BEST Battery and Electrochemistry Simulation Tool

The Battery and Electrochemistry Simulation Tool (BEST) is our software environment for the physics-based three-dimensional Multiscale Simulation of lithium-ion batteries.

In contrast to phenomenological surrogate models, »physics-based« means we describe ion, charge and energy transport by physical laws formulated as partial differential equations, see Workflow.

We provide more information on the simulation model in the following publications:

G. Less, J. H. Seo, S. S. Han, A. M. Sastry: Micro-Scale Modeling of Li-Ion Batteries: Parameterization and Validation, J. Electrochem. Soc. 159 (2012) A697-A704
A. Latz and J. Zausch: Thermodynamic consistent transport theory of Li-ion batteries, Journal of Power Sources 196 (2011) 3296–3302

Our strength is to combine this kind of modelling with specifically developed, efficient numerical solvers that are implemented in C++ in our own software product BEST.

Showcase of a CC-CV charge simulation on a fully resolved microstructure performed within BEST. The three-dimensional solution fields on the left show the evolution of the lithium concentration over time within the electrolyte and electrode active materials.

With BEST we Provide a Simulation Tool for:

Predicting cell performance
Virtual cell design on microscopic electrode scale ( e.g. optimization of binder content and distribution) and macroscopic cell level (e.g. cell format or tab-size and placement)
Optimizing charging strategies
Analysis of limiting factors using e.g. rate tests or electrochemical impedance spectroscopy (EIS)
Investigating aging and degradation phenomena, e.g. Solid Electrolyte Interphase (SEI) growth, mechanical aging, lithium plating
and more

The usage of BEST is not limited to the above applications. BEST is constantly extended and adapted to the needs of our customers.

Special Features and Projects

Silicon-based anodes: voltage hysteresis, electrode expansion and mechanical degradation (Projects DEFACTO and ALIB)
Prediction of heat production (Project TopBat) and analysis of internal resistances
Electrochemical degradation (Projects structur.e and MULTIBAT)
Electrode structuring and electrochemical impedance spectroscopy (Projects ABBA-VEEB, structur.e, and Cell-Fi)
Coupling to virtual vehicle simulation (Project MultiskalenBEV)

Coupling to Other Software Tools

To describe the mechanical cell behaviour and the state-of-charge dependent electrode expansion we combine the strengths of BEST and our efficient structural mechanics solver FeelMath.
BEST is also available in the module BatteryDict of the GeoDict software of Math2Market. There it integrates completely with GeoDicts capabilities for microstructure generation, import of micro-computed tomographies, and structure analysis.
By providing a library interface we use BEST in the virtual vehicle simulation environment VMC.

Multiscale Simulations: From Electrode to Cell Level

Apart from the material parameters, the geometrical parameters are also relevant for the behavior of a battery cell. This is a multiscale problem because both the microstructure of the electrodes (e.g. particle sizes and arrangement) as well as the macroscopic dimensions (e.g. layer thickness or extent) are influencing. For both levels, BEST offers the best solution with its BESTmicro and BESTmeso modules. In both cases the battery behavior is calculated fully three-dimensionally in order to be able to reproduce the real geometry as accurately as possible.

The primary solution fields of the simulation are lithium plating potential concentration and electrical potentials. These three-dimensional solution fields are stored regularly in the open vtk-format. Additionally, a large set of derived local and global variables are computed (e.g. cell voltage, lithium plating, local current density, etc.).

BEST is available for Linux and Windows operating systems.

BEST offers two main software modules for the cell scale: BESTmicro for detailed microstructure simulations and BESTmeso for efficient simulations of effective cell characteristics. For both levels, BEST offers the best solution with its BESTmicro and BESTmeso modules. In both cases the battery behavior is calculated fully three-dimensionally in order to be able to reproduce the real geometry as accurately as possible. — © Fraunhofer ITWM
BEST offers two main software modules for the cell scale: BESTmicro for detailed microstructure simulations and BESTmeso for efficient simulations of effective cell characteristics.

Workflow

BEST requires the specification of

a computational domain (ie. Battery cell consisting of anode, cathode, separator, possibly conductive additives and current collectors).
a set of material parameters for the respective materials (e.g. lithium diffusion constant in active electrode material, ionic conductivity in electrolyte, etc.). These parameters may be simple constants or may depend on concentration or temperature.
an operation protocol, e.g. a constant or time-dependent current, cell voltage, or power profile. Also more complex operation protocols are possible, e.g. current controlled by anode potential.

Example Projects

Electrochemical Impedance Spectroscopy (EIS)

EIS is a widely used, non-destructive method for characterizing Li-ion batteries. We simulate them with our BEST software.

Simulation of Cell Aging and Degradation

During operation and even during storage, Li-ion batteries are exposed to a variety of degradation processes that lead to cell ageing.

Simulation of the Production of Batteries

We simulate battery production processes to make them as efficient as possible without negatively affecting the product properties.

BMWK Project »structur.e«

The aim of the project »structur.e« is to enable a shorter charging time and a greater range for electromobility.

Battery Simulation BEST Supports Virtual Development of Novel Battery Cells

ERDF Project ABBA-VEEB (Extension of the battery simulation BEST to a design platform for the virtual development and testing of battery cells)

New Methods in Development and Production of Battery Cells

The DEFACTO project aims to revolutionize cell production for electric vehicles in Europe.

Battery Cells with Integrated Sensors

Concept development and testing of cells that are individually equipped with voltage and temperature sensors with the support of BEST.

Volume Change and Phase Separation in Electrode Materials

In the AiF project ALIB the existing electrochemical simulation models of BEST were expanded.

Predict the Life of Lithium-Ion Batteries

The MULTIBAT project focuses on the prediction of battery life.

Simulation-Based Design of Fuel Cells

The aim of the research group OPTIGAA is to enable the computer-assisted design of fuel cells.

XERIC: Innovative Climate Control System for Electric Vehicles

The XERIC project is developing a new climate control system that is more energy-efficient in battery powered electric vehicles.

Modeling and Simulation of Li-Ion Batteries

BEST – Battery and Electrochemistry Simulation Tool

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