RPT With Degradation Experiment

[MirAbbasAli2A]

Hello -

I am having some difficulty plotting an RPT with degradation experiment. I was following the example notebook on RPT with degradation and wrote the following code:

import pybamm
import matplotlib.pyplot as plt
import numpy as np
from os import path
import pandas as pd

model = pybamm.lithium_ion.DFN(options = {
"thermal":"lumped",
"dimensionality":0,
"cell geometry": "arbitrary",
"SEI": "solvent-diffusion limited",
"SEI porosity change": "true",
"particle mechanics": ("swelling and cracking", "swelling and cracking"),
"SEI on cracks": "true",
"loss of active material": "stress-driven",
"calculate discharge energy": "true",
"lithium plating": "partially reversible",
"lithium plating porosity change": "true"
},
name="TDFN",
)

param = pybamm.ParameterValues("OKane2022")

#Simple cycling experiment
N=20

cccv_experiment = pybamm.Experiment([
("Charge at C/2 until 4.2V",
"Hold at 4.2V until C/20",
"Discharge at 1C until 2.5V",
)
]*N
)

charge_experiment = pybamm.Experiment([(
"Charge at C/2 until 4.2V",
"Hold at 4.2V until C/20",
)])

rpt_experiment = pybamm.Experiment([(
"Discharge at C/3 until 2.5V",
)])

#Run model

cccv_sols = []
charge_sols = []
rpt_sols = []
M = 11
for i in range(M):
if i != 0: # skip the first set of ageing cycles because it's already been done
sim = pybamm.Simulation(model, experiment=cccv_experiment, parameter_values=param)
cccv_sol = sim.solve(starting_solution=rpt_sol)
sim = pybamm.Simulation(model, experiment=charge_experiment, parameter_values=param)
charge_sol = sim.solve(starting_solution=cccv_sol)
sim = pybamm.Simulation(model, experiment=rpt_experiment, parameter_values=param)
rpt_sol = sim.solve(starting_solution=charge_sol)
cccv_sols.append(cccv_sol)
charge_sols.append(charge_sol)
rpt_sols.append(rpt_sol)

#Plot Discharge Capacity

cccv_cycles = []
cccv_capacities = []
rpt_cycles = []
rpt_capacities = []
for i in range (M):
for j in range(N):
cccv_cycles.append(i*(N+2)+j+1)
start_capacity = rpt_sol.cycles[i*(N+2)+j].steps[2]["Discharge capacity [A.h]"].entries[0]
end_capacity = rpt_sol.cycles[i*(N+2)+j].steps[2]["Discharge capacity [A.h]"].entries[-1]
cccv_capacities.append(end_capacity-start_capacity)
rpt_cycles.append((i+1)(N+2))
start_capacity = rpt_sol.cycles[(i+1)(N+2)-1]["Discharge capacity [A.h]"].entries[0]
end_capacity = rpt_sol.cycles[(i+1)*(N+2)-1]["Discharge capacity [A.h]"].entries[-1]
rpt_capacities.append(end_capacity-start_capacity)
plt.scatter(cccv_cycles,cccv_capacities,label="Ageing cycles")
plt.scatter(rpt_cycles,rpt_capacities,label="RPT cycles")
plt.xlabel("Cycle number")
plt.ylabel("Discharge capacity [A.h]")
plt.legend()

I keep getting an error of "list index out of range" for the following line of code: "start_capacity = rpt_sol.cycles[i*(N+2)+j].steps[2]["Discharge capacity [A.h]"].entries[0]". In fact, I downloaded the example notebook and tried plugging M=11 and N=20 and I get the exact same error. I don't get the error when I use the notebook values of M=5 and N=10.

Forgive me for the seemingly simplistic nature of this question, but could anyone tell me why I getting the list index out of range error when I simply try to change the values of M and N?

My basic purpose here is to plot the discharge capacity over the number of cycles with the rpt portion of my experiment. If there is a simpler way to do this, please do let me know as well.

Thank you for your time.

[MirAbbasAli2A]

Never mind, I figured it out. Was an error with my code.

[yazyr]

@MirAbbasAli2A Hi! Could you kindly let me know what was the issue with your code? I'm trying to do a similar experiment and it would be a great favour if you could guide me what the error was? Thanks

[MirAbbasAli2A]

Hey, I had to declare rpt_sol and cccv_sol = None before the initial for loop. Then it worked.