Online Estimation of Capacity Fade and Power Fade of Lithium-Ion Batteries Based on Input–Output Response Technique

Lithium-ion batteries present promising potential in electrified transportation due to their high-power density and long cycle life. However, during the life cycle, lithium-ion batteries are subject to degrading capacity and power. This paper presents an online estimation approach of capacity fade and analyzes the power fade of lithium-ion batteries using an input-output response method. By processing the waveforms of response, one can predict the actual capacity and internal resistance which characterizes the battery health. In the end, the proposed method is validated experimentally. This provides an online estimation tool to describe the aging effects of batteries. Finally, this analysis suggests an optimal operating depth of discharge considering the battery efficiency.