动力型磷酸铁锂电池关键性能与电解液锂盐浓度的关系

The Relationship between the Key Performances of Power Lithium Iron Phosphate Battery and the Lithium Salt Concentration of Electrolyte

磷酸铁锂电池在动力领域受到广泛的关注,因为极片孔隙率低、厚度厚,电解液中锂盐浓度对电池各关键性能的影响更为显著。本文利用不同锂盐浓度电解液制备高能量密度磷酸铁锂电池,并考察了容量、内阻、倍率、高低温、循环性能。实验表明,1.1~1.2 mol/L的锂盐浓度电解液制备电池,有低温放电性能好、倍率放电性能高、5C放电倍率循环容量保持率高的优势,而0.9~1.0 mol/L的锂盐浓度电解液制备的电池,内阻低、1C充放电循环性能好、高温性能稍优、经济效益高,可用于对循环性能及成本的要求高的电池。

Lithium iron phosphate batteries have attracted extensive attention in the field of electric vehicles. Because of the low porosity and high thickness of the electrode, the lithium salt concentration in the electrolyte has more significant impacts on the key performances of the battery. In this paper, the high energy density lithium iron phosphate battery was prepared by using different salt concentration electrolyte, and the capacity, resistance, rate capability, high-low temperature performance, cycle capacity retention were investigated. The results show that batteies prepared by the electrolyte with 1.1~1.2 mol/L salt concentration has the advantages of high discharge capacity retention under low temperature or high rate, and good cycle performance when using 5C discharge, while the batteries prepared with 0.9~1.0 mol/L lithium salt cncentration electrolyte have the advantages of low resistance, good 1C charge-discharge cycle performance, slightly better high temperature performance and high economic benefit. The electrolyte with 0.9~1.0 mol/L lithium salt cncentration can be used in batteries which are required high cycle performance and cost.