Table of Contents
ISRN Automotive Engineering
Volume 2014, Article ID 525630, 9 pages
Research Article

A Power Buffer in an Electric Driveline: Two Batteries Are Better Than One

Division for Electricity, Uppsala University, Ångström, Laboratoriet, P.O. Box 534, 751 21 Uppsala, Sweden

Received 13 November 2013; Accepted 9 December 2013; Published 2 February 2014

Academic Editors: W. Li and H. H. Liu

Copyright © 2014 Juan de Santiago et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Fuel cells and high energy density batteries have limited overrated capacity and slow power response. Ultracapacitors and flywheels are proposed to overcome these limitations and to facilitate regenerative braking in hybrid and electric vehicles. The simulations presented in this paper show that a Secondary Energy Storage Unit (SESU) enhances the performance of the drivelines as previously suggested and provides additional improvements. A combined design of the primary energy source and the SESU reduces the total weight and volume and increases the battery lifetime. A full-electric driveline is simulated using a standard EPA FTP-75 drive cycle. Then the same vehicle is simulated with as SESU and the results are compared. The same is done for a hybrid driveline. Two drivelines are used as references and then enhanced with an SESU; four simulations are presented in total. Simulation results show that an energy storage device with very low energy and high power allows better battery selection and energy management.