#492 get working for 3d (in theory)

Author: valentinsulzer

pybamm/models/full_battery_models/base_battery_model.py

@@ -686,16 +686,6 @@ def set_voltage_variables(self):
         eta_r_av = eta_r_p_av - eta_r_n_av
         eta_r_av_dim = eta_r_p_av_dim - eta_r_n_av_dim
 
-        # terminal voltage (Note: phi_s_cn is zero at the negative tab)
-        phi_s_cp = self.variables["Positive current collector potential"]
-        phi_s_cp_dim = self.variables["Positive current collector potential [V]"]
-        if self.options["dimensionality"] == 0:
-            V = phi_s_cp
-            V_dim = phi_s_cp_dim
-        elif self.options["dimensionality"] in [1, 2]:
-            V = pybamm.BoundaryValue(phi_s_cp, "positive tab")
-            V_dim = pybamm.BoundaryValue(phi_s_cp_dim, "positive tab")
-
         # TODO: add current collector losses to the voltage in 3D
 
         self.variables.update(
@@ -708,12 +698,11 @@ def set_voltage_variables(self):
                 "X-averaged reaction overpotential [V]": eta_r_av_dim,
                 "X-averaged solid phase ohmic losses": delta_phi_s_av,
                 "X-averaged solid phase ohmic losses [V]": delta_phi_s_av_dim,
-                "Terminal voltage": V,
-                "Terminal voltage [V]": V_dim,
             }
         )
 
         # Battery-wide variables
+        V_dim = self.variables["Terminal voltage [V]"]
         eta_e_av_dim = self.variables.get("X-averaged electrolyte ohmic losses [V]", 0)
         eta_c_av_dim = self.variables.get(
             "X-averaged concentration overpotential [V]", 0

pybamm/models/submodels/electrode/base_electrode.py

@@ -130,14 +130,23 @@ def _get_standard_current_collector_potential_variables(self, phi_s_cn, phi_s_cp
         # Local potential difference
         V_cc = phi_s_cp - phi_s_cn
 
+        # terminal voltage (Note: phi_s_cn is zero at the negative tab)
+        # Voltage is local current collector potential difference at the tabs, in 1D
+        # this will be equal to the local current collector potential difference
+        phi_s_cp_dim = U_ref + phi_s_cp * pot_scale
+        V = pybamm.boundary_value(phi_s_cp, "positive tab")
+        V_dim = pybamm.boundary_value(phi_s_cp_dim, "positive tab")
+
         variables = {
             "Negative current collector potential": phi_s_cn,
             "Negative current collector potential [V]": phi_s_cn * pot_scale,
             "Positive current collector potential": phi_s_cp,
-            "Positive current collector potential [V]": U_ref + phi_s_cp * pot_scale,
+            "Positive current collector potential [V]": phi_s_cp_dim,
             "Local current collector potential difference": V_cc,
             "Local current collector potential difference [V]": U_ref
             + V_cc * pot_scale,
+            "Terminal voltage": V,
+            "Terminal voltage [V]": V_dim,
         }
 
         return variables

pybamm/models/submodels/external_circuit/voltage_control_external_circuit.py

@@ -35,7 +35,6 @@ def set_algebraic(self, variables):
         # External circuit submodels are always equations on the current
         # Fix voltage to be equal to terminal voltage
         i_cell = variables["Total current density"]
-        # TODO: change this to terminal voltage
-        V = variables["Local current collector potential difference"]
+        V = variables["Terminal voltage"]
         # TODO: find a way to get rid of 0 * i_cell
         self.algebraic[i_cell] = V - self.param.voltage_with_time + 0 * i_cell

pybamm/spatial_methods/zero_dimensional_method.py

@@ -23,6 +23,13 @@ def __init__(self, options=None):
     def build(self, mesh):
         self._mesh = mesh
 
+    def boundary_value_or_flux(self, symbol, discretised_child, bcs=None):
+        """
+        In 0D, the boundary value is the identity operator.
+        See :meth:`SpatialMethod.boundary_value_or_flux`
+        """
+        return discretised_child
+
     def mass_matrix(self, symbol, boundary_conditions):
         """
         Calculates the mass matrix for a spatial method. Since the spatial method is