When batteries catch fire

When batteries catch fire

There's no point in turning a blind eye, because the electrified cars are here and won't go away," says Andreas Nunberg, who organizes high-voltage training courses together with his partner Emanuel Wulgarellis. The two experienced automotive experts are a little surprised at the reluctance of some workshop owners to deal with the electrical issue. "The effort involved in making a workshop fit for battery-powered vehicles should certainly not be underestimated," he said Nunberg. The batteries in damaged hybrid and electric cars can ignite up to three weeks after an accident. It is therefore not advisable to park it in the workshop hall; rather, the damaged vehicle should be parked in a so-called quarantine area where a safe distance from other vehicles or buildings is maintained. “If there is a fire, the insurance will check it afterwards,” warns Emanuel Wulgarellis. A battery removed from the vehicle should be stored in a special container in an explosion-proof manner. “Even minor damage to the sheet metal can result in a short circuit in the cells, which subsequently leads to a fire,” warn the experts.

“The effort involved in making a workshop fit for battery vehicles is certainly not to be underestimated.”ANDREAS NUNBERG, EXPERT

CANNOT DELETE

“Extensive fire tests by the Austrian Federal Fire Department have shown that a burning lithium-ion battery cannot be extinguished with any currently known fire retardant,” explain Nunberg and Wulgarellis. Conclusion: Burning batteries can only be cooled until the chemical process is complete. The fire extinguishing attempts were carried out this summer at a training site run by the disaster relief service in Lower Austria. Co-organizers of the fire tests were representatives of TÜV Süd, the University of Leoben, the EU research center JRC, and the Hamburg professional fire department/University of Rostock. The researchers took samples of the contaminated soil, the pollutants in the air and in the extinguishing water as well as the residues on the fire. “The samples are currently being evaluated and the results will be presented this year,” says Wulgarellis. But one thing is already certain today: the clouds of smoke that arise when lithium-ion batteries burn are by no means harmless. “I'd rather not imagine what would happen if an electric car caught fire in an underground car park,” says Nunberg. The tests of extinguishing agents such as glass beads, gel, metal fire powder, foam and water showed that although water could stop the smoke almost immediately, it took a considerable amount of time for the temperature to drop noticeably. The embers powder, on the other hand, had almost no extinguishing effect. The gel extinguisher was able to immediately suppress the flame development and the temperature, but the fire material continued to smoke considerably and the fire gases could ignite again at any time. Even the initially promising extinguishing granules made of glass beads could not stop the battery fire.

LAST RESORT WATER BATH

Only completely submerging a burning electric vehicle in a water bath ensures that the chemical reaction slowly comes to a standstill. “The only problem is that the car has to stay in the tank for a week and afterwards around 11,000 liters of highly toxic water are left over,” explains Andreas Nunberg. All attempts to speed up the cooling process have so far failed. During the extinguishing tests, a Cobra cutting extinguishing device was also tried out, which presses water through the battery casing at a pressure of 300 bar. The lithium-ion battery responded immediately by exploding several cells, with individual cells also being blown off. The experts' conclusion: The Cobra cutting and extinguishing device can easily gain access through the casing of an HV battery, but it triggers a completely undesirable reaction inside. All preventative measures should therefore be taken in the workshop to prevent a battery fire from occurring in the first place. “If you know the dangers and train appropriate work processes, you are on the safe side,” say Nunberg and Wulgarellis. Under the company name WN-Technical Training, they offer workshops and blue light organizations high-voltage training at levels HV1, HV2 and HV3 as well as the necessary recurring refreshers. Their credo: “We want to take away the fear of everyone who comes into contact with electric cars.”