Heat Transfer Coefficient Only Affects Temperature, Not Current/Voltage/Power

[Maguixx]

Issue Description

I performed two discharge simulations with different heat transfer coefficient values (10 and 290) and noticed that only the temperature profile changes between the two cases. The current, voltage, resistance, and thermal power profiles remain identical.

Expected Behavior

I expected that changing the heat transfer coefficient would affect not only the temperature but also the electrochemical behavior (current, voltage, power) since temperature typically influences: Battery internal resistance, reaction kinetics, diffusion coefficients...

Observed Behavior

• Heat transfer coefficient = 10: Temperature rises significantly during discharge
• Heat transfer coefficient = 290: Temperature remains relatively stable
• All other variables (current, voltage, resistance, thermal power): Identical profiles in both cases

Questions

1. Is this the expected behavior in PyBaMM?
2. Does the heat transfer coefficient only affect heat dissipation to the environment without coupling back to the electrochemical model?
3. Are there specific model settings or parameters that need to be enabled to account for temperature-dependent electrochemical properties?

Simulation Details

• Model: DFN model with lumped thermal model
• Discharge conditions: : Discharge at 4A for 3600 seconds
• Heat transfer coefficient values tested: 10, 290

Attached Results

These are the graphs with 10 HTC

and these are the graphs with 290 HTC

Any insights on whether this is expected behavior or if there are additional settings needed to couple thermal and electrochemical effects would be greatly appreciated!

[rtimms]

Which parameter set are you using? Not all of them include temperature dependence

[Maguixx]

I'm using the Chen2020 parameter set as the base, with the following thermal parameters updated:

Cell specifications

"Cell volume [m3]": 1.65e-5,
"Cell cooling surface area [m2]": 4.18e-3,
"Ambient temperature [K]": 296.15, # 23°C
"Initial temperature [K]": 296.15,
"Nominal cell capacity [A.h]": 4,

Thermal conductivities

"Negative electrode thermal conductivity [W.m-1.K-1]": 0.7,
"Positive electrode thermal conductivity [W.m-1.K-1]": 0.7,
"Separator thermal conductivity [W.m-1.K-1]": 0.7,
"Negative current collector thermal conductivity [W.m-1.K-1]": 34,
"Positive current collector thermal conductivity [W.m-1.K-1]": 34,

Total heat transfer coefficient

"Total heat transfer coefficient [W.m-2.K-1]": 290,

Between the two simulations, only the "Total heat transfer coefficient" value changes (from 10 to 290). All other parameters remain identical.

Questions:

Should I change or add any specific parameters to enable temperature-dependent electrochemical behavior?
Why doesn't the heat transfer coefficient affect the other variables (current, voltage, resistance, thermal power)? Is this because the Chen2020 parameter set lacks temperature-dependent electrochemical parameters? because the most important parameter for me to check is the heat transfer coefficient
Which parameter set would you recommend if I want to observe how thermal management (HTC changes) affects the electrochemical performance?