Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31917
Battery Grading Algorithm in 2nd-Life Repurposing Li-ion Battery System

Authors: Ya Lv, Benjamin Ong Wei Lin, Wanli Niu, Benjamin Seah Chin Tat


This article presents a methodology that improves reliability and cyclability of 2nd-life Li-ion battery system repurposed as energy storage system (ESS). Most of the 2nd-life retired battery systems in market have module/pack-level 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 cell-level 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 pack-level 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 non-invasive methodology, is able to detect outlier cells based on historical voltage data and calculate cell-level historical maximum temperature data using semi-analytic methodology. In this way, the individual battery cell in the 2nd-life 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 non-invasive, compatible with all kinds of retired Li-ion battery systems which lack of cell-level SOH indication, as well as potentially being embedded into battery management software for preventive maintenance and real-time cyclability optimization.

Keywords: Battery grading algorithm, 2nd-life repurposing battery system, semi-analytic methodology, reliability and cyclability.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 545


[4] Kailong LIU, Kang LI, Qiao PENG, Cheng ZHANG, A brief review on key technologies in the battery management system of electric vehicles
[5] Nejad S, Gladwin D T, Stone D A. A systematic review of lumped parameter equivalent circuit models for real-time estimation of lithium-ion battery states. Journal of Power Sources, 2016, 316: 183–196
[6] Berecibar M, Gandiaga I, Villarreal I, et al. Critical review of state of health estimation methods of Li-ion batteries for real applications. Renewable & Sustainable Energy Reviews, 2016, 56: 572–587
[7] Bi J, Zhang T, Yu H, et al. State-of-health estimation of lithium-ion battery packs in electric vehicles based on genetic resampling particle filter. Applied Energy, 2016, 182: 558–568
[8] Gholizadeh M, Salmasi F R. Estimation of state of charge, unknown nonlinearities, and state of health of a lithium-ion battery based on a comprehensive unobservable model. IEEE Transactions on Industrial Electronics, 2014, 61(3): 1335–1344
[9] You G, Park S, Oh D. Real-time state-of-health estimation for electric vehicle batteries: A data-driven approach. Applied Energy, 2016, 176: 92–103
[10] Ahmad P., Shriram S. and Gi-Heon K. (2013). Large Format Li-Ion Batteries for Vehicle. Available: Applications (
[11] Long Lam, University of Technology Delft, 23 August 2011.A Practical Circuit based Model for State of Health Estimation of Li-ion Battery Cells in Electric Vehicles
[12] Woodbank Communications Ltd (2005). Battery and Energy Technologies: Lithium Battery Failures. Available:
[13] Agwu Daberechi D., Opara F. K., Chukwuchekwa N, Dike. D. O., Uzoechi L., Department of Electrical and Electronic Engineering, Federal University of Technology, Owerri. (FUTO), Nigeria. Review of Comparative Battery Energy Storage Systems (Bess) for Energy Storage Applications in Tropical Environments
[14] Ya Lv. Semi-Analytic Method in Fast Evaluation of Thermal Management Solution in Energy Storage System
[16] Lluc Canals CasalsB. Amante GarcíaCamille Cana. Second life batteries lifespan: Rest of useful life and environmental analysis