Multi-Cell Testing Topologies for Defect Detection Using Electrochemical Impedance Spectroscopy: A Combinatorial Experiment-Based Analysis

Abstract

Given the increasing use of lithium-ion batteries, which is driven in particular by electromobility, the characterization of cells in production and application plays a decisive role in quality assurance. The detection of defects particularly motivates the optimization and development of innovative characterization methods, with simultaneous testing of multiple cells in the context of multi-cell setups having been researched to economize on the number of cell test channels required. In this work, an experimental study is presented demonstrating the influence of a defect type in one cell on five remaining interconnected cells in eight combinatorially varied topologies using galvanostatic electrochemical impedance spectroscopy. The results show that regularities related to the interconnection position are revealed when considering the change in the specific resistance ZIM,min at the transition from the charge transfer to the diffusion region between the reference and fault measurements, allowing it to function as a defect identifier in the present scenario. These results and the extensive measurement data provided can serve as a basis for the evaluation and design of multi-cell setups used for simultaneous impedance-based lithium-ion cell characterizations.