Axial flux motors have magnetic flux parallel to the motor's axis of rotation, a stark contrast to traditional radial flux motors where the magnetic field is perpendicular to the axis. The stator and rotor are arranged in parallel, disc-like configurations, with the magnetic field closed axially, forming a flat and compact structure. Electrification of the stator windings generates axial flux, and the permanent magnets embedded in the rotor experience Lorentz torque under the influence of this magnetic field, driving the rotor to rotate. Due to the short and directional deflection of the magnetic flux path, magnetic energy is utilized more efficiently. Based on the arrangement of the stator and rotor discs, axial flux motors mainly have several configurations: Dual-rotor single-stator type: A rotor disc is arranged on each side of a stator disc, symmetrically clamping the stator, with the magnetic flux closed between the two rotors. This structure has the smallest axial dimension and the highest torque density, and is currently the mainstream solution in the market, accounting for approximately 66% of the market share. Single-rotor dual-stator type: The rotor disc is placed in the center, with a stator disc on each side. This design has a larger stator area, higher power density and efficiency, and is often used in applications with stringent performance requirements, such as commercial vehicle drives and electric fans.

Yoke-less stator design: The yoke in the stator core is eliminated, and the winding is carried by an independent tooth module. This reduces stator iron loss weight by about 80% and reduces winding difficulty, further increasing power density by 2 to 3 times, making it suitable for high-end applications that are extremely sensitive to weight and performance.

Core performance advantages

Axial flux motors have significant advantages over traditional radial motors in terms of power/torque density, size, weight, and efficiency.

High Power Density and High Torque Output:

The flat disc structure allows for a relatively larger rotor diameter, resulting in higher torque under the same electromagnetic force. Designs such as dual-rotor structures utilize a larger effective magnetic flux area and a higher winding fill factor, significantly improving power output per unit volume. Axial flux motors can achieve a power density up to four times that of traditional motors, with torque density increased by over 120%. The peak power density of products from the British company YASA exceeds 8kW/kg, offering significant advantages in size and weight for aerospace propulsion.

Compact Size and Lightweight:

Axial flux motors are typically flat disc-shaped, with an outer diameter comparable to radial motors of the same class but a thickness only about one-third, achieving an overall volume reduction of more than half. Under similar material conditions, the motor's weight is also significantly reduced. China manufacturers' "dual-rotor" series products from Pangu Power reduce both weight and axial length by approximately 50% compared to traditional drive systems of the same power. For electric vehicles, this lightweight and compact characteristic saves valuable chassis space for more batteries or increased passenger space, and reduces overall vehicle weight to improve range.

High-efficiency direct drive:

Axial flux topology reduces ineffective material and energy losses. Fewer electromagnetic components are required for the same power output, reducing additional losses at bearings and stator ends, resulting in a 1-2 percentage point increase in overall efficiency. Furthermore, axial flux motors can be directly connected to loads, eliminating the need for intermediate mechanisms such as differentials and drive shafts at wheel hubs or robot joints, thus reducing mechanical transmission losses. Many designs can maintain high efficiency across a wide operating range, with the high-efficiency flux area of ​​the hub motor covering over 90%. However, the current power factor of axial flux motors is relatively low, only around 0.35-0.55 in some designs, and the speed range is also slightly limited, which somewhat affects performance in certain applications. These weaknesses are gradually being improved with advancements in control algorithms and topology.

Application Scenarios and Trends

Axial flux motors are rapidly expanding their applications in multiple high-end fields, especially in new energy vehicles and emerging humanoid robots, where they are considered a key power source for disrupting traditional technologies.

New Energy Vehicles and Aerospace:

In the electric vehicle sector, axial flux motors have already been used in supercars and luxury brands. High-performance models such as the Ferrari SF90 Stradale utilize axial flux motors as front axle drives to reduce weight and lower engine compartment height.

Mercedes-Benz's acquisition of YASA allows it to apply axial flux technology to its AMG series of all-electric vehicles, improving overall vehicle power density and range efficiency.

Axial flux hub motor solutions are beginning to be implemented in commercial vehicles such as buses, while disc-driven wheel-side drive systems have been put into use in new energy buses in more than 50 cities across China.

Humanoid Robots and High-End Equipment:

Humanoid robots are considered a promising next "blue ocean" application for axial flux motors. The joint drives of humanoid robots require high torque output within extremely limited space, and must withstand frequent impacts and load changes. The technical characteristics of axial flux motors are highly compatible with these requirements. Their high torque density and impact resistance make them ideal for high-load joints such as the hip and knee joints of robots. The ultra-miniaturized design of new PCB axial flux motors is also highly suitable for precision actuators such as dexterous hands and wrists. Leading domestic company Panhu Power adopts an "axial flux motor + planetary reducer" solution in the humanoid robot field. By leveraging the high torque density of the motor and the speed-increasing effect of the planetary gears, they achieve both miniaturization and lightweight design of the joint drive components, while significantly enhancing load-bearing capacity and impact resistance. This is particularly suitable for the lower limb joints of robots, improving movement efficiency while effectively ensuring the safety and reliability of the robot during walking. Pangu Dynamics' newly released PDS5K robot joint drive assembly weighs only 2.8kg, has a diameter of 130mm and a thickness of 109mm, yet can output a rated torque of 156N·m and a peak torque of up to 437N·m, achieving an excellent balance between lightweight and high performance. Currently, several humanoid robot prototypes have verified the advantages of axial flux drive.

Driven by emerging demands in new energy vehicles and robotics, the axial flux motor market is entering a period of rapid growth. According to industry forecasts, the global axial flux motor market size will surge from less than $200 million in 2023 to approximately $14.48 billion in 2030, representing a CAGR of 73.5%. This explosive growth is primarily attributed to the expanding applications in new energy vehicles, electric aircraft, and high-end robotics, as well as the improved technological maturity and reliability of axial flux motors themselves. The Chinese market is also viewed favorably, with the penetration rate of axial flux motors in new energy vehicle drives, grid energy storage, and industrial equipment expected to reach 20-50% by 2030. This huge market potential has attracted numerous domestic and international manufacturers to compete in this field. Internationally, innovative companies such as YASA (UK), Magnax (Belgium), and Infinitum Electric (USA) are at the forefront of technology. YASA has already achieved mass production of axial flux motors, which have been adopted by Mercedes-Benz; Magnax has launched a prototype with a power density exceeding 10kW/kg; and Infinitum is renowned for its PCB stator motors.

Domestically, established motor companies like Wolong Electric Drive and Dayang Electric are leveraging their manufacturing advantages to develop axial flux motors, while a number of emerging high-tech companies are also gaining prominence. Among them, startups such as Pangu Power, Yikun Power, and Xiaoxiang Electric have mastered core technologies and achieved mass production, winning orders in niche markets such as commercial vehicles, electric ships, and humanoid robots.

Pangu Power has established four automated production lines, shipping over 10,000 motors annually, becoming the first globally to achieve large-scale industrial application of axial flux motors. This indicates that the domestic supply chain is rapidly maturing. It is foreseeable that more manufacturers will join this race in the coming years, further improving the supply chain and driving down costs.

Technological Bottlenecks and Costs

Despite its promising prospects, axial flux motors still face significant challenges in manufacturing processes and cost control before they can widely replace traditional technologies.

Manufacturing Bottlenecks: The disc structure places stringent demands on machining and assembly precision. The air gap between the stator and rotor must be extremely uniform; even micron-level deviations can lead to electromagnetic performance degradation or even rotor rubbing. The traditional method of using silicon steel sheets stacked on the stator core is unsuitable for axial topologies. Using wound cores or soft magnetic composite materials instead is more complex and has a lower degree of automation. In terms of winding arrangement, achieving high-density windings while ensuring good heat dissipation is challenging due to the limited flat space. Regarding the rotor, as the speed increases, the large-diameter disc rotor will experience enormous centrifugal and magnetic pull forces. To ensure structural strength, carbon fiber is typically used to wrap and tighten the permanent magnets, which increases assembly difficulty and cost.

Cost and Supply Chain Challenges: The current material and manufacturing costs of axial flux motors are significantly higher than those of mature radial motors. High-performance rare-earth permanent magnets, especially those requiring high temperatures, are expensive and dependent on heavy rare-earth elements. Carbon fiber materials and specialized insulation components are also costly. On the other hand, due to its early stage of industrialization, many key components require customized development. The investment in related specialized processing equipment is huge, but production volume is limited, making it difficult to achieve economies of scale. This results in the current unit power cost of axial flux motors being about 20% to 30% higher than traditional products.

Technology Route Selection: Currently, multiple technology routes are developing in parallel within the axial flux motor industry, including dual-rotor single-stator, single-rotor dual-stator, yokeless stator, and PCB stator, each with its own advantages and disadvantages. It is still uncertain which one will become the mainstream solution in the future.

The industry is actively exploring innovations in both materials and structure.

In terms of materials, the use of soft magnetic composite materials to form the stator magnetic circuit in one piece through powder metallurgy is becoming a major trend. This allows for the integral casting of complex magnetic pole structures, with a scrap rate of less than 5%, facilitating mass production. Attempting to partially replace NdFeB with low-cost permanent magnet materials such as ferrite is also a direction for cost reduction. Research shows that, with optimized design, ferrite magnets can potentially achieve performance close to NdFeB, while the cost is only about one-tenth.

Structurally, the development of yokeless stators and PCB stator technologies has attracted significant attention. The yokeless design significantly reduces the weight of the motor core and facilitates automated winding insertion. PCB stators utilize etched copper wires instead of traditional windings, reducing copper usage by approximately two-thirds and significantly improving manufacturing cycle time. These new approaches are expected to fundamentally simplify the manufacturing process of axial flux motors, improve yield, and reduce costs, paving the way for large-scale applications.

Axial flux motors, with their unique advantages of high power density and lightweight, flat design, are gradually becoming a favored technology in high-end fields such as electric vehicles and humanoid robots. The active deployment of domestic companies in this development process has garnered considerable attention. In particular, Paghu Power, as a leading axial flux motor company in China, has not only been the first to achieve large-scale mass production of this technology but is also continuously expanding the innovative applications of axial flux motors in new energy vehicles and robots.