隔膜对LiFePO_4高倍率软包锂离子电池性能的研究

Effect of separators on the performance of high-rate soft-pack lithium-ion battery

影响锂离子电池快速充放电的因素很多,包括电池设计、正负极的尺寸、正负极材料结构、正负极面密度、正负极材料压实、电极表面电阻、电解质传质阻力等。本文研究了隔膜对LiFePO_4锂离子电池高倍率充放电性能影响。选取正极材料D50在(1.0～4.0)μm,比表面积(12～15)m^2/g,负极材料D50在(10.0～18.0)μm,比表面积(1.0～2.5)m^2/g,隔膜为16μm三层共挤时电池具有较好的倍率性能;室温下,在(2.0～3.65)V范围内,30C,40C放电容量分别是1C的91.99%,91.10%。室温下,在(2.0～3.65)V范围内,4C充电,4C放电,循环6145次,容量保持80.79%。

There are many factors affect the rapid charge and discharge of lithium ion batteries,including battery design,the size,material structure,surface density,and material compaction of positive and negative electrodes,electrode surface resistance,electrolyte mass transfer resistance,etc.In this paper,the effect of separator on the high rate charge and discharge performance of LiFePO4 lithium ion battery was studied.The positive electrode material D50 is1.0μm^4.0μm,the specific surface area is 12 m2/g^20 m2/g,the negative electrode material D50 is 10.0μm^18.0μm,the specific surface area is 1.0 m2/g^2.5 m2/g,and when the separator is 16μm three-layer coextrusion,the battery has better rate performance.At room temperature with the voltage range of 2.0 V^3.65 V,30 C,40 Cdischarge capacity retention are91.99%and 91.10%of 1 C.At room temperature with the voltage range of 2.0 V^3.65 V,4 C charge,4 Cdischarge,cycle 6145 times,the capacity retention is maintained at 80.79%.