Use the Model setting to choose between a Lumped cell or a Two electrodes model.

For the Lumped cell model, two subnodes are added by default — Cell Equilibrium Potential and Voltage Losses. For the Two electrodes model, three subnodes are added by default — Negative Equilibrium Potential, Positive Equilibrium Potential, and Voltage Losses. In both cases, only one instance each of these subnodes can be present in the interface, so you cannot add additional instances of these subnodes, and they cannot be deleted. The selection of these subnodes are locked to the selection of the Batteries node.

Additional subnodes such as Thermal Event, Capacity Loss (for the Lumped cell model), Negative Charge Inventory Loss (for the Two electrodes model), Positive Charge Inventory Loss (for the Two electrodes model), Negative Host Capacity Loss (for the Two electrodes model), Positive Host Capacity Loss (for the Two electrodes model), and Short Circuit can be also be added. All capacity loss subnodes are singleton nodes and the selection is locked to the selection of the Batteries node. The Short Circuit subnode is also a singleton node with a default empty selection, that can be set to any of the domains of the Batteries node. The settings of all the capacity loss subnodes and the Short Circuit subnode are similar to the corresponding nodes in The Lumped Battery Interface.

Enable Specify battery properties from materials to automatically set up some inputs (discussed below) from a material specified in the Materials node, that has been assigned to the selection of the Batteries node. These inputs are set to From Material and disabled in the user interface. It is possible to assign different materials to the individual battery cells, thereby modeling packs with cells that have different individual parameter settings using the Specify battery properties from materials checkbox.

For the Lumped cell model with Specify battery properties from materials enabled, the Initial battery cell capacity, all open circuit voltage related properties on the Cell Equilibrium Potential subnode (either the Open circuit voltage at reference temperature, the Temperature derivative of open circuit voltage and the Reference temperature, or the Open circuit voltage and the Thermoneutral voltage), and all overpotential related properties on the Voltage Losses subnode (the Ohmic overpotential at 1C, the Dimensionless charge exchange current, and either the Diffusion time constant or the RC time constant and the RC potential at 1C) are automatically set to From Material and disabled in the user interface. These inputs are taken from a material specified in the Materials node, that has been assigned to the selection of the Batteries node.

For the Two Electrodes model with Specify battery properties from materials enabled, the Initial negative host capacity, the Initial positive host capacity, and all overpotential related properties on the Voltage Losses subnode (the Ohmic overpotential at 1C, the Dimensionless charge exchange current, negative/positive, and either the Diffusion time constant, negative/positive or the RC time constant, negative/positive, and the RC potential at 1C, negative/positive) are automatically set to From Material and disabled in the user interface. These inputs are taken from a material specified in the Materials node, that has been assigned to the selection of the Batteries node. Note that for the Two Electrodes model, the Specify battery properties from materials checkbox does not control any of the inputs belonging to the Negative Equilibrium Potential and Positive Equilibrium Potential subnodes. The negative and positive electrode material needs to be specified explicitly on the individual subnodes, and the respective equilibrium potential related properties on the Negative Equilibrium Potential and Positive Equilibrium Potential subnodes are set up accordingly.

For the Lumped cell model, if Specify battery properties from materials is enabled and the concentration overpotential is enabled and set to Particle diffusion on the Voltage Losses subnode, the Heat of mixing contribution can either be included or excluded in the total heat source. Enabling Heat of mixing, requires the Particle material to be set. The Open circuit voltage at reference temperature and the Temperature derivative of open circuit voltage (or the Thermoneutral voltage) are automatically set up from the Materials node. Note that if Specify battery properties from materials is not enabled and the concentration overpotential is enabled and set to Particle diffusion, the heat of mixing contribution is always included by default in the total heat source, and there are no additional settings on the Voltage Losses subnode.

For the Two electrodes model, if concentration overpotential is included and modeled based on diffusion in an idealized particle, the heat of mixing contribution is not included, and the battery heat source is calculated as discussed in Theory for the Lumped Battery Interface.

For the Lumped cell model, the Initial battery cell capacity (C) specifies the initial battery capacity.

For the Two electrodes model, the Initial negative host capacity (C) and Initial positive host capacity (C) specify the respective electrode initial host capacities.

For the Lumped cell model, the Initial cell state of charge (1) specifies the state of charge of the battery when the simulation starts.

For the Two electrodes model option, the initial charge distribution can be defined by specifying either the Initial cell state of charge (1) or the Initial cell voltage (V). Additionally, the total charge inventory of the cell needs to be set. This can be done either based on the Positive electrode host capacity, the Negative electrode host capacity, or an Explicit value. It is also possible to enable Add formation loss to reduce the initial charge inventory, assuming that some charge inventory has been irreversibly lost prior to the start of the simulation. The formation loss can be set either to Fraction of negative host capacity, Fraction of positive host capacity, or an explicit Charge value.

This section is applicable to the Two electrodes model option. In this section, the Cell voltages at 0% and 100% SOC are defined. These voltages are used to connect the SOC of the battery cell to the individual electrode charge levels.

The Cell voltages at 0% and 100% SOC can be defined either From operational potential limits or User defined. For the From operational potential limits case, the settings of the Operational Potential Limits section in the Negative Equilibrium Potential and Positive Equilibrium Potential nodes are used to define the 0% and 100% SOC cell voltages.

This section is applicable to the Lumped cell model. In this section, select either the Reference equilibrium potential and temperature derivative option or the Equilibrium potential and thermoneutral potential option. The appropriate inputs are thereby enabled in the Cell Equilibrium Potential node.