Trucks
Trucks
Going electric has many environmental benefits: but how does it affect safety? Are battery-electric trucks safe to charge? How should they be serviced and maintained? And is there really an increased risk of fire?
In recent years, media reports of lithium-ion batteries in consumer goods combusting into flames have contributed to a common misconception about the safety of battery-electric vehicles. However, studies show that fires are less common in electric vehicles than internal combustion engines. Transitioning to electric still raises new safety issues, but the risks are not higher – just different.
The biggest difference between an electric driveline and a combustion engine is the huge battery packs. For example, a Volvo FH Aero Electric can consist of up to six battery packs weighing more than 500 kg each. But do they represent a fire risk?
“If an electric truck has a serious crash, there could be leakage, and in the worst-case scenario, internal shortcuts could cause a fire,” says Pontus Enhager, Product Manager Electromobility at Volvo Trucks. “In the unlikely event of an electric vehicle catching fire, it will typically burn for a longer period compared to a non-electric vehicle, since damaged battery cells release electrolytes gradually. However, just like we did with our diesel vehicles, we have worked extensively to mitigate the effects and consequences of a serious crash.”
Some of the factors that need to be addressed to limit the risk of fire include temperature management, robust casing, and monitoring of all related systems to prevent risks such as overcharging.
Despite some misconceptions, fires are less common in electric vehicles than internal combustion engines.
There are safety systems that work around the clock to minimize the risk of something happening in the first place
To build a battery you need several battery cells, which are assembled into battery modules. These modules are then assembled into a battery pack. To minimize the effects of an accident, the batteries are enclosed in a sturdy and weather-proof shell, and the battery packs are integrated together with the steel side crash structure of the truck’s chassis. This helps them withstand temperature variations, water intrusion, debris from the road and collisions.
The size and weight of the batteries, and the sensitivity of their cells, also puts special requirements on their protection and mountings. “Traction battery packs weigh hundreds of kilos each and Volvo’s current electric trucks can carry up to six batteries”, adds Pontus. “It’s important that they are securely fastened and protected against external impact, to make sure they remain in place and minimize risks in the event of a collision.”
To facilitate this, the entire driveline and the energy storage unit are located and packaged to maximize protection, with electronics and cabling protected by the main beams and designated crash structure of the chassis. The structures surrounding the batteries are tested to withstand the energy from a standard passenger car driving straight into them.
Watch this film to learn more about Volvo Trucks’ crash tests for its electric vehicles.
Battery packs are integrated into the steel side crash structure of the truck’s chassis, to protect them from temperature variations, water intrusion, debris from the road and collisions.
All electric trucks are equipped with safety systems where all electronics are connected and monitored. This is in order to proactively prevent malfunctioning components in the batteries from spreading to other parts of the vehicle.
“These safety systems work around the clock to minimize the risk of something happening in the first place,” Pontus says. “For example, Volvo’s trucks are equipped with an advanced battery management system, which enables real-time monitoring of the batteries and fault detection, and by extension this enables preventive actions.”
For example, if the battery monitoring system should detect abnormal temperatures in one of the batteries, a notification will appear in the instrument cluster as well as a red warning symbol and an acoustic signal notifying the driver to stop the vehicle. If necessary, the electrical power to the affected battery will deactivate within fractions of a second. The truck should then be taken to a workshop, so that the batteries can be inspected.
“Inside the batteries, there are layers of heat barriers to prevent heat transfer from a malfunctioning cell to another. If heat builds up and causes high internal pressure, it will be detected. The battery pack will be electrically disconnected from the vehicle.”
Work involving high-voltage systems should be carried out according to strict procedures and protocols, and must be handled by specially trained, certified technicians. “Maintenance and repair of an electric truck has a lot in common with working with a conventional one,” says Pontus. “The biggest difference is the batteries and the internal energy management system. But if service technicians are trained in how to handle them correctly, these components will not compromise their safety.”
Overall, there is a wide range of safety aspects that are unique to battery-electric trucks. This puts a lot of demands on truck manufacturers. However, with the right attention and awareness of all possible risks, an electric truck offers the exact same level of safety as any other truck.
If you still have questions about battery-electric trucks, you might find the answer in our FAQs. You can also learn more about Volvo’s electric truck range, as well as guidance on going electric.
Servicing and maintenance of electric trucks should only be handled by specially trained and certified technicians.
