BEV Thermal Demo: Warm Start, Cold Ambient

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

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 warm initial temperatures for the cabin and battery with a cold ambient temperature, and run the simulation.

celsius_to_kelvin = 273.15
temp_amb = -6.7 + celsius_to_kelvin
temp_init_bat_and_cab = 22.0 + 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_init_bat_and_cab
veh_dict["pt_type"]["BEV"]["res"]["thrml"]["RESLumpedThermal"]["state"]["temperature_kelvin"] = (
    temp_init_bat_and_cab
)
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] * 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 warm 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_ws_ca.py