Wycisk OCP Restructure - Add Initial Hysteresis State Parameter

CHANGELOG.md

@@ -16,6 +16,7 @@
 package to install PyBaMM with only the required dependencies. ([conda-forge/pybamm-feedstock#70](https://github.com/conda-forge/pybamm-feedstock/pull/70))
 - Separated extrapolation options for `pybamm.BoundaryValue` and `pybamm.BoundaryGradient`, and updated the default to be "linear" for the value and "quadratic" for the gradient. ([#4614](https://github.com/pybamm-team/PyBaMM/pull/4614))
 - Double-layer SEI models have been removed (with the corresponding parameters). All models assume now a single SEI layer. ([#4470](https://github.com/pybamm-team/PyBaMM/pull/4470))
+- Wycisk OCP model now requires an parameter to set the initial condition. ([#4374](https://github.com/pybamm-team/PyBaMM/pull/4374))
 
 ## Bug fixes
 

src/pybamm/models/submodels/interface/open_circuit_potential/wycisk_ocp.py

@@ -147,7 +147,7 @@ def set_rhs(self, variables):
         domain, Domain = self.domain_Domain
         phase_name = self.phase_name
 
-        current = variables[
+        i_surf = variables[
             f"{Domain} electrode {phase_name}interfacial current density [A.m-2]"
         ]
         # check if composite or not
@@ -165,12 +165,12 @@ def set_rhs(self, variables):
         h = variables[f"{Domain} electrode {phase_name}hysteresis state"]
 
         dhdt = (
-            K * (current / (Q_cell * (dQdU**K_x))) * (1 - pybamm.sign(current) * h)
+            K * (i_surf / (Q_cell * (dQdU**K_x))) * (1 - pybamm.sign(i_surf) * h)
         )  #! current is backwards for a halfcell
         self.rhs[h] = dhdt
 
     def set_initial_conditions(self, variables):
         domain, Domain = self.domain_Domain
         phase_name = self.phase_name
         h = variables[f"{Domain} electrode {phase_name}hysteresis state"]
-        self.initial_conditions[h] = pybamm.Scalar(0)
+        self.initial_conditions[h] = self.phase_param.h_init

src/pybamm/parameters/lithium_ion_parameters.py

@@ -460,7 +460,9 @@ def _set_parameters(self):
         self.hysteresis_switch = pybamm.Parameter(
             f"{pref}{Domain} particle hysteresis switching factor"
         )
-        self.h_init = pybamm.Scalar(0)
+        self.h_init = pybamm.Parameter(
+            f"{pref}Initial hysteresis state in {domain} electrode"
+        )
 
         if self.options["open-circuit potential"] != "MSMR":
             self.U_init = self.U(self.sto_init_av, main.T_init)

tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_mpm.py

@@ -81,7 +81,7 @@ def test_wycisk_ocp(self):
                 + 0.1,
                 "Negative particle hysteresis decay rate": 1,
                 "Negative particle hysteresis switching factor": 1,
-                # "Negative electrode OCP hysteresis [V]": lambda sto: 1,
+                "Initial hysteresis state in negative electrode": -0.5,
             },
             check_already_exists=False,
         )