Characterize an Equivalent Circuit Battery

This example uses:

Using MathWorks® tools, estimation techniques, and measured lithium-ion or lead acid battery data, you can use CAGE to characterize a resistor-capacitor (RC) circuit battery with open circuit voltage, series resistance, and 1 through N RC pairs. The number of RC pairs reflects the number of time constants that characterize the battery transients. Typically, the number of RC pairs ranges from 1 through 5. For this example, the number of RC pairs is 3.

The workflow steps characterize a lithium-ion polymer (LiPo) battery. The steps use numerical optimization techniques to determine the number of recommended RC pairs, provide initial estimates for the battery model circuit parameters, and estimate parameters to fit a model to experimental pulse discharge data. The results provide the open circuit voltage, series resistance, and RC pair parameter data.

To open the project with steps 1-4 complete, in the CAGE Case Studies pane:

  1. Select Equivalent circuit battery characterization.

  2. Click Open Example.

  3. Proceed with Step 5: Optimize Estimates.

WorkflowDescription

Estimate Equivalent Circuit Lithium-Ion Battery Data

Live script providing workflow steps 1 through 3.

Step 1: Load and Preprocess Data

Load and preprocess time series battery discharge voltage and current data.

Step 2: Determine Number of RC Pairs

Determine the number of necessary time constants (TC) for estimation.

Step 3: Estimate Parameters

For battery discharge data, estimate these values:

  • Open-circuit voltage, Em

  • Series resistance, R0

  • RC pair(s) time constant(s), Tau

  • RC pair(s) resistance(s), Rx

Step 4: Import Strategy

Import Simulink® model with battery discharge data

Step 5: Optimize Estimates

For battery discharge data, optimize:

  • Open-circuit voltage, Em

  • Series resistance, R0

  • RC pair(s) time constant(s), Tau

  • RC pair(s) resistance(s), Rx

Note

If you want to characterize a battery by using a Battery (Table-Based) (Simscape Battery), Equivalent Circuit Battery (Powertrain Blockset), or Estimation Equivalent Circuit Battery (Powertrain Blockset) block, use the procedure described in Calibrate Powertrain Blockset and Simscape Battery Blocks to complete steps 3–5 instead.

References

[1] Ahmed, R., J. Gazzarri, R. Jackey, S. Onori, S. Habibi, et al. "Model-Based Parameter Identification of Healthy and Aged Li-ion Batteries for Electric Vehicle Applications." SAE International Journal of Alternative Powertrains. doi:10.4271/2015-01-0252, 4(2):2015.

[2] Gazzarri, J., N. Shrivastava, R. Jackey, and C. Borghesani. "Battery Pack Modeling, Simulation, and Deployment on a Multicore Real Time Target." SAE International Journal of Aerospace. doi:10.4271/2014-01-2217, 7(2):2014.

[3] Huria, T., M. Ceraolo, J. Gazzarri, and R. Jackey. "High fidelity electrical model with thermal dependence for characterization and simulation of high power lithium battery cells." IEEE® International Electric Vehicle Conference International Electric Vehicle Conference. March 2012, pp. 1–8.

[4] Huria, T., M. Ceraolo, J. Gazzarri, and R. Jackey. "Simplified Extended Kalman Filter Observer for SOC Estimation of Commercial Power-Oriented LFP Lithium Battery Cells." SAE Technical Paper 2013-01-1544. doi:10.4271/2013-01-1544, 2013.

[5] Jackey, R. "A Simple, Effective Lead-Acid Battery Modeling Process for Electrical System Component Selection." SAE Technical Paper 2007-01-0778. doi:10.4271/2007-01-0778, 2007.

[6] Jackey, R., G. Plett, and M. Klein. "Parameterization of a Battery Simulation Model Using Numerical Optimization Methods." SAE Technical Paper 2009-01-1381. doi:10.4271/2009-01-1381, 2009.

[7] Jackey, R., M. Saginaw, T. Huria, M. Ceraolo, P. Sanghvi, and J. Gazzarri. "Battery Model Parameter Estimation Using a Layered Technique: An Example Using a Lithium Iron Phosphate Cell." SAE Technical Paper 2013-01-1547. Warrendale, PA: SAE International, 2013.

See Also

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