Page 217 - Çevre Şehir İklim İngilizce - Sayı 3

Orhan Topal

any incidents that may occur during the charging of the electric and hybrid
1 vehicles, the charging station should also be electrically insulated in the
similar way. Taking into account that high/low voltage systems and connection
cables may be energized in case of such incidents etc. emergency cases to be
faced by emergency teams; it is the critical importance to know the locations
of the cable routes on the vehicle for cutting off the connections (cables) and/
or disabling the relevant connections if necessary, and the locations of circuit
breakers such as MSD (manuel service disconnect) if used.
Due to the fact that high voltage propulsion batteries in electric & hybrid
vehicles are potential source of danger; the basic inputs to be considered
in their design for emergency cases can be listed as ensuring the electrical
insulation between high voltage systems - chassis, providing sufficient air gap
between the conductive parts, establishing insulation resistance monitoring
system, using connectors that are durable against possible electric arcs, using
orange cables for high voltage warning labels and high voltage components
(DGUV 8686, 2022). There are also precautions that should be taken regarding
the mounting zones specific to propulsion system, body protection and
toxic electrolyte leakage caused by batteries in case of possible crashes
and accidents (Electric Vehicle Safety, 2021: Annex-20). In addition, another
important issue is the protection of casualties and emergency responders
against the danger of electric shock. In the event of a possible crashes , the
most effective method is to ensure the insulation of high voltage propulsion
battery system or discharging of the high voltage propulsion battery which
is integrated with crash avoidance systems and starting from the pre- crash
moment (UNECE, 2022: Regulation No. 94 and No. 95).

1. The Main Risk Factors in Electric & hybrid Vehicle Accidents

The risks during the intervention in accidents and emergencies involving
electric & hybrid vehicles can be addressed in 3 main categories: electrical,
thermal and chemical risks. In this scope, following aspects regarding the
electrical risks are primarily discussed.
Normally, contactors that are in the power propulsion systems of electric &
hybrid vehicles are triggered by the crash sensors in case of any accident and/
or deploying of air-bags in the vehicle, and this ensures the interruption of
electrical connection between the high voltage propulsion battery system and
other propulsion system compounds. Moreover, additional precautions Plug-
in hybrid vehicles such as discharging of capacitors through their discharge
resistors inside the propulsion motor driver and short-circuit of propulsion
motor impeller can prevent the possible hazards (VDA, 2020).

202 Journal of Environment, Urbanization and Climate