Why did fuel cell technology seemingly disappear as a possible alternative to gas/petrol in vehicles?
In: Technology
Hydrogen fuel cells are a type of chemical battery. They produce electricity by separating hydrogen and oxygen with a membrane. When allowing them to come together that membrane collects electrical energy from the reaction.
You can allow the product of the reaction (water) to escape via exhaust, and refill the fuel cell with hydrogen and oxygen when it runs out (refillable), or you can collect the water and use electricity to re-separate it into the gases to be reused (rechargable battery).
The first problem with hydrogen/oxygen batteries is their energy density. A fuel cell with the same electrical specs as a lithium ion battery, for example, weighs many times more. That means a vehicle powered by fuel cells will weigh more and therefore require more electricity to go the same distance as one powered by lighter, more efficient batteries. If the electricity comes from fossil fuels, the fuel cell has a larger carbon footprint per distance traveled. IIRC fuel cell vehicles powered by the grid had similar or larger carbon footprints per mile/km than hybrid vehicles.
The second problem is the storage of hydrogen gas. Hydrogen is the smallest and lightest atom. It’s so small that it can easily escape any container by passing directly through the material of the walls. That makes it impossible to store a fuel cell in a “charged” state.
The third problem is safety. Hydrogen and oxygen each react violently with each other and practically everything else. Keeping them next to each other, separated by a thin membrane, in a collision prone vehicle, is not a great idea.
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