Hydrogen Tanks : sealing under pressure
Hydrogen tanks play a critical role in the hydrogen field, serving as specialized pressure vessels designed to safely store and transport hydrogen gas. Hydrogen is highly flammable, extremely light, and composed of very small molecules, so these tanks are engineered to withstand high pressures (typically 350–700 bar in automotive applications) and prevent leaks over long periods. They can be made from metal, composite materials, or a combination, balancing strength, weight, and durability. Hydrogen tanks are used in a wide range of applications. In the automotive sector, they power Fuel Cell Electric Vehicles (FCEVs), including cars, buses, trucks, and trains, and serve as on-board storage for mobile power solutions. In the industrial sector, they provide stationary hydrogen storage for fuel cell power plants and refueling stations for vehicles.
As key components of the growing hydrogen economy, hydrogen tanks enable safe, reliable, and efficient hydrogen storage and distribution, supporting clean energy solutions, sustainable transportation, and diverse industrial applications.
What applications, inside a H₂ tank?
In hydrogen storage systems, sealing and bonding play a critical role in ensuring safety, durability, and long-term performance. Due to hydrogen’s extremely small molecular size and the high pressures involved, even the smallest leak can compromise system integrity.
Valve bonding and sealing are especially critical areas. The valve is the primary interface between the hydrogen tank and the external system, controlling filling, storage, and release of hydrogen. Proper sealing and bonding at this point ensure leak-tight connections, mechanical stability, and resistance to pressure, vibration, and temperature variations throughout the tank’s service life.
Another key area is dome protection. The dome region of a hydrogen tank is subjected to high mechanical stress and environmental exposure. Sealing and protective materials applied in this area help prevent hydrogen permeation, protect composite layers, and shield the tank from moisture, chemicals, and external damage. This protection is essential to maintain structural integrity and ensure safe operation over time.
Together, these sealing and bonding solutions enable safe hydrogen containment, extend tank lifetime, and support the reliable operation of hydrogen storage systems in demanding applications such as fuel cell vehicles and energy infrastructure.
The challenges of bonding and sealing inside a H₂ tank
Bonding and sealing inside hydrogen tanks is particularly challenging due to the unique properties of hydrogen and the extreme conditions under which the tanks operate. Hydrogen molecules are very small, making them prone to permeate through materials that are normally gas-tight. At the same time, hydrogen tanks operate under high pressures (up to 700 bar in automotive applications) and experience temperature fluctuations, vibration, and mechanical stress.
Critical areas for bonding and sealing include valve interfaces, dome regions, and connections between metallic and composite components. These points are potential leak paths and must maintain mechanical integrity and chemical resistance over the tank’s lifetime.
Effective bonding and sealing solutions must therefore provide :
- Leak-tight performance under high pressure
- Durability under vibration and temperature changes
- Resistance to hydrogen permeation and environmental factors
- Compatibility with different tank materials (metal, composites)
TB3953 : a two-component elastic adhesive
- Strong adhesion to a wide range of materials
- After curing, it becomes a rubber-like strong elastic material. It has significantly higher strength and elongation than other elastic adhesives
- The pot life (gel time) after mixing of the two components is relatively long, thereby allowing sufficient time for application
- The curing time can be shortened by heating after bonding, so the curing speed can be controlled according to the situation
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