Motors generate significant heat during operation, and cooling performance directly affects efficiency, lifespan, and reliability. The two mainstream cooling methods are air cooling and liquid cooling. Air cooling uses air as the cooling medium, with fans generating airflow to dissipate heat. Its advantages include simple structure, low cost, and easy maintenance, making it suitable for low-power or low-heat applications. Liquid cooling, on the other hand, uses liquids such as water or oil with high specific heat capacity to absorb heat. The coolant circulates through pipes, quickly carrying heat away from the motor interior. Compared with air cooling, liquid cooling offers better thermal stability and temperature control, especially for high-power-density motors and new energy vehicle drive motors that demand superior cooling. Both technologies have their own applicable fields. Choosing the right cooling solution based on motor power density and application scenario is key to ensuring long-term stable operation.

Motor efficiency classes are important indicators of energy-saving performance. From IE1 to IE5, the efficiency level increases progressively, with IE5 being the highest international standard currently available. Data shows that IE5 motors reduce losses by about 40% compared with the commonly used IE3 motors. Taking a 15kW 4-pole motor as an example, upgrading from IE3 to IE5 ultra-high efficiency motor can save more than 4,000 kWh of electricity per year, reducing annual CO₂ emissions by 2.9 tons. IE5 motors offer an average efficiency improvement of about 1.3% over IE4 and about 2.9% over IE3. Driven by global carbon neutrality goals, countries are continuously raising the entry barriers for motor efficiency. High-efficiency motors not only reduce electricity costs but also contribute to sustainable development, becoming a key element in the green transformation of industrial and transportation sectors.

The power core of electric two-wheelers mainly falls into two types: hub motors and mid-mounted motors, each with distinct structural designs and application scenarios. Hub motors are installed directly in the center of the rear wheel, with fewer moving parts, offering low cost, easy maintenance, and good range performance – ideal for daily commuting on flat urban roads. Mid-mounted motors are placed in the middle of the frame and drive the rear wheel via a chain or belt. This layout provides better weight distribution and higher torque output, with faster acceleration response, making it suitable for high-performance e-motorcycles and riding on complex terrain. When choosing, consumers can decide based on their daily riding environment and performance needs: for economical and practical use mainly on flat roads, hub motors are a good choice; for challenging terrain and a more dynamic riding experience, mid-mounted motors are more appropriate.

In the field of electric drive, permanent magnet synchronous motors (PMSM) have become the mainstream choice for a wide range of applications due to their outstanding performance. Compared with traditional motors, PMSMs embed permanent magnet materials in the rotor. During normal operation, the rotor and stator magnetic fields run synchronously, with no induced current in the rotor windings, eliminating rotor resistance and hysteresis losses, thus significantly improving motor efficiency. At the same time, permanent magnets replace the electric excitation structure in traditional induction motors, bringing advantages such as high torque at low speeds, high power factor, compact size, low noise, and high reliability. Currently, PMSMs are widely used in e-bikes, robots, CNC machine tools, fans, pumps, and more. With continuous improvements in magnet performance and cost optimization, this technology is evolving toward higher power, higher functionality, and miniaturization.