N/P比对铁锂/硅碳体系全电池性能的影响  

Effect of N/P ratio on performance of LFP/Si-C composite system in full-cell batteries

作　　者：郭旺中 于宝军 陈超 GUO Wangzhong;YU Baojun;CHEN Chao(Tianjin Lishen New Energy Technology Co.,Ltd.,Tianjin 300384,China)

机构地区：[1]天津力神新能源科技有限公司,天津300384

出　　处：《电源技术》2025年第4期715-719,共5页Chinese Journal of Power Sources

摘　　要：硅负极因有着极高的比容量而受到广泛关注,在负极中少量添加即可显著提升负极比容量,但是其巨大的体积膨胀会制约其循环寿命。在全电池中,可以通过改变N/P比来调节负极利用率,控制硅负极的嵌锂深度,从而改变电池比能量和循环性能。制作了1.09、1.06和1.03三种N/P比的聚合物软包电池,测试结果表明随着N/P比的降低,负极中硅总量减少,电池质量减轻,使电池的首次效率和比能量升高,但是在长循环测试时,硅负极嵌脱锂深度进行,体积膨胀加剧,最终导致循环寿命缩短。因此,在磷酸铁锂体系中引入硅负极,并设计合适的N/P比,有望以牺牲循环寿命为代价提升铁锂体系比能量至200 Wh/kg。Silicon anodes has attracted widespread attention due to its extremely high specific capacity.Only minor amounts of Si added in the anode can significantly improve batteries specific capacity,but the huge volume expansion will limit its stability.In full-cells,the utilization rate of anode can be adjusted by changing the N/P ratio,and the lithium insertion depth of the silicon anode can be controlled,thereby changing its energy density and cycling performance.In this work,we produced pouch Li-ion batteries with three N/P ratios of 1.09,1.06,and 1.03.As the N/P ratio decreased,the battery quality decreased,the total silicon content decreased,the energy density and initial coulombic efficiency of the battery increased.However,during the cycling process,the lithium insertion and extraction depth of the silicon increased,and the volume expansion intensified,ultimately leading to a shortened cycling life.Therefore,introducing silicon into the LFP system and designing an appropriate N/P ratio is expected to improve the energy density of LFP system to 200 Wh/kg at the cost of cycle life.

关 键 词：硅碳 N/P比 磷酸铁锂 能量密度 循环寿命 

分 类 号：TM912.9[电气工程—电力电子与电力传动]