10 years ago, electric and hybrid cars made people giggle about their mention. But these prototypes were nothing more than the human brilliance that paved the way for the future of road traffic. Electric vehicles are not a fashion trend, they represent the next revolution in automotive technology. It is not so hard to understand why there is such a hype about electric cars. Here are some of the points:
By nature, electric motors are much more efficient than internal combustion engines (ICE). They achieve efficiencies well above 90% compared to an average of 20% for ICE. This means a greater economic incentive, as electric motors have an average of 6Km/Kwh (kilometers per kilowatt hour of energy) compared to 2.5Km/Kwh for ICE running on gasoline. Efficiency with ICE is a big problem because there is not much room for improvement. As you can see, in physics the laws of thermodynamics come into play, which theoretically limits the efficiency of these designs to about 40%.
Full Torque on Start-Up
Next, electric motors are able to deliver full torque when starting up, i.e. at zero rpm, which means you get much more power from the start. However, ICEs differ in that they can only reach their full torque in a certain speed range, so you have to change gears when you reach that optimum speed range. So the Tesla Roadster, a fully electric sports car, can reach 0-60mph in well under 4 seconds, and that at only about 250 hp. For a similar performance with ICE cars, you would look at 500 hp cars or more.
Where are Electric Cars?
The reason why you don’t see electric cars everywhere yet, however, is that there are areas that need to be improved. Perhaps the biggest drawback of electric cars is their power source. Conventional ICE burns petrol, which itself is very energy-tight, i.e. contains a lot of energy. Thus, the energy density of gasoline is about 13Kwh/Kg (kilowatt hour per kilogram) or 8.9Kwh/L (kilowatt hour per liter). Electric cars are currently based on lithium-ion batteries with an energy density of 0.2Kwh/Kg, some of them even reaching 0.4Kwh/Kg. However, this is quite low.
All this means that you have to carry a heavy charge of batteries in order for these electric cars to have an adequate range. The Tesla Roadster, for example, recently managed to complete the 500-kilometer landmark with a single charge. With a 53Kwh battery pack weighing almost a thousand pounds, that’s an efficiency of 9.5Km/Kwh!
The second problem with battery technology is charging time. At a home electrical outlet, a typical connection of 240 volts at 13 amps (amps) would take 17 hours to charge a 53Kwh battery pack. However, with its 70 amp high-performance connector kit, this can drop to 3 hours. Future models are expected to charge quickly for 45 minutes. A third problem is the lifespan of the batteries, which have a limited charge cycle.
However, these deficiencies are expected to be overcome in the future with investments in technologies such as lithium-air batteries with capacities of up to 5Kwh/Kg. Large companies such as IBM, Bosch, and Panasonic are at the forefront of future battery technologies.
Advantages of Electric Cars
Comfort is another advantage when it comes to electric cars. In today’s society, electricity is the universal form of energy. You can charge your car in so many places, at home, at charging stations, at work or even at the neighbors’ if you dare. You don’t have to queue up at gas stations. The bonus is that the electricity only costs 12 cents per kilowatt-hour, so you basically consider a full charge for under $7 compared to filling your fuel tank at about $40 or more.
Electric cars have no emissions. They have no air inlet or outlet. It’s true that the electricity used most likely comes from coal-fired power plants, but the problem is the way electricity is generally generated, which has other alternatives. Not only do electric cars not pollute the air, but they also reduce noise pollution. They are so quiet that some authorities are thinking about solutions to warn the visually impaired who rely heavily on their hearing.
A few weeks ago I saw an episode with the highest gear in which the moderators had brought their cars into the Andes and the engine power decreased significantly because there was less oxygen in the air. I know it wouldn’t be fair to mention such a situation as an advantage of the electric car, as such situations are realistically rare.