What is the material of Toyota Mirai hydrogen tank?
The Toyota Mirai uses carbon-fiber reinforced polymer (CFRP) composite hydrogen tanks with a polymer inner liner, forming Type IV high-pressure storage rated for around 700 bar. This combination keeps the tanks light yet strong enough to safely store hydrogen at high pressure.
Tank technology in the Mirai
The Mirai stores hydrogen at high pressure and uses multiple CFRP-based tanks to achieve its total storage capacity. Each tank features a polymer inner liner wrapped by carbon-fiber composites, enabling a high strength-to-weight ratio and resistance to hydrogen permeation and corrosion.
Type IV construction and CFRP rationale
Type IV hydrogen tanks employ a polymer (plastic) inner liner with a carbon-fiber reinforced polymer overwrap. There is no metal liner, which reduces weight while maintaining structural integrity at 700 bar. The CFRP outer shell is designed to withstand impacts and pressure cycling during refueling and driving.
Liner and overwrap function
The plastic liner confines the hydrogen and resists leakage, while the carbon-fiber wrap provides the necessary strength and stiffness. The combination results in a lighter storage system compared with metal-lined alternatives, improving overall vehicle efficiency.
Safety and testing
Hydrogen tanks used in the Mirai are subjected to rigorous safety testing, including burst, impact, and thermal assessments, to meet international standards for high-pressure fuel containers. The materials and construction are chosen to minimize permeation and to maintain shape and integrity even in adverse conditions.
Summary
In short, the Toyota Mirai’s hydrogen tanks are Type IV CFRP composite vessels with a polymer liner, designed for 700 bar operation. This approach provides a balance of light weight, strength, safety, and durability essential for practical hydrogen fuel-cell vehicle use.
