What is a Hydrogen Energy Vehicle?
2 Answers
Hydrogen energy vehicles, as the name suggests, are vehicles that use hydrogen as their energy source, converting the chemical energy generated by hydrogen reactions into mechanical energy to propel the vehicle. Hydrogen energy vehicles are divided into two types: one is hydrogen internal combustion engine vehicles, which use internal combustion engines to burn hydrogen (usually obtained through methane decomposition or water electrolysis) to generate power to drive the vehicle. The other is hydrogen fuel cell vehicles, where hydrogen or hydrogen-containing substances react with oxygen in the air within the fuel cell to generate electricity that drives an electric motor, which in turn propels the vehicle. Advantages of hydrogen energy vehicles: excellent combustion performance, quick ignition, a wide flammable range when mixed with air, high ignition point, and fast combustion speed; they rely on a new energy source that is abundant and not dependent on fossil fuels; high calorific value, with hydrogen's calorific value being the highest among all fossil fuels, chemical fuels, and biofuels, except for nuclear fuel. Disadvantages of hydrogen energy vehicles: as a new automotive energy source, hydrogen can only be used in hydrogen fuel cell vehicles, with the biggest drawback being the high cost of fuel cells. Principle of hydrogen energy vehicles: hydrogen energy vehicles use hydrogen as the primary energy source for mobility. Traditional internal combustion engines typically use diesel or gasoline, while hydrogen vehicles use gaseous hydrogen. Fuel cells and electric motors replace conventional engines, i.e., hydrogen fuel cells. Hydrogen can replace petroleum as a fuel, with its combustion products being water and small amounts of nitrogen oxides, causing minimal air pollution. Hydrogen can be produced in large quantities from water electrolysis and coal gasification, and it does not require major modifications to automotive engines, giving hydrogen energy vehicles broad application prospects.
Hydrogen fuel cell vehicles are cars that use hydrogen as fuel. From an engineer's perspective, here's how they work: primarily relying on a hydrogen fuel cell system, hydrogen combines with oxygen from the air to generate electricity and water through a chemical reaction, which then powers the electric motor to run the car. Compared to gasoline vehicles, they produce zero tailpipe emissions, only emitting water vapor, making them very eco-friendly. However, hydrogen needs to be stored under high pressure to ensure safety, and refueling takes just minutes for a range of several hundred kilometers. The downside is the current scarcity of hydrogen refueling stations, with fewer than a thousand worldwide, and most hydrogen production still relies on fossil fuels, not achieving complete carbon neutrality. Technically, they perform stably under extreme temperatures, making them suitable for heavy-duty transport like buses or trucks. Compared to electric vehicles, they solve the slow-charging issue but come with higher costs that require promotion for wider adoption. Countries are currently researching improvements to reduce prices and enhance efficiency.
