[Bug]: If particle mechanics is enabled on one electrode, stress-induced diffusion is enabled on both

[DrSOKane]

PyBaMM Version

develop branch

Python Version

3.10.12

Describe the bug

If the "particle mechanics" option is enabled on either electrode, the "stress-induced diffusion" option is enabled on both, unless otherwise specified. See the example below, where the voltage is much lower if stress-induced diffusion is explicitly disabled in the positive electrode.

I can add some code to base_battery_model to fix this, but I'm aware that code has to handle a lot of complex cases already so not sure how to proceed...

Steps to Reproduce

import pybamm import matplotlib.pyplot as plt model1 = pybamm.lithium_ion.DFN({"particle mechanics": ("swelling only", "none")}) param = pybamm.ParameterValues("OKane2022") exp = pybamm.Experiment(["Discharge at 1C until 2.5 V"]) sim1 = pybamm.Simulation(model1, parameter_values=param, experiment=exp) sol1 = sim1.solve() model2 = pybamm.lithium_ion.DFN({"particle mechanics": ("none", "swelling only")}) sim2 = pybamm.Simulation(model2, parameter_values=param, experiment=exp) sol2 = sim2.solve() model3 = pybamm.lithium_ion.DFN( { "particle mechanics": ("swelling only", "none"), "stress-induced diffusion": ("true", "false"), } ) sim3 = pybamm.Simulation(model3, parameter_values=param, experiment=exp) sol3 = sim3.solve() model4 = pybamm.lithium_ion.DFN( { "particle mechanics": ("none", "swelling only"), "stress-induced diffusion": ("false", "true"), } ) sim4 = pybamm.Simulation(model4, parameter_values=param, experiment=exp) sol4 = sim4.solve() Q1 = sol1["Discharge capacity [A.h]"].data V1 = sol1["Voltage [V]"].data Q2 = sol2["Discharge capacity [A.h]"].data V2 = sol2["Voltage [V]"].data Q3 = sol3["Discharge capacity [A.h]"].data V3 = sol3["Voltage [V]"].data Q4 = sol4["Discharge capacity [A.h]"].data V4 = sol4["Voltage [V]"].data plt.figure() plt.plot(Q1,V1,label="model1") plt.plot(Q2,V2,label="model2",linestyle="dashed") plt.plot(Q3,V3,label="model3",linestyle="dotted") plt.plot(Q4,V4,label="model4",linestyle="dashdot") plt.legend() plt.show()

Relevant log output

[DrSOKane]

This PR should catch most combinations of options that cause this bug. Interestingly, the thing that triggered this is that someone found they were getting different results depending on whether particle mechanics was set to "none" or ("none", "none"). The fix I added won't catch that one!