Current Status and Development Trend of Electric Vehicle Transmissions
Author:
Release Time:
2025-07-12
Traditional transmissions coordinate engine speed and vehicle speed to optimize engine performance. Specifically, because the engine's optimal speed range is narrow (generally 1000-4000rpm ), speeds that are too low prevent torque output, while excessively high engine speeds result in inefficiency. Therefore, gasoline vehicles must shift gears to adjust the gear ratio and maintain the engine speed within its optimal range. For gasoline vehicles, a transmission is essential for normal operation.
Electric vehicles are not without transmissions; a reducer can be considered a single-speed transmission, which is also a type of transmission. Because the operating range of an electric motor is wide (generally 0-15000rpm ). High torque can be output at low speeds, even zero speed, and constant power can be output at high speeds. Therefore, motor characteristics generally match vehicle needs, eliminating the need for multi-speed transmissions. A single-stage reducer or two-speed transmission is sufficient.
Currently, most pure electric vehicles in China do not have a physical transmission. While some vehicles may have a gear shift lever and gear display on the instrument panel, these are simulated gears to cater to consumer expectations. The electric motor itself can operate stably at various speeds without the assistance of a gear transmission mechanism. Furthermore, conventional transmissions cannot be used in pure electric vehicles primarily due to their size and weight, which are too large relative to the vehicle. The battery pack already occupies most of the undercarriage space, leaving little room for a transmission. Additionally, the transmission efficiency is insufficient. The weight of the transmission could also reduce the actual driving range.
Given the above, most pure electric vehicles on the market use single-speed transmissions. Advantages include: low cost, simple structure and easy installation, low failure rate, low power loss, and small size. Disadvantages include: limited speed improvement once the vehicle reaches its maximum speed, limiting the vehicle's top speed; a single gear ratio typically cannot simultaneously optimize both power and economy.
Multi-speed transmissions: Current motor characteristics cannot meet the power and economy needs under all operating conditions. A multi-speed transmission can effectively adjust the motor's output performance.
High-speed operation: By increasing the operating speed of the motor and using an appropriate transmission system and control strategy, the allowable range of regenerative braking can be widened to adapt to more operating conditions, making the vehicle more energy-efficient and increasing the driving range. Currently, the maximum speed of many manufacturers' drive motors has reached 14000rpm or more. With the development of high-speed drive motors, the high-speed operation of electric vehicle transmissions will also become a trend.
Modularity: Integrating the motor, transmission, and controller into a single unit results in a more compact vehicle structure, superior performance, easier control, and lower costs. The integrated design and management control of modular electromechanical coupled transmission systems is the development direction of electric vehicle power transmission systems.
Contact Us
Add：Automobile Industrial Park, Industrial Cluster Area, Changyuan County, Henan Province
