An RC model to represent the voltage profile of a second-life lithium-ion battery

This paper evaluated a first-order equivalent circuit model to represent the voltage profile of a second-life lithium-ion battery sourced from an electric vehicle. Experimental tests were conducted to build look-up tables for the battery and construct the model using the least squares method to fit the simulated and experimental operating curves. The model was validated based on a real battery operating curve. The battery tests were carried out in a controlled environment to avoid the influence of external factors. The mean absolute percentage error in the voltage magnitude divergence between the experimental and simulated curves was 0.676%. The results were also extended to a second-order model; however, the mean absolute percentage error for the second-order model was 0.861%.