Safe Battery Control Using Cascade-Control-Barrier Functions

This article proposes a control barrier function (CBF) approach for fast charging and discharging of batteries under temperature, state of charge (SoC), and terminal voltage constraints. To improve numerical efficiency, we derive a cascade CBF formulation, which divides this safety problem into multiple layers that are easier to formulate and implement. The proposed algorithm exhibits a computational speed that is seven times faster than the model predictive control (MPC) and 3.6 times faster than the traditional single-layer (central) CBF. In the charging scenario, experimental results indicate that the proposed algorithm reduces charging time by 20% in comparison to traditional constant current, constant voltage (CC-CV) methods without violating electro-thermal safety constraints. The discharging experiment illustrates that the cascade CBF effectively limits the battery’s performance to ensure compliance with safety constraints.