diff --git a/example_retrieve_battery_data.py b/example_retrieve_battery_data.py
new file mode 100644
index 0000000000000000000000000000000000000000..27a4d2f07a244ccdc07cb74ca536071279bade37
--- /dev/null
+++ b/example_retrieve_battery_data.py
@@ -0,0 +1,32 @@
+import os
+from glob import glob
+
+from extraction.retrieve_battery_data import extract_charge_discharge_impedance
+
+
+def example_how_to_use_this_module():
+    all_folders_containing_batteries_mat_files = [
+        "./data/BatteryAgingARC_25_26_27_28_P1/",
+        "./data/BatteryAgingARC_25-44/",
+        "./data/BatteryAgingARC_45_46_47_48/",
+        "./data/BatteryAgingARC_49_50_51_52/",
+        "./data/BatteryAgingARC_53_54_55_56/",
+        "./data/BatteryAgingARC-FY08Q4/",
+    ]
+
+    filepaths = [y for x in os.walk("./data/") for y in glob(os.path.join(x[0], '*.mat'))]
+    filepaths = sorted(filepaths)
+
+    # TODO warning for for the [:1]
+    for filepath in filepaths[:]:
+        print(filepath)
+        charge_items, discharge_items, impedance_items = extract_charge_discharge_impedance(filepath)
+        print(len(charge_items[0]["voltage_measured"]) == len(charge_items[1]["voltage_measured"]))
+        print(len(charge_items[0]["voltage_measured"]) == len(discharge_items[0]["voltage_measured"]))
+        print(len(charge_items[0]["voltage_measured"]))
+        print(len(charge_items[1]["voltage_measured"]))
+        print(len(discharge_items[0]["voltage_measured"]))
+
+
+if __name__ == "__main__":
+    example_how_to_use_this_module()
diff --git a/explore_data.py b/explore_data.py
index f89ecb5c9c057976db854da4e041032969ef74ed..2bc99c912199ca15df4830a0a2cf725cb0345405 100644
--- a/explore_data.py
+++ b/explore_data.py
@@ -116,7 +116,7 @@ def impedance_iteration(impedance_items, filename):
         sense_current = item[3][0][0][0][0] # Current in sense branch (Amps)| Complexes
         battery_current = item[3][0][0][1][0] # urrent in battery branch (Amps)| Complexes
         current_ratio = item[3][0][0][2][0] # Ratio of the above currents| Complexes
-        battery_impedance = item[3][0][0][3] # attery impedance (Ohms) computed from raw data| Complexes but multiple array of 1 complexe
+        battery_impedance = item[3][0][0][3] # Battery impedance (Ohms) computed from raw data| Complexes but multiple array of 1 complexe
         rectified_impedance = item[3][0][0][4] # alibrated and smoothed battery impedance (Ohms)| Complexes but multiple array of 1 complexe
         re = item[3][0][0][5][0][0] # Estimated electrolyte resistance (Ohms)| float_
         rct = item[3][0][0][6][0][0] # Estimated charge transfer resistance (Ohms)| float_
diff --git a/extraction/__init__.py b/extraction/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/extraction/extract_item_into_dict.py b/extraction/extract_item_into_dict.py
new file mode 100644
index 0000000000000000000000000000000000000000..1e3ad38a88a56d750daa00f440f2fb3e7c64dd74
--- /dev/null
+++ b/extraction/extract_item_into_dict.py
@@ -0,0 +1,79 @@
+"""This file tries to split one matlab item into a dictionnary"""
+
+def _convert_matlab_datetime_vector_to_utc(date_vector):
+    """Convert matlab datetime format into a UTC format"""
+    # f'{val:02}' TODO
+    string_time = str(int(date_vector[0])) + "-" + \
+        f'{int(date_vector[1]):02}' + "-" + \
+        f'{int(date_vector[2]):02}' + "T" + \
+        f'{int(date_vector[3]):02}' + ":" + \
+        f'{int(date_vector[4]):02}' + ":" + \
+        f'{float(date_vector[5]):06.3f}'
+
+    return string_time
+
+
+def _format_temperature(temp):
+    """There are 3 main temparatures, if they are close we want to put them in the same category"""
+    # /!\Disclaimer/!\ This is completly related to the NASA battery dataset.
+    if temp < 6:
+        return 4
+    elif temp < 26:
+        return 24
+    else:
+        return 43
+
+
+def extract_charge_from_item(item):
+    dict_item = {}
+
+    dict_item["test_type"] = item[0][0]  # charge impedence discharge
+    dict_item["ambiant_temp"] = _format_temperature(item[1][0][0]) # temperature: 4 ~24 ~43
+    dict_item["datetime"] = _convert_matlab_datetime_vector_to_utc(item[2][0])
+
+    dict_item["voltage_measured"] = item[3][0][0][0][0] # Battery terminal voltage (Volts) floats
+    dict_item["current_measured"] = item[3][0][0][1][0] # Battery output current (Amps) floats
+    dict_item["temperature_measured"] = item[3][0][0][2][0] # Battery temperature (degree C) floats
+    dict_item["current_charge"] = item[3][0][0][3][0] # Current measured at charger (Amps) floats
+    dict_item["voltage_charge"] = item[3][0][0][4][0] # Voltage measured at charger (Volts) floats
+    # MEH
+    dict_item["time"] = item[3][0][0][5] # Time vector for the cycle (secs) floats
+
+    return dict_item
+
+
+def extract_discharge_from_item(item):
+    dict_item = {}
+
+    dict_item["test_type"] = item[0][0]  # charge impedence discharge
+    dict_item["ambiant_temp"] = _format_temperature(item[1][0][0]) # temperature: 4 ~24 ~43
+    dict_item["datetime"] = _convert_matlab_datetime_vector_to_utc(item[2][0])
+
+    dict_item["voltage_measured"] = item[3][0][0][0][0] # Battery terminal voltage (Volts) floats
+    dict_item["current_measured"] = item[3][0][0][1][0] # Battery output current (Amps) flaots
+    dict_item["temperature_measured"] = item[3][0][0][2][0] # Battery temperature (degree C) floats
+    dict_item["current_charge"] = item[3][0][0][3][0] # Current measured at charger (Amps) floats
+    dict_item["voltage_charge"] = item[3][0][0][4][0] # Voltage measured at charger (Volts) floats
+    # MEH
+    dict_item["time"] = item[3][0][0][5][0] # Time vector for the cycle (secs) floats
+    dict_item["capacity"] = item[3][0][0][6][0] # Battery capacity (Ahr) for discharge till 2.7V float_
+
+    return dict_item
+
+
+def extract_impedance_from_item(item):
+    dict_item = {}
+
+    dict_item["test_type"] = item[0][0]  # charge impedence discharge
+    dict_item["ambiant_temp"] = _format_temperature(item[1][0][0]) # temperature: 4 ~24 ~43
+    dict_item["datetime"] = _convert_matlab_datetime_vector_to_utc(item[2][0])
+
+    dict_item["sense_current"] = item[3][0][0][0][0] # Current in sense branch (Amps)| Complexes
+    dict_item["battery_current"] = item[3][0][0][1][0] # urrent in battery branch (Amps)| Complexes
+    dict_item["current_ratio"] = item[3][0][0][2][0] # Ratio of the above currents| Complexes
+    dict_item["battery_impedance"] = item[3][0][0][3] # Battery impedance (Ohms) computed from raw data| Complexes but multiple array of 1 complexe
+    dict_item["rectified_impedance"] = item[3][0][0][4] # alibrated and smoothed battery impedance (Ohms)| Complexes but multiple array of 1 complexe
+    dict_item["re"] = item[3][0][0][5][0][0] # Estimated electrolyte resistance (Ohms)| float_
+    dict_item["rct"] = item[3][0][0][6][0][0] # Estimated charge transfer resistance (Ohms)| float_
+
+    return dict_item
diff --git a/extraction/retrieve_battery_data.py b/extraction/retrieve_battery_data.py
new file mode 100644
index 0000000000000000000000000000000000000000..329c0df9e039455535b6e4872109d657933ad622
--- /dev/null
+++ b/extraction/retrieve_battery_data.py
@@ -0,0 +1,42 @@
+import scipy.io
+import os
+import numpy as np
+
+from extraction.extract_item_into_dict import extract_impedance_from_item
+from extraction.extract_item_into_dict import extract_charge_from_item
+from extraction.extract_item_into_dict import extract_discharge_from_item
+
+
+def _filter_mat(mat, test_type):
+    """Keep only one type (e.g. impedance) from the matlab file"""
+    return [x for x in mat if x[0][0] == test_type]
+
+
+def _split_mat(mat):
+    """Split matlab file into charge/discharge/impedance"""
+    raw_charge_items = _filter_mat(mat, "charge")
+    raw_discharge_items = _filter_mat(mat, "discharge")
+    raw_impedance_items = _filter_mat(mat, "impedance")
+
+    return raw_charge_items, raw_discharge_items, raw_impedance_items
+
+
+def _load_mat_file(filepath):
+    """Load the matlab file"""
+    filename = filepath.split("/")[-1].split(".")[0]
+    raw_mat = scipy.io.loadmat(filepath)
+    mat = raw_mat[filename][0][0][0][0]
+
+    return mat
+
+
+def extract_charge_discharge_impedance(filepath):
+    mat = _load_mat_file(filepath)
+
+    raw_charge_items, raw_discharge_items, raw_impedance_items = _split_mat(mat)
+
+    charge_items = [extract_charge_from_item(raw_charge) for raw_charge in raw_charge_items]
+    discharge_items = [extract_discharge_from_item(raw_discharge) for raw_discharge in raw_discharge_items]
+    impedance_items = [extract_impedance_from_item(raw_impedance) for raw_impedance in raw_impedance_items]
+
+    return charge_items, discharge_items, impedance_items