diff --git a/src/pybamm/models/full_battery_models/lithium_ion/basic_ecm_split_OCV.py b/src/pybamm/models/full_battery_models/lithium_ion/basic_ecm_split_OCV.py
index 9195a7433d..55895e6c9d 100644
--- a/src/pybamm/models/full_battery_models/lithium_ion/basic_ecm_split_OCV.py
+++ b/src/pybamm/models/full_battery_models/lithium_ion/basic_ecm_split_OCV.py
@@ -33,9 +33,7 @@ def __init__(self, name="ECM with split OCV"):
         V = pybamm.Variable("Voltage [V]")
 
         # model is isothermal
-        I = pybamm.FunctionParameter(
-            "Current function [A]", {"Time [s]": pybamm.t}
-        )
+        I = pybamm.FunctionParameter("Current function [A]", {"Time [s]": pybamm.t})
 
         # Capacity equation
         self.rhs[Q] = I / 3600
@@ -68,8 +66,8 @@ def __init__(self, name="ECM with split OCV"):
         V = Up - Un - I * R
 
         # Parameters for Voltage cutoff
-        voltage_high_cut = pybamm.Parameter('Upper voltage cut-off [V]')
-        voltage_low_cut = pybamm.Parameter('Lower voltage cut-off [V]')
+        voltage_high_cut = pybamm.Parameter("Upper voltage cut-off [V]")
+        voltage_low_cut = pybamm.Parameter("Lower voltage cut-off [V]")
 
         self.variables = {
             "Negative particle SOC": c_n,
diff --git a/tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py b/tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
index e14dc7f803..dbf43133f3 100644
--- a/tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
+++ b/tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
@@ -4,43 +4,55 @@
 import pybamm
 import numpy as np
 
+
 class TestECMSplitOCVModel:
     def test_run_model_with_parameters(self):
         model = pybamm.lithium_ion.ECMsplitOCV()
-        
+
         # example parameters
         qp0 = 8.73231852
         qn0 = 5.82761507
-        c0_n = 0.9013973983641687*0.9
-        c0_p = 0.5142305254580026*0.83
+        c0_n = 0.9013973983641687 * 0.9
+        c0_p = 0.5142305254580026 * 0.83
 
         # OCV functions
         def Un(theta_n):
-            Un = 0.1493 + 0.8493*np.exp(-61.79*theta_n) + 0.3824*np.exp(-665.8*theta_n) \
-            - np.exp(39.42*theta_n-41.92) - 0.03131*np.arctan(25.59*theta_n - 4.099) \
-            - 0.009434*np.arctan(32.49*theta_n - 15.74)
+            Un = (
+                0.1493
+                + 0.8493 * np.exp(-61.79 * theta_n)
+                + 0.3824 * np.exp(-665.8 * theta_n)
+                - np.exp(39.42 * theta_n - 41.92)
+                - 0.03131 * np.arctan(25.59 * theta_n - 4.099)
+                - 0.009434 * np.arctan(32.49 * theta_n - 15.74)
+            )
             return Un
 
         def Up(theta_p):
-            Up = -10.72*theta_p**4 + 23.88*theta_p**3 - 16.77*theta_p**2 + 2.595*theta_p + 4.563
+            Up = (
+                -10.72 * theta_p**4
+                + 23.88 * theta_p**3
+                - 16.77 * theta_p**2
+                + 2.595 * theta_p
+                + 4.563
+            )
             return Up
-        
+
         pars = pybamm.ParameterValues(
             {
-                'Positive electrode capacity [A.h]' : qp0,
-                'Ohmic resistance [Ohm]' : 0.001,
-                'Negative electrode initial SOC' : c0_n,
-                'Lower voltage cut-off [V]' : 2.8,
-                'Positive electrode initial SOC' : c0_p,
-                'Upper voltage cut-off [V]' : 4.2,
-                'Negative electrode capacity [A.h]' : qn0,
-                'Current function [A]' : 5,
-                'Positive electrode OCP [V]' : Up,
-                'Negative electrode OCP [V]' : Un,
+                "Positive electrode capacity [A.h]": qp0,
+                "Ohmic resistance [Ohm]": 0.001,
+                "Negative electrode initial SOC": c0_n,
+                "Lower voltage cut-off [V]": 2.8,
+                "Positive electrode initial SOC": c0_p,
+                "Upper voltage cut-off [V]": 4.2,
+                "Negative electrode capacity [A.h]": qn0,
+                "Current function [A]": 5,
+                "Positive electrode OCP [V]": Up,
+                "Negative electrode OCP [V]": Un,
             }
         )
 
         # solve the model
         sim = pybamm.Simulation(model, parameter_values=pars)
         t_eval = np.linspace(0, 3600)
-        sim.solve(t_eval)
\ No newline at end of file
+        sim.solve(t_eval)
diff --git a/tests/unit/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py b/tests/unit/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
index 67266de5ae..a26b42a459 100644
--- a/tests/unit/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
+++ b/tests/unit/test_models/test_full_battery_models/test_lithium_ion/test_ecm_split_OCV.py
@@ -3,7 +3,8 @@
 #
 import pybamm
 
+
 class TestECMSplitOCV:
     def test_ecmsplitocv_well_posed(self):
         model = pybamm.lithium_ion.ECMsplitOCV()
-        model.check_well_posedness()
\ No newline at end of file
+        model.check_well_posedness()