It sounds really obvious, electric vehicles use a motor to run on electricity obtained from batteries. But as easy as it sounds, it is equally a technological marvel how the electric cars have crossed all the hurdles and have become so usable. To start with a simple fact, we can’t store electricity so we store electrical energy in the chemicals inside a battery. To understand how electric cars work, let’s dig deeper into how the battery works.
How Does an Electric Car Work
How a battery works in Electric Car
A battery contains 3 main components: a cathode, an anode, and the electrolyte separating the anodes and cathodes as well as serving as a medium for the charged particles to move from one terminal to another equilibrating the chemical potential across the terminals. During the state of discharge, the anode releases electrons to the negative terminal in ions in the electrolyte, while at the cathode it excepts electrons, thus completing the circuit and the flow of electrons. This way the stored chemical energy is converted into useful electrical energy. Hence generating the electric current.
Over these years of continuous development of battery technology has led to a stage where we can have enough energy density in a battery to power a vehicle with good performance and practical ranges. The modern age batteries are mostly long metal spiral-shaped cases consisting of three thin sheets pressed together. Inside the case is the electrolyte, mostly organic ether in which the mentioned sheets are submerged.
Out of the three sheets, the one in the middle is a separator made up of micro-perforated plastic. The negative electrode is made of carbon while a positive electrode is made of lithium cobalt oxide. When in the charging state, the lithium ions in the battery move from the positive electrode to the negative electrode through the electrolyte while attaching to the carbon. Opposite to this during discharge, the lithium ions move back to the lithium cobalt oxide from the carbon.
Basically every battery works on this very principle but the ability of lithium ions to store huge amounts of electrical energy in the form of chemical energy is what made it take a leap in battery technology. Hence electric cars were able to make the jump from novelty to reality. Another major advantage of lithium-ion batteries is that it can be recharged over and over and over again. The cells in the battery of an electric car are wired in the best possible combination of series and parallel to increase both Voltage and Amperage.
Working principle of electric vehicle
Now having understood how the energy is stored in batteries lets move further learning how this energy can be used to get work done, that is in our case, make the car run. Another important fact is that wrapping wires and passing currents through them generate magnetic fields. This magnetic field generates a tangible physical force that is used in electric motors to actuate motion. As used in a Tesla Model S, the electric motor used is an Induction motor.
This motor has two parts: the Rotor and the Stator. The rotor is a series of conduction bars short-circuited by end rings. A 3 phase AC pulse is given to the stator producing a 4-pull rotating magnetic field. When electricity passes through the stator, it induces an electric current on the metal bars of the rotor. Hence the rotation field caused by the stator causes the now charged rotor to set in motion. The frequency of the AC current through the stator determines the speed of the rotor.
In the case of an electric car, pressing the accelerator pedal actually increases the frequency of the current. An inverter installed in this setup just beside the motor and its purpose is to switch the direct current from the batteries to an alternating current needed for the motor. It also controls the frequency and amplitude of the current, affecting the motor’s power output. This depends on a variable frequency drive. All this setup actually does not makes any contact except the bearings that keep the rotor in place.
This no-contact setup prevents any wear between the rotor and the stator. All this results in a useful torque that can be seen up-to a rev range of 18000 RPM, eliminating the use of gears or torque converters. Other benefits include much better efficiency as there are fewer moving parts, a significant reduction in weight of the motor replacing the engine, but there is a massive battery pack that is situated at the bed of the car also helping in improving the car handling and dynamics.
One of the biggest concerns in electric cars is discharging all the energy in the battery, and high RPM spinning rotors is the generation of heat. All the systems are coupled with a liquid cooling system preventing overheating. Then there is the regenerative braking. Each induction motors when not rotating the wheels can be spun by the wheels when they are rolling and breaking, making the motor act like an alternator which in return charges the battery.
This was all about working of an electric car, If you have any queries then let us know in the comment section.