SLAAEF5B March   2024  – June 2025 MSPM0G1505 , MSPM0G1506 , MSPM0G1507 , MSPM0G3506 , MSPM0G3507 , MSPM0H3216 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Algorithm Introduction
    1. 2.1 Battery Basic Knowledge Introduction
    2. 2.2 Different SOCs and Used Technologies
      1. 2.2.1 NomAbsSoc Calculation
        1. 2.2.1.1 Coulometer With OCV Calibration
        2. 2.2.1.2 Data Fusion
        3. 2.2.1.3 Battery Model Filter
      2. 2.2.2 CusRltSoc Calculation
        1. 2.2.2.1 EmptySoc and FullSoc
        2. 2.2.2.2 Core Temperature Evaluation
      3. 2.2.3 SmoothRltSoc Calculation
    3. 2.3 Algorithm Overview
      1. 2.3.1 Voltage Gauge Introduction
      2. 2.3.2 Current Gauge Introduction
      3. 2.3.3 Capacity Learn Introduction
      4. 2.3.4 Mixing Introduction
  6. 3Gauge GUI Introduction
    1. 3.1 MCU COM Tool
    2. 3.2 SM COM Tool
    3. 3.3 Data Analysis Tool
  7. 4MSPM0 Gauge Evaluation Steps
    1. 4.1 Step 1: Hardware Preparation
    2. 4.2 Step 2: Get a Battery Model
      1. 4.2.1 Battery Test Pattern
      2. 4.2.2 Battery Model Generation
    3. 4.3 Step 3: Input Customized Configuration
    4. 4.4 Step 4: Evaluation
      1. 4.4.1 Detection Data Input Mode
      2. 4.4.2 Communication Data Input Mode
    5. 4.5 Step 5: Gauge Performance Check
      1. 4.5.1 Learning Cycles
      2. 4.5.2 SOC and SOH Accuracy Evaluation
  8. 5MSPM0 Gauge Solutions
    1. 5.1 MSPM0L1306 and 1 LiCO2 Battery
      1. 5.1.1 Hardware Setup Introduction
      2. 5.1.2 Software and Evaluation Introduction
      3. 5.1.3 Battery Test Cases
        1. 5.1.3.1 Performance Test
        2. 5.1.3.2 Current Consumption Test
    2. 5.2 MSPM0G3507, BQ76952 and 4 LiFePO4 Batteries
      1. 5.2.1 Hardware Setup Introduction
      2. 5.2.2 Software and Evaluation Introduction
      3. 5.2.3 Battery Test Cases
        1. 5.2.3.1 Performance Test 1 (Pulse Discharge)
        2. 5.2.3.2 Performance Test 2 (Load Change)
    3. 5.3 MSPM0L1306 and BQ76905
  9. 6Summary
  10. 7References
  11. 8Revision History

4.2.1 Battery Test Pattern

For the test machine, users can use any machine that can charge and discharge the battery, and the tested data can be recorded. The paired test machine with the supplied GUI is keithley 2602A source meter, which is controlled through a USB to rs232 wire, paired with NI_VISA.

To get a more accurate model, users need to discharge the battery with low current (for example, 0.1C for 20 minutes). The rest time after each pulse needs to be 1-2 hours. Then, users can take the Vcell as OCV. Finally, with this setting, users get about 30 points, which is the minimum data size of SOC-OCV table. TI recommends to reduce the discharge current and discharge time at the beginning and at the end to catch the voltage rapid change and increase accuracy, especially for LiFePO4 battery.

Note: When doing a battery test, the tested battery needs to take the PCB and battery socket influence into consideration. Otherwise the tested resistor is smaller than the real circuit resistor.

Table 4-1 shows a suggested test pattern for LiCO2 and LiMn2O4. For LiFePO4, refer to this as well.

Table 4-1 Battery Test Pattern
ParameterValueComment
Test temperatureApprox. 25°C
Start voltageApprox. 4.3-4.4VMake sure the start voltage is no lower than the application max charge voltage
End voltageApprox. 2.5-3.0VMake sure the rest voltage is no higher than the application min discharge voltage
Discharge currentApprox. 0.05C-0.1C (Capacity)Low current means more points. Recommended to use 0.05C for first and last 5% capacity
Discharge timeApprox. 10-20 minutesLow discharge time means more point. Recommended to use 10 minutes for first and last 5% capacity
Rest time1-2 hoursLonger is better. However, 1 hour is enough

Figure 4-1 shows a battery model example test case. This charges the battery to full (4350mV) and rests for 1 hour, with the voltage drops to 4322mV. Then, the battery does a pulse discharge with 20 minutes and rests for 1 hour to get the OCV under different SOC. The test is terminated at 2450mV. After 1 hour rest, the voltage increases to 2864mV. So, the OCV range of the SOC-OCV table is from 4322mV to 2864mV.

Note: For battery test pattern, make sure the tested OCV range is wide enough to avoid that the calibrated OCV beyond the SOC-OCV table range in real applications. The simplest way is to let the OCV range of the SOC-OCV table to cover the battery operation range (MaxFullChgVoltThd to EmptyDhgVoltThd). For example, the SOC-OCV table (OCV range is from 4322mV to 2864mV) can be an excellent choice for a battery which operates between 4200mV and 3000mV.
Pulse Discharge Test CaseFigure 4-1 Pulse Discharge Test Case

If you use the GUI and the suggested source meter to do the battery test, remember to use the source meter in four wire mode, which can reduce the voltage detection error caused from line resistance. The suggested setup is shown in Figure 4-2. The MCU COM tool is used to get the battery run data. The SM COM tool is used to control the source meter to generate pulse battery charge and collect the voltage and current data to generate the battery parameters later.

Hardware Structure to Get Battery ModelFigure 4-2 Hardware Structure to Get Battery Model

If you use your own test machine to do the test, you can construct the test data according to the SMData format and using SM COM tool later for battery model generation. Here is the SMData format. You need to input your tested Vcell and Icell data in Row B and Row C from Line 2. And then name the file with "-SmData.csv" at last.

SmData TypeFigure 4-3 SmData Type