The most critical factor in whether electric vehicles can really hit the road is the improvement of range. At present, most of the major automakers' research on car power is focused on the battery. It is undeniable that the battery, as the power source of electric vehicles, should be in the most important position. However, to greatly improve the range of electric vehicles, it is not only necessary to assemble high-powered battery packs, but also there are many details that need to be overcome with current technology.
1. The driving environment of electric vehicles
The same electric vehicle will achieve different maximum mileage when driven in different environments. First of all, the temperature has a great impact on the lithium battery widely used in current electric vehicles. The energy application of lithium batteries belongs to the redox reaction, which releases electric ions through chemical reactions to achieve charging and discharging. Due to the chemical properties of lithium elements are very active, so in the low and high-temperature state (winter/summer), the reaction strength is different, the discharge density is different, the use of the battery time is different, and cause the car's driving range is different.
Secondly, as with conventional cars, wind direction, wind, road conditions, and urban traffic conditions are also factors that affect the range of electric vehicles (urban traffic conditions, the current light hybrid drive system plays an important role in improving battery life and environmental protection).
2. Rolling resistance and air resistance
The most critical factor for electric vehicles to be truly on the road is the improvement of range. At present, most of the major car manufacturers' research on vehicle power is focused on this aspect of the battery. It is undeniable that the battery, as the power source of electric vehicles, deserves to be in the most important position. However, to greatly improve the range of electric vehicles, it is not only necessary to assemble high-powered battery packs, but also there are many details that need to be overcome with current technology.
1. The driving environment of electric vehicles
The same electric vehicle will achieve different maximum mileage when driven in different environments. First of all, the temperature has a great impact on the lithium battery widely used in current electric vehicles. The energy application of lithium battery belongs to the redox reaction, which releases electric ions through chemical reactions to achieve charging and discharging. Due to the chemical properties of lithium elements are very active, so in the low and high temperature state (winter/summer), the reaction strength is different, the discharge density is different, the use of the battery time is different, and cause the car's driving range is different.
Secondly, as with conventional cars, wind direction, wind, road conditions and urban traffic conditions are also factors that affect the range of electric vehicles (urban traffic conditions, the current light hybrid drive system plays an important role in improving battery life and environmental protection).
2. Rolling resistance and air resistance
In theoretical mechanics, the hindering effect on the rolling of an object is called rolling resistance. Rolling resistance is usually caused by gravity, and it is a moment effect. That is to say, if the car is heavier, the greater the rolling resistance it is subjected to when moving. Therefore, reducing the rolling coefficient can improve the range of electric vehicles to a certain extent.
Air resistance, as the name implies, is the resistance caused by the friction between the car and the air while driving. Since the shape design of electric vehicles is related to the location of the battery and motor, the shape design of electric vehicles is more flexible than that of conventional vehicles. By placing the internal components of the vehicle more rationally, a more reasonable exterior design can be obtained, which can reduce the air resistance coefficient and improve the driving range accordingly.
3. Battery parameters and performance
The battery is the most important part of the electric vehicle, and there are many areas that need to be discussed. Here, we just briefly analyze how to improve the range of electric vehicles by improving the battery technology, including battery weight, shape, energy density, and discharge rate.
Since the battery weight is a very high percentage of the total weight of an EV, its size will determine the rolling resistance factor and thus affect the range.
The shape of the battery is also one of the design challenges that need to be overcome. Currently, the most used battery in the field of electric vehicles is the columnar lithium battery, and the arrangement and combination of hundreds of batteries will cause excessive volume, which will affect the structural design of the car to reduce wind resistance and indirectly affect the driving range. At present, Nissan LEAF and Chevrolet Voltlander use the new type of plate lithium battery in the volume design has certain advantages and will play a role in promoting the design of future electric vehicle structures.
Energy density and discharge rate are important factors that affect the range of the battery, high battery energy, long discharge time is the key to extending the range of electric vehicles. There is still a long way to go for batteries. Nanotechnology batteries and solid-state technology batteries with higher performance in the same volume are still in their initial stage.
4. Energy consumption of auxiliary devices
Auxiliary devices do not only refer to the familiar lighting, audio, air conditioning, and onboard control systems but also include air compressors for the braking system, hydraulic pumps for the steering system and other power assist systems. These auxiliary facilities, in addition to air conditioning, will combine to consume 6%-12% of the total energy. If this energy consumption can be reduced, more power output can be provided to the powertrain. Thus, the driving range will be extended.
To sum up, improving the range of electric vehicles requires the efforts and research of scientists in many aspects. In general, the main focus is on the battery, and if we can reduce weight, reduce the size, improve performance and enhance environmental adaptability, we can significantly increase the range. This is supported by the design of electric vehicles to reduce wind resistance and the reduction of energy consumption of ancillary devices.
