BEV Thermal Demo: Cold Start, Cold Ambient

This demo simulates a Battery Electric Vehicle (BEV) with thermal modeling under cold start and cold ambient conditions, where the cabin and battery begin at the same temperature as the surrounding air.

import os
import sys
from pathlib import Path

import seaborn as sns

sys.path.insert(0, str(next(p / "demo_scripts" for p in (Path.cwd(), *Path.cwd().parents) if (p / "demo_scripts").is_dir())))

import fastsim as fsim
from plot_utils import (
    plot_bev_hvac_pwr,
    plot_bev_res_energy,
    plot_bev_res_pwr,
    plot_bev_temperatures,
    plot_road_loads,
)

sns.set_theme()

SHOW_PLOTS = os.environ.get("SHOW_PLOTS", "true").lower() == "true"
SAVE_FIGS = os.environ.get("SAVE_FIGS", "false").lower() == "true"

Setup and Simulation¶

Load a thermal BEV, set cold initial temperatures for the cabin and battery to match the cold ambient, and run the simulation.

celsius_to_kelvin = 273.15
temp_amb_and_init = -6.7 + celsius_to_kelvin

# load 2020 Chevrolet Bolt BEV with thermal model
veh = fsim.Vehicle.from_resource("2020 Chevrolet Bolt EV thrml.yaml")

veh_dict = veh.to_pydict()
veh_dict["cabin"]["LumpedCabin"]["state"]["temperature_kelvin"] = temp_amb_and_init
veh_dict["pt_type"]["BEV"]["res"]["thrml"]["RESLumpedThermal"]["state"]["temperature_kelvin"] = (
    temp_amb_and_init
)
veh = fsim.Vehicle.from_pydict(veh_dict)

veh.set_save_interval(1)

# load cycle and set ambient temperature
cyc_dict = fsim.Cycle.from_resource("udds.csv").to_pydict()
cyc_dict["temp_amb_air_kelvin"] = [temp_amb_and_init] * len(cyc_dict["time_seconds"])
cyc = fsim.Cycle.from_pydict(cyc_dict)

sd = fsim.SimDrive(veh, cyc)
sd.walk()

df = sd.to_dataframe()
sd_dict = sd.to_pydict(flatten=True)

Visualize Results¶

Battery power, energy, component temperatures, Heating, Ventilation, and Air Conditioning (HVAC) power demand, and road loads under cold start, cold ambient conditions.

fig_res_pwr, ax_res_pwr = plot_bev_res_pwr(df, save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

fig_res_energy, ax_res_energy = plot_bev_res_energy(df, save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

fig_temps, ax_temps = plot_bev_temperatures(df, save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

fig_hvac, ax_hvac = plot_bev_hvac_pwr(df, save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

fig, ax = plot_road_loads(df, veh, save_figs=SAVE_FIGS, show_plots=SHOW_PLOTS)

Source: fastsim/docs/demo_scripts/thermal/demo_bev_thrml_cs_ca.py