Abstract

Second-life batteries have focused increasing interest as they can participate in a more sustainable energy mix. A key challenge for second-life batteries use comes with the knowledge of their State-of-Health (SoH). One solution commonly adopted for this purpose is to perform Electrochemical Impedance Spectroscopy (EIS), which can be performed online, considering a signal excitation in the battery. Hardware allowing such signal excitation is then of main importance, and the interface DC-DC converter of the battery is a solution. However, existing interface DC-DC converter with signal excitation capability generally consider basic power conversion topologies such as the buck-boost converter, letting apart the optimization of the converter for its use in a given application. To address this issue, this paper proposes a high-efficiency partial power converter (PPC) for second-life battery interface, with signal excitation capability. It is verify that the proposed PPC allows signal excitation for different excitation patterns, both in open and closed-loop. Furthermore, it is shown that the proposed PPC allows higher efficiency compared to state-of-the-art buck-boost, with estimated maximum efficiency of 99.4%. © 2025 IEEE.