Flex-to-Install Application Performance of Power Sources Subjected to Varying Fold Orientations, C-Rates and Depths of Charge

摘要

Asset monitoring using flexible electronics may require the power sources to be flexed-to-install on non-planar surfaces during installation close to the sensor locations. The power sources may power sensors and microcontrollers tasked with acquiring data periodically till the time that the data can be downloaded for purpose of offline processing and condition-assessment of the monitored asset. Review of published literature reveals that data on performance and reliability of power sources under flexure is limited and the existing studies are not as detailed. In this paper, a test methodology has been developed for thin form flexible Lithium-ion power sources subjected to simultaneous static flexure and accelerated life testing to evaluate their capacity retention. The tests have been repeated for varying charging C-rates (1C and 2C) and fold orientations (transverse and longitudinal). In order to replicate real-world conditions, the power sources have been subjected to partial as well as deep cycling tests which run up to 150 cycles. The battery terminal voltage and current are logged during testing and are used to compute the capacity and its degradation. The effects of cycle depth, charge C-rate, depth of charge, presence or absence of flexure, and fold orientation have been characterized and a regression model has been developed to capture the dependencies on predictor variables in the data-set.