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Thermal Event
The settings of this subnode set up an event-based heat source in a battery pack. The node is typically used to study cell-to-cell propagation of thermal runaway phenomena, where the time-dependent heat source triggered by the event stems from exothermic reactions due to (irreversible) decomposition of the electrolyte and/or electrode materials. Multiple thermal event nodes may be used to model the effect of heat sources from different reactions. The selection of this subnode applies by default to the selection of the Batteries node, but may be altered.
The thermal event is triggered by an Event condition, which could be when either the maximum or average cell temperature exceeds a corresponding trigger temperature, or if the simulated time exceeds the explicit time that is specified. The event can only be triggered once per battery cell. The Heat source after event is to be specified as a function of time elapsed after triggering of the event, and this can be done using options of Local table, User defined, or From definitions. After the event has been triggered, the thermal event heat source is added to the total sum of all heat sources for the battery cell.
In addition, the event may also induce changes in the ohmic overpotentials (internal resistance) of the battery cells and/or induce cell short circuits. Add ohmic overpotential after event can be used to specify Ohmic overpotential at 1C after event (V), and the specified value will be added to the corresponding value specified in the Voltage Losses subnode after the event. Add short circuit after event can be used to specify Short circuit conductance after event (S), and the specified value will add a short circuiting current after the event in a similar way as the Short Circuit node. If a Short Circuit subnode is already present, the event-induced short circuit current will be added in parallel.