Polynomial Augmented Extended Kalman Filter to Estimate the State of Charge of Lithium-Ion Batteries

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

In battery-electric vehicles, an accurate knowledge of the current state of charge (SOC) of the battery is crucial for safe and efficient operation. Offset-free SOC estimation for Lithium-ion batteries (LIB) during operation still is a challenging problem, due to the uncertain output nonlinearity present in battery models. In battery management systems employed in such vehicles, the age- and cycle-dependent relationship between the open circuit voltage (OCV) and the state of charge of each cell (SOC) can be kept track of using lookup tables. Between the scattered data points, linear interpolation is often used. Another common approach is to switch between models, each with a different piecewise polynomial fit of low order. In this contribution, a single polynomial fit of a higher order with state-dependent coefficients for the whole SOC-OCV range is proposed, so as to avoid switching and facilitate usage of Taylor-based linearization algorithms like in the extended Kalman filter. While the polynomial order is high, the number of parameters is only three; the parameters are estimated and updated by the Kalman filter itself. This augmentation of the observer's state vector with said polynomial parameters is inspired by the idea of an increased “stochastization,” introducing redundancy that aids to achieve a more accurate SOC estimation. In this sense, the algorithm can be described as a model-adaptive extended Kalman estimator. Two variants of a polynomial EKF are investigated: polynomial EKF with output and with state nonlinearity models. Their performances are compared in real experiments using a dedicated test bench based on a Samsung ICR18650-26F cell, demonstrating the effectiveness of the algorithms. The variant that includes the terminal voltage in the state vector, i.e. the state nonlinearity variant of the EKF, shows better result, also compared to the existing literature.
Original languageEnglish
Article number8933348
JournalIEEE Transactions on Vehicular Technology
Volume69
Issue number2
Pages (from-to)1452-1463
Number of pages12
ISSN0018-9545
DOIs
Publication statusPublished - 02.2020

    Research areas

  • Engineering - battery management systems, Kalman filters, lithium batteries, electric vehicles

DOI

Recently viewed

Activities

  1. The Later Life Workplace Index (LLWI): Key Learnings From a Multi-National Research Project
  2. Podiumsdiskussion zu MEDEA
  3. How is Research Creation as Other Knowledge?
  4. 9th International Multi-Conference on Systems, Signals and Devices - SSD 2012
  5. Discussant für Barbara Kump (WU Vienna) Nobody Talks About It - Everyone Does It: Intuition in Interpretative Organizational Research
  6. Eschatological Commitments
  7. Workshop: "Mit Leben Rechnen"
  8. International conference ICT for Language Learning - ICT 2013
  9. Albert, Alice, Alfred: Variations of Love in the Victorian Era
  10. Biotic and abiotic degradation of S-metolachlor and its commercial product Mercantor Gold® in aqueous media
  11. Sherman Alexie’s Flight: Fighting the Frontier in the 21st Century
  12. Cambridge University Press (Verlag)
  13. Heidegger und Husserl
  14. 2nd PERL International Conference 2012
  15. Ryukoku Universität (Externe Organisation)
  16. 39. Jahrestagung der Gesellschaft fur Informatik - INFORMATIK 2009
  17. Shifts in Institutional Infrastructure Configurations: The Case of Integrated Care in Germany
  18. Encounter at Dynamic Eye Level: 15 Roles Adopted by Actors in Science-Practice Collaborations
  19. »Cultural Aspects of National Socialism«. Reconsidering an unfinished project of the International Institute of Social Research
  20. Fakultät Bildung (Organisation)
  21. 71st Annual Meeting of the Academy of Management - AOM 2011 (Veranstaltung)
  22. Fakultät Bildung (Organisation)
  23. Copernicus – Legal and Regulatory Considerations for Sentinel Satellite Data Policy in the Digital Era
  24. Governance. An International Journal of Policy, Administration, and Institutions (Fachzeitschrift)
  25. Political Studies (Fachzeitschrift)