Verification oriented development of a scalable battery management system for lithium-ion batteries

This paper describes the model-based development and validation of a flexible scalable battery management system (BMS) for lithium-ion batteries (LiFePO4) using a verification-oriented development methodology. The BMS consists of a central control unit and decentral cell modules. It measures voltages, currents and temperatures to ensure safe and slow aging operating states. Furthermore, appropriate algorithms estimate the state of charge and predict the maximum battery power in a defined prediction horizon Δt, based on the measurement data. The entire capacity of the production-related slightly differing battery cells can be optimally used by using passive or active load balancing methods which equalize the cell charging levels. The BMS also has a CAN interface for integration into a vehicle ECU network. The development of an Extended Kalman Filter (EKF) as a state of charge (SOC) estimator will be shown as an example for the model-based design process.