RCAIDE.Library.Methods.Powertrain.Sources.Batteries.Lithium_Ion_NMC.update_nmc_cell_age
update_nmc_cell_age#
- update_nmc_cell_age(battery, segment, battery_conditions, increment_battery_age_by_one_day)[source]#
Updates the aging model for 18650 lithium-nickel-manganese-cobalt-oxide batteries.
- Parameters:
battery (BatteryModule) – The battery module containing NMC cells
segment (Segment) – The mission segment in which the battery is operating
battery_conditions (Conditions) –
- Object containing battery state with the following attributes:
- cell.state_of_chargenumpy.ndarray
State of charge of the cell [unitless, 0-1]
- voltage_under_loadnumpy.ndarray
Battery voltage under load [V]
- cell.cycle_in_dayint
Number of cycles the battery has undergone [days]
- cell.charge_throughputnumpy.ndarray
Cumulative charge throughput [Ah]
- cell.temperaturenumpy.ndarray
Battery cell temperature [K]
- cell.capacity_fade_factorfloat
Factor representing capacity degradation [unitless, 0-1]
- cell.resistance_growth_factorfloat
Factor representing internal resistance growth [unitless, ≥1]
increment_battery_age_by_one_day (bool) – Flag to increment the battery age by one day
- Returns:
This function modifies the battery_conditions object in-place.
- Return type:
None
Notes
This function implements a holistic aging model for NMC batteries based on research by Schmalstieg et al. The model accounts for:
Capacity fade due to: - Calendar aging (time-dependent, voltage-dependent, temperature-dependent) - Cycling aging (charge throughput-dependent, voltage-dependent, DOD-dependent)
Resistance growth due to: - Calendar aging (time-dependent, voltage-dependent, temperature-dependent) - Cycling aging (charge throughput-dependent, voltage-dependent, DOD-dependent)
The model uses the following key equations:
Capacity fade factor: E_fade_factor = 1 - α_cap * t^0.75 - β_cap * √Q
Resistance growth factor: R_growth_factor = 1 + α_res * t^0.75 + β_res * Q
- where:
t is time in days
Q is charge throughput
α_cap, β_cap, α_res, β_res are coefficients dependent on voltage and temperature
References
[1] Schmalstieg, Johannes, et al. “A holistic aging model for Li(NiMnCo)O2 based 18650 lithium-ion batteries.” Journal of Power Sources 257 (2014): 325-334.