5 reasons why electric vehicles have speed limits.
Electric vehicles are environmentally friendly and have all the convenient driving features, but their top speed is lower than that of traditional internal combustion engine vehicles.
In recent years, electric vehicles have gradually become an alternative mode of transportation to traditional internal combustion engine vehicles due to their environmental friendliness.
However, electric vehicles have many limitations in terms of high-speed travel, and their top speeds are even much lower than those of vehicles using fossil fuels. Here are five reasons to explain this.
1. Protect battery life.
When talking about vehicles using internal combustion engines (ICE), the top speed is usually limited by the powertrain and engine oil. But the situation is different for electric vehicles (EVs).
Manufacturers aim to make electric vehicles sustainable for everyday commuting. Therefore, the top speed of electric vehicles will be limited to keep the battery and electrical circuits within certain temperature ranges.
Because if the maximum speed of an electric vehicle is set higher, the battery will overheat, causing its lifespan to degrade faster than the warranty period. The lifespan of an electric vehicle battery is typically 10-15 years.
Additionally, engine RPM also plays a crucial role when considering the top speed of an electric vehicle. For example, Tesla has used a carbon ceramic coating for moving parts to prevent them from contacting and causing friction with the stationary parts of the electric motor.
This allows the Tesla Model S's engine to reach a rev limit of 20,000 rpm with a top speed of 260 km/h. However, conserving battery power is the main reason electric vehicle manufacturers limit the top speed of electric vehicles.
Studies show that if electric vehicles maintain speeds above 100 km/h, battery consumption is 68% higher compared to driving at speeds below 50 km/h. This research also confirms that to keep electric vehicle batteries in optimal condition, drivers should ideally adhere to a certain speed limit.
2. Brake protection
If electric vehicles are driven at maximum speed, the brakes will wear out and the battery will be depleted in less than 10-12 minutes. The Tesla Model 3 has a speed-assist feature, allowing drivers to set speed limits while driving.
However, there are some limitations, such as the driver being unable to exceed a set speed or a warning signal flashing on the dashboard. This is primarily to protect the brakes, otherwise the system would wear out very quickly.
3. Gear ratio
The gear ratio is essentially the rotational speed of one gear relative to the others. Electric vehicle manufacturers limit the vehicle's top speed using the gear ratio so that it only produces enough torque for everyday driving needs.
This means that electric vehicles will only be able to reach speeds sufficient for daily commuting. This process also impacts the acceleration of electric vehicles, but primarily the top speed. Electric vehicles have only a single-speed gearbox, allowing the engine to have a higher rev range compared to other conventional vehicles.
For example, a standard ICE vehicle has a rev range of no more than 7,000 rpm, while most electric vehicles can reach up to 20,000 rpm, as mentioned above.
Some manufacturers have used two-speed gearboxes for electric vehicles, notably the Porsche Taycan and Audi e-Tron GT. However, two-speed gearboxes add weight to the vehicle and affect its performance. Many people wonder if electric vehicles have similar gearboxes to ICE cars, but in reality, electric vehicles don't need as many gears to operate.
4. Vehicle weight
Horsepower only affects a vehicle's top speed depending on the gear ratio. But that's not the only limiting factor when it comes to the top speed of electric vehicles, as the aerodynamics and weight of electric vehicles can also affect their top speed.
If we consider the aerodynamic drag of electric vehicles, the drag increases with each acceleration, which affects the charging of the electric vehicle's battery. Furthermore, electric vehicles are generally heavier than gasoline-powered vehicles, mainly due to the battery pack and its protective frame, making it difficult for them to operate at higher speeds.
Another reason electric vehicles lack high acceleration is their simple technology. If complex technologies were incorporated to achieve high top speeds, electric vehicles would be less durable for everyday use.
For example, a complex inverter would provide the precise voltage needed to operate an electric vehicle at higher speeds, which not only increases the cost of the electric vehicle but also makes it more expensive.
However, electric vehicle manufacturers are now focusing more on range and safety than on acceleration. This is because, for a relatively new mode of transportation like electric vehicles, consumers are still looking for safer models rather than faster ones.
5. Safety
As mentioned above, in order to make electric vehicles safer to drive, automakers rarely focus on the speed and acceleration capabilities of electric vehicles.
Most potential consumers prefer driving at moderate speeds and need the ability to travel long distances, which means that if the electric vehicle industry focuses more on acceleration and higher top speeds, they will struggle to sell vehicles.
Maintaining a moderate speed not only enhances the safety of electric vehicles but also extends the lifespan of their batteries. Furthermore, only fully charged electric vehicles can deliver maximum power.
In short, the safety of the driver and other road users is the primary reason why automakers don't add a complex system to increase the top speed of electric vehicles.