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Hydrogen Car: How It Works

The Germans and the Japanese have studied hydrogen cars as an alternative for running electric cars. Although Tesla considered hydrogen cars unviable, Europe decides to put the package on this technology. 

So let’s see how the variant of the electric car, the hydrogen car, works.

Principle of operation

If we had to sum up the system in one sentence, we would say that it is an electric motor that runs on non-polluting fuel (in use, not in production). 

Instead of recharging a battery with a plug and electricity, you fill it with a liquid. 

The only difference with an electric motor is at the level of energy storage, here in liquid and not chemical form.

Hydrogen = Hybrid?

Almost. As they systematically have an extra lithium battery. It is, therefore, possible to have operation solely either with hydrogen or the conventional battery, or both at the same time.

Hybrid cars are more common and easier to use in countries that don’t have hydrogen fuel stations. Thus, you can find used cars for sale in UAE from a hybrid type, but it’s unlikely to find hydrogen ones.


  1. Hydrogen Tank

This tank can store between 5 to 10 kg of hydrogen knowing that each kilogram contains 33.3 kWh of energy (to compare electric cars that have between 35 and 100 kWh). 

The tank is solid to withstand an internal pressure between 350 and 700 bars.

  1. Fuel Cell

The fuel cell powers the electric motor of the car, as does a conventional lithium battery. However, it needs hydrogen from the tank. It is partly composed of the very expensive platinum, but the most modern versions manage to do without it.

  1. Backup Battery

Although not necessarily essential, it is the norm on hydrogen vehicles. It serves as a backup battery, power booster (can work in parallel with the fuel cell), and above all it serves to recover kinetic energy during deceleration and braking.

  1. Power Electronics

The power electronics manage, ax, and rectify (conversion between alternating and direct currents) the various currents circulating through the various parts of the car.

Fuel Cell Operation

The goal is to extract electrons (electricity) from the hydrogen to send it to the electric motor. The whole is done by a controlled electrochemical reaction which makes it possible to partition the electrons on one side (towards the motor) and the protons on the other (in the fuel cell).

All coming together in the end in the cathode where the reaction ends: the final “mixture” gives water that is evacuated from the system (exhaust).

As hydrogen approaches the anode, it will lose its nucleus (proton) by oxidation. The electrons will then continue on their way to the right to the electric motor.

In return, the injection of O2 (oxygen from the air thanks to a compressor) on the cathode side, will naturally allow the formation of the water molecule (which will catalyze all the elements into a single molecule which is an assembly of H and O).

Difference Between Hydrogen Car & Lithium Battery Electric Car

The cars are the same, except for their “energy reservoir”. So these are electric cars using rotor/stator motors (whether induction, permanent magnet, or even reluctance).

If a lithium battery also works thanks to a chemical reaction within it (a reaction which naturally produces electricity: more precisely electrons), nothing comes out of it, there is only an internal transformation.

To return to the initial state (recharging) it suffices to pass current (connect to the sector) and the chemical reaction starts again in the opposite direction. The concern is that it takes time, even with superchargers.

For the hydrogen engine, the battery empties its hydrogen at the time of the chemical reaction. It is emptied by an exhaust which evacuates water vapor (a result of the chemical reaction).

From a logical point of view, we could therefore adapt any electric car into a hydrogen car, it suffices to replace the lithium battery with the fuel cell. So in your mind, the “hydrogen engine” should be thought of as an electric motor first and foremost. It is not because it refuels like an essence that it necessarily approaches it.

The main technical concern of hydrogen is at the level of storage security. The problem lies in refueling the car and in having a tank strong enough to deal with any accident. Of course, the additional cost is also a major obstacle, and it seems to be less viable than lithium-ion, the cost of which is falling drastically.

In many countries around the world, the future seems to be to the EVs and the hydrogen will be left to other industries. Currently, if you want to sell your car in Dubai and try the hydrogen car the Toyota will be your best choice with a hydrogen fuel station in Toyota’s Al Badia showroom, Dubai Festival City.

Author: Sultan Asad

Sultan Asad is the Branding Manager at WeBuyCarsDXB. More than 5000 customers from all over the UAE have chosen We Buy Cars DXB as a trustworthy car selling service that provides a hassle-free way for any person selling their car by taking care of the deal front to end in under 30 minutes.

Get more acquainted with their hassle-free way to buy a car in under 30 minutes at WeBuyCarsDXB.