RCAIDE.Library.Methods.Powertrain.Sources.Batteries.Lithium_Ion_NMC.compute_nmc_cell_performance

compute_nmc_cell_performance#

compute_nmc_cell_performance(battery_module, state, bus, coolant_lines, t_idx, delta_t)[source]#

Computes the performance of a lithium-nickel-manganese-cobalt-oxide (NMC) battery cell.

Parameters:

battery_module (RCAIDE.Library.Components.Sources.Battery_Modules.Lithium_Ion_NMC) –
Battery module component with the following attributes:
- tagstr
  Identifier for the battery module
- cellData
  
  Cell properties
  
  electrode_areafloat
  Area of the electrode [m²]
  
  surface_areafloat
  Surface area of the cell [m²]
  
  massfloat
  Mass of a single cell [kg]
  
  specific_heat_capacityfloat
  Specific heat capacity of the cell [J/(kg·K)]
  
  discharge_performance_mapfunction
  Function that maps state of charge, temperature, and current to voltage
- maximum_energyfloat
  Maximum energy capacity of the module [J]
- electrical_configurationData
  
  Electrical configuration
  
  seriesint
  Number of cells in series
  
  parallelint
  Number of cells in parallel
state (RCAIDE.Framework.Mission.Common.State) –
State object containing:
- conditionsData
  
  Flight conditions
  
  energydict
  
  Energy conditions indexed by component tag
  
  [bus.tag]Data
  
  Bus-specific conditions
  
  energynumpy.ndarray
  Energy stored in the bus [J]
  
  power_drawnumpy.ndarray
  Power draw on the bus [W]
  
  current_drawnumpy.ndarray
  Current draw on the bus [A]
  
  battery_modulesdict
  
  Battery module conditions indexed by tag
  
  [battery_module.tag]Data
  
  Battery module conditions
  
  energynumpy.ndarray
  Energy stored in the module [J]
  
  voltage_open_circuitnumpy.ndarray
  Open-circuit voltage [V]
  
  powernumpy.ndarray
  Power output [W]
  
  internal_resistancenumpy.ndarray
  Internal resistance [Ω]
  
  heat_energy_generatednumpy.ndarray
  Heat energy generated [W]
  
  voltage_under_loadnumpy.ndarray
  Voltage under load [V]
  
  currentnumpy.ndarray
  Current [A]
  
  temperaturenumpy.ndarray
  Temperature [K]
  
  state_of_chargenumpy.ndarray
  State of charge [0-1]
  
  cellData
  Cell-specific conditions with same properties as module
- numericsData
  
  Numerical properties
  
  number_of_control_pointsint
  Number of control points in the mission
bus (RCAIDE.Library.Components.Systems.Electrical_Bus) –
Electrical bus component with the following attributes:
- tagstr
  Identifier for the electrical bus
- battery_module_electric_configurationstr
  Configuration of battery modules (“Series” or “Parallel”)
- battery_moduleslist
  List of battery modules connected to the bus
coolant_lines (list) – List of coolant lines for thermal management
t_idx (int) – Current time index in the simulation
delta_t (numpy.ndarray) – Time step size [s]

Returns:

stored_results_flag (bool) – Flag indicating if results were stored
stored_battery_module_tag (str) – Tag of the battery module for which results were stored

Notes

This function models the electrical and thermal behavior of an NMC battery cell based on experimental data. It updates various battery conditions in the state object, including: current energy, temperature, heat energy generated, load power, current, open-circuit voltage, charge throughput, internal resistance, state of charge, depth of discharge, and voltage under load.

The model includes:

Internal resistance calculation
Thermal modeling (heat generation and temperature change)
Electrical performance (voltage and current calculations)
State of charge and depth of discharge updates

Major Assumptions

All battery modules exhibit the same thermal behavior
The cell temperature is assumed to be the temperature of the entire module
Battery performance follows empirical models based on experimental data

Theory The internal resistance is modeled as a function of state of charge:

\[R_0 = 0.01483 \cdot SOC^2 - 0.02518 \cdot SOC + 0.1036\]

Heat generation includes both Joule heating and entropy effects:

\[ \begin{align}\begin{aligned}\dot{q}_{entropy} = -T \cdot \Delta S \cdot i / (nF)\\\dot{q}_{joule} = i^2 / \sigma\\Q_{heat} = (\dot{q}_{joule} + \dot{q}_{entropy}) \cdot A_s\end{aligned}\end{align} \]

References

[1] Zou, Y., Hu, X., Ma, H., and Li, S. E., “Combined State of Charge and State of Health estimation over lithium-ion battery cell cycle lifespan for electric vehicles,” Journal of Power Sources, Vol. 273, 2015, pp. 793-803. doi:10.1016/j.jpowsour.2014.09.146 [2] Jeon, D. H., and Baek, S. M., “Thermal modeling of cylindrical lithium ion battery during discharge cycle,” Energy Conversion and Management, Vol. 52, No. 8-9, 2011, pp. 2973-2981. doi:10.1016/j.enconman.2011.04.013

compute_nmc_cell_performance#

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