Abstract
Accurate estimation of battery pack capacity is crucial in determining electric vehicle driving range and providing valuable suggestions for battery health management. This article proposes an improved capacity co-estimation framework for cells and battery pack using partial charging process. The transformation characteristics of cell capacity difference within the battery pack on the external voltage curve are discussed. The charging voltage curve is segmented according to the feature points extracted from battery incremental capacity curve, and the linear correlation between the voltage curve segments and capacity decline is analyzed to obtain the optimal transformation part, which is verified through a series of cycle aging data. Subsequently, by optimizing the transformation coefficients, we achieve capacity estimation for each cell within the battery pack utilizing only a partial charging voltage profile at approximately 30 % SOC. We further establish a connection between the battery pack and its series cells to enable pack capacity estimation. The proposed method is verified based on two sets of battery pack tests comprising 60 cells in series and with severe capacity inconsistency. The results show that the estimation errors of cells are <2 % and the errors of battery packs are <1 %.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
