A parametric open circuit voltage model for lithium ion batteries

C. R. Birkl*, E. McTurk, M. R. Roberts, P. G. Bruce, D. A. Howey

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

117 Citations (Scopus)
1 Downloads (Pure)

Abstract

We present an open circuit voltage (OCV) model for lithium ion (Li-ion) cells, which can be parameterized by measurements of the OCV of positive and negative electrode half-cells and a full cell. No prior knowledge of physical parameters related to particular cell chemistries is required. The OCV of the full cell is calculated from two electrode sub-models, which are comprised of additive terms that represent the phase transitions of the active electrode materials. The model structure is flexible and can be applied to any Li-ion cell chemistry. The model can account for temperature dependence and voltage hysteresis of the OCV. Fitting the model to OCV data recorded from a Li-ion cell at 0°C, 10°C, 20°C, 30°C and 40°C yielded high accuracies with errors (RMS) of less than 5 mV. The model can be used to maintain the accuracy of dynamic Li-ion cell models in battery management systems by accounting for the effects of capacity fade on the OCV. Moreover, the model provides a means to separate the cell's OCV into its constituent electrode potentials, which allows the electrodes’ capacities to be tracked separately over time, providing an insight into prevalent degradation mechanisms acting on the individual electrodes.
Original languageEnglish
Pages (from-to)A2271-A2280
Number of pages10
JournalJournal of The Electrochemical Society
Volume162
Issue number12
DOIs
Publication statusPublished - 1 Sept 2015

Keywords

  • Lattice-gas model
  • Intercalation compounds
  • Capacity estimation
  • Charge estimation
  • Insertion
  • State
  • Identification
  • Hysteresis
  • Electrodes
  • Graphite
  • Battery
  • Battery management system
  • Lithium ion
  • Open circuit voltage
  • Parametric model

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