電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組制造商來(lai)說，針對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)系(xi)(xi)(xi)統(tong)構(gou)建安全且可靠的(de)(de)(de)產品是至(zhi)關(guan)重要的(de)(de)(de)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)包(bao)(bao)中的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)管(guan)理電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)可以(yi)監(jian)控鋰離子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)運行狀態(tai)，包(bao)(bao)括了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)阻抗、溫度(du)(du)、單(dan)(dan)(dan)元電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)、充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)和放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)以(yi)及充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)等，以(yi)為系(xi)(xi)(xi)統(tong)提供(gong)詳細的(de)(de)(de)剩余運轉時間(jian)和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)健(jian)康狀況信息，確保(bao)系(xi)(xi)(xi)統(tong)作出正(zheng)確的(de)(de)(de)決策。此外，為了改進(jin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)安全性能，即使只有一種(zhong)故障(zhang)發生(sheng)，例如過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)、短路(lu)、單(dan)(dan)(dan)元和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)包(bao)(bao)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)過高(gao)、溫度(du)(du)過高(gao)等，系(xi)(xi)(xi)統(tong)也會關(guan)閉兩個和鋰離子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)串聯的(de)(de)(de)背靠背（back-to-back）保(bao)護MOSFET，將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)單(dan)(dan)(dan)元斷開(kai)。基于(yu)阻抗跟(gen)蹤技(ji)術(shu)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)管(guan)理單(dan)(dan)(dan)元（BMS）會在整個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)使用周期內監(jian)控單(dan)(dan)(dan)元阻抗和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)失衡，并有可能檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)微小短路(lu)（micro-short），防止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)單(dan)(dan)(dan)元造成火災乃至(zhi)爆炸。

鋰離子電池安全

       過高的工作溫度將加速電池的老化，并可能導致鋰離子電池包的熱失控（thermal run-away）及爆炸。對于鋰離子電池高度活性化的含能材料來說，這一點是備受關注的。大電流的過度充電及短路都有可能造成電池溫度的快速上升。鋰離子電池過(guo)度(du)充(chong)電(dian)期(qi)間(jian)，活躍得金屬鋰(li)沉積在(zai)(zai)電(dian)池(chi)的正極(ji)，其材(cai)料極(ji)大的增(zeng)加了(le)爆炸的危險性，因為(wei)鋰(li)將有(you)可能(neng)與(yu)多種材(cai)料起反應而(er)爆炸，包括了(le)電(dian)解液及陰(yin)極(ji)材(cai)料。例如，鋰(li)/碳插層混合(he)物(wu)（intercalated compound）與(yu)水發生(sheng)反應，并釋放出氫(qing)氣(qi)，氫(qing)氣(qi)有(you)可能(neng)被反應放熱所引燃。陰(yin)極(ji)材(cai)料，諸(zhu)如LiCoO2，在(zai)(zai)溫(wen)度(du)超過(guo)175℃的熱失控溫(wen)度(du)限（4.3V單元(yuan)電(dian)壓）時，也將開始與(yu)電(dian)解液發生(sheng)反應。

      鋰離(li)子(zi)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)使(shi)(shi)(shi)用很薄的(de)(de)(de)微(wei)(wei)(wei)孔膜(mo)（micro-porous film）材(cai)料，例如聚烯烴(jing)(jing)，進行電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)正負極(ji)(ji)的(de)(de)(de)電(dian)(dian)(dian)(dian)子(zi)隔離(li)，因為(wei)(wei)此類材(cai)料具有卓(zhuo)越的(de)(de)(de)力學性能(neng)、化學穩定(ding)性以及(ji)可(ke)接受的(de)(de)(de)價格。聚烯烴(jing)(jing)的(de)(de)(de)熔(rong)點(dian)范圍較低，為(wei)(wei)135℃至 165℃，使(shi)(shi)(shi)得(de)聚烯烴(jing)(jing)適用于作(zuo)為(wei)(wei)熱保險（fuse）材(cai)料。隨著(zhu)溫(wen)度的(de)(de)(de)升(sheng)高并達到聚合體(ti)的(de)(de)(de)熔(rong)點(dian)，材(cai)料的(de)(de)(de)多孔性將失(shi)效，其目的(de)(de)(de)是使(shi)(shi)(shi)得(de)鋰離(li)子(zi)無(wu)法(fa)在(zai)電(dian)(dian)(dian)(dian)極(ji)(ji)之(zhi)間(jian)(jian)流(liu)動，從而(er)(er)關(guan)斷電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)。同時，熱敏陶瓷（PCT）設備(bei)以及(ji)安全排出口（safety vent）為(wei)(wei)鋰離(li)子(zi)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)提供(gong)了額外的(de)(de)(de)保護。電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)外殼(ke)，一般作(zuo)為(wei)(wei)負極(ji)(ji)接線端，通常為(wei)(wei)典型的(de)(de)(de)鍍鎳金屬板。在(zai)殼(ke)體(ti)密封的(de)(de)(de)情況下(xia)，金屬微(wei)(wei)(wei)粒將可(ke)能(neng)污染電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)內部。隨著(zhu)時間(jian)(jian)的(de)(de)(de)推移(yi)，微(wei)(wei)(wei)粒有可(ke)能(neng)遷移(yi)至隔離(li)器，并使(shi)(shi)(shi)得(de)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)陽極(ji)(ji)與(yu)陰極(ji)(ji)之(zhi)間(jian)(jian)的(de)(de)(de)絕(jue)(jue)緣層(ceng)老化。而(er)(er)陽極(ji)(ji)與(yu)陰極(ji)(ji)之(zhi)間(jian)(jian)的(de)(de)(de)微(wei)(wei)(wei)小短(duan)路(lu)將允許電(dian)(dian)(dian)(dian)子(zi)肆意的(de)(de)(de)流(liu)動，并最終使(shi)(shi)(shi)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)失(shi)效。絕(jue)(jue)大多數情況下(xia)，此類失(shi)效等同于電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)無(wu)法(fa)供(gong)電(dian)(dian)(dian)(dian)且功(gong)能(neng)完全終止。在(zai)少數情況下(xia)，電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)有可(ke)能(neng)過(guo)熱、熔(rong)斷、著(zhu)火乃至爆炸。這就是近期所報道(dao)的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)(chi)(chi)故障的(de)(de)(de)主要根源，并使(shi)(shi)(shi)得(de)眾多的(de)(de)(de)廠商不得(de)不將其產品召(zhao)回。

電池管理單元（BMS）以及電池保護

      電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)材料(liao)的(de)不(bu)斷(duan)開發提(ti)升(sheng)了熱失(shi)控的(de)上限溫度。另(ling)一方面，雖然(ran)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)必須通過(guo)(guo)嚴(yan)格(ge)的(de)UL安(an)全(quan)測試，例如(ru)UL1642，但提(ti)供正確的(de)充電(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)并(bing)很好的(de)應對多種(zhong)有可能(neng)出現的(de)電(dian)(dian)(dian)(dian)(dian)(dian)子原(yuan)件故(gu)(gu)(gu)障仍(reng)然(ran)是系(xi)統(tong)設計人員的(de)職責所在。過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓、過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)、短路、過(guo)(guo)熱狀態(tai)以及外部分立元件的(de)故(gu)(gu)(gu)障都有可能(neng)引起(qi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)突變(bian)的(de)失(shi)效。這就意味著需要采取多重的(de)保護(hu)――在同(tong)一電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)包內具有至少兩個獨(du)立的(de)保護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)路或(huo)機制。同(tong)時，還希(xi)望具備用于檢(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)內部微小短路的(de)電(dian)(dian)(dian)(dian)(dian)(dian)子電(dian)(dian)(dian)(dian)(dian)(dian)路以避免(mian)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)故(gu)(gu)(gu)障。

     電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)計電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路設計用(yong)于精確的(de)(de)指示可用(yong)的(de)(de)鋰(li)離子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)。該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路獨特的(de)(de)算法允(yun)許(xu)實時(shi)(shi)的(de)(de)追蹤電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)包(bao)的(de)(de)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)變化(hua)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)阻抗、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流、溫度以(yi)及(ji)其它電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路信(xin)息。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)計自(zi)動的(de)(de)計算充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)及(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)速率、自(zi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)以(yi)及(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)單(dan)(dan)元老(lao)化(hua)，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)使用(yong)壽命(ming)期限內(nei)(nei)實現了高精度的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)計量(liang)。例(li)如(ru)，一系列(lie)專利的(de)(de)阻抗追蹤電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)計，包(bao)括(kuo)bq20z70，bq20z80以(yi)及(ji)bq20z90，均可在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)壽命(ming)期限內(nei)(nei)提供高達(da)1%精度的(de)(de)計量(liang)。單(dan)(dan)個熱(re)敏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻被用(yong)于監測鋰(li)離子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)溫度，以(yi)實現電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)單(dan)(dan)元的(de)(de)過熱(re)保護，并用(yong)于充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)及(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)限定。例(li)如(ru)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)單(dan)(dan)元一般不允(yun)許(xu)在(zai)(zai)低(di)于0℃或(huo)(huo)高于45℃的(de)(de)溫度范圍內(nei)(nei)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，且(qie)不允(yun)許(xu)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)單(dan)(dan)元溫度高于65℃時(shi)(shi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。如(ru)檢測到(dao)過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓、過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流或(huo)(huo)過熱(re)狀態，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)計IC將(jiang)指令(ling)控制(zhi)AFE關(guan)閉(bi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)及(ji)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)MOSFET Q1及(ji)Q2。當(dang)檢測到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)欠壓（under-voltage）狀態時(shi)(shi)，則將(jiang)指令(ling)控制(zhi)AFE關(guan)閉(bi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)MOSFET Q2，且(qie)同時(shi)(shi)保持充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)MOSFET開啟(qi)，以(yi)允(yun)許(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

     AFE的(de)(de)主(zhu)要任務(wu)是(shi)對過(guo)(guo)(guo)(guo)載(zai)、短路(lu)的(de)(de)檢(jian)測(ce)，并保護(hu)充電(dian)(dian)(dian)(dian)(dian)及放電(dian)(dian)(dian)(dian)(dian)MOSFET、電(dian)(dian)(dian)(dian)(dian)池單(dan)元以及其它線路(lu)上的(de)(de)元件(jian)，避(bi)免過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流狀態(tai)。過(guo)(guo)(guo)(guo)載(zai)檢(jian)測(ce)用于檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)池放電(dian)(dian)(dian)(dian)(dian)流向上的(de)(de)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流（OC），同時，短路(lu)（SC）檢(jian)測(ce)用于檢(jian)測(ce)充電(dian)(dian)(dian)(dian)(dian)及放電(dian)(dian)(dian)(dian)(dian)流向上的(de)(de)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)流。AFE電(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)過(guo)(guo)(guo)(guo)載(zai)和短路(lu)限定(ding)以及延遲時間均(jun)可(ke)通(tong)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)量計數據閃(shan)存編程設定(ding)。當檢(jian)測(ce)到(dao)過(guo)(guo)(guo)(guo)載(zai)或(huo)短路(lu)狀態(tai)，且達到(dao)了(le)程序設定(ding)的(de)(de)延遲時間，則充電(dian)(dian)(dian)(dian)(dian)及放電(dian)(dian)(dian)(dian)(dian)MOSFET Q1及Q2將被關閉，詳細的(de)(de)狀態(tai)信息(xi)將存儲于AFE的(de)(de)狀態(tai)寄存器(qi)，從(cong)而電(dian)(dian)(dian)(dian)(dian)量計可(ke)讀取并調查導致(zhi)故障的(de)(de)原因(yin)。

對于計量2、3或4個鋰離子電池包(bao)的(de)(de)(de)電(dian)(dian)(dian)(dian)量計(ji)(ji)芯片集(ji)解(jie)決(jue)方案來說，AFE起了很重要的(de)(de)(de)作用。AFE提供了所(suo)需的(de)(de)(de)所(suo)有高壓接口以及硬件電(dian)(dian)(dian)(dian)流(liu)保(bao)護特性。所(suo)提供的(de)(de)(de)I2C兼容(rong)接口允許電(dian)(dian)(dian)(dian)量計(ji)(ji)訪問AFE寄存器(qi)并配置AFE的(de)(de)(de)保(bao)護特性。AFE還集(ji)成了電(dian)(dian)(dian)(dian)池(chi)單元平(ping)衡(heng)控制。多(duo)數(shu)情況下，在(zai)多(duo)單元電(dian)(dian)(dian)(dian)池(chi)包(bao)中，每個獨立電(dian)(dian)(dian)(dian)池(chi)單元的(de)(de)(de)電(dian)(dian)(dian)(dian)荷狀態(tai)（SOC）彼此不(bu)同，從而(er)導致了不(bu)平(ping)衡(heng)單元間(jian)的(de)(de)(de)電(dian)(dian)(dian)(dian)壓差(cha)別(bie)。AFE針對每一(yi)的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)單元整合了旁(pang)通通路。此類旁(pang)通通路可用于(yu)降低(di)至每一(yi)單元的(de)(de)(de)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)，從而(er)為電(dian)(dian)(dian)(dian)池(chi)單元充電(dian)(dian)(dian)(dian)期間(jian)的(de)(de)(de)SOC平(ping)衡(heng)提供了條件。基于(yu)阻抗追蹤電(dian)(dian)(dian)(dian)量計(ji)(ji)對每一(yi)電(dian)(dian)(dian)(dian)池(chi)單元化學電(dian)(dian)(dian)(dian)荷狀態(tai)的(de)(de)(de)確(que)(que)定，可在(zai)需要單元平(ping)衡(heng)時做(zuo)出正(zheng)確(que)(que)的(de)(de)(de)決(jue)策。

       具(ju)有不同激活時(shi)間的(de)(de)多極(ji)過電流保(bao)護(hu)限（如(ru)圖2所示）使(shi)得(de)電池(chi)(chi)包保(bao)護(hu)更為強健。電量(liang)計具(ju)有兩(liang)層的(de)(de)充電/放(fang)電過電流保(bao)護(hu)設定，而(er)AFE則提(ti)供(gong)了(le)第三層的(de)(de)放(fang)電過電流保(bao)護(hu)。在(zai)短路狀(zhuang)態下，MOSFET及電池(chi)(chi)可能在(zai)數秒(miao)內毀壞，電量(liang)計芯片集完全依靠AFE來自動的(de)(de)關(guan)斷(duan)MOSFET，以免產生毀壞。

當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量計(ji)IC及其所(suo)關聯(lian)的(de)(de)(de)AFE提(ti)供(gong)過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)保(bao)(bao)護時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)監(jian)測(ce)的(de)(de)(de)采樣(yang)特性限制了此類(lei)保(bao)(bao)護系統的(de)(de)(de)響應(ying)(ying)時(shi)(shi)間(jian)。絕大(da)多數應(ying)(ying)用要求能快速響應(ying)(ying)，且實(shi)時(shi)(shi)、獨(du)立(li)的(de)(de)(de)過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)監(jian)測(ce)器(qi)(qi)，并與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量計(ji)、AFE協(xie)同(tong)運作。該監(jian)測(ce)器(qi)(qi)獨(du)立(li)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量計(ji)及AFE，監(jian)測(ce)每一電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)單元(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，并針(zhen)對每一達到(dao)硬(ying)件編碼過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)限的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)單元(yuan)提(ti)供(gong)邏(luo)輯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)平輸出(chu)。過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)保(bao)(bao)護的(de)(de)(de)響應(ying)(ying)時(shi)(shi)間(jian)取(qu)決(jue)于外(wai)部延遲電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)的(de)(de)(de)大(da)小。在典型的(de)(de)(de)應(ying)(ying)用中，秒量級保(bao)(bao)護器(qi)(qi)的(de)(de)(de)輸出(chu)將觸發化學保(bao)(bao)險絲(si)或其它(ta)失效保(bao)(bao)護設備，以(yi)永久(jiu)性的(de)(de)(de)將鋰離子電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)與系統分離。

電(dian)(dian)(dian)(dian)池(chi)包永久性(xing)的(de)(de)(de)失(shi)(shi)效(xiao)保護(hu)對于電(dian)(dian)(dian)(dian)池(chi)管理(li)單元來說(shuo)，很重要(yao)的(de)(de)(de)一點是要(yao)為非(fei)正常(chang)狀(zhuang)(zhuang)態(tai)下的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)包提(ti)供(gong)趨于保守的(de)(de)(de)關斷(duan)。永久性(xing)的(de)(de)(de)失(shi)(shi)效(xiao)保護(hu)包括了過(guo)電(dian)(dian)(dian)(dian)流的(de)(de)(de)放(fang)(fang)電(dian)(dian)(dian)(dian)及(ji)充電(dian)(dian)(dian)(dian)故(gu)障(zhang)狀(zhuang)(zhuang)態(tai)下的(de)(de)(de)安全(quan)、過(guo)熱的(de)(de)(de)放(fang)(fang)電(dian)(dian)(dian)(dian)及(ji)充電(dian)(dian)(dian)(dian)狀(zhuang)(zhuang)態(tai)下的(de)(de)(de)安全(quan)、過(guo)電(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)故(gu)障(zhang)狀(zhuang)(zhuang)態(tai)（峰值電(dian)(dian)(dian)(dian)壓(ya)）以(yi)及(ji)電(dian)(dian)(dian)(dian)池(chi)平衡故(gu)障(zhang)、短(duan)接放(fang)(fang)電(dian)(dian)(dian)(dian)FET故(gu)障(zhang)、充電(dian)(dian)(dian)(dian)MOSFET故(gu)障(zhang)狀(zhuang)(zhuang)態(tai)下的(de)(de)(de)安全(quan)。制造(zao)商(shang)可選擇任意(yi)組合上(shang)述的(de)(de)(de)永久性(xing)失(shi)(shi)效(xiao)保護(hu)。當檢測到任意(yi)的(de)(de)(de)此類故(gu)障(zhang)，則(ze)保護(hu)設(she)備(bei)將(jiang)熔(rong)斷(duan)化學保險絲，以(yi)使(shi)得電(dian)(dian)(dian)(dian)池(chi)包永久性(xing)的(de)(de)(de)失(shi)(shi)效(xiao)。作為電(dian)(dian)(dian)(dian)子(zi)元件故(gu)障(zhang)的(de)(de)(de)外部失(shi)(shi)效(xiao)驗證，電(dian)(dian)(dian)(dian)池(chi)管理(li)單元設(she)計用于檢測充電(dian)(dian)(dian)(dian)及(ji)放(fang)(fang)電(dian)(dian)(dian)(dian)MOSFET Q1及(ji)Q2的(de)(de)(de)失(shi)(shi)效(xiao)與否。如(ru)果(guo)任意(yi)充電(dian)(dian)(dian)(dian)或放(fang)(fang)電(dian)(dian)(dian)(dian)MOSFET短(duan)路，則(ze)化學保險絲也(ye)將(jiang)熔(rong)斷(duan)。

      據報道(dao)，電(dian)池(chi)內(nei)部的(de)(de)(de)微(wei)小(xiao)短(duan)路(lu)(lu)也是導致近(jin)期多起電(dian)池(chi)召回的(de)(de)(de)主要(yao)原因。如(ru)何(he)檢測電(dian)池(chi)內(nei)部的(de)(de)(de)微(wei)小(xiao)短(duan)路(lu)(lu)并防止(zhi)電(dian)池(chi)著火乃(nai)至爆炸(zha)呢(ni)？外殼封閉處理過程中，金屬微(wei)粒及(ji)其它雜質有可(ke)能污(wu)染(ran)電(dian)池(chi)內(nei)部，從而(er)引起電(dian)池(chi)內(nei)部的(de)(de)(de)微(wei)小(xiao)短(duan)路(lu)(lu)。內(nei)部的(de)(de)(de)微(wei)小(xiao)短(duan)路(lu)(lu)將(jiang)極大地增(zeng)加電(dian)池(chi)的(de)(de)(de)自放(fang)電(dian)速率，使得開路(lu)(lu)電(dian)壓較之正常狀態下的(de)(de)(de)電(dian)池(chi)單元有所降(jiang)低。阻抗追蹤電(dian)量計(ji)監測開路(lu)(lu)電(dian)壓，并從而(er)檢測電(dian)池(chi)單元的(de)(de)(de)非均衡性――當(dang)不同電(dian)池(chi)單元的(de)(de)(de)開路(lu)(lu)電(dian)壓差異(yi)超過預先設置(zhi)的(de)(de)(de)限定值。當(dang)出(chu)現此類失效(xiao)(xiao)時(shi)，將(jiang)產生永久性失效(xiao)(xiao)的(de)(de)(de)告警并斷(duan)開MOSFET，化學保險(xian)絲也可(ke)配置(zhi)為(wei)熔(rong)斷(duan)。上述(shu)行為(wei)將(jiang)使得電(dian)池(chi)包無法作為(wei)供(gong)電(dian)源并因此屏蔽了電(dian)池(chi)包內(nei)部的(de)(de)(de)微(wei)小(xiao)短(duan)路(lu)(lu)電(dian)池(chi)單元，從而(er)防止(zhi)了災害(hai)的(de)(de)(de)發生。

小結

電池管理單元(yuan)對于確(que)保(bao)終端用戶(hu)的安全(quan)性是至關重要的。強健的多極保(bao)護――過(guo)電壓(ya)、過(guo)電流(liu)、過(guo)熱、電池單元(yuan)非均衡以(yi)及MOSFET失效監測(ce)，極大地改善了電池包的安全(quan)性。通過(guo)監測(ce)電池單元(yuan)的開環電壓(ya)，阻抗追蹤技術可檢測(ce)電池內部的微小短路，并進而永久性的失效電池，確(que)保(bao)了終端用戶(hu)的安全(quan)。