Safe-Handling of e-vehicles after accidents: Recommendations for the rescue chain

Summary:

Through literature research and expert interviews, the current tactical standard of the fire brigades in dealing with crashed electric vehicles was determined. In addition, a survey of firefighters on existing skills and experience in this field was conducted.
The identification of the drive system of an accident vehicle can be assessed as uncritical. Reliable tools are available here with the possibility of a license plate query by the rescue control center and the common AUTO acronym for the initial investigation. In addition, 64 % of the survey participants have already taken part in a training course and 28 % in an emergency response with an electric vehicle.
With the help of the hazard matrix, the hazards posed by an accident electric vehicle can be assessed. In addition to escaping gases and liquids, the thermal runaway and high voltage components, the uncertainty of the emergency services in dealing with the electric vehicle also poses a threat to the successful course of the operation. The survey shows that only about 50% of the participants feel well prepared for dealing with an electric vehicle.
In addition to the usual procedure in the event of a traffic accident with conventionally powered vehicles, some additional measures are required. To stabilize the situation, it is necessary to safely decommission the electric vehicle. Above all, high-voltage technology must be secured for this purpose. During the rescue work, mechanical stress on the high-voltage battery through force introduction or cutting operations must be avoided. 63% of the survey participants stated that they were more cautious when using electric vehicles than with conventionally powered vehicles.
93% of the survey participants agreed with the statement „It is difficult to assess the condition of the traction battery after a traffic accident“. This is the biggest challenge in the current tactical standard, as the procedure for rescuing the vehicle occupants and the necessary protective clothing of the emergency services depend on the battery condition. The risk is that the danger posed by the battery is assumed to be too great. Due to the tactical approach chosen afterwards, further patient damage can occur in extreme cases.
As a result of the research work to date, there is a demand for a way to read out the battery data in order to be able to assess the current state of the battery after an accident. For this purpose, information on the cell chemistry, the battery temperature and an evaluation of the cell voltage are required. Several prototypes of hardware and software applications have already been developed at THI, which, for example, enable the simple evaluation of data from the battery management system with a corresponding smartphone app.