容量是衡量電池質量的重要因素之一，電池低容是樣品、量產中經常遇到的問題。因此尋找分析電池低容是鋰電池生產制造中重要的工作之一。那么鋰電池低容分析方法都有哪些呢？下面我們就一起來學習探討一下吧。

聽到有電芯低容，第一個反應應該是確認低容問題是否屬實。簡單來說，先是要確認分容工藝是否設置錯誤（比如放電電流是不是設置大了、充電時間是不是設置短了）；如果分容工步設置無問題，就需要更換測試點之后對電芯進行重新分容，同時心里默念著“二次分容后一定不要再低容了”。當然對于量產乃至樣品而言，分容柜誤差造成的批量低容的概率很低，一般情況下都是電芯真的有問題了。若復測之后依舊低容，那就可以確認低容問題真的存在了（同時在復測的時候最好留一個心眼：滿充3pcs復測電芯，以備后用）。

確認了(le)(le)低(di)容(rong)存(cun)在之(zhi)(zhi)后，需要(yao)(yao)(yao)進(jin)(jin)一(yi)步確認低(di)容(rong)發生(sheng)的(de)頗度和嚴(yan)重(zhong)度，從整體上(shang)掌握低(di)容(rong)的(de)實際情況(kuang)。樣(yang)品往(wang)往(wang)就是(shi)一(yi)批(pi)，不(bu)(bu)(bu)多說；但量(liang)產(chan)型號(hao)則(ze)存(cun)在“該型號(hao)一(yi)直低(di)容(rong)”及“該型號(hao)偶發低(di)容(rong)”這(zhe)兩(liang)種情況(kuang)。對于(yu)前(qian)者，分析(xi)要(yao)(yao)(yao)以(yi)設計(ji)、選材(cai)角度及量(liang)產(chan)長期遇到(dao)的(de)頑國問(wen)題作為切入點和優(you)先考慮方向（例(li)如是(shi)不(bu)(bu)(bu)是(shi)這(zhe)個材(cai)料匹配是(shi)不(bu)(bu)(bu)曾(ceng)驗證過(guo)(guo)的(de)？是(shi)不(bu)(bu)(bu)是(shi)最近產(chan)線經(jing)常(chang)(chang)出現(xian)同一(yi)個會引(yin)起低(di)容(rong)的(de)異常(chang)(chang)但一(yi)直拖拖拉拉未曾(ceng)解決）；對于(yu)后者，則(ze)需要(yao)(yao)(yao)從產(chan)線操作及工(gong)藝變更來作為優(you)先考慮對象（例(li)如是(shi)不(bu)(bu)(bu)是(shi)這(zhe)一(yi)批(pi)負極(ji)壓死了(le)(le)？是(shi)不(bu)(bu)(bu)是(shi)產(chan)線為了(le)(le)產(chan)量(liang)縮短(duan)了(le)(le)老化時(shi)間？是(shi)不(bu)(bu)(bu)是(shi)工(gong)藝較之(zhi)(zhi)前(qian)進(jin)(jin)行了(le)(le)改變而這(zhe)一(yi)改變有(you)引(yin)發低(di)容(rong)的(de)風險）。頻度確認了(le)(le)之(zhi)(zhi)后，還要(yao)(yao)(yao)確認一(yi)下相(xiang)對不(bu)(bu)(bu)太重(zhong)要(yao)(yao)(yao)的(de)嚴(yan)重(zhong)度，也就是(shi)低(di)容(rong)電芯的(de)比例(li)以(yi)及容(rong)量(liang)低(di)于(yu)要(yao)(yao)(yao)求值的(de)比例(li)。確認嚴(yan)重(zhong)度更大程度上(shang)是(shi)為了(le)(le)可能的(de)放寬(kuan)容(rong)量(liang)規(gui)格及判定缺貨數(shu)量(liang)提供依(yi)據，而對于(yu)問(wen)題本身的(de)分析(xi)，意義沒有(you)確認頻度一(yi)樣(yang)重(zhong)要(yao)(yao)(yao)，不(bu)(bu)(bu)過(guo)(guo)依(yi)舊必不(bu)(bu)(bu)可少(shao)。

整體(ti)上(shang)把(ba)握了低容實際(ji)情況之(zhi)(zhi)后(hou)，就(jiu)要開始分析了。對于(yu)水平較高(gao)且遇到過同樣問(wen)(wen)題的(de)專家(jia)而言(yan)(yan)，拆(chai)3pcs 電(dian)芯(xin)就(jiu)應該可(ke)(ke)以大體(ti)斷(duan)定(ding)低容的(de)實際(ji)原因(yin)(yin)。但對于(yu)一般人而言(yan)(yan)，一是(shi)我們很難有類似的(de)能力(li)及積累，二是(shi)拿三個電(dian)芯(xin)照片(pian)無法充分向上(shang)級和同事說明(ming)問(wen)(wen)題（即使你(ni)的(de)結論是(shi)正確的(de)）。因(yin)(yin)此則需要更為系(xi)統一些的(de)方(fang)法。在系(xi)統的(de)分析之(zhi)(zhi)前，可(ke)(ke)以先將之(zhi)(zhi)前復測滿(man)充的(de)低容電(dian)芯(xin)拆(chai)開看一下界面(mian)，若(ruo)無問(wen)(wen)題，則很可(ke)(ke)能是(shi)正極(ji)涂布偏輕或(huo)設(she)計余量(liang)不足的(de)原因(yin)(yin)；若(ruo)界面(mian)有問(wen)(wen)題，則可(ke)(ke)能是(shi)制程(cheng)中或(huo)設(she)計中方(fang)方(fang)面(mian)面(mian)的(de)問(wen)(wen)題（這不廢(fei)話嘛）。

分(fen)析(xi)開始(shi)了。首(shou)先需要最少(shao)低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)8pcs電(dian)(dian)芯+容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)合(he)(he)格(ge)(ge)(ge)的(de)8pcs電(dian)(dian)芯。低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)電(dian)(dian)芯再隨機分(fen)兩(liang)組(zu)(zu)(zu)(zu)(zu)為(wei)低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)A組(zu)(zu)(zu)(zu)(zu)及低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)B組(zu)(zu)(zu)(zu)(zu)，容(rong)(rong)(rong)(rong)(rong)(rong)量(liang)(liang)合(he)(he)格(ge)(ge)(ge)電(dian)(dian)芯隨機分(fen)兩(liang)組(zu)(zu)(zu)(zu)(zu)為(wei)合(he)(he)格(ge)(ge)(ge)A組(zu)(zu)(zu)(zu)(zu)及合(he)(he)格(ge)(ge)(ge)B組(zu)(zu)(zu)(zu)(zu)。而(er)(er)后(hou)(hou)將兩(liang)個A組(zu)(zu)(zu)(zu)(zu)電(dian)(dian)芯放(fang)電(dian)(dian)至(zhi)靜止電(dian)(dian)壓3.0V左右（文武習慣(guan)于(yu)(yu)0.5C放(fang)電(dian)(dian)至(zhi)3.0V后(hou)(hou)再0.2C放(fang)電(dian)(dian)至(zhi)2.5V；當然(ran)對(dui)象(xiang)是(shi)(shi)鉆酸鋰(li)和(he)三元+石(shi)墨負極(ji)(ji)(ji)(ji)）；而(er)(er)后(hou)(hou)拆解低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)及合(he)(he)格(ge)(ge)(ge)電(dian)(dian)芯，將正(zheng)(zheng)極(ji)(ji)(ji)(ji)片(pian)以(yi)85℃以(yi)上(shang)(shang)的(de)溫度真空烘(hong)(hong)烤24h（具體烘(hong)(hong)烤參(can)數(shu)文武沒有DOE驗(yan)證過不(bu)過可(ke)以(yi)確(que)定給出的(de)參(can)數(shu)是(shi)(shi)可(ke)以(yi)完(wan)成分(fen)析(xi)的(de)），而(er)(er)后(hou)(hou)稱(cheng)量(liang)(liang)低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)正(zheng)(zheng)極(ji)(ji)(ji)(ji)片(pian)與合(he)(he)格(ge)(ge)(ge)正(zheng)(zheng)極(ji)(ji)(ji)(ji)片(pian)的(de)重(zhong)(zhong)(zhong)量(liang)(liang)差(cha)異；若低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)極(ji)(ji)(ji)(ji)片(pian)重(zhong)(zhong)(zhong)量(liang)(liang)明顯低(di)(di)(di)于(yu)(yu)合(he)(he)格(ge)(ge)(ge)正(zheng)(zheng)極(ji)(ji)(ji)(ji)片(pian)或(huo)低(di)(di)(di)于(yu)(yu)工藝范圍，則基本可(ke)以(yi)判斷(duan)低(di)(di)(di)容(rong)(rong)(rong)(rong)(rong)(rong)為(wei)正(zheng)(zheng)極(ji)(ji)(ji)(ji)涂布偏輕(qing)所致。對(dui)于(yu)(yu)烘(hong)(hong)烤后(hou)(hou)稱(cheng)量(liang)(liang)極(ji)(ji)(ji)(ji)片(pian)重(zhong)(zhong)(zhong)量(liang)(liang)文武有兩(liang)點(dian)需要補充：一(yi)是(shi)(shi)雖然(ran)正(zheng)(zheng)極(ji)(ji)(ji)(ji)的(de)首(shou)次不(bu)可(ke)逆(ni)鋰(li)源(yuan)會使正(zheng)(zheng)極(ji)(ji)(ji)(ji)損失一(yi)點(dian)重(zhong)(zhong)(zhong)量(liang)(liang)，但(dan)總不(bu)可(ke)逆(ni)鋰(li)源(yuan)的(de)重(zhong)(zhong)(zhong)量(liang)(liang)僅占正(zheng)(zheng)極(ji)(ji)(ji)(ji)鋰(li)源(yuan)的(de)5%左右、占正(zheng)(zheng)極(ji)(ji)(ji)(ji)片(pian)重(zhong)(zhong)(zhong)量(liang)(liang)的(de)0.5%以(yi)下，即(ji)使再加上(shang)(shang)由(you)析(xi)鋰(li)所造成的(de)不(bu)可(ke)逆(ni)鋰(li)源(yuan)，其引起(qi)的(de)正(zheng)(zheng)極(ji)(ji)(ji)(ji)偏輕(qing)也(ye)(ye)不(bu)會低(di)(di)(di)于(yu)(yu)極(ji)(ji)(ji)(ji)片(pian)總重(zhong)(zhong)(zhong)的(de)1%；電(dian)(dian)解液在烘(hong)(hong)烤過程中不(bu)可(ke)能完(wan)全被(bei)烤干(gan)，但(dan)實際殘留部(bu)分(fen)的(de)重(zhong)(zhong)(zhong)量(liang)(liang)相(xiang)對(dui)極(ji)(ji)(ji)(ji)片(pian)重(zhong)(zhong)(zhong)量(liang)(liang)而(er)(er)言也(ye)(ye)很有限(xian)。總體來說，烘(hong)(hong)烤正(zheng)(zheng)極(ji)(ji)(ji)(ji)后(hou)(hou)稱(cheng)量(liang)(liang)極(ji)(ji)(ji)(ji)片(pian)重(zhong)(zhong)(zhong)量(liang)(liang)與卷繞前極(ji)(ji)(ji)(ji)片(pian)實際重(zhong)(zhong)(zhong)量(liang)(liang)相(xiang)比，誤差(cha)不(bu)會超過2%。

況且有容(rong)量(liang)合(he)(he)格正極(ji)重量(liang)與低(di)容(rong)極(ji)片重量(liang)相對比，此種方(fang)法還是(shi)比較可(ke)信的(de)（另外還聽(ting)說過(guo)(guo)(guo)(guo)可(ke)以通(tong)過(guo)(guo)(guo)(guo)極(ji)片上面擦(ca)拭什么東西(xi)會(hui)更(geng)有助(zhu)于電解液的(de)烤干，其細節及(ji)原理(li)文武(wu)不懂，希望(wang)有知道的(de)朋(peng)友不吝指教）。二是(shi)同樣的(de)方(fang)法不適合(he)(he)于負極(ji)，原因為負極(ji)化成時(shi)會(hui)增加很多的(de)重量(liang)，但可(ke)以通(tong)過(guo)(guo)(guo)(guo)實驗(yan)(yan)給出化成后負極(ji)增重比例(li)進而反推負極(ji)片重量(liang)、判斷低(di)容(rong)是(shi)否為負極(ji)過(guo)(guo)(guo)(guo)量(liang)不足引(yin)起(qi)；但文武(wu)沒有做過(guo)(guo)(guo)(guo)類似實驗(yan)(yan)，有興趣的(de)朋(peng)友可(ke)以自己測試一下。

若確認了(le)(le)正(zheng)極偏輕為低(di)容(rong)的(de)(de)原因的(de)(de)話(hua)則是(shi)萬幸，但實(shi)(shi)際上這萬幸的(de)(de)概率往(wang)往(wang)是(shi)萬一而已。這樣(yang)的(de)(de)話(hua)就(jiu)要(yao)靠對(dui)(dui)低(di)容(rong)B組(zu)(zu)及合格(ge)B組(zu)(zu)的(de)(de)分(fen)析了(le)(le)。B組(zu)(zu)電(dian)(dian)芯(xin)需要(yao)滿充，而后拆解對(dui)(dui)比負(fu)極界(jie)面差異(yi)(yi)。低(di)放電(dian)(dian)容(rong)量低(di)等(deng)價于(yu)低(di)充電(dian)(dian)容(rong)量等(deng)價于(yu)負(fu)極滿充界(jie)面會有異(yi)(yi)常(chang)。其實(shi)(shi)大部分(fen)情況，只(zhi)要(yao)低(di)容(rong)發生了(le)(le)，那(nei)不(bu)論(lun)電(dian)(dian)芯(xin)是(shi)低(di)容(rong)還是(shi)容(rong)量合格(ge)，其界(jie)面都會有類似(si)的(de)(de)異(yi)(yi)常(chang)，只(zhi)是(shi)程(cheng)度不(bu)同(tong)而已。記(ji)錄(lu)電(dian)(dian)芯(xin)界(jie)面情況時，也(ye)需要(yao)同(tong)時記(ji)錄(lu)對(dui)(dui)應電(dian)(dian)芯(xin)實(shi)(shi)際容(rong)量，最(zui)后一般會得到(dao)類似(si)于(yu)低(di)容(rong)程(cheng)度高(gao)的(de)(de)電(dian)(dian)芯(xin)其界(jie)面異(yi)(yi)常(chang)更為嚴重的(de)(de)結論(lun)。