High-Voltage Battery Cooling System - SMART Fortwo 451 Series Introduction Into Service Manual

High-voltage battery cooling system

Since the optimal operating conditions of the
high-voltage battery are bound by tight temper-
ature limits, the battery management system
control unit can decouple the coolant circuit of
the high-voltage battery from the rest of the
cooling circuit via an electromotive water valve if
necessary.
The cooling circuit of the high-voltage battery
then consists of:
• 2 coolant pumps
• High-voltage battery heater
• Chiller (only with code (V03) Battery cooling
system)
• Electric expansion valve (only with code (V03)
Battery cooling system)
• Electromotive water valve (coolant pump
switchover valve)
The chiller is only installed on vehicles with code
(V03) Battery cooling system. It is a refrig-
erant/coolant heat exchanger which is connected
to the refrigerant circuit of the air conditioning
and the cooling circuit of the high-voltage
battery. The electric expansion valves of the
chiller and of the evaporator for interior cooling
can be actuated by the battery management
system control unit.
The high-voltage battery can thus be cooled
independently of the interior climate control.
Introduction of smart fortwo electric drive (3rd Generation) • Model Series 451
High-voltage battery cooling system
i Note
In the smart fortwo electric drive, R134a is used
as refrigerant and ND8 is used as refrigerant
oil, including for service.
High-voltage battery heater
Since the capacity of the high-voltage battery drops
at low temperatures, the high-voltage battery can
be heated by the high-voltage battery heater during
the charging process at temperatures below 0°C.
The high-voltage battery heater is located in the
cooling circuit of the high-voltage battery, is
supplied with power by the 12 V on-board electrical
system and actuated by the drivetrain control unit.
G5 High-voltage battery
R101 High-voltage battery heater
P54.10-3703-00
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