Batteries play a pivotal role in the automotive industry, particularly in battery electric vehicles, with a significant impact on both lifetime and driving range. The main focus of this chapter is a brief literature review on the characterization of batteries and a description of a comprehensive, yet real-time model of a lithium-ion battery for numerical simulation and analysis in electric vehicle applications. First, this chapter explores the diverse landscape of battery technologies, including lead-acid, nickel-metal hydride, lithium-ion, and lithium-sulfur. Then, a review of lithium-ion batteries will be conducted, and the battery capacity degradation model, based on a semiempirical Arrhenius degradation model, is presented. After the review of battery modeling, the equivalent circuit model is proposed for modeling the lithium-ion battery cell. The equivalent circuit model is accurate enough to represent the dynamic behaviors of the cell and can be run in real-time. Instead of using a physical battery, the parameters of the equivalent circuit model are estimated using the electrochemical high-fidelity model of the battery cell in MapleSim. This high-fidelity model can be integrated into a real-time digital simulator for an advanced numerical simulation analysis. This approach helps reduce dangers associated with training in high-risk or hazardous scenarios, providing cost-effective training alternatives that eliminate the need for an actual battery. After the estimation of all parameters, the resulting equivalent circuit model is compared with the electrochemical high-fidelity model of the battery cell through its implementation in dSPACE SCALEXIO. It is demonstrated that not only the model runs in the real-time digital simulator, but also the discrepancy between the battery model and the electrochemical model is minimal.