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Forget pistons, gearboxes, and belts: the electric cars have none of these. These vehicles are much easier to operate than a diesel or gasoline car.
In appearance, an electric car generally looks like any other vehicle. To see the differences, you have to take a look under the hood and under the floor. Instead of an internal combustion engine using heat for energy, it uses electricity. To understand step-by-step how an electric car works, we will follow the path of electricity, from the grid to the wheel.
Electric Cars Recharging
It all starts with recharging. To refuel, an electric car must be plugged into a socket or charging station. The connection is made through a cable with suitable connectors. There are several, corresponding to the desired charging mode. For charging at home, at work or at small public terminals, you generally use your own cable with “type 2” connectors. On the quick-release terminals, the cable is attached and offers two standards: the European “CCS Combo” and the Japanese “Chademo”. While this may seem complicated at first, it is actually easier once you get used to it. There is no risk of error: the connectors are not the same shape and therefore cannot be plugged into the wrong socket.
Once the connection is made, the alternating electric current (AC) which circulates in the distribution network travels along the cable connected to the car. It carries out a series of checks via its on-board computer. In particular, it ensures that the current is of good quality, properly configured and that the earth phase is sufficient to guarantee safe recharging. If everything is correct, the car allows electricity to pass through a first on-board element: the converter.
This organ transforms the alternating current of the network into direct current (DC). This is because batteries can only store energy in the form of direct current. To avoid this step and recharge faster, some stations themselves convert electricity to inject direct current directly into the battery. These are the so-called “fast charging” and “ultra-fast” DC stations like those that can be found at motorway stations. Very expensive and bulky, these terminals cannot currently be installed in a private home.
In the battery, the current is distributed among the thousands of cells that compose it. They come in the form of small stacks or pockets assembled together. The amount of energy stored by the battery is expressed in kilowatt-hours (kWh), equivalent to the “liter” of a fuel tank, and the flow of electricity delivered is expressed in kilowatt “kW”. An example to understand: a 50 kWh battery that recharges at a power of 10 kW can recharge in about 5 hours. Why “around”? Because above 80%, the batteries automatically reduce the charging speed. Like a bottle of water that you fill with a tap, you have to reduce the flow to avoid splashing.
The current stored in the battery is then directed to one or more electric motors. Its operation is very simple: under the action of a magnetic field generated in the stator, the motor rotor rotates. It can transmit its movement to the wheels directly or through a single-speed reduction gearbox to optimize its rotational speed.
Electric Cars Transmission
Thus, the electric car does not have a gearbox. It is unnecessary because an electric motor is capable of operating without a problem up to several tens of thousands of revolutions per minute. It provides the rotation directly unlike a heat engine which must convert the rectilinear motion of the pistons into circular motion. Logically, there are far fewer moving parts in an electric car than in a thermal vehicle. It does not need oil for its engine, has no timing belt, and therefore requires much less maintenance.
Another advantage for battery-powered vehicles is that they can generate electricity. Indeed, when an electric motor rotates “in a vacuum” without being supplied with current, it makes it. This happens every time you take your foot off the accelerator pedal or apply the brakes. The recovered energy is thus directly injected into the battery.
Most recent models of electric cars even offer modes to choose the power of this regenerative brake. When set to maximum, it brakes the vehicle strongly without straining the discs and pads while saving a few kilometers of autonomy. In thermal cars, this energy is simply wasted and accelerates the wear of the braking system.
Technical breakdown is therefore rarer on electric cars. However, it can happen that you run out of power after poor anticipation on the part of the driver, such as in a gasoline or diesel car. In this case, the vehicle warns in advance of the low battery level, usually between 5 and 10% remaining. One or more messages are displayed on the dashboard or the central display and warn the user.
It is possible to drive an additional 20 to 50 km depending on the model before reaching a charging point. Beyond that, the car begins to gradually slow down by reducing engine power. Other signals strongly urge the driver to find a parking lot to stop. Then at the very end of the battery, a “turtle” mode engages and no longer allows you to exceed ten km / h. It is imperative to park before coming to a complete stop.