How Do Electric Cars Work? Key Principles & Applications
What is Electric Vehicle?
An electric vehicle is an alternative to gas emitting vehicles that operate on electric motors.
These vehicles use one or more electric motors or traction motors for propulsion.
Electric vehicles are the technology of choice for eco-friendly car buyers.
These systems obtain power from a collector system by electricity from off-vehicle sources or can be self-contained with a battery, electric generator, or solar panels to transform fuel to electricity.
The advantages of utilizing these vehicles are they don’t harm the environment.
Many alternatives are in use at present, such as E-rickshaw, electric scooters to promote a safe environment.
Looking at the present situation, the use of electric vehicles has become crucial.
What is an Electric Car?
An electric car is an automobile that is prompted by one or more electric motors by using energy that is stored in rechargeable batteries.
The first practical electric cars were produced in1880s, and became more popular in the late 18th and early 19th century.
From 2008, a rebirth in manufacturing electric vehicles occurred due to advancement in batteries to ensure the safety of the environment with the desire to reduce greenhouse gases and improve urban air quality.
Electric cars are one of the transportations that can be charged at charge stations that can be installed at both homes and public places.
Several governments all around the world have established government incentives for plug-in electric vehicles.
One of the models of a car named Tesla Model three became the world's best-selling with a maximum electric range of 500 km (310 miles).
Due to this, the model became the world's all-time best-selling electric car by early 2020.
At present, the plug-in car market is shifting towards fully electric battery vehicles, and the global ratio between annual sales of battery electric vehicles (BEVs).
The plug-in hybrid electric vehicles (PHEVs) rose from 56:44 in 2012, 60:40 in 2015, and 74:26 in 2019.
How to Make a Battery Powered Car for a School Project?
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Materials Required:
Plastic can
DC motor
AA batteries
Switch to create a simple circuit
AA battery holder
Four bottle caps
Plastic pulleys
Rubber band
Wood skewers or dowel rod
Plastic cups
Propeller
Tools Needed
Screw
Paper clips
Razor knife
Scissors
Hot glue gun
Motor mount
Steps to Make a Battery-powered Car is Outlined Below:
1. Mount an Axle:
To create an axle, we need to cut two straws wider than the Pringles can.
Glue the straws to the can extending from the box about an inch on each side, and then insert the dowel rods or skewers.
2. Create the Wheels:
To create the wheels, we can use many day-to-day objects like plastic cups. Use scissors to cut out the circles for the wheels.
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3. Make Holes in these Circles.
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4. Mount the Wheels:
To mount the wheels, push the skewers or dowel rod through the center of the wheel.
If the connection is loose, we would be requiring a dab of hot glue to secure it,and wait for the glue to cool, making sure the wheels are as straight as possible.
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5. Battery Holder:
Attach the battery holder to the center of the Pringles using hot glue, and make sure the wire from the battery holder can reach the end of the can.
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6. Propeller Platform:
Cut two pieces of the cardboard and glue them together.
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7. Propeller:
Connect the propeller to the shaft of the dc motor.
8. Mount the Motor:
Glue the center of the motor to the cardboard platform, and then make sure that the terminals of the motor are on the top and visible.
If we wish to reuse this project in the future, we can mount the motor with zip ties in place of hot glue.
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9. Wire the Motor:
Add batteries to the holder and touch the black wire to one terminal on the motor and the red wire to the other. Verify that the propellor is away from the motor. Push the black wire in a proper terminal and twist it a few times to secure it, but don’t connect the red wire.
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10. Connect the Switch:
Cut the red wire from the battery holder in half and strip one end. Push the stripped wire into the middle hole of the switch and twist it a number of times to secure.
Now, take the other end of the red wire into the outer hole of the switch and twist to secure. Then, twist the other end of the red wire to the open terminal on the motor and glue the switch to the Pringles can.
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All Set! We successfully created a propeller car from a can of Pringles.
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All we need to do is to add batteries and flip the switch, and the car starts moving.
FAQs on Electric Car Physics Explained for Students
1. What is the fundamental physics principle behind an electric car?
The fundamental principle is the conversion of energy. An electric car converts stored electrical energy from its battery pack into mechanical energy in the motor. This mechanical energy then turns the wheels, producing kinetic energy and making the car move. This entire process is governed by the principles of electromagnetism.
2. What are the key physical components that make an electric car work?
The operation of an electric car relies on the interaction between a few core components:
Battery Pack: Stores electrical energy in the form of Direct Current (DC). This is the car's "fuel tank."
Inverter: Converts the DC power from the battery into Alternating Current (AC) power, which is required by most modern electric car motors.
Electric Motor: Uses the AC power to generate a magnetic field that creates torque, rotating the driveshaft and turning the wheels.
Drivetrain: Transmits the mechanical power from the motor to the wheels.
3. How does an electric motor use physics to turn the wheels?
An electric motor works based on the Lorentz force, a fundamental principle of electromagnetism. When electric current from the inverter flows through coils of wire inside the motor, it generates a magnetic field. This field interacts with another magnetic field (from permanent magnets or other electromagnets). This interaction creates a rotational force, or torque, on the motor's shaft. This torque is then transferred through the drivetrain to spin the car's wheels.
4. What is regenerative braking and how does it work based on physics?
Regenerative braking is a system where the electric motor operates in reverse. When you slow down, the car's momentum keeps the wheels spinning, which in turn spins the motor. This transforms the motor into a generator. Based on the principle of electromagnetic induction, this process converts the car's kinetic energy back into electrical energy. This recaptured energy is sent back to the battery, slightly recharging it and increasing the car's overall efficiency.
5. Does an electric car's battery provide AC or DC power?
An electric car's battery pack provides Direct Current (DC) power. This is because batteries store and release energy through a chemical process that causes electrons to flow consistently in one direction. Any component in the car that requires Alternating Current (AC), such as the main drive motor, must use a device called an inverter to convert the battery's DC output.
6. Why do many electric cars use AC motors if the battery only supplies DC power?
Although the battery supplies DC power, an electronic inverter is used to convert it to AC power before it reaches the motor. This is done because AC induction motors offer significant advantages for vehicle performance. They are highly efficient across a wide range of speeds, require less maintenance because they are brushless, and allow for precise power control. The benefits in performance and reliability make the addition of an inverter a worthwhile trade-off.
7. How does the physics of an electric car differ from a petrol car in terms of efficiency?
The key difference is in energy conversion efficiency. An electric motor is far more efficient, converting about 85-95% of its electrical energy into mechanical energy to move the car. In contrast, an internal combustion engine (ICE) in a petrol car converts only about 20-35% of the fuel's chemical energy into motion. The majority of the energy in an ICE is lost as waste heat, a fundamental consequence of the laws of thermodynamics that govern heat engines.
8. What physical factors limit the range of an electric car on a single charge?
Several physical factors directly impact an electric car's range:
Battery Capacity (Energy Density): The total amount of energy (measured in kWh) the battery can store.
Vehicle Mass: A heavier car has more inertia and requires more force (and thus energy) to accelerate and move (F=ma).
Aerodynamic Drag: The force of air resistance that opposes the car's motion, which increases significantly with speed.
Rolling Resistance: The friction between the tires and the road surface, which the motor must constantly overcome.
Ambient Temperature: Cold temperatures can reduce a battery's chemical efficiency, and energy used for cabin heating or cooling also reduces the available range.
9. From a physics perspective, why is an electric car's acceleration often so quick and smooth?
The rapid acceleration of an electric car is due to its motor's ability to deliver instantaneous torque. An electric motor can produce its maximum rotational force from a complete standstill (0 RPM). In contrast, an internal combustion engine needs to rev up to a specific RPM range to achieve peak torque. This immediate availability of torque in an EV eliminates lag and the need for a traditional gearbox, resulting in a continuous, smooth, and powerful acceleration.
