Water jet tech from Swedish firm Cold Cut Systems could be deployed against the increasing threat of so-called thermal runaway blazes in batteries, following successful tests by the Swedish Civil Contingencies Agency (SCCA).
The risk of fires in EVs, though small, is a big worry for fire services. Lithium-ion batteries burn fiercely, potentially producing ‘jet flames’ and venting highly toxic gases including 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, and it also takes a vast quantity of water to extinguish an EV fire safely using traditional means – up to 150,000 litres. Internal combustion vehicle fires are typically extinguished using less than 4,000 litres.
As batteries can re-ignite spontaneously hours or days after being apparently extinguished, current practice may involve letting a battery burn itself out in a controlled fire – which has been recommended by some EV manufacturers, or flooding the battery by partially submerging the vehicle for an extended period. This is often impractical or difficult.
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 fire fighters 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 originally launched in 1997 as a means of safely cutting metal in explosive environments such as oil refineries, but was soon in use with fire fighting teams at paper factories, coal mines and chemical plants. Cold Cut says it has supplied systems to 14 UK fire services for other roles.
“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,” company CEO Johan Ivarsson told Auto Express. The system has already been adopted by British company Prospeed, for its new 6×6 Rapid Intervention vehicle designed to access underground and multi storey car parks that traditional fire tenders can’t reach.
While EV fires are still rare, they’re increasing as more cars appear on the roads. London is most affected currently, with the fire service reporting well over 200 electric car fires in the last five years, with a big jump in 2021.
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