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segmentData

Classify and organize raw battery measurement data by identifying cycling phase, cycling mode, and data validity

Since R2024b

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Syntax

segData = segmentData(bdp)

Description

segData = segmentData(bdp)analyzes the raw data table in the batteryTestDataParser object bdp, identifies the cycling phase, cycling mode, and data validity for each timestamp in bdp, and incorporates this information as additional columns in the bdp data table, which segmentData also returns separately in segData. Calling segmentData also sets the object property bdp.IsSegmented to true.

example

Examples

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Open Live Script

Load the data cleanData10, which contains cleaned battery data through the tenth test cycle. It is known that Cycle 0 contains incorrectly collected data. Display the first five lines.

This example data represents only a small portion of battery life, at the beginning of the cycling test. 

load clean_bat_data cleanData10
head(cleanData10,5)
    Data_Point          DateTime          Step_Index    Cycle_Index    Current    Voltage    Charge_Capacity    Discharge_Capacity    Charge_Energy    Discharge_Energy       dV/dt       Internal_Resistance    Temperature
    __________    ____________________    __________    ___________    _______    _______    _______________    __________________    _____________    ________________    ___________    ___________________    ___________

        1         13-May-2017 03:21:40        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.457   
        2         13-May-2017 03:21:40        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.457   
        3         13-May-2017 03:21:50        0              0            0       3.3018            0                   0                   0                 0            -2.6703e-05         0.022012            30.445   
        4         13-May-2017 03:22:00        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.501   
        5         13-May-2017 03:22:10        0              0            0       3.3018            0                   0                   0                 0            -8.5831e-06         0.022012            30.501

The table includes current, voltage, and temperature measurements, as well as indices for step and cycle index. The table also includes other measurements, such as Internal_Resistance.

Create Battery Test Data Parser

Create the batteryTestDataParser object bdp. Use dot notation to assign variable names in the table to properties. In this example, the battery cycle is temperature controlled to a roughly constant value, and can be excluded from the analysis. Therefore, do not set the TemperatureVariable property name.

bdp = batteryTestDataParser(cleanData10);

bdp.CurrentVariable = "Current";
bdp.VoltageVariable = "Voltage";
bdp.TimeVariable = "DateTime";
bdp.CycleIndexVariable = "Cycle_Index";
bdp.StepIndexVariable = "Step_Index"
bdp = 
  BatteryTestDataParser with properties:

           CurrentVariable: "Current"
           VoltageVariable: "Voltage"
              TimeVariable: "DateTime"
        CycleIndexVariable: "Cycle_Index"
         StepIndexVariable: "Step_Index"
       TemperatureVariable: ""
            ExcludedCycles: [1x0 double]
                 Tolerance: 5.0000e-05
     NumInterpolatedPoints: 1000
                WindowSize: 10
               IsSegmented: 0
    IsTemperatureAvailable: 0

bdp contains the properties that you set, and ignores other table columns.

Exclude Known Erroneous Cycle Data

Exclude Cycle-0 data from processing by setting the ExcludedCycles property to 0.

bdp.ExcludedCycles = 0;

Segment Data

Segment the data so that it can be analyzed by cycle and step.

bdpseg = segmentData(bdp);
head(bdpseg,5)
    Data_Point          DateTime          Step_Index    Cycle_Index    Current    Voltage    Charge_Capacity    Discharge_Capacity    Charge_Energy    Discharge_Energy       dV/dt       Internal_Resistance    Temperature    CyclingModes    CyclingPhases    IsValid
    __________    ____________________    __________    ___________    _______    _______    _______________    __________________    _____________    ________________    ___________    ___________________    ___________    ____________    _____________    _______

        1         13-May-2017 03:21:40        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.457        Undefined        Undefined       false 
        2         13-May-2017 03:21:40        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.457        Undefined        Undefined       false 
        3         13-May-2017 03:21:50        0              0            0       3.3018            0                   0                   0                 0            -2.6703e-05         0.022012            30.445        Undefined        Undefined       false 
        4         13-May-2017 03:22:00        0              0            0       3.3018            0                   0                   0                 0            -1.5259e-05         0.022012            30.501        Undefined        Undefined       false 
        5         13-May-2017 03:22:10        0              0            0       3.3018            0                   0                   0                 0            -8.5831e-06         0.022012            30.501        Undefined        Undefined       false

The software adds columns for Step_Index, Cycle_Index, and IsValid. Because the data begins with Cycle 0 and you are excluding this cycle, IsValid is set to false for this data. The data table encapsulated by bdp also contains these new columns.

Create Battery Test Feature Extractor

Create a batteryTestFeatureExtractor object bft.

bft = batteryTestFeatureExtractor()
bft = 
  BatteryTestFeatureExtractor with properties:

       CyclingPhase: "Charge"
         Statistics: 1
    CycleCumulative: 1
                 CC: 1
                 CV: 1
               CCCV: 1
                 IC: 1
                 DV: 0
                 DT: 0

Using dot notation, specify that both charge and discharge cycles be used for features. Accept the default settings for the feature set selections.

bft.CyclingPhase = "Both";

Extract Features

Use extract to extract the specified features into the feature table ft.

ft = extract(bft,bdp);

Display the first five rows of ft.

head(ft,5)
    Cycle_Index    Charge_cumulativeCapacity    Charge_cumulativeEnergy    Charge_duration    Charge_startVoltage    Charge_Voltage_max    Charge_Voltage_min    Charge_Voltage_mean    Charge_Voltage_std    Charge_Voltage_skewness    Charge_Voltage_kurtosis    Charge_Current_max    Charge_Current_min    Charge_Current_mean    Charge_Current_std    Charge_Current_skewness    Charge_Current_kurtosis    Charge_Step5_IC_peak    Charge_Step5_IC_peakWidth    Charge_Step5_IC_peakLocation    Charge_Step5_IC_peakProminence    Charge_Step5_IC_peaksArea    Charge_Step5_IC_peakLeftSlope    Charge_Step5_IC_peakRightSlope    Charge_Step5_IC_area    Charge_Step5_IC_max    Charge_Step5_IC_min    Charge_Step5_IC_mean    Charge_Step5_IC_std    Charge_Step5_IC_skewness    Charge_Step5_IC_kurtosis    Charge_Step5_CC_duration    Charge_Step5_CC_currentMedian    Charge_Step5_CC_slope    Charge_Step5_CC_energy    Charge_Step5_CC_skewness    Charge_Step5_CC_kurtosis    Charge_Step6_IC_peak    Charge_Step6_IC_peakWidth    Charge_Step6_IC_peakLocation    Charge_Step6_IC_peakProminence    Charge_Step6_IC_peaksArea    Charge_Step6_IC_peakLeftSlope    Charge_Step6_IC_peakRightSlope    Charge_Step6_IC_area    Charge_Step6_IC_max    Charge_Step6_IC_min    Charge_Step6_IC_mean    Charge_Step6_IC_std    Charge_Step6_IC_skewness    Charge_Step6_IC_kurtosis    Charge_Step6_CC_duration    Charge_Step6_CC_currentMedian    Charge_Step6_CC_energy    Charge_Step6_CC_skewness    Charge_Step6_CC_kurtosis    Charge_Step9_IC_peak    Charge_Step9_IC_peakWidth    Charge_Step9_IC_peakLocation    Charge_Step9_IC_peakProminence    Charge_Step9_IC_peaksArea    Charge_Step9_IC_peakLeftSlope    Charge_Step9_IC_peakRightSlope    Charge_Step9_IC_area    Charge_Step9_IC_max    Charge_Step9_IC_min    Charge_Step9_IC_mean    Charge_Step9_IC_std    Charge_Step9_IC_skewness    Charge_Step9_IC_kurtosis    Charge_Step9_CC_duration    Charge_Step9_CC_currentMedian    Charge_Step9_CC_energy    Charge_Step9_CC_skewness    Charge_Step9_CC_kurtosis    Charge_Step9_CV_duration    Charge_Step9_CV_voltageMedian    Charge_Step9_CV_slope    Charge_Step9_CV_energy    Charge_Step9_CV_skewness    Charge_Step9_CV_kurtosis    Charge_Step9_CCCV_energyRatio    Charge_Step9_CCCV_energyDifference    Charge_Step5_CC_tInv    Discharge_cumulativeCapacity    Discharge_cumulativeEnergy    Discharge_duration    Discharge_startVoltage    Discharge_Voltage_max    Discharge_Voltage_min    Discharge_Voltage_mean    Discharge_Voltage_std    Discharge_Voltage_skewness    Discharge_Voltage_kurtosis    Discharge_Current_max    Discharge_Current_min    Discharge_Current_mean    Discharge_Current_std    Discharge_Current_skewness    Discharge_Current_kurtosis    Discharge_Step10_IC_peak    Discharge_Step10_IC_peakWidth    Discharge_Step10_IC_peakLocation    Discharge_Step10_IC_peakProminence    Discharge_Step10_IC_peaksArea    Discharge_Step10_IC_peakLeftSlope    Discharge_Step10_IC_peakRightSlope    Discharge_Step10_IC_area    Discharge_Step10_IC_max    Discharge_Step10_IC_min    Discharge_Step10_IC_mean    Discharge_Step10_IC_std    Discharge_Step10_IC_skewness    Discharge_Step10_IC_kurtosis    Discharge_Step10_CC_duration    Discharge_Step10_CC_currentMedian    Discharge_Step10_CC_slope    Discharge_Step10_CC_energy    Discharge_Step10_CC_skewness    Discharge_Step10_CC_kurtosis    Discharge_Step10_CC_tInv    Discharge_Step10_CV_duration    Discharge_Step10_CV_voltageMedian    Discharge_Step10_CV_slope    Discharge_Step10_CV_energy    Discharge_Step10_CV_skewness    Discharge_Step10_CV_kurtosis    Discharge_Step10_CCCV_energyRatio    Discharge_Step10_CCCV_energyDifference
    ___________    _________________________    _______________________    _______________    ___________________    __________________    __________________    ___________________    __________________    _______________________    _______________________    __________________    __________________    ___________________    __________________    _______________________    _______________________    ____________________    _________________________    ____________________________    ______________________________    _________________________    _____________________________    ______________________________    ____________________    ___________________    ___________________    ____________________    ___________________    ________________________    ________________________    ________________________    _____________________________    _____________________    ______________________    ________________________    ________________________    ____________________    _________________________    ____________________________    ______________________________    _________________________    _____________________________    ______________________________    ____________________    ___________________    ___________________    ____________________    ___________________    ________________________    ________________________    ________________________    _____________________________    ______________________    ________________________    ________________________    ____________________    _________________________    ____________________________    ______________________________    _________________________    _____________________________    ______________________________    ____________________    ___________________    ___________________    ____________________    ___________________    ________________________    ________________________    ________________________    _____________________________    ______________________    ________________________    ________________________    ________________________    _____________________________    _____________________    ______________________    ________________________    ________________________    _____________________________    __________________________________    ____________________    ____________________________    __________________________    __________________    ______________________    _____________________    _____________________    ______________________    _____________________    __________________________    __________________________    _____________________    _____________________    ______________________    _____________________    __________________________    __________________________    ________________________    _____________________________    ________________________________    __________________________________    _____________________________    _________________________________    __________________________________    ________________________    _______________________    _______________________    ________________________    _______________________    ____________________________    ____________________________    ____________________________    _________________________________    _________________________    __________________________    ____________________________    ____________________________    ________________________    ____________________________    _________________________________    _________________________    __________________________    ____________________________    ____________________________    _________________________________    ______________________________________

         1                  1.0912                      3.8091                 1837.2               3.2889                 3.6004                3.2889                3.5127                0.076284                -0.26567                    2.0059                   6.6013               0.064569               2.1754                 2.3511                  0.94798                    2.3503                    5.4806                    0.028983                         3.53                          0.48663                         0.15111                        14.045                           -17.479                      0.47486                 5.4806                 0.20359                 1.8284                 1.8936                   0.91305                      2.2617                      260.48                        6.5999                           NaN                   1.6668                     -1.1606                     3.3064                    6.0466                   0.0015526                       3.4968                          0.031648                            NaN                           NaN                               NaN                      0.28551                 37.411                 3.3344                  6.5201                 5.7697                    4.0684                      19.896                      289.56                         3.96                         1.1145                    0.23118                      1.8814                    2.7514                   0.041081                        3.4178                           2.2495                        0.093172                        86.649                           -40.036                      0.17691                 2.7514                 0.14988                0.83718                 0.82946                   1.1874                       2.968                      579.99                          1.1                        0.61058                      1.401                      4.4162                      610.01                        3.6002                     -0.00073938                 0.11516                    1.8343                       5.892                        5.3022                             0.49542                            NaN                      1.0858                         3.3053                    1186.2                  3.3297                   3.3297                   1.9996                    2.7518                   0.46306                    -0.69494                       1.7957                    -0.021996                 -4.4004                  -3.6203                   1.6577                      1.6544                         3.741                       6.7975                        0.11988                            3.1491                               6.6874                             0.53131                            40.006                               -124.84                           1.0703                     6.7975                    -0.014311                   0.80703                     1.5432                        2.3837                          7.7647                           875.8                             -4.4                          0.00030465                      3.2745                         -1.363                          3.6784                        760.95                        300.43                            1.9999                         0.00093293                     0.016935                       -2.3131                          9.8519                            193.36                                  3.2575                
         2                  1.1011                      3.8354                 1846.4               3.1837                 3.6004                3.1837                3.5029                0.088036                -0.73117                    3.6177                   6.6015                0.05476               2.2175                 2.3674                  0.90434                    2.2705                    5.5806                   0.0057399                       3.5324                          0.27875                        0.022226                        55.087                            -31.76                      0.44216                 5.5806                 0.13184                 1.2509                  1.678                    1.5393                      3.9561                      242.78                        6.6003                      0.013906                   1.5463                    -0.96454                     2.5803                    6.2122                   0.0023982                        3.495                          0.063827                       0.010988                        25.474                           -9.7076                      0.28528                 37.379                 3.5681                  6.7183                 5.8188                    4.0179                       19.36                       289.6                         3.96                         1.1142                     0.3299                      1.9009                    2.8966                   0.041309                        3.4156                           2.3838                        0.097776                        101.48                           -38.962                      0.18304                 2.8966                 0.14602                0.86161                 0.88746                   1.2188                      3.0379                         600                          1.1                         0.6313                     1.5064                      4.9068                         590                        3.6002                     -0.00069836                 0.10311                    2.1156                      7.6634                        6.1227                             0.52819                         0.7253                      1.0876                         3.3111                    1191.7                  3.3199                   3.3199                   1.9996                    2.7293                   0.46952                    -0.62182                        1.679                    -0.022033                 -4.4006                  -3.5379                   1.7243                      1.4985                         3.249                       6.7984                        0.11951                            3.1457                               6.6764                             0.54736                            38.573                               -127.79                           1.0721                     6.7984                    -0.019335                   0.81345                     1.5523                         2.374                          7.7118                          877.32                             -4.4                          0.00030269                      3.2804                        -1.3602                          3.6885                        761.05                        304.33                            1.9999                         0.00088585                     0.016846                       -2.3857                          10.332                            194.73                                  3.2635                
         3                  1.1268                      3.9237                 1851.9               3.0906                 3.6004                3.0906                3.4951                0.099424                  -1.171                    5.1736                   6.6013               0.051631               2.3933                 2.4829                  0.78503                    1.9785                     5.543                    0.023424                       3.5319                          0.46554                         0.11941                        7.7787                           -24.902                      0.52472                  5.543                0.091083                 1.1408                    1.7                    1.6561                      4.2318                      287.82                        6.5999                      0.016691                   1.8347                     -1.0243                     2.7645                    6.2728                   0.0015434                       3.4902                          0.020799                            NaN                           NaN                               NaN                      0.28518                 37.805                 3.6316                  6.7985                 5.8824                    4.0208                      19.379                      289.61                         3.96                         1.1141                     0.3022                      1.9029                    3.0041                   0.040571                        3.4171                           2.4841                         0.10175                        88.355                           -51.569                      0.18597                 3.0041                 0.13535                0.87385                 0.90858                   1.2478                      3.1188                      609.99                          1.1                        0.64142                     1.6531                      5.6046                         580                        3.6002                     -0.00073569                0.097314                    1.6633                      5.2229                        6.5913                             0.54411                         6.0581                      1.0972                         3.3433                    1198.5                  3.4424                   3.4424                   1.9996                    2.7497                   0.47889                     -0.6258                       1.7303                    -0.022201                 -4.4005                  -3.5499                   1.7126                      1.5172                        3.3065                       6.7829                        0.12166                            3.1522                               6.7482                             0.53042                            40.973                               -120.47                           1.0818                     6.7829                    -0.021383                   0.75001                     1.5018                        2.5311                          8.5461                          885.19                             -4.4                          0.00030422                      3.3127                        -1.3307                          3.7906                        760.88                        303.26                            1.9999                         0.00094755                     0.016758                       -2.4133                          9.9184                            197.68                                   3.296                
         4                  1.1285                      3.9265                   1854               3.0425                 3.6004                3.0425                3.4886                 0.10833                 -1.4374                    6.0532                   6.6018               0.053802               2.4518                 2.4836                  0.73677                    1.9175                    5.5386                    0.018892                       3.5263                          0.40434                        0.098235                        22.395                            -12.47                      0.51326                 5.5386                0.077485                 1.0178                 1.6221                    1.8529                       4.987                      281.47                           6.6                      0.017771                   1.7912                     -0.8937                     2.4507                    6.2692                   0.0034412                       3.4926                          0.077164                       0.011037                         6.021                           -29.907                      0.28448                 37.957                 3.8414                  6.8738                 5.9451                    3.9968                      19.115                      289.63                         3.96                          1.114                    0.43977                      1.9856                    3.0445                   0.040016                        3.4159                           2.5082                        0.099078                        94.507                           -46.675                       0.1861                 3.0445                 0.13527                0.88531                 0.92738                   1.2342                      3.0851                         610                          1.1                        0.64157                     1.5256                      4.9396                      575.01                        3.6002                     -0.00071665                0.094806                    1.8886                      6.4618                        6.7672                             0.54677                         8.4167                       1.097                         3.3423                    1197.7                  3.4182                   3.4182                   1.9996                     2.735                     0.481                    -0.57359                       1.6517                    -0.022873                 -4.4004                  -3.5176                    1.739                      1.4618                        3.1404                       6.7829                          0.121                            3.1502                               6.7368                             0.53385                            41.007                               -125.91                           1.0815                     6.7829                   -0.0073165                   0.76354                     1.5115                        2.4976                          8.3636                          884.95                             -4.4                          0.00029715                      3.3115                        -1.2773                          3.5595                        765.91                        302.74                                 2                         0.00085562                     0.016897                       -2.5036                          11.241                            195.99                                  3.2946                
         5                  1.1089                      3.8666                 1840.9               3.2517                 3.6004                3.2517                3.5057                0.080206                -0.28465                    2.2471                   6.6012               0.054041               2.2484                 2.3956                  0.88864                    2.2173                    5.5227                    0.023587                       3.5334                          0.42688                         0.11951                        3.4916                           -35.718                      0.50984                 5.5227                 0.17263                 1.6987                 1.9009                    1.0187                      2.4386                      279.64                           6.6                           NaN                   1.7887                     -1.0714                     3.0945                     6.347                   0.0021218                       3.4908                           0.04628                       0.011198                        16.809                           -20.958                      0.28503                 37.672                 3.6557                  6.8669                  5.902                    3.9845                      19.021                       289.6                         3.96                         1.1139                    0.31689                      1.8507                    3.0711                   0.039906                        3.4177                           2.5572                         0.10124                        74.786                           -56.712                      0.18762                 3.0711                 0.14183                0.87892                 0.93035                   1.2626                      3.1556                         615                          1.1                        0.64671                     1.6549                      5.3183                      575.01                        3.6002                     -0.00070527                 0.09545                    2.0023                      7.0948                        6.7754                             0.55126                            NaN                      1.0899                         3.3189                    1191.5                   3.319                    3.319                   1.9957                    2.7191                   0.47534                    -0.57212                       1.6031                    -0.022711                 -4.4004                  -3.5032                   1.7484                      1.4358                        3.0653                       6.7769                        0.12188                            3.1521                               6.6506                              0.5366                            40.214                               -122.29                           1.0744                     6.7769                    -0.013659                   0.81197                     1.5549                        2.3806                          7.7339                          879.13                             -4.4                          0.00030022                      3.2881                        -1.3286                          3.5449                        760.85                        302.39                            1.9999                         0.00089706                     0.017049                        -2.309                          9.7528                            192.86                                   3.271

The feature table starts at Cycle 1.

Plot the charge voltage kurtosis.

plot(ft.Cycle_Index,ft.Charge_Voltage_kurtosis)
title("Charge Voltage Kurtosis by Cycle")

Figure contains an axes object. The axes object with title Charge Voltage Kurtosis by Cycle contains an object of type line.

Input Arguments

collapse all

Raw battery data to segment, specified as a batteryTestDataParser object.

Output Arguments

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Segmented battery data, returned in the same form—table or timetable—as the data table in bdp. segmentData adds three additional columns to segData, as described in the following table.

VariableData Description
CyclingPhasesCycling phase, returned as "Discharge", "Rest", "Charge", or "Undefined".
CyclingModeCycling mode, returned as "CC" (constant current), "CV" (constant voltage), "Rest", or "Undefined".
IsValidData validity flag, returned as true (valid) or false (invalid). Data is flagged as invalid, and therefore unsuitable for subsequent calculations, for conditions such as if their phase and mode cannot be determined, the step duration is anomalously long or short, or the cycle falls outside of user-specified exclusions.

Version History

Introduced in R2024b

See Also

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