Improving battery charging performance by using sinusoidal current charging with the minimum AC impedance frequency

This paper aims to explore the optimal charging frequency of the LiFePO₄ battery by the analysis of the AC impedance. The experiments show that the optimal charging frequency is at the minimum AC impedance frequency f_Zmin. In such a condition, the LiFePO₄ battery charging time and charging efficiency are improved about 5.6% and 6.8%, respectively. In addition, the increased temperature of the battery can be slowed down about 6.3°C, the aging phenomenon of the LiFePO₄ battery can be reduced, and then the battery life cycle can be prolonged.