鋰電池熱失控由于電池的生熱速率遠高于散熱速率，且熱量大量累積而未及時散發出去所引起的。鋰電池熱失控是一個能量正反饋循環過程：升高的溫度會導致系統變熱，系統變熱后溫度升高，又反過來讓系統變得更熱。

過(guo)充(chong)(chong)觸發(fa)鋰電(dian)(dian)池(chi)(chi)熱(re)失(shi)控：電(dian)(dian)池(chi)(chi)本身有(you)過(guo)沖保護，但是當這種過(guo)沖保護出(chu)現(xian)問題失(shi)靈的(de)情況下，電(dian)(dian)池(chi)(chi)還在繼續充(chong)(chong)電(dian)(dian)就(jiu)會導(dao)致電(dian)(dian)池(chi)(chi)過(guo)沖觸發(fa)熱(re)失(shi)控。隨著電(dian)(dian)池(chi)(chi)的(de)不斷(duan)使(shi)用(yong)，電(dian)(dian)池(chi)(chi)的(de)老化現(xian)象逐漸(jian)嚴重，且電(dian)(dian)池(chi)(chi)組的(de)一(yi)致性(xing)越來越差(cha)，此(ci)時的(de)電(dian)(dian)池(chi)(chi)如果(guo)過(guo)充(chong)(chong)極易出(chu)現(xian)熱(re)安全問題。所以任何(he)時候都應(ying)該按使(shi)用(yong)說明(ming)進行安全充(chong)(chong)電(dian)(dian)。

過熱觸發鋰(li)電(dian)(dian)(dian)池熱失控：鋰(li)電(dian)(dian)(dian)池正常使(shi)用中，當電(dian)(dian)(dian)池保(bao)持(chi)高速放(fang)電(dian)(dian)(dian)或遇到(dao)極(ji)(ji)限工況時(shi)，必須持(chi)續(xu)大(da)電(dian)(dian)(dian)流放(fang)電(dian)(dian)(dian)，這時(shi)電(dian)(dian)(dian)池內部的溫度開始慢(man)慢(man)升高，當電(dian)(dian)(dian)池熱量大(da)量積累時(shi)，若不(bu)及時(shi)限制(zhi)其(qi)放(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)流，極(ji)(ji)有(you)可(ke)能造(zao)成鋰(li)電(dian)(dian)(dian)池熱失控現(xian)象(xiang)。

機械觸發鋰電(dian)(dian)池(chi)熱失(shi)控：鋰電(dian)(dian)池(chi)包(bao)(bao)遭遇撞擊變形、電(dian)(dian)池(chi)包(bao)(bao)內部短路(lu)、以及其他(ta)對電(dian)(dian)池(chi)包(bao)(bao)造成損壞(huai)的(de)行為都(dou)有可(ke)能引發電(dian)(dian)池(chi)的(de)熱失(shi)控。

鋰電池(chi)熱失控發生(sheng)的流程：

第(di)1階(jie)段：電(dian)池內部熱失(shi)控階(jie)段

電池在80~90℃時(shi)是(shi)(shi)安全的(de)，溫(wen)(wen)度(du)升(sheng)高(gao)(gao)到(dao)90~120℃之間時(shi)SEI膜開始(shi)分(fen)解，釋放熱量，溫(wen)(wen)度(du)升(sheng)高(gao)(gao)。但(dan)是(shi)(shi)當溫(wen)(wen)度(du)達到(dao)120~130℃時(shi)保護層SEI膜遭到(dao)破(po)壞，負極(ji)與溶(rong)劑(ji)、粘結劑(ji)反應，溫(wen)(wen)度(du)升(sheng)高(gao)(gao)，隔(ge)膜融化關閉(bi)。溫(wen)(wen)度(du)繼續升(sheng)高(gao)(gao)至150℃

之上后，內部電(dian)解質(zhi)開(kai)始進行(xing)分解，繼續釋放熱(re)量，進一步加熱(re)電(dian)池。

第2階(jie)段：電池(chi)鼓(gu)包(bao)階(jie)段

電池(chi)溫(wen)度達(da)到(dao)200℃之(zhi)上時，正極材料(liao)分解，釋放出大量(liang)熱和(he)氣體，持續升(sheng)溫(wen)。250-350℃嵌鋰態(tai)負極開始(shi)與電解液發生反(fan)應。

第3階(jie)段：電(dian)池熱(re)失控，爆(bao)炸失效階(jie)段在反應發(fa)生(sheng)過程中，電(dian)解液與正極(ji)反應產生(sheng)的氧氣劇烈反應并進一步使電(dian)池發(fa)生(sheng)熱(re)失控。

其實一(yi)般鋰電(dian)(dian)池內短(duan)路在電(dian)(dian)子(zi)產品中出(chu)現的(de)(de)概(gai)率(lv)(lv)是千萬(wan)分之一(yi)，也就是說平時(shi)生活中用到的(de)(de)單個電(dian)(dian)池安全性(xing)相對較高。但是在大(da)的(de)(de)鋰電(dian)(dian)池組中，需要幾千個電(dian)(dian)池組成(cheng)，這樣發(fa)(fa)生熱(re)失控的(de)(de)概(gai)率(lv)(lv)就由千萬(wan)分之一(yi)上(shang)升到千分之一(yi)。而且大(da)電(dian)(dian)池一(yi)旦發(fa)(fa)生危險，后果將(jiang)非常(chang)嚴重，所以建議大(da)家要科學使用。