Compared with traditional fuel vehicles, new energy vehicles with electric drive as the main form have basically the same appearance, mechanical processes between the wheels and the ground, steering, suspension and braking systems. The main difference is the use of different Power system. The internal combustion engine of a fuel vehicle uses the fuel mixture to burn in the cylinder to do work to propel the vehicle forward, while the electric vehicle is powered by a battery (or other energy storage device) to rotate the motor to generate mechanical energy to drive the vehicle forward. Therefore, the handling stability, ride comfort and passability of new energy vehicles are the same as those of fuel vehicles. In addition to increasing the feedback braking performance, the braking performance is also the same as that of fuel vehicles. The main difference in driving performance lies in power performance and driving range. , And the performance of these two aspects is directly related to the performance and characteristics of the battery.
(1) Power performance index
Like traditional cars, the dynamic performance of new energy vehicles can also be described by the maximum speed, acceleration performance and maximum gradeability indicators. However, since the motor has the concepts of instantaneous power, hourly power and continuous power, this factor needs to be considered in the understanding of performance indicators. For example, the motor drive power corresponding to the climbing ability is the instantaneous power of the motor.
①Maximum speed
The maximum speed refers to the maximum speed that a car can reach on a level, good asphalt or cement road under no wind conditions. According to Chinese regulations, the last 500m of the 1.6km long test section is used as the test area for the highest speed. A total of 4 round trips are taken, and the unit is km/h.
②Acceleration performance
The acceleration performance is described by the acceleration time, including the acceleration time of the car in situ and the acceleration time of overtaking. The unit is second (s). The acceleration intensity (including selecting the most appropriate shift timing) is the time required to reach a predetermined speed after gradually shifting to a high gear. The time required for a common vehicle speed to accelerate from 0 to 96km/h is evaluated. Overtaking acceleration time, the time required to accelerate to a certain high speed with the highest gear or the second highest gear. The shorter the acceleration time, the better the acceleration of the car, and the power of the whole car will increase immediately.
③ Climbing ability
The gradeability is described by the maximum gradeability of the car. Maximum gradeability refers to the maximum grade that can be climbed in the first gear on a good road when the car is fully loaded. Climbing degree is expressed by the angle value of the slope (expressed in degrees) or the percentage of the ratio (tangent value) of the height difference between the start and end points of the slope and its horizontal distance.
(2) Continuous driving mileage indicator
The performance index of driving range is not particularly important for traditional cars. Because the layout and construction of gas stations are relatively reasonable and complete, traditional cars can continue to drive as long as they refuel in time. For new energy vehicles, except for fuel cell vehicles, other vehicles need to be charged, and the charging process is relatively long. You can continue driving after charging for a long time. Therefore, the indicator of driving range is particularly important for new energy vehicles.
The driving range of an electric vehicle refers to the maximum distance that an electric vehicle can drive continuously under specific working conditions after its power battery pack is fully charged, and the unit is kilometers (km).
For electric vehicles, the continuous driving range is divided into the calibrated continuous driving range and the normal operating range continuous driving range. The calibrated driving range refers to the maximum distance that a vehicle can travel on a straight, non-slope hard road under the conditions of no wind and suitable temperature under the specified load in accordance with the relevant national standards. The calibrated driving range is a standard index used to determine the continuous driving performance of electric vehicles. The level of this index is the standard for judging the pros and cons of different types of electric vehicles. In the actual use of electric vehicles, there is a big gap between the working conditions and road conditions of the vehicle and the calibrated driving range test. For example, when an electric vehicle travels on a section with a lot of downhill slopes, its actual driving range is greater than the calibrated driving range, while on a section with a majority of uphill slopes, the actual driving range may be much smaller than the calibrated driving range.
The main factors that affect the driving range of electric vehicles are the environmental conditions, driving conditions, rolling resistance and air resistance, battery performance, total mass of electric vehicles, and energy consumption of auxiliary devices such as air conditioning and lighting.
