# BATTERY_THERMAL_RUNAWAY_MODEL

Specifies a thermal runaway model and its parameters.

## Type

AcuSolve Command

## Syntax

BATTERY_THERMAL_RUNAWAY_MODEL("name") {parameters...}

## Parameters

- equation_type (enumerated) [four_equation]
- Type of thermal runaway model.
- four_equation
- Four equation thermal runaway heat generation model from Hatchard.
- five_equation
- Hatchard thermal runaway heat generation model (four_equation) with additional heat generation due to electrolyte decomposition.

- formulation_type (enumerated) [lumped]
- Method used for thermal runaway.
- nodal
- Thermal runaway heat contribution is calculated at each node in a battery cell.
- lumped
- Thermal runaway heat contribution is modeled as a lumped parameter for a battery cell.

- ecm_model (enumerated) [yes]
- Turn on ecm model for thermal runaway.
- yes
- Model thermal runaway heat generation with an ECM model included for the batteries operating under normal conditions.
- no
- Model only thermal runaway heat generation.

- internal_short_circuit (enumerated) [off]
- Add internal short circuit equation to thermal runaway model.
- off
- Internal short circuit equation is disabled.
- on
- Internal short circuit equation is enabled.

- internal_short_circuit_temperature (real) [=438.15]
- Temperature at which internal short circuit occurs.
- sub_iteration_initial_time_step_size (real) [=1000]
- Initial time step for sub-stepping the reaction kinetic equation.
- sub_iteration_minimum_time_step_size (real) [=1e-4]
- Minimum time step for sub-stepping the reaction kinetic equations.
- sub_iteration_time_step_size_tolerance (real) [=1e-3]
- Sensitivity of the change in sub-step time step size to changes in the solution. For example, a small tolerance value will lead to smaller thermal runaway ODE sub-stepping time step sizes.
- anode_decomposition_frequency_factor (real) [=2.5e13]
- Pre-exponential (frequency) factor for the anode decomposition reaction rate.
- sei_decomposition_frequency_factor (real) [=1.67e15]
- Pre-exponential (frequency) factor for the sei (solid electrolyte interphase) decomposition reaction rate.
- cathode_decomposition_frequency_factor (real) [=6.67e11]
- Pre-exponential (frequency) factor for the cathode decomposition reaction rate.
- electrochemical_reactions_frequency_factor (real) [=3.37e12]
- Pre-exponential (frequency) factor for the electrochemical reaction rate.
- electrolyte_decomposition_frequency_factor (real) [=5.14e25]
- Pre-exponential (frequency) factor for the electrolyte decomposition reaction rate.
- anode_decomposition_activation_energy (real) [=2.24e-19]
- Minimum energy needed for the anode decomposition reaction to occur.
- sei_decomposition_activation_energy (real) [=2.24e-19]
- Minimum energy needed for the sei decomposition reaction to occur.
- cathode_decomposition_activation_energy (real) [=2.03e-19]
- Minimum energy needed for the cathode decomposition reaction to occur.
- electrochemical_reactions_activation_energy (real) [=1.58e-19]
- Minimum energy needed for the electrochemical (short circuit) reaction to occur.
- electrolyte_decomposition_activation_energy (real) [=4.544e-19]
- Minimum energy needed for the electrolyte decomposition reaction to occur.
- anode_mass (real) [=0.006]
- Mass of the anode material in battery core.
- cathode_mass (real) [=0.012]
- Mass of the cathode material in battery core.
- sei_mass (real) [=0.006]
- Mass of the sei in battery core.
- electrolyte_mass (real) [=0.004]
- Mass of the electrolyte in battery core.
- anode_decomposition_reaction_enthalpy (real) [=1.714E6]
- Specific enthalpy for the anode decomposition reaction.
- cathode_decomposition_reaction_enthalpy (real) [=3.14E5]
- Specific enthalpy for the cathode decomposition reaction.
- sei_decomposition_reaction_enthalpy (real) [=2.57E5]
- Specific enthalpy for the sei decomposition reaction.
- electrochemical_reaction_enthalpy (real) [=4.989E6]
- Enthalpy of the short circuit derived from joule heating.
- electrolyte_decomposition_reaction_enthalpy (real) [=1.55E5]
- Specific enthalpy for the electrolyte decomposition reaction.
- initial_anode_lithium_fraction (real) [=0.75]
- Fractional amount of lithium intercalated in the anode.
- initial_sei_lithium_fraction (real) [=0.15]
- Fraction of lithium-containing species in the solid electrolyte interphase.
- initial_sei_thickness (real) [=0.033]
- Thickness of the solid electrolyte interphase.
- initial_degree_of_cathode_conversion (real) [=0.04]
- Initial degree of conversion of cathode material for cathode decomposition.
- initial_electrolyte_fraction (real) [=1.0]
- Initial electrolyte fraction.