Background: how hydrogen cars work and when they will appear on the roads

In Spain, where I live now, there are quite a lot of electric cars - I meet them almost every day, both on the roads and at the charging stations. And every year electric cars become more and more (not only in Spain, of course). But there is an alternative - cars on hydrogen fuel, which also do not pollute the nature, since their exhaust is water. The topic of today's reference is hydrogen machines, their principle of operation and prospects.

When did the first hydrogen cars appear?

Invented the hydrogen-powered internal combustion engine by François Isaac de Rivaz in 1806. He received hydrogen by electrolysis of water. The piston engine that the inventor created is called the De Rivaz engine.


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The ignition was spark, the engine had a connecting rod-piston system of work. Well, the cylinder was set in motion by the detonation of a mixture of hydrogen and oxygen by an electric spark — it had to be manually generated at the time of lowering the piston. Two years later, the same inventor built a self-propelled device with a hydrogen engine.

But hydrogen was more or less widely used for the operation of automobile engines many years later. In 1941, in the besieged Leningrad, GAZ-AA automobile engines were modified by Lieutenant B. I. Shelische. The engines controlled the barrage aerostats winches (they were fueled with hydrogen, and there were many gas reserves in Leningrad), but they were automobile engines. In addition, several hundred engines were modified in cars.

Beginning in the 1980s, a number of countries, including the United States, Japan, Germany, the USSR, and Canada, started experimental production of cars that run on hydrogen, gasoline-hydrogen mixtures, and mixtures of hydrogen with natural gas.

In 1982, the Kvant oil refinery and the RAF plant developed the world's first experimental hydrogen minibus Kvant-RAF with a combined power plant based on a 2 kW hydrogen-air fuel cell and a 5 kWh nickel-zinc storage battery.

Over the years, such cars have been developed in different countries for the most part as an experiment. After the green car concept became popular, large corporations like Toyota became interested in hydrogen cars. Since the 2000s, car companies have begun to develop commercial car concepts.

And where to get hydrogen?

Hydrogen can be obtained by different methods:

• steam reforming of methane and natural gas;
• coal gasification;
• water electrolysis;
• pyrolysis;
• biotechnology.

The most economical method of producing hydrogen is now considered steam reforming. This is the name for the production of hydrogen from light hydrocarbons (methane, propane-butane fraction) using steam reforming. Reforming is the process of catalytic conversion of hydrocarbons in the presence of water vapor. Water vapor is mixed with methane at high temperature (700–1000 ° C) and high pressure using a catalyst.

When steam reforming, hydrogen is cheaper to produce than using any other methods, including electrolysis.

The most harmless method of producing hydrogen is electrolysis — the production of hydrogen from water using electric current. The purity of hydrogen is close to 100%. Apart from pollution to produce electricity, such installations are almost environmentally friendly, since in the process of operation only hydrogen and oxygen are released.

Another environmentally friendly method for producing hydrogen is a biomass reactor.


A source

Hydrogen can be produced both in a large factory and in a relatively small enterprise. The larger the production - the lower the cost of gas. But in the first case, the cost of delivering hydrogen to the refueling sites of cars increases.

How does the fuel system work and what are the options?

It is best to consider the principle of operation of such a system on the example of serial hydrogen cars Toyota Mirai. The basis is a fuel cell, an electrochemical system that converts particles of hydrogen and oxygen into water. Inside such an element is a proton-conducting polymer membrane that separates the anode and cathode. Usually it is carbon plates coated with a catalyst.

At the anode catalyst, molecular hydrogen loses electrons, cations are passed through the membrane to the cathode, and electrons are transferred to an external circuit. On the cathode catalyst, the oxygen molecules combine with an electron and a proton, forming water. Vapor or liquid is the only reaction product.


The advantage of fuel cells based on proton-exchange membranes is high power density and relatively low operating temperature. They quickly heat up and start producing energy almost immediately after the start.

Mirai uses fuel cells with high specific power per unit volume (3.2 kW / l), with a maximum power of 124 kW. The direct current produced by the fuel cell is converted to alternating with a simultaneous increase in voltage to 650 V. Electricity enters the lithium-ion battery. For the movement of the machine consumes energy stored in it.

Hydrogen in the Mirai fuel cell comes from high-pressure cylinders (about 700 atm). The control unit in the car controls the mode of operation of the fuel cell and the charge / discharge of the battery.

According to Toyota, 100 km of Mirai requires up to 750 grams of hydrogen. Mirai owners say about a kilogram of hydrogen per 100 km .

Such cars are dangerous? Why?

Since hydrogen is a combustible gas, it must be transported and stored carefully. We need highly sensitive gas analyzers that can give a signal in the event of a leak. True, hydrogen is a very volatile gas (after all, it is the lightest chemical element) and when released into the atmosphere, hydrogen quickly rises.

It burns very quickly. The airship "Hindenburg" burned just 32 seconds. Due to the transience of the fire, not all passengers died, 62 out of 97 people who survived in the dirigible gondola survived.



However, if there are a lot of cars on hydrogen, new traffic safety measures will be required. Machines with internal combustion engines are also dangerous - in the event of an accident and a breakdown of the tank, gasoline or diesel fuel leaks onto the road and may ignite. If a tank with hydrogen is broken, the gas will evaporate very quickly . But if the source of an open flame or sparks is close, the hydrogen can catch fire.



In Mirai and other models of hydrogen cars are very strong tanks for hydrogen. Toyota has made its tanks bulletproof, their walls are made of heavy-duty fiber shoots from large-caliber weapons. For tests, the company hired snipers and only a .50 caliber bullet was able to penetrate the tank after double hitting the same place.

If you comply with safety measures, hydrogen cars are no more dangerous than cars with internal combustion engines.

What is the service life of fuel cells?

So far, this information is only for Mirai. Toyota declares that one cell is guaranteed to operate over a length of 250,000 km. Then, if the work of the cell deteriorates, it can be replaced in the service center.

What companies are already producing or are going to produce cars on hydrogen?

Hydrogen cars are developing Honda, Toyota, Mercedes-Benz and Hyundai - these companies already have ready vehicles. Others show so far only concepts (by the way, workers) or simply beautifully rendered pictures. Audi and Ford are among the former, BMW is among the latter (to be fair, in 2007, BMW released a batch of 100 experimental “hydrogen” models, which remained an experiment) and Lexus.

So far, only Toyota Mirai and Honda Clarity have been launched into the series. They can be purchased in the USA and Europe.

How much is it?

At the moment, hydrogen cars are slightly more expensive than usual in terms of operation. So, when traveling in Europe with a length of 480 km, the cost of fuel for the owner of an ordinary car will be about $ 45, while the owner of Mirai will pay about $ 57. And this is despite the fact that the government of some countries subsidizes the production of hydrogen for cars. The cost of 1 kg of hydrogen is an average of $ 11.45.

How is hydrogen cars better than electric cars?

Actually, the question is not entirely correct. The fact is that both a hydrogen powered car with a fuel cell and a “clean” electric car are electric cars. Just in one case, the car is filled with hydrogen, in the second - with electricity.

If we compare the cost of most electric cars and Toyota Mirai, then they are comparable, these are several tens of thousands of US dollars. The cost of the Hyundai ix35 Fuel Cell is about $ 53 thousand, the Toyota Mirai is $ 57 thousand, the Honda Clarity is $ 59 thousand. The cost of Tesla electric cars starts at $ 45 thousand. BMW electric cars cost about $ 50 thousand.

Hydrogen cars quickly refuel - it takes only 3-5 minutes, unlike electric cars, where you need from half an hour to several hours to recharge.

The main advantage of hydrogen transport is that fuel cells serve for many years and require almost no maintenance. If you take a “clean” electric car with its huge battery, then its service life is only 1–1.5 thousand cycles, that is 3-5 years. Moreover, the hydrogen car will work without any problems in the cold (including winding up), but the battery of the electric car will lose its charge.

What are the prospects for hydrogen cars and when they can be seen on the roads?

Hydrogen cars already romp on the roads of Europe and the USA (perhaps there are single instances in other regions). But there are few of them - a few thousand, which cannot be called a massive introduction.

The problem that is currently preventing the spread of hydrogen vehicles is the lack of infrastructure (just a few years ago, a similar problem was relevant for electric vehicles). We need specialized factories for the production of hydrogen, transport systems for hydrogen and refueling.


Hydrogen filling stations in 2019 ( source )

In addition, hydrogen is obtained quite expensive, so if electric cars are bought, in particular, to save on fuel, in the case of a hydrogen machine, this is not an option. With the massive emergence of factories for the production of hydrogen for cars, as well as service infrastructure, we can expect a much larger number of vehicles on hydrogen on public roads.

But there is no guarantee that it will happen at all or not - it is unclear. Automakers like Toyota are actively promoting their cars and the advantages of hydrogen in the transport sector. But the competition is too great, both among ordinary cars with internal combustion engines, and among electric vehicles.