Fuel cell design for hydrogen vehicles typically uses which storage system?

• A. Liquid hydrogen storage system
• B. Metal hydride slurry system
• C. Cryogenic solid-state hydrogen storage
• D. Compressed hydrogen gas system

Answer: (D)

Storing hydrogen as compressed gas in high-strength, lightweight tanks is the typical design for hydrogen vehicles. Hydrogen has a lot of energy per mass, but very little energy per volume, so squeezing it into a dense form is essential. Compressing the gas to high pressures—common targets are around 350 bar for many light vehicles and up to 700 bar for newer designs—lets a practical amount of fuel fit into a manageable tank size without adding excessive weight. The tanks are designed with strong materials and safety features, including pressure relief systems and robust containment, to handle the high-pressure storage safely. Refueling is fast, similar to filling a conventional fuel tank, and the system delivers hydrogen at the right pressure to the fuel cell.

Other storage approaches exist but are less practical for everyday vehicles. Liquid hydrogen requires cooling the fuel to cryogenic temperatures and maintaining insulation to prevent boil-off, which adds energy cost and system complexity. Metal hydride or other solid-state storage concepts tend to be heavy and bulky, making them less favorable for automotive use where weight and space are at a premium.