An equivalent electrical circuit model is implemented for simulation purposes and to model the transient behavior of the battery cell. This is due to low computational requirements and the approximation of voltage precision. To determine internal DC resistance and the transient response of terminal voltage, a first-order electrical battery model has been embedded in an optimization framework to minimize the error of modeled voltage response and battery voltage response. shows the optimization framework of battery parameterization. Moreover, shows the identified response to the imposed current. Each response and the corresponded current is fed to an optimization algorithm to minimize the voltage error between the simulated and actual voltages.