Investigation of adhesion testing setups for electrodes in Li-ion battery cells

This thesis project investigates the best testing quality control setup to measure the adhesion of the interface coating/metallic foil of electrodes in lithium-ion battery cells. In fact, there is no specific standard (ISO/ASTM) for this kind of adhesion testing to date. Firstly, a review of the literature concerning lithium-ion batteries and adhesion test methods is given. The importance of the coating adhesion of electrodes is described. In fact, it is a critical mechanical property of the electrodes as it affects the electrochemical lifetime, cycle performance and stability of battery cells. Secondly, three different tests were studied in more detail: the 180° peel test, the 90° peel test and the z-direction pull test. Method development efforts were carried out, to find the best specimen preparation method and the best parameters to be used during each test. Once this was finalised, Measurement System Analysis (MSA) studies were carried out on all three test methods to validate and compare the suitability of the method as a routine quality control inspection for battery manufacturing. Finally, the outcome of the MSA studies, with practical considerations about the tests, were compared to make a decision on which adhesion test suits best the Quality Control laboratory at Northvolt.