Energy recapture through deceleration – regenerative braking in electric vehicles from a user perspective

Abstract

We report results from a 1-year field study (N = 80) on user interactions with regenerative braking in electric vehicles. Designed to recapture energy in vehicles with electric powertrains, regenerative braking has an important influence on both the task of driving and energy consumption. Results from user assessments and data from onboard data loggers indicate that most drivers quickly learned to interact with the system, which was triggered via accelerator. Further, conventional braking manoeuvres decreased significantly as the majority of deceleration episodes could only be executed through regenerative braking. Still, some drivers reported difficulties when adapting to the system. These difficulties could be addressed by offering different levels of regeneration so that the intensity of the deceleration could be individually modified. In general, the system is trusted and regarded as a valuable tool for prolonging range.

Practitioner Summary: Regenerative braking in electric vehicles has direct implications for the driving task. We found that drivers quickly learn to use and accept a system, which is triggered via accelerator. For those reporting difficulties in the interaction, it appears reasonable to integrate options to customise or switch off the system.

Keywords:

• electric vehicles
• regenerative braking
• skill acquisition
• trust
• acceptance

Acknowledgements

This study was funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. We are grateful for the support of our consortium partners, Vattenfall Europe AG (Dr C.F. Eckhardt and F. Schuth) and the BMW Group (G. Schmidt, Dr M. Hajesch, Dr A. Keinath and Dr M. Schwalm) which made our research possible. We thank Dr M. Hajesch for his valuable comments on the manuscript. We also gratefully thank Katja Gabler, Florian Fritzsche and their colleagues at the BMW Group for performing data pre-processing of the logger data.