Technical Paper
Parameter Determination for the Battery Equivalent Circuit Model Using a Numerical Integro-Differential Method
2020-04-14
2020-01-1179
The battery equivalent circuit model consisting of an open circuit voltage (OCV) source and a resistor in series with parallel resistor-capacitor (RC) elements is widely used in system-level simulation. The accuracy of the transient I-V characteristics of the battery model strongly relies on the values of the RC parameters prescribed in the circuit. One of the solutions for determining RC parameters is curve-fitting the measurement data of the battery voltage in the relaxation period obtained from a charge or discharge current pulse test. Since the equation used for curve-fitting can be expressed as the sum of multiple exponential functions which are nonlinear with respect to the RC parameters, the nonlinear least-square (LS) algorithm shows poor performance or even fails due to its sensitiveness to initial guesses of the solutions.