3D Printed Device for Mechanical Fatigue Testing and Analysis of Li-ion Batteries and Electrodes

In the last several years, there has been interest in the development of flexible batteries as a substitute for traditional Li-ion batteries. Flexible batteries can fold, bend, and twist; studies have shown that mechanical stresses and fatigue may decrease battery performance and cause defects. In this paper, the viability of producing a mechanical fatigue-testing device from 3D printed and other off-the-shelf components was explored. The device was made using a servomotor and LCD screen controlled by a programmed Arduino board, and successfully met the expectations to be cheap, easily reproducible, versatile, and applicable to the testing of battery components. In a proof-of-concept test, the device was used to perform repeated folding tests on lithium cobalt oxide cathodes in different configurations, which were then characterized using a laser microscope. 3D topographical renderings suggested that bending at acute angles induces defects on the surface of the electrode where the electrode is creased. In future work, the device will be used to further explore the effect of mechanical fatigue on Li-ion battery components.