Frequency Response Informed Order Reduction Approaches for Pseudo-2D Model for Li-Ion Batteries

Abstract

To simulate the battery performance quickly using the P2D model,1,2 various simplifications and mathematical reformulations are introduced. One such simplification is the polynomial profile approximation in the solid phase. Such simplifications result in a significant reduction in the simulation time while having a minor compromise in the accuracy, especially for highly fluctuating currents. Building on the previous work by Subramanian et al.,3,4 in this presentation, the Hexic profile polynomial approximations are proposed. The frequency response-based criteria were used to derive the optimal coefficients which give rise to the best possible Hexic model for a given family of current profiles.5 Compare to the Quartic model (QP) based simplifications, the proposed Hexic model (HP) provides comparable computational time (t sim) but offers a factor of 3 improvements in the average error in the cell voltage calculation (εavg [mV]). However, compared to the fully converged FD model, it offers significant improvement in computational time at the cost of 0.5 mV average error in the cell voltage (see Figure 1).In the context of the P2D model, Hexic profile-based solid phase concentration treatment leads to much better prediction (compared to the parabolic and quartic profiles) of the internal variables such as current distribution in electrodes and the stress distribution (radial and tangential stresses inside the solid particles) generated during lithiation and de-lithiation process.The presentation will also discuss critical comparison between the global polynomial-based models (orthogonal collocation and Galerkin approaches) and the frequency domain-based approaches.References Doyle, T. F. Fuller, and J. Newman, J Electrochem Soc, 140, 1526 (1993).Newman and K. E. Thomas-Aleya, John Wiley & Sons, New Jersey (1991).R. Subramanian, J. A. Ritter, and R. E. White, J Electrochem Soc, 148, E444 (2001).R. Subramanian, V. D. Diwakar, and D. Tapriyal, J Electrochem Soc, 152, A2002 (2005).Mishra, V. R. Subramanian and B. Suthar, J Electrochem Soc, 169 (12), 120532 (2022). Figure 1