FCEV truck fire

A private car vehicle parked on a street in an industrial area took fire at night for unknown reasons. The fire spread to hydrogen-powered trucks parked inside the fence of a logistic company for agricultural products. The thermally activated pressure relief devices built on the storage units of the truck operated as designed by releasing hydrogen, which probably participated to the general fire.

The fire brigade intervention lasted 3 hours. Nobody was injured. 

The INITIATING CAUSE was a fire started on a personal car parked near the FCEV trucks. 
The thermally activated pressure relief devices (TPRD)correctly activated upon temperature increase and released the hydrogen from the onboard tanks.  

The ROOT CAUSE is unknown. Because the fire started outside the company grounds in a parked vehicle, the local police started an investigation, suspecting arson rather than a mechanical vehicle fault.

CGH2 tanks,
Li-ion battery,
trucks

One of the sources reported that the trucks had full tanks, corresponding to approximately 61 kg H2.

The exact technical specifications of the trucks are unknown, but approximately the following:

• 90 kW stacks, x2 = 180 kW H2 fuel cell system
• 72 kWh Li-ion battery pack
• 350 kW e-motor,
• CGH2 onboard tanks: pressure = 35 MPa, 31 or 62 kg depending on the configuration
• Max Driving range = approximately 720 km (under optimal conditions)

The private vehicle and two trucks were burned to ground. A third truck was damaged. 

The property damage was not reported, but the cost of a FCEV truck can be assessed around 450000 euros, so that the total damage results above one million.  

The fire brigades intervened with more than 100 persons and were able to extinguish the fire in 3 hours. They succeed in avoiding fire escalation to the buildings. A major concern was lithium-ion power batteries installed on the FCEV trucks. They had to be kept cool and supervised for more hours. 

This is a case where the safety measures worked as expected, preventing over-pressurisation of the tanks and their possible rupture. These measures rely on a critical hardware called TPRD (Thermally actuated pressure relief device). It releases excess pressure or gas from a high pressure gas tank when the surrounding environment reaches a predetermined temperature, set at a value well below the tank's material degradation from heat. The trigger mechanism is based (i) on the melting of an eutectic alloys, releasing a spring or seal or a liquid-filled glass bulb that breaks when reaching the reaction temperature.