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Fire protection for electric and hybrid vehicles

There is a global transition to renewable fuels and an increasing demand for electric and hybrid vehicles (EV and HEV). As more electric vehicles become operational, their involvement in fire incidents will likely rise.

The significant fire risks associated with vehicles being powered by batteries and high-power electric engines/devices are not widely understood. For example, the consequence of a malfunctioning Li-ion battery can be severe, potentially resulting in a thermal runaway situation with rapid-fire and heat propagation as well as the emission of toxic gasses, posing a significant threat to vehicle drivers, occupants as well as the environment in which the vehicle is operating.

Burning electric vehicle

Fire risks

You could argue that fire risks increase when introducing electric vehicles. For example, a significant part of the fire risks in a traditional combustion engine vehicle is related to the vehicle's electrical system.

These risks are further accentuated in an electric vehicle with more electrical components, wiring, and higher power running through the electrical system. In addition, the Li-ion battery adds a whole new risk element to an electric vehicle.

Challenging risks with Li-Ion batteries

When Li-ion batteries fail through short-circuiting, overcharging, high temperatures, mechanical damage and overheating, this might cause thermal runaway. Thermal runaway occurs when a temperature generated within a battery exceeds the amount of heat that is dissipated to its surroundings. Through this, it becomes self-sustaining as it creates oxygen which feeds the fire.

As the heat source and the fuel both exist within the battery, these fires can develop quickly. The release of flammable electrolytes makes fire extinguishing very difficult. In addition, there are a lot of toxic gases being emitted, such as hydrogen fluoride, which can cause severe damage to both the skin and the respiratory tract.

Dafo Li Ion Risk And Solution

Dafo Vehicle Fire Protection

Through multiple international collaborative research projects in which studies were made of fire risks associated with lithium-ion batteries in vehicles, Dafo Vehicle Fire Protection has developed the fire protection system solution Safe EVTM that addresses and mitigates these risks effectively and safely. 

The suppression agent Forrex EV™ is part of the complex system solution, providing adequate cooling capacity to slow the fire development and allow the safe evacuation of passengers.

Depending on the protection level that needs to be achieved, the early warning detection system solution Safe EV™ can be applied outside the battery packs or as an integrated part. The solution can be limited to detection only without the suppression application.

The protective zones

The full-coverage multi-zone fire protection solution responds to the urgent need for risk mitigation in EV and HEV vehicles.

The main risk scenarios are typically divided into four protection zones to cover all EV or HEV vehicle risk areas. The different protection zones are protected in various ways by robust detection and suppression systems – liquid- and gas-based solutions.

Zone 1 - Engine compartment

Zone 2 - Electrical hazards

Zone 3 - Traditional hazards

Zone 4 - Batteries

The system will detect potential battery failure at the earliest possible stage and take immediate action by cooling, using the suppression agent Forrex EV™. This will effectively stop, or delay, a potentially hazardous situation without the fire developing further.

Bus with different fire zones

Safe EV™ delivers to the market a concept that didn’t exist until now: a system that can offer real protection against battery fires, using a new suppression agent, Forrex EV™, which is specifically developed for EV applications.

Anders Gulliksson

Product Manager