锂离子电池放电截至电压对循环容量衰减影响  

Discharge Cutoff Voltage Impact on Cycle Fading of Lithium Ion Battery

作　　者：王辰云 Wang Chenyun(Amperex Technology Limited,Ningde 352100,China)

机构地区：[1]宁德新能源科技有限公司,福建宁德352100

出　　处：《广东化工》2022年第22期271-274,267,共5页Guangdong Chemical Industry

摘　　要：测试循环放电截至电压在2.70~3.20 V电压范围内的锂离子电池容量衰减,界定了比较合理的放电截至电压窗口为≥2.85 V。把完成1000次循环后的电池进行拆解,用其正极极片和负极极片分别制作了扣式半电池及极片样品,对扣式半电池进行克容量测试和循环伏安(CV)测试可逆性,对极片涂层材料进行ICP,SEM,EDS,XRD,Raman等形貌、结构、组分分析,发现影响电池循环容量衰减的主要因素是正极材料钴酸锂的活性锂离子在负极端的持续损失,表现为钴酸锂生成不可逆的CoO和Co_(3)O_(4)所致。钴酸锂损失的活性锂离子一部分用于修复负极表面的SEI膜变成死锂;一部分沉积在涂层颗粒间隙或石墨晶格层间中,没有再脱出嵌回钴酸锂发挥容量。Checked the different cycle capacity fading in the discharge cutoff voltage range from 2.70 V to 3.20 V,and defined the reasonable window of cutoff voltage for no less than 3.85 V.Teared down the cells after 1000 cycles,built coin cells using the electrodes from cells and Lithium metal plate.Based on the capacity check and CV test of coin cells,and combined with result of ICP,SEM,EDS,XRD,and Raman,it was confirmed that the most of capacity fading of cells come from the active Li+loss of LiCoO_(2)during cycling,which produced some Co_(3)O_(4) and CoO and then lead to LiCoO_(2)capacity fading.A part of the lost Li+dead on renewing the SEI of the anode layer surface,and other part of the lost Li+was retained in the graphite particle gaps or the graphite crystal layers.

关 键 词：锂离子电池 放电截止电压 容量衰减 循环寿命 钴酸锂 

分 类 号：TQ[化学工程]