First things first: electric vehicles (EVs) are statistically less likely to catch fire than an internal combustion engine car. But fires involving a lithium-ion battery can be much more serious and difficult to extinguish, especially if in an enclosed space such as an underground or multi-storey car park (where a vehicle might be charging, for example), which large fire engines cannot access.
Once an EV battery pack is on fire, the energy contained with the cells is released and can cause "thermal runaway": a type of chain reaction within battery cells where the initial heat causes a chemical reaction which produces even more heat, driving the temperature higher, causing further chemical reactions. And so on.
The issue was highlighted by a fire in a carpark at Stavanger airport in Norway, in January. Large fire and rescue vehicles were not able to enter the structure in the early stages of the fire due to height restrictions. By the time crews entered on foot with fire-fighting equipment and water, the blaze had developed beyond control.
Previous EV firefighting methods have been extreme: immersing the entire car in water for days, or enclosing them in shipping containers.
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But now, a UK company has developed a "rapid intervention vehicle" which can deliver crew and equipment to locations where height may be limited and minimise fire damage/danger early.
Prospeed Motorsport's HiLoad 6x6 uses a Toyota Hilux as a donor, but fitted with an entirely new chassis. With the replacement chassis and a torque splitter system, the 6x6 offers 3000kg payload - almost triple the standard 4x4 Hilux’s capacity. The loadspace is also extended by 1230mm.
Although longer, The HiLoad’s height is 1850mm - low enough to allow access to the majority of parking structures.
The vehicle can be fitted with the Coldcut Cobra system for extinguishing EV battery fires (pictured below).
The gun-like Cobra Ultra High Pressure Lance (UHPL) system uses an abrasive suspended in water to pierce a hole through floor pans and inject water at 300bar – more than 100 times the pressure of the air in a typical car tyre – throughout the module casing. This water cools directly inside the battery and reduces the possibility of thermal runaway.
Unlike alternatives which involve pumping thousands of litres of water into the vehicle in an attempt to cool the whole battery, independent tests from the Swedish Civil Contingencies Agency show the Coldcut Cobra system can prevent cell propagation within 10 minutes, using just 240 litres of water – less than a bath-full and 20 per cent of the HiLoad’s tank capacity.
The vehicle is currently being trialled in the Czech Republic. It is already "part of one EV car manufacturer’s firefighting fleet", says Prospeed (without specifying which).
The company is also working in the defence market to offer 4x4 and 6x6 versions as part of a light utility vehicle fleet, which to replace ageing Land Rover Defender and Pinzgauer fleets.
The Hiload is assembled in York in the UK, or the company can ship the 6x6 conversion as a module for final assembly overseas.