Dynamic Multi-Dimensional Numerical Transport Study of Lithium-Ion Battery Active Material Microstructures for Automotive Applications

Graphite is a critical material used as the negative electrode in lithium-ion batteries. Both natural and synthetic graphites are utilized, with the latter obtained from a range of carbon raw materials. In this paper, efforts to synthesize graphite from coal as a domestic feedstock for synthetic graphite are reported. Domestic coal-derived graphite could address national security and energy issues by standing up domestic supply chains for battery critical materials. The performance in lithium-ion coin cells of this coal derived graphite is compared to a commercial battery-grade graphite. For the first time, a multi-species, multi-reaction modeling technique is applied to synthetic graphite derived from coal. Key thermodynamic, transport, and kinetic parameters are obtained for the coal derived graphite and compared to the same parameters for commercial battery-grade graphite. Modeling of synthetic graphites will allow for virtual evaluation of these materials toward production of domestically sourced graphite.

Section: Multi-species Multi-reaction Analysis and Porous Electrode M...mentioning

confidence: 99%

Application of the Multi-Species, Multi-Reaction Model to Coal-Derived Graphite for Lithium-Ion Batteries

Paul,

Magee,

Wilczewski

et al. 2024

“…In this work, we focused on using MD methods to inform the electrolyte material properties, and plan to focus future work on characterizing the material properties of solid active materials. For this work, we utilize the methods typical of our previous studies on electrochemical characterization, 15,17 volume change, [18][19][20][21][22] and heat generation 6,[23][24][25][26] for large format battery cells to inform the remaining cell design and material properties through characterization, analytical methods prior to formation, and post-formation teardown analysis.…”

Section: Porous Electrode Theory and Heat Generationmentioning

confidence: 99%

Leveraging Molecular Dynamics to Improve Porous Electrode Theory Modeling Predictions of Lithium-Ion Battery Cells

Dix

Lowe

Avei

et al. 2023

Self Cite

Lithium-ion battery cell modeling using physics-based approaches such as porous electrode theory is a powerful tool for battery design and analysis. Cell metrics such as resistance and thermal performance can be quickly calculated in a pseudo-two-dimensional (P2D) framework. For engineering of electric vehicle batteries, speed and fidelity of electrochemical models is paramount in a competitive landscape. Physics-based models allow for high fidelity but require detailed knowledge of the cell component material properties. Acquiring these material characteristics typically requires time-consuming and expensive experiments limiting the ability to quickly screen through cell designs. One approach to circumvent costly experiments is to use molecular dynamics to calculate electrolyte transport properties. We demonstrate how cell modeling using simulated transport properties enables predictions of cell level metrics, allowing for experiment-free component screening. We also show how the variation in transport property predictions from molecular dynamics affects the final cell level performance predictions.

“…Full order model.-The fundamental governing equations, boundary conditions, and construction of the electrochemical model used in this study have been described in previous work. 42,43 In this continuum model approach, the mass transfer and the solid phase potential in the anode particles and the cathode particles are described by Fickian diffusion and Ohm's law, respectively. Mass transfer in the electrolyte phase is described by concentrated solution theory.…”

Section: Kinetics Expressionmentioning

confidence: 99%

Reduced Order Electrochemical-Thermal Modeling of Cylindrical Cells Containing Graphite-Silicon Anodes Considering Thermal Gradients and Hysteresis

Du,

Park,

Choe

et al. 2024

Electrochemical thermal modeling of cylindrical cells presents unique challenges compared to other cell formats due to the effect of internal temperature gradients, which typically requires time-consuming simulations due to the number of mesh elements solved numerically. Adding to the difficulty, the emergence of silicon anodes induces voltage hysteresis that affects the cell behavior. In this paper, a reduced-order electrochemical-thermal model is developed for a 21700 cell, which is highlighted by three microcells considering the effects of internal temperature gradients, and an anodic stress model capturing the hysteresis effects caused by the silicon content. The electrochemical, thermal, and mechanical behaviors are investigated. During operations, a temperature gradient arises in the radial direction, resulting in a decrease in local resistance and an increase in reaction rate at the high-temperature core location. The presence of silicon causes a voltage hysteresis that is dominant in the low SOC range, which affects not only the irreversible but also the entropic heat generation. The proposed method achieves an 85% calculation time reduction compared with the existing literature method and a 95% reduction compared with the full order method, while maintaining the accuracy of the terminal voltage and heat generation rate predictions that are validated by experiments.