feat: introduce BaseBatterySubModel and update related tests (#2221)

CHANGELOG.md

@@ -36,6 +36,7 @@
 
 ## Features
 
+- Added `BaseBatterySubModel` to handle battery-specific domain validation separately from `BaseSubModel` ([#5254](https://github.com/pybamm-team/PyBaMM/pull/5254))
 - Added uniform grid sizing across subdomains in the x-dimension, ensuring consistent grid spacing when geometries have varying lengths. ([#5253](https://github.com/pybamm-team/PyBaMM/pull/5253))
 - Added the `electrode_phases` kwarg to `plot_voltage_components()` which allows choosing between plotting primary or secondary phase overpotentials. ([#5229](https://github.com/pybamm-team/PyBaMM/pull/5229))
 - Added the `num_steps_no_progress` and `t_no_progress` options in the `IDAKLUSolver` to early terminate the simulation if little progress is detected. ([#5201](https://github.com/pybamm-team/PyBaMM/pull/5201))

src/pybamm/__init__.py

@@ -78,6 +78,7 @@
 
 # Submodel classes
 from .models.submodels.base_submodel import BaseSubModel
+from .models.submodels.base_battery_submodel import BaseBatterySubModel
 
 from .models.submodels import (
     active_material,

src/pybamm/models/submodels/__init__.py

@@ -1,4 +1,4 @@
-__all__ = ['active_material', 'base_submodel', 'convection',
+__all__ = ['active_material', 'base_submodel', 'base_battery_submodel', 'convection',
            'current_collector', 'electrode', 'electrolyte_conductivity',
            'electrolyte_diffusion', 'equivalent_circuit_elements',
            'external_circuit', 'interface', 'oxygen_diffusion', 'particle',

src/pybamm/models/submodels/base_battery_submodel.py

@@ -0,0 +1,42 @@
+import pybamm
+
+from .base_submodel import BaseSubModel
+
+
+class BaseBatterySubModel(BaseSubModel):
+    """
+    Base class for all battery-specific submodels.
+    Contains domain checks and other logic specific to battery modeling.
+    """
+
+    ok_domain_list = [
+        "negative",
+        "separator",
+        "positive",
+        "negative electrode",
+        "negative electrolyte",
+        "separator electrolyte",
+        "positive electrode",
+        "positive electrolyte",
+        None,
+    ]
+
+    def __init__(
+        self,
+        param,
+        domain=None,
+        name="Unnamed battery submodel",
+        external=False,
+        options=None,
+        phase=None,
+    ):
+        # normalize domain
+        domain_lower = domain.lower() if isinstance(domain, str) else domain
+
+        if domain_lower not in self.ok_domain_list:
+            raise pybamm.DomainError(
+                f"Invalid domain '{domain}' for battery submodel. "
+                f"Allowed: {self.ok_domain_list}"
+            )
+
+        super().__init__(param, domain, name, external, options, phase)

src/pybamm/models/submodels/base_submodel.py

@@ -112,17 +112,13 @@ def domain(self):
 
     @domain.setter
     def domain(self, domain):
+        """
+        Sets the domain for the submodel.
+        For general submodels, no restrictions are applied.
+        """
+        self._domain = domain
         if domain is not None:
-            domain = domain.lower()
-        ok_domain_list = ["negative", "separator", "positive", None]
-        if domain in ok_domain_list:
-            self._domain = domain
-            if domain is not None:
-                self._Domain = domain.capitalize()
-        else:
-            raise pybamm.DomainError(
-                f"Domain '{domain}' not recognised (must be one of {ok_domain_list})"
-            )
+            self._Domain = str(domain).capitalize()
 
     @property
     def domain_Domain(self):

tests/unit/test_models/test_submodels/test_base_battery_submodel.py

@@ -0,0 +1,18 @@
+import pytest
+
+import pybamm
+
+
+class DummyParam:
+    def __init__(self):
+        self.domain_params = {"Negative": {}, "Positive": {}}
+
+
+def test_valid_domain():
+    submodel = pybamm.BaseBatterySubModel(DummyParam(), "Negative")
+    assert submodel.domain == "Negative"
+
+
+def test_invalid_domain():
+    with pytest.raises(pybamm.DomainError):
+        pybamm.BaseBatterySubModel(DummyParam(), "InvalidDomain")

tests/unit/test_models/test_submodels/test_base_submodel.py

@@ -16,9 +16,9 @@ def test_domain(self):
         submodel = pybamm.BaseSubModel(None, None)
         assert submodel.domain is None
 
-        # bad string
-        with pytest.raises(pybamm.DomainError):
-            pybamm.BaseSubModel(None, "bad string")
+        # bad string — BaseSubModel no longer validates domains
+        submodel = pybamm.BaseSubModel(None, "bad string")
+        assert submodel.domain == "bad string"
 
     def test_phase(self):
         # Without domain