The growing need for wearable devices, fitness accessories, and biomedical equipment has led to the upsurge in research and development of thin flexible battery research and development. These equipment and asset monitoring applications require versatile installation of power sources on non-planar surfaces. For power sources in wearable electronics, perseverance towards repetitive mechanical stresses induced by human body motion is necessary along with the usual desirable characteristics such as high capacity, high C-rate capability, and good life cycle stability. Studies that document the reliability of power sources subject to static and dynamic folding are numbered and at times fail to follow definitive test protocols that inhibit their reproducibility of real-life battery use scenarios. Particularly, manual mechanical stressing of the power sources instead of a mechanical test setup is a key shortcoming in the existing literature. This is followed by a dearth of significant battery life cycling and in-situ mechanical stressing of the tested power sources. The present study aims to overcome these deficiencies by testing a commercial Li-ion power source under static as well as dynamic folding. Also, battery use factors such as varying depths of charge and higher charging C-rates were incorporated in the test matrix to evaluate the capacity degradation under a range of operating conditions. Furthermore, the orientation of the fold and its speed were varied to evaluate the effect of different mechanical stress topologies on the power source. Finally, a regression model was developed to capture the effect of these use parameters on battery capacity degradation.


State of Health Estimation of Li-Ion Battery Subjected to Flex-to-Install and Dynamic Folding With Varying Orientations, Folding Speeds, Depths of Charge and C-Rates

Division / Sponsors: 
Electronic & Photonic Packaging Division (EPPD)

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2020/volume/84041

InterPACK2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.