High voltage

Broken down vehicles and vehicles involved in an accident

Information on the product

Special care must be taken for vehicles with high-voltage (HV) systems that have broken down or been involved in an accident, as the high voltages in the on-board power supply system present potential dangers. For electric vehicles and hybrid vehicles in particular, roadside assistance providers and other trained personnel must ensure that damaged high-voltage components are handled safely, and must take suitable protective measures for their own safety. Although vehicle manufacturers rely on intrinsically safe systems, dealing with broken down vehicles in accidents requires special expertise.

Mechatronics technicians carry out important maintenance work, check the on-board battery and the mains for direct current and analyse central components such as current dispensers, batteries and transmission. At the same time, manufacturers are continuously working to improve the safety of vehicle parts in order to minimise damage and reduce the risk to roadside assistance providers and other personnel.

This article sets out what needs to be taken into account when identifying, retrieving and maintaining vehicles with high-voltage systems.

Disclaimer

To protect workshop employees, the German Social Accident Insurance (DGUV) stipulates the following qualifications for persons who carry out work on series production vehicles equipped with high-voltage systems and associated components.

All information in this publication has been carefully researched and compiled. However, we are unable to provide any guarantee nor to accept any legal liability for the completeness or currency of the information provided. All liability on our part for damages, whether direct or indirect, material or immaterial, arising as the result of the use or misuse of information or incomplete/incorrect information is excluded, insofar as it is not the result of wilful intent or gross negligence on our part.

This information sheet predominantly considers German and European standards.
Please note: the relevant applicable statutory provisions and safety provisions may differ between countries.

Identifying high-voltage vehicles

Vehicles with a high-voltage system can be identified by various features:

Designations on the vehicle, e.g. electric drive, hybrid, plug-in hybrid
"E" as the last digit of a German number plate
Electric charging connection, potentially as a second connection next to the tank opening in hybrid vehicles
Appropriate information in the vehicle registration certificate
Orange high-voltage wires or plugs
Stickers with warning notices that refer to high voltage
Charging indicators in the display

The rescue sheet

The rescue sheet shows components relevant to the rescue such as airbags, belt tensioners, battery, the fuel tank or body reinforcements in a vehicle diagram. The rescue sheet helps the fire brigade to quickly and safely identify the optimum points to apply rescue equipment such as spreaders and hydraulic cutters.
Rescue sheets/ rescue data sheets contain information such as:

Installation location of the battery or batteries
Location of the high-voltage isolating device
Positions of the high-voltage cables
Further components in the high-voltage system

When towing hybrid and electric vehicles, note the following:

Minimum qualification 1S
Always follow the manufacturer's specifications.
For safety reasons, the drive wheels must not rotate. The vehicle should be transported using a flatbed vehicle.

In the case of vehicles involved in an accident, also note the following:

Visually inspect the vehicle for structural battery damage.
If structural battery damage is present: Evacuate the area and call the fire brigade.
If there is no structural battery damage: Monitor the battery temperature and call the fire brigade if the temperature rises.
If necessary, deactivate the high-voltage system according to the manufacturer's specifications (minimum qualification 2S).

When vehicles arrive in the repair shop after an accident

Unlike vehicles with a combustion-only engine, reconditioning must not be started immediately on hybrid and electric vehicles.

Follow the manufacturer's instructions.
Externally intact battery ≠ intact battery
Internal uncontrolled reactions ("thermal runaway") = fire
Park the vehicle in a quarantine area (secured area with safety distances) for a certain period of time.
Mark the vehicle with a warning sign.
Disconnect the high-voltage battery if it is possible to do so safely.
If the airbag has been triggered, the high-voltage system is automatically disconnected. Nevertheless, the voltagefree status must be determined.
Continuously monitor the battery temperature in accordance with the manufacturer's specifications. If the temperature increase exceeds the manufacturer's specifications: Call the fire brigade.
(Damaged) high-voltage batteries are classified as hazardous goods. They may be shipped only by trained personnel (qualification 3S*). Transport and storage only in accordance with the manufacturer's specifications.