From the cost point of view, compared with the fixed gear reducer, although the cost of the transmission has been increased by 1,000 to 3,000 yuan by using a two-speed transmission, but at the same time, the cost of the motor and battery has a certain degree of decrease. Due to the improvement of work efficiency, the power consumption per 100 kilometers is reduced, which in turn reduces the cost of electricity consumption, and also reduces the charging frequency and lengthens the working cycle. From the perspective of the life cycle of the battery, the use of a two-speed transmission will reduce the cost of the entire life cycle of electric vehicles.
From the perspective of comfort, the multi-speed transmission reduces the working speed of the motor through a high transmission ratio at high speeds, thereby improving the NVH characteristics of the vehicle. Moreover, the premise of improving the comfort is to solve as much as possible the technical difficulties of comfort caused by the shock vibration generated during the shifting process of the multi-speed transmission. Automotive automatic transmissions mainly include hydraulic automatic transmission (AT), mechanical continuously variable automatic transmission (CVT), electromechanical automatic transmission (AMT) and dual-clutch automatic transmission. Among them, AMT has the advantages of high efficiency, low cost, simple structure, good production inheritance, convenient maintenance, etc., and is most suitable for pure electric commercial vehicles.