Battery Design Module Updates

For users of the Batteries & Fuel Cells Module, the name of the module has changed to the Battery Design Module in version 5.6, while retaining all the functionality. Users with a current subscription of the Batteries & Fuel Cells Module will receive the Battery Design Module as part of the upgrade to version 5.6. New features include automatic generation of iterative solvers, a new Linearization option, and two new tutorial models. Learn more about the battery design updates below.

Automatic Generation of Iterative Solvers

The Iterative Geometric and Algebraic Multigrid solvers are now automatically generated by the study step nodes (however, a Direct solver will still always be used by default). Enabling one of the iterative solvers may decrease memory use and computational time for large simulations.

Highly Conductive Porous Electrode

The new Highly Conductive Porous Electrode domain node is available in most electrochemistry interfaces. This feature can be used for porous electrodes with a high conductivity in the electron-conducting electrode phase. It replaces the spatial variable for the electrode potential by a global variable, thereby reducing the number of degrees of freedom of the problem.

Linearization of Concentration Dependence in Electrode Kinetics

The new Linearization option improves kinetics for nonunit reaction orders by circumventing issues when evaluating powers of negative numbers. This feature is available in the Electrode Reaction and Porous Electrode Reaction nodes in the Tertiary Current Distribution interfaces when using the Nernst equation for the equilibrium potential in combination with either the Mass action law or Lumped multistep for the exchange current density. The new Linearization option is turned on by default when creating a new model and is used by all tutorial models featuring the Nernst equation and mass action law or lumped multistep kinetics options.

New Porous Medium Feature

A new feature for handling a porous medium is available for defining the different phases: solids, fluids, and immobile fluids. In the Heat Transfer in Porous Media interface, the Porous Medium feature is used to manage the material structure with a dedicated subfeature for each phase: Fluid, Porous Matrix, and optionally, Immobile Fluids. This new workflow provides added clarity and improves the user experience. It also facilitates multiphysics couplings in porous media in a more natural way. Combined with the Moisture Transport and Porous Media Flow interfaces, the heat transfer in porous media improvements enable the modeling of nonisothermal flow and latent heat storage in porous media.

You can see this new setup in the following models:

Revamped Porous Media Features for Transport of Diluted Species

The Transport of Diluted Species in Porous Media interface is revamped to use the new Porous Medium node. Two new domain features, the Porous Medium and the Unsaturated Porous Medium nodes, are available in the Transport of Diluted Species in Porous Media interface. You can use the new Porous Medium node for assigning material properties to the multiple phases in a porous medium. The new nodes have dedicated containers to define the properties for the liquid, gas, and porous matrix. You can see this functionality demonstrated in the Ceramic Water Filter with Activated Carbon Core tutorial model.

A closeup view of the COMSOL Multiphysics version 5.6 UI with the settings shown for Transport of Diluted Species in Porous Media and a ceramic water filter candle model in the Graphics window.
Contaminant concentration in a ceramic water filter candle.

New and Enhanced Functionality for the Electrical Circuit Interface

For Time Dependent studies, the Electrical Circuit interface has been equipped with an "event-based" Switch feature. This allows you to model the "instantaneous" on-off switching of certain connections in the circuit. The switch can be current controlled, voltage controlled, or controlled by user-defined Boolean expressions.

Furthermore, Parameterized Subcircuit Definitions are added. Together with the Subcircuit Instance, these allow you to create your own building blocks containing smaller circuits, and use multiple parameterized variants of those in your larger circuit. Finally, the state, event, and solver machinery has been improved, especially the transient modeling of nonlinear (semiconductor) devices, which has become more robust.

The circuit improvements are primarily developed for the AC/DC Module, but other modules that provide access to the Electrical Circuit interface will benefit too. You can view the new functionality in these updated models:

Wide Support for Eigenfrequency Analysis

The Eigenfrequency study is now supported for most of the AC/DC Module interfaces: Electric Currents, Electric Currents in Shells, Electric Currents in Layered Shells, Electrical Circuit, Electrostatics, and Magnetic Fields. In addition to supporting full-wave cavity mode analysis in the Magnetic Fields interface, it is possible to run eigenfrequency analyses with models involving electrical circuits. The eigenfrequency support is primarily developed for the AC/DC Module, but other modules that provide one of the affected physics interfaces will benefit from it too.

The COMSOL Multiphysics version 5.6 UI showing the Model Builder, Global Evaluation settings with the Data and Expressions sections expanded, and a probe plot for the eigenfrequency analysis of an RLC circuit.
The resonance peak of a simple RLC circuit. The eigenfrequency and Q-factor are analyzed and compared to analytically determined values.

New Lithium Sulfur Battery Tutorial Model

The new Lithium-Sulfur Battery tutorial in the Application Library can be used for modeling the charge-discharge behavior for a lithium-sulfur battery at various rates. The model is defined in the Tertiary Current Distribution, Nernst-Planck interface, and makes use of the new Dissolving-Depositing Species feature on the Separator node. Convergence is greatly improved by the new Linearization option.

New Tutorial Models and Applications

COMSOL Multiphysics® version 5.6 brings two new tutorial models and one example app to the Battery Design Module.

Lithium-Sulfur Battery

A 1D plot of the discharge voltage curves in a Li-S battery.
Discharge voltage curves of a lithium-sulfur battery.
Application Library Title:
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1D Isothermal Nickel-Cadmium Battery

A 1D plot of the discharge voltage curves in a nickel-cadmium battery.
Discharge voltage curves of a nickel-cadmium battery.

Application Library Title:
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Lithium Battery Pack Designer

A simulation app for designing lithium battery packs with a card for inputs on the left, simulation results in the middle, and a help wizard on the right.
Perform parameter estimation of battery parameters and model the temperature distribution in a battery pack. The number of batteries and configuration can be modified in order to investigate the impact on the internal temperature gradients. Note: requires the Optimization Module.

Application Library Title:
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