491825 低容失效分析

ATLConfidential491825LowCapacityFA背景&原因调查2491825的从2月中下旬开始连续容量抽检不通过，对比之前的抽检通过率~80%而言非常异常。分析容量分布，发现呈双峰。主峰Mean~213.5mAh，属于正常；小峰Mean~206mAh，属于异常。3By膜卷分析发现低容量主要来自S2215012100072、S2215020300070。其中S2215012100072更异常。Mean偏小，且呈双峰背景&原因调查4受这两个膜卷（~230K电芯）的影响，491825的容量Mean在2月份一直下降，到了3月初已经降到Mean~210mAh。Mean~210mAh背景&原因调查5将容量与注液前的重量做相关，发现容量与重量呈很好的相关。参考2014年12月份Minicell阴极重量偏轻导致低容量的经验，初步判定此次低容量仍然阴极重量偏轻有关。此处异常点是称重异常背景&原因调查阴极涂膜工序极片留样分析_称小圆片重量6将阴极涂膜工序极片留样用小冲头（面积154.025mm^2）冲小圆片称重，发现：边料偏轻~10mg(单面)/20mg（双面）头部削薄区偏轻~15mg(单面)/30mg（双面），尾部削薄区正常。单面双面重轻阴极涂膜工序极片留样分析_估算容量7根据冲小圆片称重计算理论容量值：整体容量值比设计值偏小~1mAh边料最边上一条容量值偏低较多，~8mAh，倒数第二条容量值偏低~2.5mAh。

12345678910111213单面A332338341339343342346347345347345345333B347352353356362356355356355357359354345C347350353357355354355358361356358353347D345355356355355362358357357360354356344

E350355359357358360359357358354354356348双面A617641632639633635641637643644646640621B639661658660661659662663662661666649645C632655658657660658656657656660663652633D653662659661660659658658661660661650634

E640650665660659661662663659661663655633小条重量设计值1.3811.3811.3811.3811.3811.3811.3811.3811.3811.3811.3811.3811.381实际值1.3331.3761.3811.3811.3851.3811.3821.3831.3831.3881.3941.3701.330

实际值(扣除小冲头误差)1.3251.3681.3721.3731.3761.3731.3741.3751.3741.3791.3851.3621.322容量设计值214.4214.4214.4214.4214.4214.4214.4214.4214.4214.4214.4214.4214.4实际值206.9213.6214.3214.3214.9214.4214.5214.7214.6215.4216.3212.7206.4

实际值(扣除小冲头误差)205.6212.3213.0213.0213.6213.1213.2213.4213.3214.1215.0211.4205.1Conclusion&Correctiveaction8Conclusion491825容量低异常是阴极极片偏轻导致。阴极极片重量偏轻是边料和削薄。Correctiveaction切入小冲模监控涂膜边料------------------------------------------------------------------------------ME/PRJ2/10/2015Done小冲模的误差问题继续研究---------------------------------------------------------------------------ME/PRJ4/7/2015Update涂膜边料偏轻的分析和改善---------------------------------------------------------------------------ME/PRJ4/7/2015Update削薄区的控制,如何避免削过头-----------------------------------------------------------------------ME/PRJ4/7/2015UpdateAppendix_小冲头误差9大圆小圆1小圆2小圆3小圆4组别大圆小圆1小圆2小圆3小圆4小圆平均大圆/10小圆-大圆误差%A0.70000.07010.07020.07040.07080.07040.07000.00040.56%B0.70120.07030.07040.07050.07080.07050.07010.0004C0.70220.07090.07030.07070.07070.07070.07020.0004D0.70290.07050.07080.07030.07030.07050.07