Simulation of Impedance Changes with Aging in Lithium Titanate-Based Cells Using Physics-Based Dimensionless Modeling

Anudeep Mallarapu, Shriram Santhanagopalan, Wataru Uno, Yuta Kanai, Yohei Uemura, Ryosuke Yagi, Shuichi Uchikoga

Research output: Contribution to journalArticlepeer-review


Quantifying aging effects in lithium-ion cells with chemistries that have a flat open circuit potential is challenging. We implement a physics-based electrochemical model to track changes in the electrochemical impedance response of lithium titanate-based cells. Frequency domain equations of a pseudo two-dimensional model are made dimensionless, and the corresponding non-dimensional parameters are estimated using a Levenberg-Marquardt routine. The model weighs the relative contributions of changes in diffusion, ionic conduction within the electrolyte phase against solid phase electronic conduction towards cell aging. Solid-phase diffusion, charge transfer resistance and double layer capacitance at the solid-liquid interface are accounted for in the particle impedance. The estimation routine tracks dimensionless parameters using accelerated cycling data from full cells over 1000 cycles. The model can be deployed within a short time for state estimation using physics-based models without requiring prior knowledge of the battery chemistry, format, or capacity.

Original languageAmerican English
Article number090519
Number of pages11
JournalJournal of the Electrochemical Society
Issue number9
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.

NREL Publication Number

  • NREL/JA-5700-87885


  • aging effects
  • electrochemistry
  • lithium-ion cells


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