Research pick: Current city buses - "How suitable is lithium-sulphur battery for electric city bus application?"

Rechargeable batteries are de rigueur in the modern world. We find them in everything from our ubiquitous smartphones and tablets to the electric vehicles in which we taxi ourselves from A to Z. Unfortunately, despite the advances in battery technology, the lithium-ion battery has its inherent problems. For instance, limited discharge time, an ultimately limited number of charge-discharge cycles, high cost of the raw metal, lithium to make them, and their overall bulk and weight. Writing in the International Journal of Powertrains, a team from the UK has looked at the developments around an alternative, the lithium-sulfur battery, that might find use in electric buses for our cities.

Victor Calvo-Serra, Abbas Fotouhi, Mehdi Soleymani, and Daniel Auger of the Advanced Vehicle Engineering Centre in the School of Aerospace, Transport, and Manufacturing at Cranfield University, in Bedfordshire, explain how they have used MATLAB/Simulink software to build and simulate an electric bus of a similar model to those currently used in London. The software also models a putative lithium-sulfur battery and compares activity and efficiency with conventional lithium-ion batteries used in such vehicles.

“The results demonstrate that the proposed Li-S battery pack can fulfill the requirements of an electric city bus in terms of power while achieving a considerable increase in vehicle’s range,” the team writes. However, they point out that current Li-S cell prototypes also suffer from limited cycling life that precludes their commercial development for the time being. However, once that limitation is overcome, the technology could ultimately drive forward the move to longer journeys for electric buses. Indeed, there is much promise in Li-S batteries and many advances have been made over the last ten years. It will be interesting to see, after such a long wait, whether three all turn up at once in the very near future.

Calvo-Serra, V., Fotouhi, A., Soleymani, M. and Auger, D.J. (2020) ‘How suitable is lithium-sulphur battery for electric city bus application?’, Int. J. Powertrains, Vol. 9, No. 4, pp.265–288.