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高比能量锂离子电池的全周期安全性

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高比能量锂离子动力电池及安全性一直是研究的重点.以高镍三元材料LiNi0.8Co0.1Mn0.1O2(NCM811)为正极活性物质、石墨复合硅氧材料为负极活性物质,制备 300 W·h/kg的动力锂离子电池,研究电池从制成到循环衰减至容量保持率为 75%的全周期安全性变化.通过加热测试,评价热稳定性变化,通过针刺测试,评价内短路耐受性的变化,并通过差示扫描量热(DSC)、SEM、四探针测试,分析安全性能变化的机制.电池在容量保持率 100%(循环前)、80%、75%时的热失控温度分别为 167℃、161℃和143℃,针刺热失控深度分别为1.99 mm、2.52 mm和3.54 mm.随着循环的进行,硅氧负极的固体电解质相界面(SEI)膜持续大幅增加,导致热稳定性下降,内短路耐受性提高.电解液的减少,导致电池生命后期的热失控放热量下降.
The full cycle safety of high specific energy Li-ion battery
The high-specific energy Li-ion power battery and the safety have always been the focus of research.A 300 W·h/kg power Li-ion battery is prepared using high-nickel ternary materials LiNi0.8 Co0.1 Mn0.1 O2(NCM811)as the cathode active material and graphite-SiOx material as the anode active material,the full cycle safety changes of the batteries are analyzed from production to cycle decay to the capacity retention of 75%.The changes of thermal stability are evaluated by heating tests,the changes in internal short-circuit tolerance are evaluated by nail penetration tests.The mechanism of safety performance changes is analyzed by differential scanning calorimeter(DSC),SEM and four-probe testing.The thermal runaway temperatures of the batteries at 100%(before cycling),80%and 75%capacity retention are 167℃,161℃and 143℃,respectively.The penetration depths while thermal runaway are 1.99 mm,2.52 mm and 3.54 mm,respectively.As the cycles continue,the solid electrolyte interphase(SEI)film on the SiOx anode continues to increase significantly,leading to a decrease in thermal stability and an improvement in its internal short-circuit tolerance.The reduction of electrolytes leads to the decrease of thermal runaway heat release in the later stage of battery life.

Li-ion batterynickel-rich cathodeSiOx anodefull cycle safetythermal stabilityinternal short-circuit resistance

张越超、高金津、高秀玲、马华

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天津市捷威动力工业有限公司,天津 300380

锂离子电池 高镍正极 硅氧负极 全周期安全性 热稳定性 内短路耐受性

2024

电池
全国电池工业信息中心 湖南轻工研究院

电池

CSTPCD北大核心
影响因子:0.336
ISSN:1001-1579
年,卷(期):2024.54(5)