Science & Technology in Action

10th Edition

The Electric Car

ESB

This lesson explores the evolution of the electric car, the science and technology behind it and the reasons why it is becoming more important to modern life. Key components are the electric motor and the battery, and there is ongoing research to make them more efficient. An A3 poster on ecars is also included.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

Introduction 
We are so used to the internal combustion engine (ICE) that we are inclined to think that the electric car is a new idea. In fact, the electric car made its first appearance in the 1880s and by the 1890s there were fleets of electric taxis in London and New York. It is interesting to learn that an electric vehicle held the world road speed record between 1899 and 1902 (106 km/h). However, petrol and diesel engines dominated the scene after that. This was due to technical improvements in the internal combustion engine and the availability of cheap fuel. 

In this lesson we discuss the evolution of the electric car, the science and technology behind it and the reasons why it is becoming more important to modern life. 

What is an electric car? 
An electric vehicle (EV) is a vehicle that uses an electric motor to propel it. Vehicles equipped with only an electric motor are called ‘fully electric’ or pure electric vehicles. Those equipped with both an ICE (internal combustion engine) and an electric motor are called hybrid electric vehicles. Those vehicles with an ICE and which can also be charged from an electrical source are called plug in hybrid electric vehicles (PHEV). In hybrids, the ICE and the electric motor can be arranged in series or in parallel. In the series configuration the battery powers the electric motor but, when the charge in the battery gets low, the ICE drives a generator that recharges the battery. In the parallel setup either the ICE or the electric motor (or both) can turn the car wheels directly. There are many types of electric vehicle, including trams, trains, trucks and cars. Cars that use electric motors are often referred to as ecars. 

There are also vehicles that use fuel cells to charge the batteries. These cells convert the chemical energy from a fuel into electricity. Hydrogen is commonly used as a fuel for this purpose. (The most environmentally friendly way of producing the hydrogen is by electrolysis of water using renewable energy sources.) 

Solar cars also exist. They use photoelectric cells that use sunlight to generate the electrical energy to charge the batteries.