The document describes a battery management system that includes: - A smart battery with a controller that calculates state of charge and communicates with a local host system, and a control circuit that regulates current and charge/discharge. - A management system with flexible architecture, accurate state of charge calculation, intelligent current control for balancing and safety, compatibility with multiple platforms, and cloud computing for data analysis and display. - The system monitors and controls lithium-ion batteries in applications like electric vehicles through current control, data communication, and a control panel that displays state of charge.