Coupled mechanical and electrochemical characterization method for battery materials

A battery separator isolates anode and cathode electrically and contributes to the ionic conductivity on the one side. On the other side, it is a highly sensitive functional component concerning mechanical loads. During production as well as the operation of a battery this thin, polymer based film is stressed by compressive and tensile forces. This contribution presents an enhanced characterization method for the separator/electrolyte system under defined mechanical load. The method is based on electrochemical impedance spectroscopy (EIS). The test bench design, functionality and the sample preparation as well as the characterization procedures are shown, before experimental results are discussed. The paper aims to contribute to the refinement of EIS data interpretation and determine critical states regarding mechanical pressure of the battery separator for both, production and operation.