  As the number of electric vehicles rapidly increases, their peak demand on
the grid becomes one of the major challenges. A battery-assisted charging
concept has emerged recently, which allows to accumulate energy during off-peak
hours and in-between charging sessions to boost-charge the vehicle at a higher
rate than available from the grid. While prior research focused on the design
and implementation aspects of battery-assisted charging, its impact at large
geographical scales remains largely unexplored. In this paper we analyse to
which extent the battery-assisted charging can replace high-speed chargers
using a dataset of over 3 million EV charging sessions in both domestic and
public setting in the UK. We first develop a discrete-event EV charge model
that takes into account battery capacity, grid supply capacity and power output
among other parameters. We then run simulations to evaluate the
battery-assisted charging performance in terms of delivered energy, charging
time and parity with conventional high-speed chargers. The results indicate
that in domestic settings battery-assisted charging provides 98% performance
parity of high-speed chargers from a standard 3 kW grid connection with a
single battery pack. For non-domestic settings, the battery-assisted chargers
can provide 92% and 99% performance parity of high-speed chargers with 10
battery packs using 3kW and 7kW grid supply respectively.
