Frost & Sullivan, in collaboration with Jiangsu Jinpeng, released the 'White Paper on Electric Tricycle Power Systems', analyzing the electric tricycle industry under power system upgrades

Definition and Classification of Electric Tricycles

An electrically operated tricycle is a three-wheeled vehicle that uses a battery as its energy source and an electric motor as its power source for carrying goods, passengers, or other special purposes. Electric tricycles can navigate through narrow roads flexibly and are widely used in short-distance transportation fields such as households, urban and rural areas, factory complexes, mining areas, sanitation, and community cleaning due to their strong applicability, mobility, simplicity of maintenance, convenience in repair, and low cost.

Electric tricycles can be divided into cargo tricycles, passenger tricycles, and special vehicles according to their purpose.

Cargo electric tricycles mainly refer to those designed and equipped for carrying goods, generally classified into three-wheeled models, four-wheeled models, and semi-topped models based on vehicle structure. Passenger electric tricycles primarily refer to those designed and equipped for carrying passengers, typically divided into fully enclosed electric tricycles and leisure models based on vehicle structure. Special vehicles mainly refer to electric tricycles that are specially made or modified with fixed devices and equipment, whose primary function is not for carrying people or goods but has a specific purpose, including express delivery electric tricycles, sanitation electric tricycles, factory-specific electric tricycles of various types, and tourist sightseeing vehicles.

In the past five years, global sales of electric tricycles increased from $8.6 billion in 2016 to $9.6 billion in 2020, with a compound growth rate of 2.4%. As the largest market for electric tricycles globally, sales in China have been declining slowly. In addition to China, markets for electric tricycles in the Americas, Southeast Asia, the Middle East, and Africa are booming, driving a slight increase in the global electric tricycle market size.

It is expected that in the next five years, Southeast Asia, the Middle East, and Africa will continue their strong growth momentum, with China also experiencing a new wave of growth. It is estimated that by 2025, the global electric tricycle market will exceed $14 billion, with an average annual compound growth rate of 8.6% over the next five years.

As the largest market for electric tricycles globally, China's demand for electric tricycles has tended to saturate over the past five years. From 2016 to 2020, the sales of electric tricycles in China gradually declined from 30 billion yuan to 26 billion yuan, with an average annual compound growth rate of -3.5% during this period.

Due to the rising costs of steel, rubber, and glass, the unit price of electric tricycles has increased accordingly. It is expected that starting from 2021, the sales market scale of electric tricycles in China will significantly increase. In the future, new batteries and intelligent applications will become popular in this industry, with sales expected to rise slightly starting from 2023. By 2025, it is estimated that the market scale of electric tricycles in China will exceed 43 billion yuan, with an average annual compound growth rate of 7.8% over the next five years.

From 2016 to 2020, the sales volume of electric tricycles in China decreased from 11 million units to 9 million units, with an average annual compound growth rate of -4.9% during this period.

In the next two years, due to the sharp increase in demand for three-wheeled leisure vehicles among the silver-haired generation, the continuous growth of express logistics vehicles, and the upgrade and iteration of existing products by original users, it is expected that the sales volume of electric tricycles will see a significant increase in 2021 and 2022. It is estimated that from 2023 to 2025, the sales volume will reach 13 to 14 million units. The average annual compound growth rate over the next five years is expected to reach 6.2%.

The power system of an electric tricycle generally consists of a drive motor, motor controller, battery, differential, wheels, etc. The motor controller receives output signals from the throttle (equivalent to the accelerator in a car), brakes, and different gears, controlling the rotation of the drive motor. It drives the wheels through mechanical transmission devices such as the differential and half shafts. Depending on the type of controller and drive motor, the power system of an electric tricycle can be divided into permanent magnet synchronous motor (PMSM) systems and brushless DC motor (BLDC) systems.

The power system of an electric tricycle is the link between the energy storage system and the wheels. Its function is to convert the electrical energy output by the battery into mechanical energy, driving the vehicle to overcome various rolling resistance, air resistance, acceleration resistance, and climbing resistance. During braking, it converts kinetic energy back into electrical energy and feeds it back into the energy storage system. Modern electric tricycles differ from traditional fuel tricycles in that their power systems can eliminate complex mechanical gear transmission structures and also provide torque-speed characteristics that meet the wide range of vehicle speeds and large load variations.

Drive motors are used to provide power and come in a variety of types. However, in the current electric tricycle industry, the mainstream drive motors are permanent magnet synchronous motors (PMSM), permanent magnet brushless DC motors (BLDC), and AC asynchronous motors (ACIM). These three types of motors have their own characteristics in terms of performance, structure, and control methods, and are suitable for different electric tricycles and usage scenarios.

Permanent magnet brushless DC motors (BLDCs) have a stator current that is square wave or trapezoidal wave. To maximize their output, the air-gap magnetic density is often designed to be square wave or nearly square wave, hence the rotor is often made into a lamination shape.

Figure: Rotor structure of square-wave permanent magnet brushless DC motor

(1. Stator, 2. Permanent magnet, 3. Rotating shaft, 4. Rotor core)

Permanent magnet synchronous motors, due to the sinusoidal stator current, typically have their air-gap magnetic density designed as a sine wave or close to a sine wave to reduce ripple torque and harmonic losses. Therefore, their rotors often adopt the structure shown in the diagram.

Figure: Rotor structure of permanent magnet synchronous motor

(1. rotor silicon steel sheet, 2. permanent magnet, 3. air-gap magnetic separator)

AC asynchronous motors belong to a type of induction motor and are one of the most widely used types in industry today. Their characteristic is that the stator and rotor are made by laminating silicon steel sheets, which results in a simple structure, reliable and durable operation, and convenient maintenance. If AC asynchronous motors adopt vector control, they can achieve controllability comparable to DC motors and a wider speed regulation range. They are currently the most widely used motors in high-power electric vehicles. However, asynchronous motors have lower efficiency and power density, suffer from severe rotor heating at high speeds, and their drive and control systems are very complex. The cost of the motor itself is also relatively high. Therefore, compared to permanent magnet motors, they are not the optimal choice for energy efficiency optimization.

Figure: Rotor structure of AC asynchronous motor

The stator winding methods of the three types of motors also differ slightly. Square-wave motors try to concentrate their full-pitch windings as much as possible to improve winding utilization; permanent magnet synchronous motors generally use distributed and short-torque windings to reduce the influence of harmonics, with a simpler and more robust structure; AC asynchronous motors usually have distributed windings.

The motor controller is the core control device used to control the start, operation, advancement and retreat, speed, stop of the driving motor, as well as other electronic components of the electric vehicle. It is an important component on electric tricycles. Electric vehicle controllers also vary in performance and characteristics depending on different model types.

The differential is a structure that enables the left and right drive wheels to rotate at different speeds. It mainly consists of left and right half-shafts, two planetary gears, and a gear carrier. Its function is to ensure that the left and right wheels roll at different speeds when the car turns or travels on an uneven road surface, thus ensuring that both drive wheels perform pure rolling motion. An ordinary differential is composed of parts such as planetary gears, planetary gear carriers (differential housing), and half-shafts. The power from the drive motor enters the differential through the transmission shaft, directly driving the planetary gear carrier, which in turn drives the left and right half-shafts, respectively driving the left and right wheels. When an electric tricycle is going straight, the speeds of the left and right wheels, along with the planetary gear carrier, are equal and in a balanced state. However, when turning, this balance is disrupted, causing the speed of the inner wheel to decrease and that of the outer wheel to increase.

The battery in an electric tricycle is a device that directly converts chemical energy into electrical energy. It is a rechargeable battery designed for recharging through reversible chemical reactions. When charging, the battery uses external electrical energy to regenerate its internal active material, storing electrical energy as chemical energy. When discharging, it converts this chemical energy back into electrical energy and outputs it. Batteries for electric tricycles can usually be divided into lead-acid batteries and lithium batteries. Lead-acid batteries are commonly used in cargo electric tricycles and fully enclosed passenger tricycles, while some new recreational tricycles use lithium batteries.

The earliest electric tricycles adopted a square-wave permanent magnet brushless DC motor system. From 2013 onwards, the square-wave permanent magnet brushless DC motor system accounted for more than 95% of the electric tricycle market, while sine-wave permanent magnet brushless DC motors and permanent magnet synchronous motors were not yet mature. At that time, the output power of the square-wave permanent magnet brushless DC motor system was about 350W to 650W. With the development of technology and the gradual increase in cargo demand, the maximum output power of the square-wave system can now reach 3kW.

In 2013, the technology of sine wave permanent magnet brushless DC motor systems and motor control systems gradually matured. Due to the comfort of starting and easier operation compared to square wave systems, sine wave systems have gradually replaced square wave permanent magnet brushless DC motor systems.

In 2020, the technical difficulties of permanent magnet synchronous motors with sine wave stator currents were overcome, and cost control was also resolved. The permanent magnet synchronous motor system demonstrated superior performance compared to brushless DC systems with square-wave or sine wave permanent magnets, quickly becoming the preferred power system for electric tricycles. At the same time, a very small number of electric tricycles use asynchronous AC motor systems or switched reluctance motor systems, but due to high costs, these two systems are usually advantageous only for power ranges above 3,000 watts.

With the continuous iteration and breakthroughs in motor technology, current main electric tricycle companies in China have adopted a new generation of power systems based on 'permanent magnet synchronous motors'. Among them, industry-leading companies such as Jinpeng, Wuyang, Ouhuang, and Zongshen, relying on their own R&D gold power systems, magnetic power systems, gold-magnetic power systems, and T-power systems, continue to lead the electric tricycle industry to focus on industry pain points and difficulties, committed to solving 'problems' such as power, speed, load capacity, range, reliability, etc., in mountainous areas.

Through comparative tests, the Jinpeng Jin power system boasts superior power and load-bearing capacity. With the same output power, it has a load-bearing capacity that is 50% higher than other power systems. Additionally, in slope climbing performance testing, Jinpeng Jin power also led the competition with a load of 450.0 Kg, achieving a time of 14.0 seconds, surpassing the power systems of three other manufacturers. In the two vehicle pull test between the Jinpeng Jin power system and the Zongshen T power system, the Jinpeng Jin power system won when using the high gear. Overall, the Jinpeng Jin power system has a clear advantage over the power systems of various manufacturers, performing excellently in different environments, demonstrating the strong adaptability of the new generation of power systems and achieving a generational leap in revolutionary technological innovation for electric tricycles.