Ya Lv and Benjamin Ong Wei Lin and Wanli Niu and Benjamin Seah Chin Tat
Battery Grading Algorithm in 2ndLife Repurposing Liion Battery System
312 - 317
2021
15
8
International Journal of Energy and Power Engineering
https://publications.waset.org/pdf/10012164
https://publications.waset.org/vol/176
World Academy of Science, Engineering and Technology
This article presents a methodology that improves reliability and cyclability of 2ndlife Liion battery system repurposed as energy storage system (ESS). Most of the 2ndlife retired battery systems in market have modulepacklevel state of health (SOH) indicator, which is utilized for guiding appropriate depth of discharge (DOD) in the application of ESS. Due to the lack of celllevel SOH indication, the different degrading behaviors among various cells cannot be identified upon reaching retired status; in the end, considering end of life (EOL) loss and packlevel DOD, the repurposed ESS has to be oversized by > 1.5 times to complement the application requirement of reliability and cyclability. This proposed battery grading algorithm, using noninvasive methodology, is able to detect outlier cells based on historical voltage data and calculate celllevel historical maximum temperature data using semianalytic methodology. In this way, the individual battery cell in the 2ndlife battery system can be graded in terms of SOH on basis of the historical voltage fluctuation and estimated historical maximum temperature variation. These grades will have corresponding DOD grades in the application of the repurposed ESS to enhance the system reliability and cyclability. In all, this introduced battery grading algorithm is noninvasive, compatible with all kinds of retired Liion battery systems which lack of celllevel SOH indication, as well as potentially being embedded into battery management software for preventive maintenance and realtime cyclability optimization.
Open Science Index 176, 2021