Active Balancing Strategy for Battery Packs in Swapping Stations Based on the Flyback Topology

July 27, 2026

Battery swapping stations can support peak shaving by charging during low-load periods and reducing grid import during peak periods. However, battery packs returned from different vehicles may have different SOC, capacity, resistance, temperature, and ageing conditions. These differences reduce the amount of stored energy that can be used safely. This thesis proposes a Flyback-based battery-to-battery active balancing strategy. At the pack level, a voltage-current-temperature SOC estimator is used to select high-SOC donor packs and low-SOC receiver packs. Energy is then transferred through an isolated Flyback path. At the station level, a mixed-integer linear programming model evaluates the effect of balancing on peak-shaving performance. The method is validated at circuit, pack, and station levels. The circuit simulation confirms isolated and directional energy transfer. In the 24-hour pack simulation, the SOC spread decreases from 0.3800 to 0.0288, with an SOC estimation mean absolute error of 0.0240. At station level, enabling B2B balancing increases the peak-shaved energy from 47.2 kWh to 164.0 kWh and reduces the residual peak gap to zero. The results show that Flyback-based B2B balancing can improve SOC consistency and increase the usable energy and peak-shaving capability of battery swapping stations.

Authors in the community:

• 

  X

  Xiang Li

  ist1115689

Supervisors of this institution:

• 

  A

  António José Castelo Branco Rodrigues

  ist12288

electrical-engineering-electronic-engineering-information-engineering - Electrical engineering, electronic engineering, information engineering

por - Portuguese

Instituto Superior Técnico