Added OCP model to take temperature as input

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

@@ -0,0 +1,60 @@
+#
+# Single open-circuit potential, same for charge and discharge
+#
+import pybamm
+from . import BaseOpenCircuitPotential
+
+
+class RKOpenCircuitPotential(BaseOpenCircuitPotential):
+    """Class for the Open Circuit Potential for implementing RK-Polynomial method
+    taking stoichimetry and temperature as input"""
+
+    def get_coupled_variables(self, variables):
+        domain, Domain = self.domain_Domain
+        phase_name = self.phase_name
+
+        if self.reaction == "lithium-ion main":
+            T = variables[f"{Domain} electrode temperature [K]"]
+            # For "particle-size distribution" models, take distribution version
+            # of c_s_surf that depends on particle size.
+            domain_options = getattr(self.options, domain)
+            if domain_options["particle size"] == "distribution":
+                sto_surf = variables[
+                    f"{Domain} {phase_name}particle surface stoichiometry distribution"
+                ]
+                # If variable was broadcast, take only the orphan
+                if isinstance(sto_surf, pybamm.Broadcast) and isinstance(
+                    T, pybamm.Broadcast
+                ):
+                    sto_surf = sto_surf.orphans[0]
+                    T = T.orphans[0]
+                T = pybamm.PrimaryBroadcast(T, [f"{domain} {phase_name}particle size"])
+            else:
+                sto_surf = variables[
+                    f"{Domain} {phase_name}particle surface stoichiometry"
+                ]
+                # If variable was broadcast, take only the orphan
+                if isinstance(sto_surf, pybamm.Broadcast) and isinstance(
+                    T, pybamm.Broadcast
+                ):
+                    sto_surf = sto_surf.orphans[0]
+                    T = T.orphans[0]
+
+            inputs = {
+                f"{Domain} particle stoichiometry": sto_surf,
+                f"{Domain} electrode temperature [k]": T,
+            }
+
+            OCP_surf = pybamm.FunctionParameter(
+                f"{Domain} electrode RK_OCP [V]", inputs
+            )
+
+            dUdT = self.phase_param.dUdT(sto_surf)
+
+            # Bulk OCP is from the average SOC and temperature
+            sto_bulk = variables[f"{Domain} electrode {phase_name}stoichiometry"]
+            T_bulk = pybamm.xyzs_average(T)
+            ocp_bulk = self.phase_param.U(sto_bulk, T_bulk)
+
+        variables.update(self._get_standard_ocp_variables(OCP_surf, ocp_bulk, dUdT))
+        return variables