Technology Consultant: Safety of Hydrogen

Hydrogen fuel cell vehicles are ultimate environmental-friendly vehicles featured with zero-emission,long-range and fast-refueling.

(I) Hydrogen’s characteristics make it a safer choice as fuel

Hydrogen is only 1/14 of air in weight. When being released into air, hydrogen will disperse rapidly and rise up with the speed of 20m/s at normal ambient temperature. However, propane and gasoline vapor may result in an explosion with any accidental spark when being released since they are heavier than air and will gathered on the ground. .

The radiation energy released by flame of hydrogen is relatively lower and the fire is not easily spread.

Toxic-free: Leakage or overflow of hydrogen will not pollute the environment.

Low flammability: When being exposed to air, the minimum explosion concentration of gasoline is 1.4% and that of hydrogen is 4%. That is to say, the probability of gasoline explosion in the air is two to three times than that of hydrogen. Moreover, the explosion will be the most  intense one when hydrogen concentration in air reaches 29%. But, in consideration of the rising and diffusive characteristics of hydrogen, it is almost impossible to reach a concentration of 29% in air. The best explosion mixing ratio of gasoline steam is only 2%, so it is more risky.

(II) Built-in hydrogen security system provides strong protection

In the applications in automotive and passenger cars, hydrogen fuel tanks are much stronger than plastic gasoline tanks.

Generally, hydrogen fuel tanks are cylinders wrapped by carbon fiber, mixed metal (type III) or polymer (type IV), which are stronger, safer and more reliable than traditional gasoline tanks. Each water tank is equipped with a separate heat activated pressure release device to allow safe draining of tank contents as temperatures rise.

The test standards of tanks are in line with the widely recognized SAE International/FMVSS and global technical regulations, with a typical service life of 15 years.