Hii guys, i am working with Lg18650 Mh1 cell. I want to simulate cell degradation for 1600 cycles and then match with my experimental result. Which parameter set will be compatible to use for my simulation?
That cell uses NMC 811 so the "OKane2022"
parameter set should at least be able to reproduce a slow discharge (C/10 or less). Try it!
@DrSOKane i want simulate at 0.5C.
I know, but doing a slow discharge is an excellent way to find out if your problem is to do with the open-circuit parameters or the C-rate dependent parameters. Do you have any experimental data for C/5 or less? If not, do the same exercise but with 0.5C.
Hii @DrSOKane i dont have experimental data for slow discharge of C/5 . I have now tried to simulate with 0.5C .
Here is the plot. I have simulated only for 300 cycles now .
Here is the same plot with zoom in.
Here is a screen shot of data I am using .
code I am using is this.
#########
import pybamm
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
import os
model = pybamm.lithium_ion.SPMe(
{
“SEI”: “solvent-diffusion limited”,
“SEI porosity change”: “true”,
“lithium plating”: “partially reversible”,
“lithium plating porosity change”: “true”, # alias for “SEI porosity change”
#“particle mechanics”: (“swelling and cracking”, “swelling only”),
#“SEI on cracks”: “true”,
“loss of active material”: “stress-driven”,
“calculate discharge energy”: “false”,
}
)
param = pybamm.ParameterValues(“OKane2022”)
var_pts = {
“x_n”: 5, # negative electrode
“x_s”: 5, # separator
“x_p”: 5, # positive electrode
“r_n”: 20, # negative particle
“r_p”: 20, # positive particle
}
param.update({
“Electrode width [m]”: 1.58 * 2.93 /5 ,
“Nominal cell capacity [A.h]”: 3.1,
})
param.update({“SEI solvent diffusivity [m2.s-1]”:2.5e-22 }, check_already_exists=False)
experiment = pybamm.Experiment(
[
“Discharge at 0.5C until 2.95V”,
“Charge at 0.5C until 4.15V”,
“Hold at 4.15V until 50mA”,
“Rest for 10 minutes”,
] * 100
)
sim = pybamm.Simulation(model, parameter_values=param, experiment=experiment)
solution = sim.solve()
time = solution[“Time [s]”].data
current = solution[“Current [A]”].data
discharge_capacity = solution[“Discharge capacity [A.h]”].data
discharge_capacities =
cycle_numbers =
for i in range(1, len(time)):
if current[i] < 0 and current[i - 1] >= 0:
discharge_capacities.append(discharge_capacity[i - 1])
cycle_numbers.append(len(discharge_capacities))
#########
Question? How can improve my simulated plot further? I have also tried to change “SEI solvent diffusivity [m2.s-1]” parameter, but this parameter didn’t have any effect in plot , when I changed the value.