Swedish extinguishing system lessens time to put out EV fires
● Li-ion fires burn fiercely ● Water jet cuts through casing
WATER jet tech from Swedish firm Cold Cut Systems could be deployed against the increasing threat of so-called thermal runaway blazes in electric vehicle batteries, following successful tests by the Swedish Civil Contingencies Agency (SCCA).
The risk of fires in EVs, although small, is a big worry for fire services. Lithium-ion batteries burn fiercely, potentially producing ‘jet flames’ and venting highly toxic gases, such as hydrogen cyanide. A number of EVs burning in a confined space, such as an underground car park, could quickly become too hot for crews to access. It also takes a vast quantity of water to extinguish an EV fire safely – up to 150,000 litres. A fire in a combustion-engined vehicle is typically put out using less than 4,000 litres.
Batteries can reignite spontaneously hours or days after being apparently extinguished, so current practice can involve letting a battery burn itself out in a controlled fire, or flooding the battery by partially submerging the vehicle for an extended period. This is often impractical.
The ColdCut Cobra system attacks the fire at its heart, using a 300bar water jet containing abrasive material able to cut through a vehicle’s floor and titanium battery casing. In this way firefighters can flood the burning cells directly, and the SCCA tests suggest the system is so efficient that just 750 litres of water are required to extinguish a burning car battery in less than 10 minutes.
The ColdCut system was launched in 1997 as a means of safely cutting metal in explosive environments such as oil refineries, but was soon in use with firefighting teams at paper factories, coal mines and chemical plants. Cold Cut says it has supplied systems to 14 UK fire services for other roles.
Company CEO Johan Ivarsson told Auto Express: “The problem of how to handle EV fires, together with increasing numbers of EVs on the roads, means we have been working with the SCCA to develop a method to handle these types of fires. We are really pleased with the outcome, and are seeing a lot of new interest.”
The system has already been adopted by British company Prospeed for its new 6x6 Rapid Intervention vehicle, designed to access underground and multi-storey car parks that traditional tenders can’t reach.
While EV fires are rare, they’re becoming more common as more cars appear on the roads. London is most affected currently, with more than 200 electric car fires reported in the past five years.
“Just 750 litres of water are required to put out a burning car battery in less than 10 minutes”