How is hydrogen stored in a hydrogen fuel cell?
Hydrogen fuel cells are an exciting technology that promises a cleaner and more sustainable future for transportation and energy. However, one of the key challenges in this technology is the storage of hydrogen, a highly flammable and lightweight gas. In this article, we’ll explore the methods used to store hydrogen in fuel cells and why these methods are critical for the safe and efficient operation of hydrogen-powered vehicles.
Why is Hydrogen Storage Important?
Hydrogen is the most abundant element in the universe, but storing it efficiently and safely is a complex task. For hydrogen fuel cells to work effectively, the hydrogen must be stored in a way that balances safety, energy density, and practicality. This is especially important in automotive applications, where space and weight are at a premium.
Methods of Hydrogen Storage
There are three primary methods for storing hydrogen in fuel cell systems. Each method has its own advantages and challenges:
Compressed Hydrogen Gas: Hydrogen can be stored as a gas in high-pressure tanks. These tanks are typically pressurized to 350-700 bar (5,000-10,000 psi). This method is widely used in hydrogen-powered vehicles because it is relatively simple and allows for quick refueling. However, the tanks must be made of strong, lightweight materials like carbon fiber to withstand the high pressure.
Liquid Hydrogen: Hydrogen can also be stored as a liquid at cryogenic temperatures (-253°C or -423°F). Liquid hydrogen has a higher energy density than compressed gas, meaning more hydrogen can be stored in the same volume. However, maintaining such low temperatures requires advanced insulation and energy-intensive cooling systems, making this method more complex and costly.
Hydrogen Storage in Solid Materials: Some systems use materials like metal hydrides or chemical compounds to absorb and release hydrogen. These materials can store hydrogen at lower pressures and temperatures, improving safety. However, they often have lower storage capacities and slower refueling times compared to compressed or liquid hydrogen.
Challenges in Hydrogen Storage
While hydrogen storage technologies have come a long way, there are still challenges to overcome:
- Safety: Hydrogen is highly flammable, so storage systems must be designed to prevent leaks and withstand extreme conditions.
- Energy Density: Hydrogen has a lower energy density by volume compared to traditional fuels like gasoline, requiring innovative storage solutions to maximize efficiency.
- Cost: Advanced materials and technologies used in hydrogen storage systems can be expensive, impacting the overall cost of hydrogen fuel cell vehicles.
The Future of Hydrogen Storage
Researchers and engineers are continuously working to improve hydrogen storage technologies. Advances in materials science, such as the development of lightweight, high-strength composites and new hydrogen-absorbing materials, are paving the way for safer, more efficient, and cost-effective storage solutions. As these technologies mature, hydrogen fuel cells are expected to play a significant role in reducing greenhouse gas emissions and transitioning to a cleaner energy future.
At Kevin's Autos, we’re passionate about staying informed on the latest advancements in automotive technology. Whether you’re curious about hydrogen fuel cells or need expert advice on maintaining your vehicle, we’re here to help!
Frequently Asked Questions
What happens to hydrogen in hydrogen fuel cells?
Hydrogen fuel cells produce electricity by combining hydrogen and oxygen atoms. The hydrogen reacts with oxygen across an electrochemical cell—similar to a battery—to produce electricity, water, and small amounts of heat.
How is hydrogen collected for hydrogen fuel cells?
Hydrogen can be produced from many different sources in different ways to use as a fuel. The two most common methods for producing hydrogen are steam-methane reforming and electrolysis (splitting water with electricity). Researchers are exploring other hydrogen production methods, or pathways.
How is hydrogen stored in a fuel cell?
Hydrogen has high energy content by weight (density) but not by volume, which is a challenge for storage. In order to store sufficient quantities of hydrogen gas, it is compressed and stored at high pressures.
How long does a tank of hydrogen last on a Toyota Mirai?
The Mirai refueling takes between 3 and 5 minutes, and Toyota expected a total range of 480 km (300 miles) on a full tank.
What is the biggest disadvantage of hydrogen fuel cells?
Disadvantages:
- Expensive to manufacture due the high cost of catalysts (platinum)
- Lack of infrastructure to support the distribution of hydrogen.
- A lot of the currently available fuel cell technology is in the prototype stage and not yet validated.
- Hydrogen is expensive to produce and not widely available. Privacy.
What happens if a hydrogen fuel cell car crashes?
The fuel cell itself does have a small inventory of hydrogen. In a crash, the fuel cell could easily be crushed and the hydrogen could cross the membrane. The fuel cell probably cannot be designed to contain the resulting pressure, so it will be necessary to safely vent any products.
How is hydrogen stored in a Toyota Mirai?
The hydrogen that powers the Mirai is stored at a high pressure of 700 bar in two compact, lightweight tanks. We have been working on their design in-house since 2000 and are more than satisfied with their strength and safety levels. Their main source of strength originates from the carbon fibre shell.
Why is hydrogen storage so difficult?
Hydrogen is explosively flammable, ignites much faster than any other hydrocarbon fuel. For this reason, hydrogen is extremely hard to handle, can't be stored for extended periods of time without A, boiling off or B, reacting with the surface material trying to contain.
Is it better to store hydrogen as a liquid or gas?
Selecting the right hydrogen storage method depends on your specific applications, transportation needs, and operational scale. While gaseous hydrogen storage offers simplicity for small-scale projects, liquid hydrogen's higher energy density and cost efficiency make it ideal for larger, long-distance operations.
What is a disadvantage of hydrogen fuel cells?
Expensive to manufacture due the high cost of catalysts (platinum) Lack of infrastructure to support the distribution of hydrogen. A lot of the currently available fuel cell technology is in the prototype stage and not yet validated. Hydrogen is expensive to produce and not widely available.
