The growing demand for sustainable energy storage solutions has prompted an increased interest in sodium-ion batteries (SIBs) as a potential alternative to the widely used lithium-ion batteries (LIBs).

This thesis presents a design and implementation of a Battery Management System (BMS) adapted for SIBs, with an emphasis on cell balancing and State of Charge (SOC) estimation. Experimental measurements were done to model the SIB cells as an Equivalent Circuit Model (ECM).

The work evaluates different balancing methods including passive, DC-DC converter-based and shared bus balancing. A BMS featuring a bidirectional flyback converter-based balancing system was implemented using Texas Instruments’ EMB1428, EMB1499 and BQ76942 Integrated Circuits (ICs). All controlled by an STM32 microcontroller which also runs the balancing algorithm and SOC estimation using an Extended Kalman Filter (EKF). The EKF was simulated where it converged with the actual SOC and then managed to track it through multiple charge and discharge cycles without an error.

This work also investigated the feasibility of replacing LIBs with SIBs in stationary energy storage systems. A modular SIB pack was designed to fit in a standard 19-inch server rack, meeting the voltage and capacity requirements of an existing inverter systems. This demonstrates that SIBs can serve as a drop-in replacement for LIBs in stationary storage systems without the need to modify the surrounding infrastructure.

SIBs are shown to offer advantages such as improved safety and the use of more abundant and less geo politically sensitive materials. This makes SIBs a viable, cost-effective and sustainable alternative to LIBs for stationary energy storage systems.