锂离子动力电池内阻模型与实验研究

Lithium ion Power Battery Internal Resistance Model and Its Experiment Study

摘要:

首先，根据多孔电极理论，建立了锂离子动力电池的仿真模型.对仿真模型的分析可知，影响电池内阻的内部因素为锂离子在电极活性材料中的固相扩散系数及由极片的电子电导率、电解液的离子电导率和活性材料的电子电导率组成的电池总电导率.分别设计制作磷酸铁锂和石墨半电池，使用恒电流间歇滴定法(GITT)对半电池进行固相扩散系数的测量.使用交流阻抗法(EIS)对半电池进行总电导率的测量.对比半电池实验数据和磷酸铁锂锂离子动力电池实验数据可知，电池的极化内阻由锂离子在电极活性材料中的固相扩散系数决定；电池的欧姆内阻由电池的总电导率决定.

关键词:锂离子电池; 多孔电极理论; 欧姆内阻; 极化内阻; 电导率; 固相扩散系数

Abstract:

According to the porous electrode theory, a simulation model of lithium ion power batteries is established. The preliminary analysis of the model indicates that the internal factors which affect the battery internal resistance is the solid phase diffusion coefficient of the electrodes and electronic conductivity, ion conductivity and electrodes conductivity of the battery. The Galvanostatic Intermittent Titration Technique (GITT) is applied to a lithium iron phosphate half cell and a graphite half cell for solid phase diffusion coefficient measurement. The Electrochemical Impedance Spectroscopy(EIS) is applied to a lithium iron phosphate half cell and a graphite half cell for electrical conductivity measurement. The polarization resistance of the battery depends on the lithium ion diffusion coefficient in the anode materials. And the ohmic resistance of the battery depends on the electrical conductivity of the battery.

Key words:lithium ion battery; porous electrode theory; ohmic resistance; polarization resistance; electrical conductivity; solid phase diffusion coefficient