可以說鋰電池的IC是電池的守護神；近年來越來越多的產品急速的采用鋰電池來當做它的主要電源，不外乎其：體積小、能量密度高、無記憶效應、循環壽命高、高電壓電池、自放電率低，等優點，也因為與鎳鎘、鎳氫電池不太一樣，所以必須考慮充電、放電時之安全，確保特性劣化的防止，但也因為如此，針對鋰電池的過充，過放，過電流及短路電流的保護更顯得重要，所以通常都會在電池包內設計保護線路用以保護鋰電池，由此可見鋰電池保護IC的重要性。鋰離子電池因能量密度高，使得難以確保電池的安全性。具體而言，在過度充電狀態下，電池溫度上升后能量將過剩，于是電解液分解(jie)而產(chan)生氣體，因內壓(ya)上升而導致(zhi)有(you)發火或破裂的危機。反(fan)之，在過(guo)度放(fang)電狀態(tai)下，電解(jie)液因分解(jie)導致(zhi)電池特性劣(lie)化及耐(nai)久性劣(lie)化（即(ji)充電次數(shu)降低）。

鋰離子電(dian)池的(de)保護(hu)電(dian)路就是要確保這樣(yang)的(de)過度充電(dian)及放電(dian)狀態(tai)時的(de)安(an)全性，并防止(zhi)特性的(de)劣(lie)化。

對鋰電池保護板IC性能的要求

①過度充電(dian)保護的高精度化

當鋰(li)離子(zi)電(dian)(dian)池(chi)有(you)(you)(you)過(guo)度(du)(du)(du)充(chong)電(dian)(dian)狀(zhuang)態(tai)時(shi)，為防止因(yin)溫度(du)(du)(du)上升(sheng)所(suo)導致的內壓上升(sheng)，須(xu)截止充(chong)電(dian)(dian)狀(zhuang)態(tai).保護(hu)IC將檢測(ce)(ce)電(dian)(dian)池(chi)電(dian)(dian)壓，當檢測(ce)(ce)到(dao)過(guo)度(du)(du)(du)充(chong)電(dian)(dian)時(shi)，則過(guo)度(du)(du)(du)充(chong)電(dian)(dian)檢測(ce)(ce)的功率(lv)MOSFET使(shi)之關斷而截止充(chong)電(dian)(dian).此(ci)時(shi)應注意的是(shi)過(guo)度(du)(du)(du)充(chong)電(dian)(dian)的檢測(ce)(ce)電(dian)(dian)壓的高精度(du)(du)(du)化(hua)，在(zai)電(dian)(dian)池(chi)充(chong)電(dian)(dian)時(shi)，使(shi)電(dian)(dian)池(chi)充(chong)電(dian)(dian)到(dao)飽滿的狀(zhuang)態(tai)是(shi)使(shi)用者很關心(xin)的問題，同(tong)時(shi)兼顧到(dao)安全性問題，因(yin)此(ci)需要在(zai)達(da)到(dao)容許電(dian)(dian)壓時(shi)截止充(chong)電(dian)(dian)狀(zhuang)態(tai).要同(tong)時(shi)符合這兩(liang)個(ge)條件，必(bi)須(xu)有(you)(you)(you)高精度(du)(du)(du)的檢測(ce)(ce)器，目前(qian)檢測(ce)(ce)器的精度(du)(du)(du)為25mv，該精度(du)(du)(du)將有(you)(you)(you)待于進(jin)一步提高.

②降低(di)保護IC的耗(hao)電

隨(sui)著使(shi)用時間的(de)增加，已充(chong)過(guo)電(dian)(dian)(dian)(dian)(dian)的(de)鋰離子電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)會逐漸(jian)降低(di)，最(zui)(zui)后低(di)到規格(ge)標(biao)準值以下(xia)，此時就(jiu)需(xu)要再(zai)度(du)(du)充(chong)電(dian)(dian)(dian)(dian)(dian).若未充(chong)電(dian)(dian)(dian)(dian)(dian)而繼續(xu)使(shi)用，可能(neng)(neng)造成由于過(guo)度(du)(du)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)而使(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)不能(neng)(neng)繼續(xu)使(shi)用.為防止過(guo)度(du)(du)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)，保護(hu)IC必須(xu)檢(jian)(jian)測電(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)，一(yi)旦達(da)到過(guo)度(du)(du)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)檢(jian)(jian)測電(dian)(dian)(dian)(dian)(dian)壓(ya)以下(xia)，就(jiu)得使(shi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)一(yi)方的(de)功率MOSFET關斷(duan)而截(jie)止放(fang)(fang)電(dian)(dian)(dian)(dian)(dian).但此時電(dian)(dian)(dian)(dian)(dian)池(chi)本身仍有自然放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)及保護(hu)IC的(de)消耗電(dian)(dian)(dian)(dian)(dian)流(liu)存在(zai)，因此需(xu)要使(shi)保護(hu)IC消耗的(de)電(dian)(dian)(dian)(dian)(dian)流(liu)降到最(zui)(zui)低(di)程度(du)(du).

③過(guo)電(dian)(dian)流(liu)(liu)/短(duan)路保護(hu)需有低(di)檢測(ce)電(dian)(dian)壓(ya)(ya)及高精(jing)度(du)的要求因(yin)不明(ming)原(yuan)因(yin)導致短(duan)路時必須立即(ji)停止(zhi)放(fang)電(dian)(dian).過(guo)電(dian)(dian)流(liu)(liu)的檢測(ce)是以功率(lv)MOSFET的Rds（on）為感應阻抗，以監(jian)視其電(dian)(dian)壓(ya)(ya)的下(xia)降，此時的電(dian)(dian)壓(ya)(ya)若比過(guo)電(dian)(dian)流(liu)(liu)檢測(ce)電(dian)(dian)壓(ya)(ya)還高時即(ji)停止(zhi)放(fang)電(dian)(dian).為了使功率(lv)MOSFET的Rds（on）在充電(dian)(dian)電(dian)(dian)流(liu)(liu)與放(fang)電(dian)(dian)電(dian)(dian)流(liu)(liu)時有效應用(yong)，需使該阻抗值盡(jin)量(liang)低(di)，目前該阻抗約為20mQ~30mQ，這樣過(guo)電(dian)(dian)流(liu)(liu)檢測(ce)電(dian)(dian)壓(ya)(ya)就可較低(di)。④耐高電(dian)(dian)壓(ya)(ya)

電池包(bao)與(yu)充電器連(lian)接時瞬間會(hui)有高壓(ya)產生，因此保護(hu)IC應滿足耐(nai)高壓(ya)的要(yao)求.

⑤低電池功耗

在保護狀態時，其靜態耗電(dian)流必須要小0.luA.

⑥零伏可充電

有些電(dian)池在存(cun)放(fang)(fang)的(de)過程(cheng)中可(ke)能因(yin)為放(fang)(fang)太久或不正(zheng)常的(de)原(yuan)因(yin)導致電(dian)壓低到0V，故保護IC需(xu)要在0V時也可(ke)以實現充電(dian).