Accident E-car: What danger is really for occupants and emergency services

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Accident E-car: What danger is really for occupants and emergency services-danger

That e-cars do not burn more frequently than those with fossil propulsion, has now been confirmed – also scientifically -. Nevertheless, in some cases a queasy feeling, blows from beaning media reporting. But what really happens in case of an accident with an electric car? Goes from an accident e-car a higher risk for occupants, emergency or environment? And what happens to an electric vehicle that has only suffered a supposedly harmless sheet metal damage? Electric car news has asked for two experts.

An electric car burns differently than a burner?

A vehicle fire in a tunnel is the horror scenario par excellence: Researchers of the Institute for Internal Internal combustion engines and thermodynamics of the TU Graz have therefore examined in a project promoted by the Austrian research funding company, together with the Austrian Federal Fire Brigade Association and other partners, as the fire of a car in a tunnel influenced its safety. The fire behavior of burners and e-cars were compared – with similar models to ensure comparability. The good news: The overall risk of a burning electric car is only negligible higher than in a conventional combustion. The fire load is approximately equal and depends essentially from the entrained energy content – from the charge level of the battery at the E-car and the tank contents at a burner. Only the pollutant load through releasing hydrofluorities is slightly higher at the E-car, but also occurs when the burner occurs when the coolant evaporates from the air conditioning. In both cases, however, the IDTLH (“Immediately Dangerous to Live and Health”) – limit values in that altitude area in which persons were left, did not exceed.

Incidentally, the fire is from the battery with the few types of fire from E cars. On the contrary, the researchers had to struggle for newer models, the battery for the fire tests at all on fire, like Dr. Daniel Fruhwirt, University Assistant and Project Representative at the Institute of TU Graz involved. “Even if the vehicle was in full fire, it was not sure if the battery is involved at all.”Claims the researcher. Therefore, a short circuit was specifically caused by introducing saline solution to test a battery edge.

What differences are there when deleting?

In any case, the deletion of a burning E-car is not a much greater technical challenge for the forces more, such as Dr. Hannes Kern emphasizes. The doctoralist doctoralist advises the industry about the defense of specific emergencies, crises and dangers and is self-enthusiastic firefighter. It’s easy longer. While a conventional vehicle is deleted in a few minutes, it would often take several hours at the E-car until it is stable for a removal. Deployment organizations such as manufacturers work on new solutions to accelerate this stabilization. The key is the cooling of the batteries to interrupt the “Thermal Runaway” mentioned process of burning the electrolytes contained in the batteries.

Even if it is researched on novel rain: “Most manufacturers agree that water is still a suitable blowing medium”, like Dr. Kern emphasized. However, new solutions are used to reduce the enormous water consumption through a direct introduction of the water into the batteries. In the so-called lance deletion system, the battery is detected distance controlled from below and the water pumped directly into the battery packs. This significantly reduces water consumption and the batteries are efficiently cooled. Disadvantage: You should know where exactly the battery pack is located. If it is divided into two positions as many models, you have to start twice.

Renault builds its own “Fireman Access” in its models, so a filler neck for direct introduction of the water into the battery. The cutting extinguishing process originally developed for residential fire fighting is already used for E cars and is recommended by Skoda. The extinguishing jet is added a cutting means that in conjunction with high pressure cuts through all materials and how quickly the access to the battery pack can expose. Furthermore, extinguishing ceilings are offered, which should suffocate the fire. These have proven to be a little successful compared to other extinguishing variants in the fire trial in full fire, like Dr. Fruhwirt emphasizes. The handling of the extinguishing blanket was difficult, so that there was always rod flames, which caused the extinguishing blanket.

What do the emergency services need?

With the variety of own solutions – for example the automaker – you have little joy at the fire department. “A uniform approach is missing, we would like to work with equipment we already carry with us anyway,” like Dr. Kern emphasized from own experience. That would significantly increase the acceptance of the forces. But the experts see the greatest potential for improvement anyway, but in the missing labeling and information transfer.

Often it is not obvious at first glance whether it is an accident car around a burner or an e-car. Currently one orients of optical clues, such as the blue font used for E-cars often used for model designations, the presence of thick orange cable strands or special admission labels for E-cars (“E” in Germany, green font in Austria). The query of the approval can also be determined which drive the vehicle has. However, before finally clarified to which drive mode it is, valuable time passes and there is an increased risk for the forces due to possibly exposed high-voltage components. It is therefore worked on a labeling requirement for vehicles with alternative drive, in the form of an ISO standard. How to look concrete is still unclear.

If it is a burning e-car, the most important information for the forces is whether the battery is even affected at all. Most fires go out of electronics. Remedy could provide an extension of the information transfer between manufacturers and forces. The automatic emergency call system “ECALL” prescribed by the EU since 2018 has already been sent to the European emergency number 112 today. It would be easy to engage in this data transmission also a simple state analysis of the battery (battery affected yes / no, charge state, high-voltage system switched off yes / no).

This actually quite simply implemented measure would also have the advantage that accident e-cars, which have only a sheet metal damage and are not on fire, can be rated simpler. Currently, no one knows if a crash without fire the high-voltage battery has been affected and thus unstable. Although the fire brigade associations have already developed recommendations for action, how to deal with such vehicles. Often rich the cover with a special safety cover, if something should do in the battery but something. In order to go safe, but these vehicles are still plugged into containers from ignorance or missing experience and flooded at least to the top of the battery with water. This often causes more damage than is actually caused by the crash. In addition, the flooding water must be disposed of expensive.

Who cares about the car?

That fees the unprecedented question, who actually carries responsibility for the “follow-up” of a casual E-vehicle. The fire brigades are only responsible for immediate security, the towing service is transported only from A to B, the disposal no place for storing such vehicles and no experience with the deletion. And car dealerships want to see such cars on their farm anyway.

So do? Dr. Kern emphasizes that the already used, model-specific “rescue cards” will gain importance. “Uneven or contradictory specifications are the biggest problem.”He explains. These rescue cards contain concrete information about the model and how to deal with to devote damage as possible. The fire brigades would also constantly develop new continuing education offers. However, the expansion of the “ECALL” system must be discussed at EU level.

Dr. Fruhwirt, on the other hand, assumes that the problem with the use and proliferation of solid batteries – in which a weakly flammable solid is used as an electrolyte – will lose brisance in a few years.

Further information: Link to the research project of the TU Graz: https: // projects.FFG.AT / Project / 3290205

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3 thoughts on “Accident E-car: What danger is really for occupants and emergency services”

  1. A somewhat inappropriate picture. Because of the very low center of grains of electric cars, these are probably in the rarest cases after an accident on the roof.

  2. If the Eauto is not burning yet, the emergency separation of the battery is usually pressed for the first time and securely turned off somewhere. Should it burn it is usually a total loss anyway and is sunk in the container. Problem Most do not have these containers. With us there is the advantage that half of the fire departments work with Audi and are trained there, so to speak and forward the to the others.

  3. Unfortunately, the TU Graz probably used extinguishing blankets that were unsuitable for e-bull. In the market, it now provides a manufacturer who successfully offers certified ceilings under the brand Vlitex. These ceilings suffocate or delete also a Li-Jo fire, but keep the fire safely under the ceiling, even over several hours if necessary. The fire department can take further action during the protected combining car.


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