Electric vehicles are not an invention of our time, they have been around for about as long as vehicles with gasoline engines. When carl benz presented his three-wheeled motor carriage in 1885 and gottlieb daimler his four-wheeled motor carriage in 1886, electrically powered cars had already been on the road in paris since 1881. They were the first vehicles at that time that could go faster than 100 km/h. Around the turn of 19. To the 20. In the United States in the twentieth century, gasoline-powered cars were in the minority at 22% – electric vehicles accounted for 38% and steam engines 40% of all road vehicles. In the meantime, the situation has changed radically in favor of the otto engine. In 1995, for example, the number of electrically powered road vehicles in Germany was only 0.01% of the total number of registered vehicles.
Since the environmental impact (noise and exhaust fumes) of road traffic in urban centers has risen sharply, the development of electric vehicles is once again being considered more intensively. Three lines of development are emerging:
– hybrid vehicles, which have an electrically powered drive (battery) and an internal combustion engine. For long distances, they can take advantage of the benefits of the internal combustion engine and the good infrastructure of filling stations, and in the city they can switch over to the emission-free and low-noise electric drive system.
– electric vehicles with fuel cells
In the following, we will only go into a little more detail about battery-powered electric vehicles.
emissions
Compared to vehicles with internal combustion engines, they have the advantage of lower noise levels, but only at first glance the huge advantage of lower emission values for exhaust gases. The electricity needed to charge the batteries has to be generated somewhere, and this naturally produces exhaust gases. However, the exhaust gases are usually produced in a place where there is not such a high concentration of people, and thus possibly a high level of pollution. Less damage is done. For those who are particularly interested, we show here a comparison of the emission values for a golf that runs on gasoline, diesel or petrol. electric energy (golf citystromer) is operated. This shows that the emission values of the electric car are not always more favorable than those of gasoline and diesel vehicles.
Energy requirements (quoted.T. From the site of the institut fur kraftfahrwesen, aachen)
The energy consumption of an electric vehicle is highly dependent on the technology used d.H. engine, battery, charging process and design principle. While today’s in the"conversion design" designed electric cars (d.H. Conventional cars that have been converted to electric drive) require between 20 and 30 kwh/100km of electricity in urban traffic, are in a design in the"purpose design" (special lightweight vehicles) final energy consumption in the range of 15 to 20 kwh/100 km feasible.
A comparison of the energy required between an electric vehicle and a conventionally powered vehicle (with gasoline or diesel) can only be made using the primary energy requirement, as there are two different, directly non-comparable final energy sources (electricity, fuel).
The basis for this is the "conversion design designed golf citystromer, which due to its extra weight, caused by the heavy battery, has the highest energy demand on the wheel. However, the final energy requirement is significantly lower than for the two conventionally powered vehicles due to the high efficiency of the electric drive train.
However, if we look at the individual primary energy requirements, there are clear advantages for direct-injection diesel. The electrically powered golf is equivalent to the gasoline-powered variant. With "purpose design-However, primary energy requirements of less than 50 kwh/100 km can be achieved with this type of vehicle, so that it is possible to achieve equivalence with conventional diesel vehicles. Those who are particularly interested can take a closer look at the following graphic (energy demand) from the institut fur kraftfahrwesen, aachen, Germany.
Batteries and range
under the hood is the electric motor and a battery pack. Another set of batteries is stowed behind the rear seat.
The structure of "conversion design-cars is very similar to that of conventional gasoline or diesel cars, except for the engine and the tank. The internal combustion engine is replaced by an electric motor (formerly a DC motor, today a three-phase motor), and the tank is replaced by a large battery.
In the "purpos design-cars, attention is paid to lightweight construction. Most of these are very small cars that are particularly suitable for urban traffic (small turning circle; little space required for parking). One tries to compensate the big disadvantage of the very heavy batteries by the lightweight construction.
Very intensive work is being done on improving batteries. The aim here is to achieve higher energy and power densities than with conventional lead batteries, but this is still a long way from the corresponding values for gasoline and diesel. The following table shows the data of some battery types:
| Battery type | energy density in wh/kg | power density in W/kg | service life / recharging cycles | cost in €/kwh | Range in km today and ca. 2006 |
| lead-gel | 30 | 75 | 75 – 90 | 125 |
 |
| nickel metal hydride | 60 | 175 | 1000 – 2000 | 500 | |
| lithium-ion | 120 | 150 | > 1000 | 250 |
Outlook
Since the purchase cost of the electric car is about. Since the fuel consumption of small cars is 40% to 50% higher than that of cars with a normal internal combustion engine, a broader introduction will only be possible when legal regulations on emissions make this necessary or when government subsidies attract customers.
studies show that the lion’s share of car journeys is only over very short distances, with the car usually occupied by only one person. A change in the way people think about small, maneuverable and economical vehicles would have to be induced. However, the small car with an internal combustion engine would already produce considerably less exhaust gases with a consumption of 2-3 liters/100 km.
If you look at the primary energy demand of the electric car, the advantage compared to the gasoline car is not very high. The aim here would be to convert solar energy into electrical energy. The adjacent picture shows a solar car, which will probably play a role in the hobby sector. Much greater opportunities for widespread use in automobiles will be offered by fuel cells fuel cells in which solar-generated hydrogen together with atmospheric oxygen generates electrical energy. Numerous automakers are now addressing the problem with great intensity.
List at least three advantages and three disadvantages that the electric car has over a car with a gasoline engine.
- the electric car is environmentally friendly, has hardly any emissions itself and is quiet. It can contribute to the reduction of pollutant emissions in urban centers.
- The electric motors used require less maintenance than internal combustion engines
- Simple, low-cost refueling plugged in (maintenance costs for e-vehicles are approx. 30% less than for combustion vehicles)
- High purchase costs
- Relatively long charging times (several hours)
- Relatively short battery life
- Range in the range of "only 200km (which would be sufficient for the vast majority of trips)
- Low payload, the weight of the batteries dominates
- Sophisticated battery management in cold season resp. With the newer more powerful battery types necessary
Estimate how expensive it will be to drive a citystromer for 100km. Compare this price with the price of driving a golf petrol engine. Calculate with the data from the table "energy consumption", how many liters of gasoline the golf needs for 100 km approximately. calorific value of gasoline: 45kj/g; density of gasoline: 0.80g/cm 3 .
According to the table (energy consumption), the citystromer needs approx. 25kwh. With a price of 0,15€ for the kilowatt hour, this results in a price of 3,75€.
The golf petrol engine has an energy demand of 66,6kwh = 66,6-3,6-10 3 kj = 2,4-10 5 kj for the distance of 100km.
If we assume that one liter of gasoline requires approx. 1,00 €, then the 100km drive of the petrol car costs about 6,60 €, which is not quite twice as much as for the electric car.
calculate how heavy the nickel-metal-hydride-batteries of a city-stromer would have to be to have the range of 100km.
If the citystromer needs 25kwh to cover a distance of 100km, then with an energy density of 60 wh/kg, the mass of the metal-hydride-battery has to be about
\[m = \frac^3>>>>\frac>>>>> \over>>>>>> \approx 400>\]
go out.