Ultimately, whether you think of a fuel cell as a type of engine or a type of battery doesn’t matter.  It’s a device that changes chemical energy to electrical energy, like both batteries and engines are capable of doing.  It has aspects that are very similar to a battery, and aspects that are very similar to an engine.  You could reasonably describe a fuel cell as both, so maybe the issue isn’t as black or white as it at first appeared.

Even small children can draw a battery.  The cylinder with a bump on one end is so ubiquitous that we still use it to represent batteries when they have a completely different shape, as in our phones and our laptops.  But many well-educated adults would be hard-pressed to draw a fuel cell.  Not many people understand how hydrogen fuel cells work, even though they rely on the same principles as the common battery.  Maybe we should take the imagery of the battery and apply it to fuel cells as well?

Just like a battery, a fuel cell will work as soon as it’s attached to an electric circuit.  It has a positive and negative side (cathode and anode) just like a battery, and the current it produces is direct current (DC) rather than the alternating current (AC) produced by a power plant.  However, the difference is that while the chemical processes in a self-contained battery will eventually run their course and require energy to be reset –if they’re rechargeable at all– a fuel cell will run continuously as long as there is hydrogen fuel to run it.

But wait a minute!  Aren’t batteries and fuel cells totally different ways to power cars?  Isn’t Elon Musk really excited about batteries but not fuel cells?  Well, yes, there are some key differences to batteries and fuel cells that we should keep in mind.  So maybe a fuel cell is more like an engine that runs on hydrogen instead of gasoline?

Ok, so let’s think of it like an engine.  It’s fed by fuel, and it burns that fuel to create the power that pushes a car forward or creates electricity for your home, just like a gasoline engine or diesel generator would.  It also generates exhaust, though in this case it’s harmless water vapor instead of climate-changing carbon dioxide and other harmful pollutants.  There’s not really an agreed-upon shape for an engine, but anyone who’s had an engine-shaped light blinking on their dashboard knows what an engine looks like.  So is this the way that we should describe a fuel cell?

Ultimately, whether you think of a fuel cell as a type of engine or a type of battery doesn’t matter.  It’s a device that changes chemical energy to electrical energy, like both batteries and engines are capable of doing.  It has aspects that are very similar to a battery, and aspects that are very similar to an engine.  You could reasonably describe a fuel cell as both, so maybe the issue isn’t as black or white as it at first appeared.