In this paper, a virtual battery model, which provides a framework for simulation of batteries in electric vehicles, is introduced. Using such a framework, we can model the performance of a battery during its usage, such as battery charge, discharge, and idle status, the impacts of internal and external temperature, manufacturing quality on joints, the cell capacity and balance management, etc. Such a framework enables providing quantitative tools for design and production engineers to predict the battery performance and provide feedback to battery design, control and manufacturing processes.