With electric vehicles having reached a critical mass thanks to the work of suppliers of electronic raw materials, manufacturers and dealerships, researchers and engineers are focused less on how to make an EV viable and more on how to improve on the established system.

This means not only exploring cheaper, higher capacity and more sustainable batteries using technologies such as solid-state electrolytes but also developing systems to make the current wave of batteries more efficient, safer and longer-lasting.

A fascinating and revolutionary technology from French car manufacturer Renault has been developed which they claim will transform the safety of EV cars as a whole and turn battery fires from a significant challenge to something that can be doused in a matter of minutes.

The Danger Of Thermal Runaway

Electric batteries rarely catch fire, and when they do it is typically due to a significant impact or major defect in another part of the device. However, when they catch fire it can quickly escalate from a small spark to a major blaze.

One of the main reasons for this is that electric fires in general are more difficult to manage; prevention is far better than cure, and putting out an electric fire safely usually requires the use of either carbon dioxide or blue dry powder extinguishers to safely put out.

The concern with battery fires, however, is the potential for thermal runaway, where due to the nature of the battery cells the fire rapidly escalates and intensifies, often taking hours, if not days to burn out.

They are also much harder to fight using conventional firefighting techniques, as they require considerable dousing with water to put out the fire, which then often causes a short circuit which sets off the next battery cell, something that can happen multiple times in a row.

Prevention And Firefighter Access

The EV manufacturing world has been working extremely hard to find solutions to electric fires, and several solutions have come into place.

The first is to use alternative battery technologies, as sodium-ion and solid-state batteries do not have the same risk of fire and thermal runaway as lithium-ion batteries do. However, until both are on the market, there needs to be a way to manage battery fires now.

This is where a new technology by Renault could potentially help significantly.Known as Fireman Access, the system consists of an opening in the case of the car’s battery with a disk stuck onto the top.

During normal use, it serves as a complete seal and ensures the battery works normally, but in the event of a fire, the huge power of a fire hose breaks the seal and the entire battery is submerged in water quickly.

Electricity and water do not mix, however, one of the most effective ways of putting out an electric fire is to overwhelm it quickly. The result, Renault claims, is that an electric fire can be put out in minutes, roughly the same amount of time as a conventional car fire.

Renault claims that it cuts the average amount of time it takes to put out an electrical fire from four hours to ten minutes, and turns it from a serious, life-threatening conflagration to a relatively routine job for firefighters.

New Safety Technology For All

Whilst the technology itself is interesting and important in its own right, what makes it unique is that Renault has made the patents available to everyone in the industry as part of a universal patent.

Whilst the system has been fitted to every major EV brand Renault owns, including Dacia and Alpine, this would ensure that the technology could be fitted to every new electric vehicle developed from this point on, and could pave the way for a revolution of safety features.

Electric batteries are not designed to catch fire, and EVs have a range of safety features already to help avoid this in everyday transport.

There are several battery cooling systems, which direct waste heat away from the battery and either disperse it from the car or use it to generate further electricity.

As well as this, a range of sensors will detect the current thermal state of the battery and adjust both power output and cooling systems to meet the needs of the batteries, including a fail-safe limp home mode if the battery temperatures cannot be managed any other way.

Electric battery fires are thankfully rare, typically only caused by accidents or otherwise unrelated malfunctions, but because every EV fire is inherently serious, technologies such as Fireman Access are vital to protect a growing number of EV drivers and passengers.