設置過(guo)(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)檢(jian)測(ce)延遲時間(jian)、過(guo)(guo)放(fang)電(dian)(dian)(dian)(dian)(dian)檢(jian)測(ce)延遲時間(jian)、放(fang)電(dian)(dian)(dian)(dian)(dian)過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流檢(jian)測(ce)延遲時間(jian)1和放(fang)電(dian)(dian)(dian)(dian)(dian)過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流檢(jian)測(ce)延遲時間(jian)2，還能(neng)通(tong)(tong)過(guo)(guo)SEL端子切換(huan)3/4節鋰離子電(dian)(dian)(dian)(dian)(dian)池串聯使(shi)用(yong)。不過(guo)(guo)，它(ta)最大的特(te)點是可以級聯使(shi)用(yong)，下節將(jiang)對(dui)S-8204B的這一(yi)功能(neng)進(jin)行(xing)詳細說明。

保護芯片級聯

上面提到(dao)的(de)電(dian)(dian)池(chi)(chi)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)最多能保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)4節(jie)(jie)(jie)(jie)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)，然而很(hen)多應用(yong)(yong)都需要5～12節(jie)(jie)(jie)(jie)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)串(chuan)聯(lian)(lian)(lian)工作，比如(ru)電(dian)(dian)動工具、電(dian)(dian)動自行車(che)和(he)UPS，此時又(you)如(ru)何解決呢？答案很(hen)簡單，就(jiu)是同時使用(yong)(yong)多個鋰電(dian)(dian)池(chi)(chi)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)。如(ru)圖1所(suo)示，兩個保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)串(chuan)聯(lian)(lian)(lian)在一起(qi)，由2個N溝(gou)道(dao)MOSFET做控制開(kai)關，可以(yi)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)8節(jie)(jie)(jie)(jie)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)，三個保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)串(chuan)聯(lian)(lian)(lian)在一起(qi)，就(jiu)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)了12節(jie)(jie)(jie)(jie)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)。這(zhe)種(zhong)多保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)的(de)串(chuan)聯(lian)(lian)(lian)就(jiu)是保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)的(de)“級聯(lian)(lian)(lian)”。以(yi)S-8204B為例(li)，兩個S-8204B聯(lian)(lian)(lian)合使用(yong)(yong)，用(yong)(yong)2個N溝(gou)道(dao)MOSFET在低壓側端進行控制，這(zhe)樣通過單顆IC可選(xuan)3節(jie)(jie)(jie)(jie)和(he)4節(jie)(jie)(jie)(jie)的(de)功能就(jiu)可以(yi)實現對(dui)6～8節(jie)(jie)(jie)(jie)串(chuan)聯(lian)(lian)(lian)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)的(de)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)。如(ru)果是5節(jie)(jie)(jie)(jie)鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)串(chuan)聯(lian)(lian)(lian)，則可以(yi)使用(yong)(yong)一個S-8204B與其他鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)串(chuan)聯(lian)(lian)(lian)，實現保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)功能。這(zhe)種(zhong)多保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)芯(xin)(xin)片(pian)的(de)靈活組合，可以(yi)完(wan)成對(dui)任意數(shu)目鋰離(li)(li)(li)子(zi)電(dian)(dian)池(chi)(chi)的(de)保(bao)(bao)(bao)(bao)護(hu)(hu)(hu)(hu)(hu)(hu)。

下面，詳細介紹一(yi)(yi)下保(bao)(bao)護(hu)芯(xin)片(pian)級聯的(de)(de)(de)(de)具體工作情況。還是以(yi)(yi)S-8204B為例(li)，其CTLC端(duan)子(zi)(zi)(zi)可由芯(xin)片(pian)外部控(kong)制(zhi)(zhi)COP端(duan)子(zi)(zi)(zi)的(de)(de)(de)(de)輸出(chu)(chu)電壓(ya)、而(er)CTLD端(duan)子(zi)(zi)(zi)則可由芯(xin)片(pian)外部控(kong)制(zhi)(zhi)DOP端(duan)子(zi)(zi)(zi)的(de)(de)(de)(de)輸出(chu)(chu)電壓(ya)。通過CTLC端(duan)子(zi)(zi)(zi)以(yi)(yi)及CTLD端(duan)子(zi)(zi)(zi)可以(yi)(yi)分別單獨控(kong)制(zhi)(zhi)COP端(duan)子(zi)(zi)(zi)與DOP端(duan)子(zi)(zi)(zi)的(de)(de)(de)(de)輸出(chu)(chu)電壓(ya)。并且(qie)，這些控(kong)制(zhi)(zhi)功能(neng)優先于芯(xin)片(pian)內部的(de)(de)(de)(de)電池充放電保(bao)(bao)護(hu)功能(neng)。如果8節電池中的(de)(de)(de)(de)某一(yi)(yi)節電池發生過充，與該(gai)電池相連接的(de)(de)(de)(de)S-8204B的(de)(de)(de)(de)COP端(duan)子(zi)(zi)(zi)輸出(chu)(chu)電壓(ya)會(hui)發生變(bian)化(hua)，該(gai)電壓(ya)變(bian)化(hua)會(hui)傳遞到與其相連接的(de)(de)(de)(de)另(ling)一(yi)(yi)個S-8204B的(de)(de)(de)(de)CTLC端(duan)子(zi)(zi)(zi)，使得(de)另(ling)一(yi)(yi)個S-8204B的(de)(de)(de)(de)COP端(duan)子(zi)(zi)(zi)輸出(chu)(chu)電壓(ya)也發生變(bian)化(hua)，從而(er)控(kong)制(zhi)(zhi)充電控(kong)制(zhi)(zhi)用MOSFET關斷，實現鋰離(li)子(zi)(zi)(zi)電池的(de)(de)(de)(de)過充電保(bao)(bao)護(hu)。

如果8節電池中的某一節電池發生過(guo)放電時，則由與該電池相連接(jie)的S-8204B的DOP端子向另一個(ge)S-8204B芯片的CTLD端子發出過(guo)放信號(hao)，改變其(qi)DOP端子的狀態(tai)，最(zui)終(zhong)使得(de)放電控制用MOSFET關斷，結束放電。

充放電時的溫度控制

另外，對(dui)充(chong)(chong)放(fang)電(dian)(dian)過(guo)(guo)程的(de)(de)(de)溫(wen)(wen)度控(kong)制(zhi)也是(shi)許多設計者需要(yao)考慮的(de)(de)(de)。在(zai)(zai)高(gao)溫(wen)(wen)的(de)(de)(de)時(shi)候(hou)對(dui)鋰(li)離子(zi)(zi)電(dian)(dian)池充(chong)(chong)放(fang)電(dian)(dian)，會有(you)爆炸(zha)的(de)(de)(de)危(wei)險；在(zai)(zai)低(di)溫(wen)(wen)的(de)(de)(de)時(shi)候(hou)充(chong)(chong)放(fang)電(dian)(dian)，會對(dui)電(dian)(dian)芯造成損(sun)害。在(zai)(zai)上面的(de)(de)(de)方案(an)中(zhong)，在(zai)(zai)S-8204B的(de)(de)(de)CTLC端(duan)子(zi)(zi)外接(jie)一溫(wen)(wen)度控(kong)制(zhi)開關(guan)(guan)（如S-5841），在(zai)(zai)鋰(li)離子(zi)(zi)電(dian)(dian)池充(chong)(chong)電(dian)(dian)過(guo)(guo)程中(zhong)溫(wen)(wen)度過(guo)(guo)高(gao)時(shi)，溫(wen)(wen)控(kong)開關(guan)(guan)的(de)(de)(de)控(kong)制(zhi)信號通(tong)過(guo)(guo)CTLC端(duan)子(zi)(zi)送(song)給(gei)COP，強(qiang)行結束(shu)鋰(li)離子(zi)(zi)電(dian)(dian)池的(de)(de)(de)充(chong)(chong)電(dian)(dian)過(guo)(guo)程。同樣，在(zai)(zai)CTLD端(duan)子(zi)(zi)外接(jie)溫(wen)(wen)度控(kong)制(zhi)開關(guan)(guan)，則能(neng)對(dui)放(fang)電(dian)(dian)過(guo)(guo)程進行溫(wen)(wen)度保護。