C h a p t e r 5
What are the differences
between onboard charging
and offboard charging?
To charge batteries found in EVs,
engineers can either rely on a charger
built into the vehicle (onboard charger) or
a charger external to the vehicle (offboard
charger).
Because onboard chargers are designed
to connect to AC mains voltages,
rectifiers are needed to convert AC
voltage into DC voltage to charge the
battery. In addition, the grid connection
exposes the vehicle to any transient
voltage present on the grid, so protection
should be taken into consideration.
For offboard chargers, the vehicle is
designed to connect to a DC charging
point, which keeps the AC/DC conversion
away from the EV and directly couples
the EV battery to the DC source.
Offboard chargers must also integrate
communication lines between the vehicle
and the charger so that the correct
amount of charging current can be
negotiated.
What advantages does
offboard charging present?
Some of the biggest advantages of
offboard charging include:
• Dynamic power flow. Communication
cables used between the DC charge
point and the EV allow the charger to
OFFBOARD CHARGING
The increasing popularity of
electrical vehicles is boosting
the need for efficient and fast
charging stations. With some
capable of up to 350 kW, we are
now getting close to the fueling
experience."
Philippe Di Fulvio
Business Development Manager, EV Infrastructure,
Littelfuse
23
7 Experts on Automotive Powertrains
