Ambient Temprature of a battery (under low temp)

General
1

Hello,

I am trying to simulate a battery under cold temprature, somewhere around 263.15 K. When I simulate the battery at room temprature it is giving me a desired discharge capacity vs cycle number graph. However, when I try update the paramter "Ambient temperature [K] " to 263.15 there does not seem to be much difference in room temp and cold temp graphs.

I am running this:

pybamm.set_logging_level(“NOTICE”)

Load Chen2020 parameter set

parameter_values = pybamm.ParameterValues(“Chen2020”) #Mohtat2020

parameter_values.update({
‘Initial concentration in negative electrode [mol.m-3]’: 24866.0,
‘Initial concentration in positive electrode [mol.m-3]’: 16038.0,
“SEI kinetic rate constant [m.s-1]”: 1e-13,
“Nominal cell capacity [A.h]”: 4.2,
“Lower voltage cut-off [V]”: 2.5,
“Upper voltage cut-off [V]”: 4.2,
})

Load the Single Particle Model (SPM)

spm = pybamm.lithium_ion.SPM({“SEI”: “ec reaction limited”})

Define the experiment

experiment = pybamm.Experiment(
[
(
“Discharge at 1C until 2.5V”,
“Charge at 1C until 4.2V”,
“Hold at 4.2V until 1C”,
)
] * 300,
termination=“80% capacity”,
)

sim = pybamm.Simulation(spm, experiment=experiment, parameter_values=parameter_values)

# Solve the model

sol = sim.solve()

also, I have been reading the source code and documentation and there does not seem to be much information regarding the Ambient temperature of the model. I wanted to ask if the Ambient temperature has been implemented? if not, I would like to get guidance on where should I start if I want to implement such a feature. The most relevant formula I found is the arrhenius equation.

I would greatly appreciate any help.

2

Hi Guri,

I believe that “Ambient temperature [K]” refers to the temperature of the surrounding environment and is only taken into account in your simulation if you use a thermal model (e.g., “thermal”: “lumped”). If no thermal model is active, this parameter is ignored, and the cell temperature remains fixed at the “Initial temperature [K]”. To simulate at a different temperature, you should adjust the “Initial temperature [K]” parameter, which sets the starting temperature of the battery. If you’re using a thermal model, you might also want to set “Ambient temperature [K]” to define the external conditions affecting heat exchange.

3

The "Chen2020" parameter set does not have much temperature dependence. Try using "ORegan2022" instead. You may need to add more mesh points in the r direction to get an accurate solution.