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

4.5.2 SOC and SOH Accuracy Evaluation

If users want to evaluate SOC accuracy, then refer to the SmoothSoc instead of the NomSoc or CusSoc. The reason is that, from end user's side, the wanted SOC is a relative SOC, which can only change from 0% to 100% and no SOC jump is seen in the SOC output.

As SmoothSoc is a relative SOC, the accurate value cannot be obtained by searching the SOC-OCV table. The point when SmoothSoc is 100% and 0% is easily seen. To know the accurate SmoothSoc value other than 0% and 100%, users need to first construct the relationship between SmoothSoc and CusRemCap by charging the battery to 100% and discharge to 0%. Then, redo the test with the same load and same temperature. After that, users can use the CusRemCap to get the accurate SmoothSoc value. Refer to Table 4-8 for further description.

Table 4-8 Get Accurate SmoothSoc Value
Accurate Value of SmoothSoc Condition
100% When current drops to FullChgCurtThd and the voltage is between MinFullChgVoltThd and MaxFullChgVoltThd.

0%

 When voltage drops to EmptyDhgVoltThd.

Other values

Get a SmoothSoc-CusRemCap table first and redo the test with the same condition to keeep the EmptySoc and FullSoc to be same. Then, users can use the CusRemCap to get the right smoothSoc value.

As shown in Section 4.5.1, at least after one discharge or charge, the MaxNomFullCap is obtained and the EmptySoc and FullSoc starts to learn and save into the matrix. To get a more accurate SmoothSoc, TI recommends users to run two battery cyles first. The first cycle is to learn the MaxNomFullCap. The second cycle is to learn and save the SmoothSoc and FullSoc. After that, the gauge algorithm works in the best performance.

The SOH equals to MaxNomFullCap / NomFullCap. In the code, add a 2% margin to SOH output to avoid being below 100% at the first battery cycle, due to NomFullCap fluctuation. If users want to check the SOH accuracy, then TI recommends to check the NomFullCap accuracy instead. To evaluate NomFullCap accuracy after multicycles, the suggested flow is:

  1. Rest the battery for 1 hour, measure the cell voltage, and map the voltage as the COV to the SOC1, using the SOC-OCV Table.
  2. After one charge or discharge cycle, rest for 1 hour, measure the OCV again, and map to the SOC2.
  3. Calculate the NomFullCap: NomFullCap=Quse/(SOC2−SOC1)​.