Load Cycle
This node is activated by enabling Load Cycle as Operation Mode on the Lumped Battery parent node. Use the node to specify a generic load cycling boundary condition in time-dependent simulations, where the switch between charge and discharge depends on the resulting cell voltage, current, elapsed time, or user-defined conditions.
The cycle is defined by adding Current, Voltage, and Rest, or Subloop child nodes.
The node can for instance be used for constant-current/constant-voltage (CCCV) when combined with rate-performance-test (RPT) cycles in battery simulations.
The node is applicable to exterior boundaries to electrode domains, and should typically be applied on the positive electrode of the cell.
The Load type can be set to either Potentiostatic and galvanostatic (the default) or Galvanostatic.
For Potentiostatic and galvanostatic, all child nodes are available for defining the load cycle.
For Galvanostatic, only Current, C Rate, Rest and Subloop child nodes may be added to the Load Cycle.
The Potentiostatic and galvanostatic option is implemented by adding an additional dependent variable for the applied current, which in some cases may be a less stable option than Galvanostatic.
Continuation Conditions
The switching between the load conditions, as specified by the child nodes, is defined internally by the use of solver events.
Enabling Use elapsed time only will define all events as explicit in time, which usually is a less computationally and more accurate option.
Disabling Use elapsed time only will define all events as implicit events, which supports dynamic load switching based on voltage, current and user-defined conditions. Use elapsed time only does not support Subloops.
Cycling Stop Condition
The cycling stop condition can be used to define when the load cycle should be terminated. Use the condition None (the default) to loop over the added child nodes indefinitely.
When the stop condition is fulfilled, the applied current is set to 0. Check Enable stop condition in default solver to also stop the time-dependent solver at this point in the simulation.
A User defined condition can be used to trigger a cycling termination based on the value of any globally available expression in the model. The transition will be defined to occur when the Induser expression switches from negative to positive. For instance, to define a temperature-dependent continuation condition to occur when the maximum temperature variable T_max exceeds 50[degC], define Induser as T_max-50[degC]. (Here, T_max can for instance be a variable defined using a Definitions > Nonlocal Couplings > Maximum operator on a domain.)