The electric car
An electric car is driven by the power produced by a motor powered by electricity.
An electric motor transforms electrical energy into mechanical energy using electromagnetic interactions. The conductive element inside it tends to move when it is inside a magnetic field and receives an electric current.
Electric motors come in all sizes, driving everything from a radio-controlled car to a locomotive. Electric motors offer many advantages over combustion engines, starting with smaller size and weight and greater technical simplicity.
Their use has advantages from the environmental point of view since they reduce the level of CO2 emissions into the atmosphere.
History
The electric car was one of the first automobiles to be developed. Electric vehicles existed before the four-stroke engine on which Diesel (diesel engine) and Benz (gasoline) based the combustion automobile.
Between 1832 and 1839, Scottish businessman Robert Anderson invented the first pure electric vehicle. Professor Sibrandus Stratingh of Groningen in the Netherlands, with the help of his assistant Christopher Becker, designed and built small-scale electric cars in 1835.
In 1897 the first electric cab was used in New York, with more than 100 examples. Just before 1900, electric cars made remarkable speed and distance records, including the breaking of the 100 km/h barrier by Camille Jenatzy on April 29, 1899 (105.88 km/h), in 1906 the Swiss brand Tribelhornlanza launched touring buses with a range of 60 to 100 km and a speed of 25 km/h.
The introduction of the Cadillac electric starter in 1913 simplified the task of starting the internal combustion engine, which before this improvement was difficult and sometimes dangerous. This innovation, together with the relatively inexpensive mass-production assembly line system implemented by Ford in 1908 contributed to the downfall of the electric vehicle. In addition, improvements came at a faster rate for internal combustion vehicles than for electric vehicles.
In the late 1920s, the electric car industry disappeared completely, being relegated to some very specific industrial applications, such as forklifts (introduced in 1923 by Yale), battery-electric bull lifts, or electric golf carts, with the first Lektra models in 1954.
In 1996, the electric car made a comeback, thus starting a continuous trickle of new electric car launches by the most important car brands.
The main components of an electric car
Charger
The charger or converter transformer is the element that absorbs alternating current electricity directly from the mains and transforms it into direct current to charge the main battery.
Battery
Lithium-ion batteries store the energy supplied by the charger in the form of direct current (DC). This main battery is how the entire electric car is powered. In cars with a DC electric motor, this battery would be directly connected to the motor. On the other hand, in electric cars with an alternating current electric motor, the battery is connected to an inverter.
Converter
The converter transforms the high DC voltage, provided by the main battery, into low DC voltage. This type of current is used to power the 12 V auxiliary batteries, which power the car's electrical auxiliary components.
Investors
The inverters or inverters are in charge of transforming the direct current that the main battery transfers into alternating current. In this way, the AC motor of the electric car can be powered.
General diagram of the components of an electric vehicle with an alternating current (AC) motor.
In the case of a car with a DC motor, this component would not exist.
Electric motor
The motor of an electric car can be an alternating current motor or a direct current motor. The difference between these two types is mainly the form of power supply. The direct current one is powered directly from the main battery, and the alternating current one is powered through the energy emitted by the battery previously transformed into alternating current through the inverter.
Hybrid electric vehicle models
There are three types of hybrid cars: MHEV (Mild Hybrid Electric Vehicle), also called micro-hybrids or light hybrids; HEV (Hybrid Electric Vehicle), conventional or self-recharging hybrids; PHEV (Plug-in Hybrid Electric Vehicle), called plug-in hybrids, are those that connect to the grid to recharge their batteries.
Hybrid electric vehicles combine an electric motor with an internal combustion engine for their operation. In constant operation, the ICE (internal combustion vehicle) drives both the powertrain and the electric motor. An electronic variation of the gear ratio regulates an optimum speed for both motors.
When overtaking, additional power is provided by the electric motor, which is powered by the batteries. When braking, the electric motor acts as an electric generator, recovering part of the kinetic energy.
At low speeds, only the electric motor drives the vehicle, with zero emissions. When stopping, the combustion engine shuts off, consuming no fuel.
Plug-in Hybrid Vehicles (PHEV)
The evolution of hybrid battery systems will allow Plug-in Hybrid Vehicles (PHEV) to be connected to the grid to cover the first tens of kilometers of a trip.
How are electric cars recharged?
Instead of refueling at a gas station, an electric car plugs into the grid to recharge its batteries. Electric recharging can be done in the garage at home with a conventional outlet or with a higher-powered one, halving the charging time. Another way to do it is at public charging points.
Depending on the model of the electric car, charging times range from 3 to 10 hours, depending on the type of recharge. Some models have computer applications that can manage the recharge remotely (program it and take advantage of more advantageous electricity rates, for example).
Another system to keep the batteries charged is to replace them when they run out. With this method, we replace in the specialized center the exhausted batteries with fully charged ones, an operation that takes less time than a recharge.
Types of electric car recharging
Conventional recharge point (230V)
Conventional electric recharging applies power levels that imply a charge with a duration of about 8 hours.
Conventional charging uses the electrical current and voltage of the same level as the home itself (16 A and 230 V). This implies that the electrical power that the point can deliver for this type of load is approximately 3.7 kW.
At this power level, the battery charging process takes about 8 hours. This solution is optimal primarily for recharging the electric vehicle overnight in a garage.
Charging the electric car during the night period is more energy efficient, as this is when there is less energy demand.
Semi-fast recharge
Semi-fast charging applies power levels that imply a charge duration of about 4 hours.
Semi-fast charging uses 32 A current and 230 V electrical voltage. This implies that the electrical power that the point can deliver for this type of charging is approximately 7.3 kW.
This solution is optimal, as in the case of conventional charging, for charging the electric vehicle overnight in a garage.
Fast recharge
Fast charging uses a higher electrical intensity and, in addition, delivers the energy in direct current, obtaining a power output in the order of 50kW. Thus, using fast charging, 65% of the battery can be charged in 15 minutes.
This solution is the one that, from the customer's point of view, resembles their current refueling habits with a combustion vehicle. Even so, fast charging should be conceived as a range extension or convenience charging.
The demands on the electrical level are greater than in conventional recharging. To give a reference, the power required for this type of installation is comparable to that of a building with 15 dwellings. Thus, fast charging may imply the adaptation of the existing electrical network.
Advantages of the electric motor in automobiles
An electric motor does not burn fuels during use, so it does not emit gases into the atmosphere.
A mass-produced electric motor is more compact, cheaper, and much simpler than an internal combustion engine. It needs no cooling circuit, no oil, and little maintenance.
It makes practically no noise when running and its vibrations are imperceptible.
It works at full performance without the need to vary its temperature. As it has no oscillating elements, it does not need flywheels or spatial fastenings that isolate it from the rest of the car. As it generates little heat and does not suffer vibrations, its life can be very long.
An electric motor does not need to change gears, except for a mechanism to distinguish forward or reverse, which may well be the polarity inversion of the motor itself.
Theoretically, an electric motor can develop a maximum torque from 0 rpm, which makes it possible to start from zero with a maximum speed.
Once the gearbox and cooling are eliminated, it opens up the possibility of decentralizing the generation of motion, placing a small motor at each wheel instead of a "central" one coupled to a transmission. This could mean a new distribution of the car's space.
As for the efficiency of the electric motor, it is around 90%. Due to thermodynamic limitations, a diesel engine would have an efficiency of up to 40%, which is higher than the efficiency of a gasoline engine.
It is easy to recover braking energy (or part of it) to recharge the batteries because an electric motor can also be an electric generator.
Another great advantage of the electric car is its reversible process. This means that just as it charges its battery through the grid, the car can also feed energy into the grid, in a reversible way. This is known as Vehicle 2 Grid .
Disadvantages of the electric motor in automobiles
The main and most important disadvantage is the autonomy of the electric car without connecting it to the grid. The fact that the batteries have to be recharged after 100 or 120 kilometers of travel greatly limits users. On the other hand, with combustion engines, the time between refueling and recharging is much longer. Even so, car brands are working to increase the autonomy of their models and we are finding more and more models with greater autonomy.
Another disadvantage related to vehicle autonomy is the refueling time since it takes hours to fully charge the vehicle.
In addition, electric batteries have an expiration date, as they degenerate with use and begin to have less charging capacity.
The need to charge electric cars means that there is more demand for electricity from microgenerators or power plants. The more demand, the more generation, and the more consumption of natural resources.
