allow double-layer capacitance to depend on temperature

CHANGELOG.md

@@ -1,14 +1,18 @@
 # [Unreleased](https://github.com/pybamm-team/PyBaMM/)
 
-## Breaking changes
+## Features
 
-- PyBaMM now has optional dependencies that can be installed with the pattern `pip install pybamm[option]` e.g. `pybamm[plot]` ([#3044](https://github.com/pybamm-team/PyBaMM/pull/3044))
+- Double-layer capacity can now be provided as a function of temperature ([#3174](https://github.com/pybamm-team/PyBaMM/pull/3174))
 
 ## Bug fixes
 
 - Parameters in `Prada2013` have been updated to better match those given in the paper, which is a 2.3 Ah cell, instead of the mix-and-match with the 1.1 Ah cell from Lain2019.
 - Error generated when invalid parameter values are passed.
-- Thevenin() model is now constructed with standard variables: `Time [s], Time [min], Time [h]` ([#3143](https://github.com/pybamm-team/PyBaMM/pull/3143)) 
+- Thevenin() model is now constructed with standard variables: `Time [s], Time [min], Time [h]` ([#3143](https://github.com/pybamm-team/PyBaMM/pull/3143))
+
+## Breaking changes
+
+- PyBaMM now has optional dependencies that can be installed with the pattern `pip install pybamm[option]` e.g. `pybamm[plot]` ([#3044](https://github.com/pybamm-team/PyBaMM/pull/3044))
 
 # [v23.5](https://github.com/pybamm-team/PyBaMM/tree/v23.5) - 2023-06-18
 
@@ -27,7 +31,7 @@
 
 ## Bug fixes
 
-- Realign 'count' increment in CasadiSolver._integrate() ([#2986](https://github.com/pybamm-team/PyBaMM/pull/2986))
+- Realign 'count' increment in CasadiSolver.\_integrate() ([#2986](https://github.com/pybamm-team/PyBaMM/pull/2986))
 - Fix `pybamm_install_odes` and update the required SUNDIALS version ([#2958](https://github.com/pybamm-team/PyBaMM/pull/2958))
 - Fixed a bug where all data included in a BPX was incorrectly assumed to be given as a function of time.([#2957](https://github.com/pybamm-team/PyBaMM/pull/2957))
 - Remove brew install for Mac from the recommended developer installation options for SUNDIALS ([#2925](https://github.com/pybamm-team/PyBaMM/pull/2925))

pybamm/models/submodels/electrode/ohm/li_metal.py

@@ -85,8 +85,12 @@ def set_rhs(self, variables):
             delta_phi = variables[
                 "Lithium metal interface surface potential difference [V]"
             ]
+            # temperature at the interface of the negative electrode with the separator
+            T = pybamm.boundary_value(
+                variables["Negative electrode temperature [K]"], "right"
+            )
 
-            C_dl = self.domain_param.C_dl
+            C_dl = self.domain_param.C_dl(T)
 
             self.rhs[delta_phi] = 1 / C_dl * (i_cc - sum_j)
 

pybamm/models/submodels/electrolyte_conductivity/surface_potential_form/composite_surface_form_conductivity.py

@@ -110,7 +110,9 @@ def set_rhs(self, variables):
             f"X-averaged {domain} electrode surface potential difference [V]"
         ]
 
-        C_dl = self.domain_param.C_dl
+        T = variables[f"X-averaged {domain} electrode temperature [K]"]
+
+        C_dl = self.domain_param.C_dl(T)
 
         self.rhs[delta_phi] = 1 / C_dl * (sum_a_j_av - sum_a_j)
 

pybamm/models/submodels/electrolyte_conductivity/surface_potential_form/full_surface_form_conductivity.py

@@ -269,7 +269,9 @@ def set_rhs(self, variables):
 
         domain, Domain = self.domain_Domain
 
-        C_dl = self.domain_param.C_dl
+        T = variables[f"{Domain} electrode temperature [K]"]
+
+        C_dl = self.domain_param.C_dl(T)
 
         delta_phi = variables[f"{Domain} electrode surface potential difference [V]"]
         i_e = variables[f"{Domain} electrolyte current density [A.m-2]"]

pybamm/models/submodels/electrolyte_conductivity/surface_potential_form/leading_surface_form_conductivity.py

@@ -97,7 +97,9 @@ def set_rhs(self, variables):
             f"X-averaged {domain} electrode surface potential difference [V]"
         ]
 
-        C_dl = self.domain_param.C_dl
+        T = variables[f"X-averaged {domain} electrode temperature [K]"]
+
+        C_dl = self.domain_param.C_dl(T)
 
         self.rhs[delta_phi] = 1 / C_dl * (sum_a_j_av - sum_a_j)
 

pybamm/parameters/lead_acid_parameters.py

@@ -303,9 +303,6 @@ def _set_parameters(self):
         self.DeltaV = self.DeltaVsurf + self.DeltaVliq
 
         self.Q_max = pybamm.Parameter(f"{Domain} electrode volumetric capacity [C.m-3]")
-        self.C_dl = pybamm.Parameter(
-            f"{Domain} electrode double-layer capacity [F.m-2]"
-        )
 
         # In lead-acid the current collector and electrodes are the same (same
         # conductivity) but we correct here for Bruggeman. Note that because for
@@ -314,8 +311,17 @@ def _set_parameters(self):
         # T_ref.
         self.sigma_cc = self.sigma(main.T_ref) * (1 - self.eps_max) ** self.b_s
 
+    def C_dl(self, T):
+        """Dimensional double-layer capacity [F.m-2]"""
+        inputs = {"Temperature [K]": T}
+        Domain = self.domain.capitalize()
+        return pybamm.FunctionParameter(
+            f"{Domain} electrode double-layer capacity [F.m-2]", inputs
+        )
+
     def sigma(self, T):
-        """Dimensional electrical conductivity"""
+        """Dimensional electrical conductivity [S.m-1]"""
+
         inputs = {"Temperature [K]": T}
         Domain = self.domain.capitalize()
         return pybamm.FunctionParameter(

pybamm/parameters/lithium_ion_parameters.py

@@ -298,10 +298,6 @@ def _set_parameters(self):
         # Tortuosity parameters
         self.b_s = self.geo.b_s
 
-        self.C_dl = pybamm.Parameter(
-            f"{Domain} electrode double-layer capacity [F.m-2]"
-        )
-
         # Mechanical parameters
         self.nu = pybamm.Parameter(f"{Domain} electrode Poisson's ratio")
         self.E = pybamm.Parameter(f"{Domain} electrode Young's modulus [Pa]")
@@ -342,6 +338,14 @@ def _set_parameters(self):
             f"{Domain} electrode current-driven interface utilisation factor [m3.mol-1]"
         )
 
+    def C_dl(self, T):
+        """Dimensional double-layer capacity [F.m-2]"""
+        inputs = {"Temperature [K]": T}
+        Domain = self.domain.capitalize()
+        return pybamm.FunctionParameter(
+            f"{Domain} electrode double-layer capacity [F.m-2]", inputs
+        )
+
     def sigma(self, T):
         """Dimensional electrical conductivity in electrode"""
         inputs = {"Temperature [K]": T}

tests/unit/test_expression_tree/test_printing/test_print_name.py

@@ -21,7 +21,7 @@ def test_prettify_print_name(self):
         )
 
         # Test subscripts
-        self.assertEqual(param.n.C_dl.print_name, r"C_{\mathrm{dl,n}}")
+        self.assertEqual(param.n.C_dl(0).print_name, r"C_{\mathrm{dl,n}}")
 
         # Test bar
         c_e_av = pybamm.Variable("c_e_av")