The Battery Pack (bp) interface (), found under the Electrochemistry > Battery Interfaces branch () offers a one-to-many approach for setting up multiple battery cell models, and for connecting them in a 3D geometry. The interface is typically used together with a heat transfer interface for modeling of thermal pack management and thermal runaway propagation problems.

The interface defines two types of domain nodes by default — Batteries and Current Conductors, which are used to define the active battery cells and the electrical wiring (current collectors, feeders, and busbars, and so on) of the pack, respectively. The location of the interconnects between the batteries and the current conductors are defined by the Negative Connectors and Positive Connectors boundary nodes, which are always also present by default.

The battery cell models (Lumped cell model and Two electrodes model) are defined similarly as for The Lumped Battery Interface. All battery models defined by a Battery Pack interface share the same parameter settings. Modeling of packs with cells different individual parameter settings can be accomplished by either using the Specify battery properties from materials checkbox available on the Batteries node or by coupling multiple separate Battery Pack and/or Lumped Battery interfaces together.

Individual cell models are defined automatically on disjoint sets of battery domains and each individual battery current load is set implicitly via potential constraints at the negative/positive connector boundaries between the battery domains and the current conductor domains. The load of the complete battery pack is defined by boundary conditions on the exterior boundaries to the current conductor domains, which can be added as subnodes to the Current Conductors node.

The Battery Pack interface also defines a heat source that can be coupled to a Heat Transfer interface, using the Electrochemical Heating node, for modeling battery cooling and thermal management. The interface is available in 3D only.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is bp.

To display this section, click the Show More Options button () and select Advanced Physics Options.

In this section you can set the checkbox Exclude heat source variable from Jacobian. The checkbox is selected by default. Note that this checkbox is relevant only when coupling to heat transfer interfaces. Excluding the heat source from the Jacobian may decrease the computation time.