Multicell battery has been widely used in various electrical and electronics devices. To achieve the optimal multicell battery design, accurately modeling battery discharge behavior of multicell battery is crucial. However, modeling discharge behavior of multicell battery is very challenging due to the nonlinear battery effects, nonuniform cell quality, and various cell connections. In this paper, we develop a circuit-based multicell battery model to accurately model the multicell battery discharge behavior in terms of available capacity, output voltage, and internal resistance with consideration of nonlinear battery effect and nonuniform cell quality. It also characterizes the cell discharge current distribution of cell strings in parallel connection. The proposed multicell battery model has been validated by extensive simulation and experimental results under various load conditions.

Battery performance prediction is crucial for battery-aware power management, battery maintenance, and multi-cell battery design. However, the existing battery models cannot capture the circuit characteristics and nonlinear battery effects, especially recovery effect. This paper aims to fill this gap by developing an enhanced circuit-based model for single-cell battery. The proposed model is validated by comparing simulation results with experimental data collected through battery testbed. The comparison shows that the proposed model can accurately characterize and predict the single-cell battery performance with considerations of various nonlinear battery effects under both constant and variable loads.