Even though hybrid cars have been on our roads for a long time, few people know how they work and what the differences are between them and electric cars, hydrogen cars and rechargeable hybrids. So…
Hybrids are quite simply petrol-powered cars – or sometimes diesel-powered – to which a small electric motor and battery have been added. The purpose of the battery and motor is to recover the kinetic energy generated during the deceleration and braking phases and convert it into electricity, which is stored in the battery. This can then be used to start up the vehicle and even, depending on the on-board technology, drive for a few hundred metres in full electric mode.
A key point is that you don’t plug in hybrids to charge them. Their electrical power is entirely recovered during the deceleration and braking phases. In fact, hybrid cars are more closely related to a vehicle with an electrically-assisted internal combustion engine than a true hybrid, where the power would be generated by both forms of motorisation in equal proportions.
Rechargeable hybrid cars
Considered to be a development of hybrid cars, rechargeable hybrids are quite simply hybrids where the battery, and sometimes the electric motor, has been upsized, and a connecter added to charge the battery directly from the electric mains.
The advantage of having a bigger battery is that you can drive dozens of kilometres in electric mode without consuming a single drop of fuel. The range covers most daily needs such as going shopping, doing the school run and going to work.
The hybrid mode comes into play on longer journeys. It’s a way of going beyond the “limitations” of electric cars in terms of range, availability of charging stations and the time it takes to charge. However, you continue to consume petrol as soon as the internal combustion engine comes into operation.
Today, rechargeable hybrids are essentially reserved for high-end cars with purchasing prices tending to top the 30,000 euro mark. The reason for this is the high number of component parts (batteries, electric motor controller etc.) which come on top of the conventional engine set-up. A rechargeable hybrid will set you back 6,000 to 9,000 euros more than a classic hybrid, depending on the model.
You don’t have a petrol tank or an internal combustion engine on an electric car. What you do have is an electric motor piloted by an electronic controller coupled with a battery. Depending on the battery size and the car model, you can drive for between 100 and several hundred kilometres and can charge the battery directly from the mains either at your home or at a public charging station.
Compared to cars equipped with internal combustion engines or hybrid cars, electric cars are much simpler in terms of design. Hence the lower maintenance costs and much lower energy-consumption costs compared to traditional fuel types.
Electric driving can be intimidating at first, but once you get to grips with it, you won’t want to go back. Electric cars are very pleasant to drive, 100% silent and generate zero emissions since they are quite simply not equipped with exhaust pipes.
The flip side of the coin? You have to deal with problems linked to range and the lack of charging infrastructures in certain areas.
Extended-range electric vehicles
The extended-range electric vehicle is basically an electric car with an internal combustion engine added on. Contrary to rechargeable hybrids, the purpose of the engine is to recharge the battery and not to make the wheels go round.
What are the advantages of this system? You benefit from an extended electric range compared to rechargeable hybrid models, while enjoying peace of mind over longer journeys. And the drawbacks? These cars are currently rare on the market and you nonetheless depend a bit on petrol since the range extender still consumes fuel.
By definition, hydrogen cars (or hydrogen fuel cell cars) are electric cars. The main difference is the means by which the electric motor is powered.
Whereas electric cars are powered by a battery storing kWh that can be charged from the electric mains, hydrogen cars use fuel cells to produce electricity directly on board from pressurised tanks (700 bar) storing hydrogen.
It should be noted that some hydrogen cars, such as the Mercedes GLC F-Cell, couples its fuel cells to a battery charged from the mains providing a range of a few dozen kilometres.
On paper, the advantages of hydrogen are impressive – zero emissions (except for water vapour) and a range that tends to be higher than electric cars, with a topping-up time of just a few minutes.
However, the development of hydrogen cars has come across a few stumbling blocks. Not many carmakers have ventured into this sector and the distribution infrastructure is scantily equipped. From a technical angle, the output of fuel cells is much criticised since it is far below battery output. And the fact remains that hydrogen is mainly produced from fossil fuels today. With electrolysis, i.e. the production of hydrogen from electricity, the conversion process generates significant losses and energy efficiency today is currently around 50 to 70%.
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This article is translated from a special report in Automobile Propre written by Mickaël Torregrossa.