鋰電池具(ju)有高電(dian)壓的(de)(de)電(dian)池(chi)單體、高比能(neng)(neng)量(liang)和(he)高能(neng)(neng)量(liang)密度，是當前比能(neng)(neng)量(liang)最高的(de)(de)電(dian)池(chi)。但正是因為鋰電(dian)池(chi)的(de)(de)能(neng)(neng)量(liang)密度比較(jiao)高，當發生(sheng)誤用或(huo)濫(lan)用時，將會引起(qi)安全事(shi)故。而電(dian)池(chi)保(bao)護板能(neng)(neng)夠(gou)解決這一(yi)問題(ti)。當電(dian)池(chi)處在充電(dian)過壓或(huo)者是放(fang)電(dian)欠(qian)壓的(de)(de)情況下，電(dian)池(chi)保(bao)護板能(neng)(neng)夠(gou)自動(dong)切斷充放(fang)電(dian)回路，其(qi)電(dian)量(liang)均(jun)衡(heng)的(de)(de)功能(neng)(neng)能(neng)(neng)夠(gou)保(bao)證單節電(dian)池(chi)的(de)(de)壓差維持在一(yi)個很(hen)小的(de)(de)范圍內。此外，還(huan)具(ju)有過溫(wen)、過流、剩(sheng)余(yu)電(dian)量(liang)估測等(deng)功能(neng)(neng)。

電(dian)池保護板系統硬件構成:MCU模(mo)塊、檢測模(mo)塊、均衡模(mo)塊。

1、電(dian)池(chi)保護板(ban)的MCU模塊

MCU是系統控(kong)制的(de)核心。本文采用的(de)MCU是M68HC08系列(lie)的(de)GZ16型號的(de)單片機。該系列(lie)所有的(de)MCU均采用增強型M68HC08中央處理器(CP08)。該單片機具(ju)有以下特性(xing)：

(1)8MHz內(nei)部(bu)總線頻率；(2)16KB的內(nei)置FLASH存儲器(qi)；(3)2個16位定時器(qi)接(jie)口模塊；(4)支持1MHz～8MHz晶(jing)振的時鐘發生器(qi)；(5)增強型(xing)串行通信接(jie)口(ESCI)模塊。

2、電(dian)池保(bao)護板的(de)檢測模塊

檢測模塊(kuai)中將對電壓檢測、電流(liu)檢測和(he)溫度(du)檢測模塊(kuai)分別進行介紹。

（1）電壓檢測模塊

本系統中，單(dan)片機將對(dui)(dui)電(dian)(dian)(dian)(dian)(dian)池組的(de)整體(ti)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)和單(dan)節電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)進行(xing)檢測。對(dui)(dui)于(yu)電(dian)(dian)(dian)(dian)(dian)池組整體(ti)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)檢測有(you)2種(zhong)方(fang)法：(1)采(cai)(cai)(cai)用(yong)專用(yong)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)檢測模塊，如霍爾電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)傳感器；(2)采(cai)(cai)(cai)用(yong)精密電(dian)(dian)(dian)(dian)(dian)阻(zu)構建電(dian)(dian)(dian)(dian)(dian)阻(zu)分(fen)壓(ya)(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)路。采(cai)(cai)(cai)用(yong)專用(yong)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)檢測模塊成本較高，而且還需(xu)要特定的(de)電(dian)(dian)(dian)(dian)(dian)源，過(guo)程比較復雜。所以采(cai)(cai)(cai)用(yong)分(fen)壓(ya)(ya)(ya)(ya)的(de)電(dian)(dian)(dian)(dian)(dian)路進行(xing)檢測。10串錳酸鋰電(dian)(dian)(dian)(dian)(dian)池組電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)變化(hua)的(de)范(fan)圍是28V～42V。采(cai)(cai)(cai)用(yong)3.9M?贅和300k?贅的(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)進行(xing)分(fen)壓(ya)(ya)(ya)(ya)，采(cai)(cai)(cai)集出(chu)來的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)信號(hao)的(de)變化(hua)范(fan)圍是2V～3V，所對(dui)(dui)應的(de)AD轉換(huan)結果為(wei)409和*。

對于單體電(dian)池的檢測，主要(yao)采用飛電(dian)容技術。

（2）電流采樣電路

電(dian)(dian)流采樣(yang)時，電(dian)(dian)池(chi)管(guan)理系統中(zhong)的(de)(de)(de)(de)(de)參數(shu)是電(dian)(dian)池(chi)過(guo)(guo)流保護的(de)(de)(de)(de)(de)重要依據。本系統中(zhong)電(dian)(dian)流采樣(yang)電(dian)(dian)路如圖2所示。當電(dian)(dian)池(chi)放(fang)電(dian)(dian)時，用康(kang)銅(tong)絲對(dui)(dui)電(dian)(dian)流信號(hao)進行檢測，將檢測到的(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)信號(hao)經過(guo)(guo)差(cha)模放(fang)大(da)(da)(da)器(qi)的(de)(de)(de)(de)(de)放(fang)大(da)(da)(da)，變為0～5V的(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)信號(hao)送至(zhi)單(dan)片(pian)(pian)機(ji)。如果放(fang)電(dian)(dian)的(de)(de)(de)(de)(de)電(dian)(dian)流過(guo)(guo)大(da)(da)(da)，單(dan)片(pian)(pian)機(ji)檢測到的(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)信號(hao)比較大(da)(da)(da)，就會(hui)驅動(dong)三(san)極管(guan)動(dong)作，改變MOS管(guan)柵(zha)極電(dian)(dian)壓(ya)，關斷放(fang)電(dian)(dian)的(de)(de)(de)(de)(de)回路。比如，對(dui)(dui)于36V的(de)(de)(de)(de)(de)錳(meng)酸(suan)鋰電(dian)(dian)池(chi)來說，設定其保護電(dian)(dian)流是60A。康(kang)銅(tong)絲的(de)(de)(de)(de)(de)電(dian)(dian)阻是5mΩ左右。當電(dian)(dian)流達到60A時，康(kang)銅(tong)絲的(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)達300mV左右。為提高精(jing)度(du)，將電(dian)(dian)壓(ya)通(tong)過(guo)(guo)放(fang)大(da)(da)(da)器(qi)放(fang)大(da)(da)(da)10倍(bei)送至(zhi)單(dan)片(pian)(pian)機(ji)檢測。

（3）溫度檢測

電(dian)(dian)池組(zu)(zu)在充、放(fang)電(dian)(dian)過程(cheng)中，一部分(fen)能量以熱量形式被釋放(fang)出來，這(zhe)部分(fen)熱量不及時(shi)排除(chu)會(hui)(hui)引起電(dian)(dian)池組(zu)(zu)過熱。如果單個鎳氫電(dian)(dian)池溫度超過55℃，電(dian)(dian)池特性就(jiu)會(hui)(hui)變(bian)質，電(dian)(dian)池組(zu)(zu)充、放(fang)電(dian)(dian)平(ping)衡就(jiu)會(hui)(hui)被打破，繼而導致電(dian)(dian)池組(zu)(zu)永久性損(sun)壞或(huo)爆炸。為防止以上情況發生(sheng)，需(xu)要對電(dian)(dian)池組(zu)(zu)溫度進行(xing)實時(shi)監測并進行(xing)散熱處(chu)理。

采用(yong)熱(re)(re)敏(min)(min)電阻(zu)作(zuo)為溫度(du)(du)傳(chuan)感器(qi)進行溫度(du)(du)采樣。熱(re)(re)敏(min)(min)電阻(zu)是一(yi)種熱(re)(re)敏(min)(min)性半導體(ti)電阻(zu)器(qi)，其電阻(zu)值隨著溫度(du)(du)的升高而下(xia)降(jiang)。電阻(zu)溫度(du)(du)特性可(ke)以(yi)近似(si)地(di)用(yong)下(xia)式(shi)來表示：

3、電池(chi)保護(hu)板的均衡模(mo)塊

電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)常用的均(jun)衡(heng)(heng)方法(fa)有(you)(you)分流法(fa)、飛速電(dian)(dian)(dian)(dian)(dian)(dian)容均(jun)衡(heng)(heng)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)法(fa)、電(dian)(dian)(dian)(dian)(dian)(dian)感能量傳(chuan)遞方法(fa)等。在(zai)本系(xi)統中，需要較多(duo)的I/O口驅(qu)動(dong)開(kai)(kai)關(guan)(guan)管(guan)，而單(dan)片機(ji)的I/O口有(you)(you)限，所以(yi)采取整(zheng)充(chong)轉單(dan)充(chong)的充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)均(jun)衡(heng)(heng)方法(fa)。原理圖如圖3所示。Q4是控制電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)整(zheng)充(chong)的開(kai)(kai)關(guan)(guan)，Q2、Q3、Q5是控制單(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)的開(kai)(kai)關(guan)(guan)。以(yi)10節(jie)(jie)錳酸(suan)鋰電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組(zu)為例，變壓(ya)(ya)器主線(xian)圈兩(liang)端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為42V，副線(xian)圈電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)4.2V。剛(gang)開(kai)(kai)始Q4導通，Q2、Q3、Q5截止(zhi)，單(dan)節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)不斷升(sheng)高，當檢測到某一節(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)達(da)到額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)4.2V以(yi)后(hou)，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)檢測芯(xin)片發出驅(qu)動(dong)信號，關(guan)(guan)閉Q4，打開(kai)(kai)Q2、Q3、Q5，整(zheng)個系(xi)統進入單(dan)充(chong)階段，未(wei)充(chong)滿的電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)繼續充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，以(yi)達(da)到額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)保(bao)持(chi)額(e)定電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)不變。經測試(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)差值(zhi)不會超過50mV。

2SOC電量檢測

在(zai)鋰離子(zi)電池管(guan)理系統中，常用的SOC計(ji)算方(fang)法(fa)有開(kai)路(lu)電壓法(fa)、庫倫計(ji)算法(fa)、阻抗(kang)測量法(fa)、綜合查(cha)表法(fa)。

(1)開(kai)路電(dian)(dian)(dian)壓(ya)(ya)(ya)法是最簡單(dan)的(de)測量方法，主要根據電(dian)(dian)(dian)池開(kai)路電(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)大小判斷SOC的(de)大小。由(you)電(dian)(dian)(dian)池的(de)工(gong)作特性可知，電(dian)(dian)(dian)池的(de)開(kai)路電(dian)(dian)(dian)壓(ya)(ya)(ya)與(yu)電(dian)(dian)(dian)池的(de)剩余容量存在著一(yi)定的(de)對應關系。

(2)庫侖計(ji)算(suan)法是通(tong)過(guo)測量(liang)電(dian)(dian)池(chi)的(de)(de)充電(dian)(dian)和放(fang)電(dian)(dian)電(dian)(dian)流(liu)，將電(dian)(dian)流(liu)值與時間值的(de)(de)乘積進行積分后(hou)計(ji)算(suan)得(de)到(dao)電(dian)(dian)池(chi)充進的(de)(de)電(dian)(dian)量(liang)和放(fang)出的(de)(de)電(dian)(dian)量(liang)，并以(yi)此來估(gu)計(ji)SOC的(de)(de)值。

(3)阻(zu)抗測量法是(shi)利(li)用電(dian)(dian)池(chi)的內阻(zu)和荷電(dian)(dian)狀態SOC之間(jian)一定的線性關(guan)系，通過測出電(dian)(dian)池(chi)的電(dian)(dian)壓、電(dian)(dian)流(liu)參數計(ji)算出電(dian)(dian)池(chi)的內阻(zu)，從而得到SOC的估計(ji)值。

(4)綜合查表(biao)(biao)法中電(dian)池的剩余容(rong)量SOC與(yu)電(dian)池的電(dian)壓、電(dian)流、溫(wen)度等參數是(shi)密(mi)切相關的。通(tong)過設(she)置一個(ge)相關表(biao)(biao)，輸入電(dian)壓、電(dian)流、溫(wen)度等參數就可以查詢(xun)得到(dao)電(dian)池的剩余容(rong)量值(zhi)。

電池保護板從電路的(de)集成度、成本、所選(xuan)MCU的(de)性能(neng)方(fang)面考慮，采用了(le)軟件編程的(de)方(fang)法。智能(neng)邏輯(ji)的(de)編程設定，能(neng)夠很好地做(zuo)到(dao)預防電池保護板爆炸的(de)事(shi)故。