Characterization of LTO Batteries and Active Balancing Modes for Energy Storage Systems of Rolling Stock Operating Non-Electrified Lines

Battery electric trains are a flexible and environmentally friendly alternatives to conventional diesel-powered rolling stock, in non-electrified railway lines. The adoption of Lithium Titanate Oxide (LTO) batteries offers a sustainable solution due to their rapid charging capabilities and thermal stability. This study presents a time-variant battery model that can be integrated within the battery management systems (BMS), to adapt the battery safe operating area (SoA) to the operational conditions of the rail vehicle. Additionally, laboratory tests are presented to characterize the proposed model and to derive its own parameters in different operating conditions. The effectiveness of the battery model is proved by analyzing its performance in terms of root mean square error (RMSE) and percentage error (MAPE). Finally, a performance comparison between the passive balancing approach from literature and two active ones – the redundant cell and the switched capacitor configurations - is proposed to highlight how efficiently manage LTO batteries.