Globally, FCEV are recognized as safe vehicles. When launching a new FCEV, Hyundai Motor Group seeks approval from multiple certification bodies in Korea and abroad for the safety of the vehicle itself (14 categories) and for the hydrogen tank (15 categories). Only when it receives the green light from all of those certification bodies, Hyundai launches its FCEV onto the market.
FCEV are engineered to remain safe in collisions, fires, and impacts. Under emergency situations, the vehicle cuts its supply of hydrogen to the stack, and it discharges any residual hydrogen into the atmosphere if it detects a fire hazard. In particular, Hyundai Motor Group’s NEXO was selected as the “safest SUV” by the Euro NCAP in 2018, and was rated as “Good” in a side crash test conducted by the Insurance Institute for Highway Safety (IIHS), a non-profit automobile safety research organization in the US.
Both instances serve as proof that NEXO is safer than most vehicles with standard internal combustion engines. In particular, Hyundai Motor Group’s NEXO was selected as the “safest SUV” by the Euro NCAP in 2018, and was rated as “Good” in a side crash test conducted by the Insurance Institute for Highway Safety (IIHS), a non-profit automobile safety research organization in the US. Both instances serve as proof that NEXO is safer than most vehicles with standard internal combustion engines.
|KNCAP||US NCAP||IIHS||Euro NCAP|
The hydrogen used for FCEV is entirely different from the heavy hydrogen or tritium used for hydrogen bombs.
Hydrogen that goes into FCEV is the typical form of hydrogen that we are all familiar with (1H). When used in FCEV, hydrogen and oxygen create power through a simple chemical reaction. Meanwhile, heavy hydrogen (2H) or tritium (3H) used for hydrogen bombs exist in minute quantities (0.015% or less) in nature.
They require a nuclear fusion reaction at a minimum temperature of 100,000,000℃ to create energy and a devastating explosion.
Pursuant to regulatory requirements, hydrogen fuel tanks must last up to 15 years (20 years in Europe), and 4,000 recharges (5,000 for Europe). However, Hyundai Motor Group uses hydrogen fuel tanks that are far safer and more durable than such minimum legal requirements.
In fact, one of Hyundai Motor Group’s research centers has carried out tests to recharge hydrogen fuel tanks 45,000 times. Moreover, Hyundai put its hydrogen fuel tanks through 15,000 recharging sessions after drop tests, extreme heat/extreme cold simulation tests, and other tests under harsh conditions, and an additional 12,000 recharging sessions after carrying out impact tests (being dropped during transportation), tests against artificial defects created by sharp blades, and more.
As such it is safe to say, Hyundai's hydrogen fuel tanks were sufficiently tested for durability. Recharging a hydrogen fuel tank at 700bar every day for 45,000 days means you can drive up to 609km per day for 123 years.
World-class safety technology for FCEV unveiled at the ‘2019 Children’s Safety-First Fair’
Pursuant to the ‘Safety regulation on pressurized containers used in automobiles’ enforced by the Ministry of Land, Infrastructure and Transport, components used in high-pressure hydrogen systems are required to pass 14 safety testing categories, including rupture tests, fire hazard tests, projectile tests, etc. Not only that, hydrogen tank components are put through a variety of other safety testing procedures that simulate head-on collisions, rear-end collisions, extreme heat, extreme cold conditions, etc.
According to test results, a tank recharged to 700bar does not explode even when it is shot by a gun. In fact, when a projectile penetrates the tank, the tank discharges hydrogen through the opening. Side and rear-end crash tests carried out under the same conditions used for internal combustion vehicles proved that hydrogen fuel tank systems are safe for everyday use.
But to make the hydrogen tanks and high-pressure hydrogen system components used for NEXO even safer, Hyundai Motor Group doubled the number of testing categories for hydrogen tanks and components compared to when the company initially developed the NEXO. Thanks to these efforts to raise the safety level of mass-produced hydrogen tanks, Hyundai Motor Group was able to satisfy domestic and international regulatory and legal requirements. Not only that, Hyundai set more than 200 additional testing categories to make sure all hydrogen tank-related components and systems are safer and more reliable than the legally required minimum threshold.
Hyundai Motor Group also used more than 200 test vehicles to make sure it can cover any potential safety and performance issues that may arise over the course of actually operating the vehicle.
Hydrogen storage tank for NEXO with superior safety performance proved through extreme testing activities
Hydrogen is roughly 14 times lighter than air, so it rapidly dissipates into the atmosphere when it is discharged. Even when a fire breaks out, the probability of fire igniting any leaked hydrogen gases is practically zero. Nevertheless, the hydrogen fuel tank, fuel supply system, and fuel cell stack on the NEXO have sensors capable of detecting any hydrogen leaks in real time.
If the sensors detect a hydrogen leak while the vehicle is on the road or when the vehicle collides with another object, it warns the driver through the supervision cluster on the driver’s side, shuts down the hydrogen fuel tank to cut off the supply of hydrogen, and prevents the leak from becoming a more severe accident. If a fire heats up the temperature around the hydrogen fuel tank above a certain threshold, the tank uses a safety valve to forcefully release hydrogen gas into the atmosphere both safely and rapidly.
As such, there is no risk of a hydrogen tank filled with hydrogen exploding. Even if the vehicle burns entirely, the hydrogen fuel tank does not explode thanks to the fire resistant material used on the exterior surface of the tank. Simply put, FCEV like NEXO are engineered to be the safest against fire and explosion hazards among all types of vehicles available on the market.
Fire safety testing of a FCEV
The inner surface of hydrogen fuel tanks is lined with a thin polyamide liner (nylon material), whereas the outer surface is made out of a 20~25mm thick carbon fiber-reinforced plastic (carbon fiber+epoxy material) capable of withstanding pressures up to 700bar. When developing hydrogen fuel tanks, engineers have to consider two factors - strength and rigidity.
Strength is important in preventing hydrogen fuel tanks from rupturing, and rigidity is important in keeping them durable. Here, strength refers to the ability of a material or structure to withstand (not break) forces it is subjected to, while rigidity refers to the ability of a material or structure to stop any deformations.
Pound for pound, carbon fiber-reinforced plastic is six times stronger and four times more rigid than steel i.e. carbon fiber-reinforced plastic is much lighter and sturdier than steel.
Hydrogen fuel tanks offer superior strength and rigidity