Automobile electronics, Electronics, Electronics components, Energy comsumption, Motors

Advantages and disadvantages of electric vehicle

In this post, is made a comparison of electric car with vehicle moved by internal combustion. Reporting the strong and weak points of electric vehicle.

To see the posts about electric car, click on the buttons below.

Electric car (Parte 1)Click here

Electric car (Parte 2)Click here

Engine and motor

The motors of electric vehicles are much more efficient. The best internal combustion engines have an efficiency of between 30 and 40%, while the electric motors have between 80 and 95% efficiency.

The combustion engine is heavier than the electric motor because the engine needs to convert the linear motion of pistons into circular using the crankshaft. It needs counterweights to keep the balance, and the engine also needs a flywheel to create a smooth rotation and transfer power to the transmission. A DC motor is used to start it.

Another important component of combustion engine is the alternator.

It is linked to engine’s axis by a belt, generates alternate current, the latter is converted to continuous, and provides energy to recharge the battery.

While the induction motor is electronically controlled by the inverter, many parts of combustion engine are dispensed. It contributes to electric cars being quieter.

At this point, the electric vehicle is better.

Resupply

The combustion vehicles are resupplied in a few minutes, while the electrics can take more than 1 hour.

Considering the current technology, the combustion vehicle is better at this point.

Energy density

The energy density of Li-ion batteries is much lower than in combustion fuels. These graphics compare the energy densities of many types of batteries and fuels. Li-ion battery with cobalt as a cathode has the biggest energy density among the batteries.

The electric vehicle’s battery pack occupies much more area in comparison to fuel tank in a combustion automobile. In the figures below, can observe battery pack size in an electric car in yellow and gas fuel in purple. The ethanol car has the same gas tank size as gasoline car.

This is another advantage of combustion vehicle.

Environmental impact

The electric vehicle does not produce emissions, which improves the air quality in urban centers. However, if electric car resupply’s source originated from a fossil fuel thermoelectric, it becomes as polluter as the gasoline car. The electric car needs lithium for batteries, this element can be extracted from mines or brines in desert. The extraction by brines causes a lower environmental impact and it is from where comes most production of this metal.

The batteries of electric vehicle need cobalt, nickel, manganese, and phosphate. An internal combustion engine needs aluminum, copper, and steel, which is produced from iron. The catalyzers for combustion automobiles need platinum, rhodium, and palladium to filter toxic gases. All these elements are extracted from mines and cause the environmental impact of mining.

A bigger number of electric vehicles will require more recharge stations and higher demand for electric energy. Therefore, it is imperative that the advance in electric cars walks together with the advance in clean and renewable energy sources.

If the energy source is clean, then electric vehicle will be clean tech.

Range

The range varies with model, however, internal combustion vehicles still have a bigger range than the electrics. The main factor is battery’s limitation and energy density. This graphic is from 2016, but it is useful to make a comparison.

These are the 6 electric cars with greatest range. To convert miles into km, access this link.

Although range of electrics tends to increase, the average of combustion vehicles is still higher.

Cost

Electric cars still are more expensive than the ones moved by combustion, a big part of cost come from batteries. However, the electric vehicle maintenance cost is smaller, because has fewer parts and doesn’t need to exchange motor oil. The cost per kilometer is also cheaper due to regenerative braking and electric energy’s price in comparison with fuels (this depends on the place).

Transmission

Transmission of electric vehicle is simpler. The graphic below shows that the optimum band, where power and torque are high, of a typical combustion engine is very narrow. The combustion engine needs a DC motor to start because the torque is too low at a lower speed. This type of engine needs a gearbox to keep the engine in operation power.

The electric motor can keep constant torque at a great range of speed. So don’t need a transmission box and has better traction control.

The electric vehicle has a clear advantage on this point.

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About Pedro Ney Stroski

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