Two-Dimensional Lithium-Ion Battery Modeling with Electrolyte and Cathode Extensions
Affiliation(s)
Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Canada.
Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Canada.
ABSTRACT
A two-dimensional model for transport and the coupled electric field is applied to simulate a charging lithium-ion cell and investigate the effects of lithium concentration gradients within electrodes on cell performance. The lithium concentration gradients within electrodes are affected by the cell geometry. Two different geometries are investigated: extending the length of the electrolyte past the edges of the electrodes and extending the length of the cathode past the edge of the anode. It is found that the electrolyte extension has little impact on the behavior of the electrodes, although it does increase the effective conductivity of the electrolyte in the edge region. However, the extension of the cathode past the edge of the anode, and the possibility for electrochemical reactions on the flooded electrode edges, are both found to impact the concentration gradients of lithium in electrodes and the current distribution within the electrolyte during charging. It is found that concentration gradients of lithium within electrodes may have stronger impacts on electrolytic current distributions, depending on the level of completeness of cell charge. This is because very different gradients of electric potential are expected from similar electrode gradients of lithium concentrations at different levels of cell charge, especially for the LixC6 cathode investigated in this study. This leads to the prediction of significant electric potential gradients along the electrolyte length during early cell charging, and a reduced risk of lithium deposition on the cathode edge during later cell charging, as seen experimentally by others.
A two-dimensional model for transport and the coupled electric field is applied to simulate a charging lithium-ion cell and investigate the effects of lithium concentration gradients within electrodes on cell performance. The lithium concentration gradients within electrodes are affected by the cell geometry. Two different geometries are investigated: extending the length of the electrolyte past the edges of the electrodes and extending the length of the cathode past the edge of the anode. It is found that the electrolyte extension has little impact on the behavior of the electrodes, although it does increase the effective conductivity of the electrolyte in the edge region. However, the extension of the cathode past the edge of the anode, and the possibility for electrochemical reactions on the flooded electrode edges, are both found to impact the concentration gradients of lithium in electrodes and the current distribution within the electrolyte during charging. It is found that concentration gradients of lithium within electrodes may have stronger impacts on electrolytic current distributions, depending on the level of completeness of cell charge. This is because very different gradients of electric potential are expected from similar electrode gradients of lithium concentrations at different levels of cell charge, especially for the LixC6 cathode investigated in this study. This leads to the prediction of significant electric potential gradients along the electrolyte length during early cell charging, and a reduced risk of lithium deposition on the cathode edge during later cell charging, as seen experimentally by others.
Cite this paper
G. F. Kennell and R. W. Evitts, "Two-Dimensional Lithium-Ion Battery Modeling with Electrolyte and Cathode Extensions," Advances in Chemical Engineering and Science, Vol. 2 No. 4, 2012, pp. 423-434. doi: 10.4236/aces.2012.24052.
G. F. Kennell and R. W. Evitts, "Two-Dimensional Lithium-Ion Battery Modeling with Electrolyte and Cathode Extensions," Advances in Chemical Engineering and Science, Vol. 2 No. 4, 2012, pp. 423-434. doi: 10.4236/aces.2012.24052.
References
[1] E. Scott, G. Tam, B. Anderson and C. Schmidt, “Anomalous Potentials in Lithium Ion Cells: Making the Case for 3-D Modeling of 3-D Systems,” The Electrochemical Society Meeting, Orlando, 13 October 2003. [2] E. Scott, G. Tam, B. Anderson and C. Schmidt, “Observation and Mechanism of Anomalous Local Potentials during Charging of Lithium Ion Cells,” The Electrochemical Society Meeting, Paris, 29 April 2003. [3] K. West, T. Jacobsen and S. Atlung, “Modeling of Porous Insertion Electrodes with Liquid Electrolyte,” Journal of the Electrochemical Society, Vol. 129, No. 7, 1982, pp. 1480-1485. doi:10.1149/1.2124188 [4] M. Doyle, T. F. Fuller and J. Newman, “Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell,” Journal of the Electrochemical Society, Vol. 140, No. 6, 1993, pp. 1526-1533. doi:10.1149/1.2221597 [5] T. F. Fuller, M. Doyle and J. Newman, “Simulation and Optimization of the Dual Lithium Ion Insertion Cell,” Journal of the Electrochemical Society, Vol. 141, No. 1, 1994, pp. 1-10. doi:10.1149/1.2054684 [6] P. Arora, M. Doyle and R. E. White, “Mathematical Modeling of the Lithium Deposition Overcharge Reaction in Lithium-Ion Batteries Using Carbon-Based Negative Electrodes,” Journal of the Electrochemical Society, Vol. 146, No. 10, 1999, pp. 3543-3553. doi:10.1149/1.1392512 [7] M. Tang, P. Albertus and J. Newman, “Two-Dimensional Modelling of Lithium Deposition during Cell Charging,” Journal of the Electrochemical Society, Vol. 156, No. 5, 2009, pp. A390-A399. doi:10.1149/1.3095513 [8] K. Eberman, P. M. Gomadam, G. Jain and E. Scott, “Material and Design Options for Avoiding Lithium-Plating during Charging,” ECS Transactions, Vol. 25, No. 35, 2010, pp. 47-58. doi:10.1149/1.3414003 [9] G. F. Kennell and R. W. Evitts, “Charge Density in Non-Isotropic Electrolytes Conducting Current,” The Canadian Journal of Chemical Engineering, Vol. 90, No. 2, 2012, pp. 377-384. [10] W. Dreyer, M. Gaberscek, C. Guhlke, R. Huth and J. Jamnik, “Phase Transition in a Rechargeable Lithium Battery,” European Journal of Applied Mathematics, Vol. 22, No. 3, 2011, pp. 267-290. doi:10.1017/S0956792511000052 [11] G. F. Kennell, “Electrolytic Transport, Electric Fields, and the Propensity for Charge Density in Electrolytes,” Ph.D. Dissertation, University of Saskatchewan, Saskatoon, 2011. [12] M. Doyle and Y. Fuentes, “Computer Simulations of a Lithium-Ion Polymer Battery and Implications for Higher Capacity Next-Generation Battery Designs,” Journal of the Electrochemical Society, Vol. 150, No. 6, 2003, pp. A706-A713. doi:10.1149/1.1569478 [13] J. Christensen, V. Srinivasan and J. Newman, “Optimization of Lithium-Titanate Electrodes for High-Power Cells,” Journal of the Electrochemical Society, Vol. 153, No. 3, 2006, pp. A560-A565. doi:10.1149/1.2172535 [14] S. G. Stewart and J. Newman, “The Use of UV/Vis Absorption to Measure Diffusion Coefficients in LiPF6 Electrolytic Solutions,” Journal of the Electrochemical Society, Vol. 155, No. 1, 2008, pp. F13-F16. doi:10.1149/1.2801378
[1] E. Scott, G. Tam, B. Anderson and C. Schmidt, “Anomalous Potentials in Lithium Ion Cells: Making the Case for 3-D Modeling of 3-D Systems,” The Electrochemical Society Meeting, Orlando, 13 October 2003. [2] E. Scott, G. Tam, B. Anderson and C. Schmidt, “Observation and Mechanism of Anomalous Local Potentials during Charging of Lithium Ion Cells,” The Electrochemical Society Meeting, Paris, 29 April 2003. [3] K. West, T. Jacobsen and S. Atlung, “Modeling of Porous Insertion Electrodes with Liquid Electrolyte,” Journal of the Electrochemical Society, Vol. 129, No. 7, 1982, pp. 1480-1485. doi:10.1149/1.2124188 [4] M. Doyle, T. F. Fuller and J. Newman, “Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell,” Journal of the Electrochemical Society, Vol. 140, No. 6, 1993, pp. 1526-1533. doi:10.1149/1.2221597 [5] T. F. Fuller, M. Doyle and J. Newman, “Simulation and Optimization of the Dual Lithium Ion Insertion Cell,” Journal of the Electrochemical Society, Vol. 141, No. 1, 1994, pp. 1-10. doi:10.1149/1.2054684 [6] P. Arora, M. Doyle and R. E. White, “Mathematical Modeling of the Lithium Deposition Overcharge Reaction in Lithium-Ion Batteries Using Carbon-Based Negative Electrodes,” Journal of the Electrochemical Society, Vol. 146, No. 10, 1999, pp. 3543-3553. doi:10.1149/1.1392512 [7] M. Tang, P. Albertus and J. Newman, “Two-Dimensional Modelling of Lithium Deposition during Cell Charging,” Journal of the Electrochemical Society, Vol. 156, No. 5, 2009, pp. A390-A399. doi:10.1149/1.3095513 [8] K. Eberman, P. M. Gomadam, G. Jain and E. Scott, “Material and Design Options for Avoiding Lithium-Plating during Charging,” ECS Transactions, Vol. 25, No. 35, 2010, pp. 47-58. doi:10.1149/1.3414003 [9] G. F. Kennell and R. W. Evitts, “Charge Density in Non-Isotropic Electrolytes Conducting Current,” The Canadian Journal of Chemical Engineering, Vol. 90, No. 2, 2012, pp. 377-384. [10] W. Dreyer, M. Gaberscek, C. Guhlke, R. Huth and J. Jamnik, “Phase Transition in a Rechargeable Lithium Battery,” European Journal of Applied Mathematics, Vol. 22, No. 3, 2011, pp. 267-290. doi:10.1017/S0956792511000052 [11] G. F. Kennell, “Electrolytic Transport, Electric Fields, and the Propensity for Charge Density in Electrolytes,” Ph.D. Dissertation, University of Saskatchewan, Saskatoon, 2011. [12] M. Doyle and Y. Fuentes, “Computer Simulations of a Lithium-Ion Polymer Battery and Implications for Higher Capacity Next-Generation Battery Designs,” Journal of the Electrochemical Society, Vol. 150, No. 6, 2003, pp. A706-A713. doi:10.1149/1.1569478 [13] J. Christensen, V. Srinivasan and J. Newman, “Optimization of Lithium-Titanate Electrodes for High-Power Cells,” Journal of the Electrochemical Society, Vol. 153, No. 3, 2006, pp. A560-A565. doi:10.1149/1.2172535 [14] S. G. Stewart and J. Newman, “The Use of UV/Vis Absorption to Measure Diffusion Coefficients in LiPF6 Electrolytic Solutions,” Journal of the Electrochemical Society, Vol. 155, No. 1, 2008, pp. F13-F16. doi:10.1149/1.2801378