SLUAA45 April   2020 BQ27Z561

 

  1.   End of Discharge SOC Jump Elimination
    1.     Trademarks
    2. 1 Introduction
    3. 2 Improve Battery Modeling
      1. 2.1 Improve Battery Modeling -- Get Matched ChemID
      2. 2.2 Improve Battery Modeling -- Use GPCRB Tool to Optimize Low-Temperature Performance
    4. 3 Optimize Gauge Configurations
      1. 3.1 Optimize Gauge Configuration -- Load Prediction
        1. 3.1.1 Load Mode
        2. 3.1.2 Load Select
        3. 3.1.3 Discharge Current Threshold and Quit Current
      2. 3.2 Optimize Gauge Configuration -- Enable Smoothing to 0% in Discharge Mode
      3. 3.3 Optimize Gauge Configuration -- Enable Fast Resistance Scaling
      4. 3.4 Optimize Gauge Configuration -- EDV in Steep Zone
    5. 4 Achieve Successful Ra Table, Qmax and DOD0 Learning
      1. 4.1 Complete a Learning Cycle to Update Ra Table and Qmax
      2. 4.2 Add a Dedicated Relaxation to Update DOD0
    6. 5 References

3.3 Optimize Gauge Configuration -- Enable Fast Resistance Scaling

The gauge gets cell resistance from interpolating Ra table, which inevitably leads to some error in SOC. The error could be large at low temperature and heavy load, especially near the end of discharge when resistance changes quickly, which may cause SOC jump issue.

Fast Resistance Scaling is an algorithm that improves SOC convergence to 0% by scaling cell resistance as (Rnew / Rold), where Rnew is the most recent measured resistance and Rold is the interpolated resistance at present DOD. After a scale is calculated, an IT simulation is triggered to utilize the new resistance information.