Amid the iterative wave of electric drive technology for new energy vehicles, amorphous alloy motors have emerged as a core track for the industry to break through performance ceilings with their extreme energy efficiency advantages. To date, GAC Aion has taken the lead in achieving the world’s only mass-produced amorphous iron core technology breakthrough, conquering the technical challenges of lamination and manufacturing for amorphous motors and completing the full-link implementation of large-scale production.
Its flagship product, the Quark Electric Drive 2.0, adopts ultra-thin 0.025mm amorphous ribbon. Officially launched in March 2023, it entered mass production in August 2024. The technology is first equipped on the Hyper HL model, helping this C-class SUV achieve an ultra-long range of 800km. The recently opened pre-booking Aion N6 also carries the same amorphous motor system, marking a new step for this technology to penetrate the broader market.
In contrast to GAC Aion’s early implementation, other automakers have not yet mass-produced amorphous motors. Although leading Chinese brands such as BYD and Geely have increased investment in this field, most industry players remain in a wait-and-see state regarding the industrialization of amorphous motors based on the progress of the supporting industrial chain, a sharp contrast to the current trend of technological homogeneity in the industry.
On the industrial chain side, global giants are also accelerating the industrialization breakthrough of amorphous technology. DENSO Corporation of Japan recently announced a strategic investment in NextCore Technologies (NCT), a Kyoto-based startup. Leveraging their respective technological strengths, the two parties will jointly promote the mass production and development of amorphous alloy motor iron cores. The specific amount of the investment was not disclosed, but both sides have clearly defined the industrialization of core components of amorphous motors as the core cooperation goal.
Previously, limited by the processing bottlenecks of amorphous alloys, such materials were only used in a few industrial fields such as distribution transformers for a long time and could not meet the mass production requirements of automotive motors. This cooperation aims to break through the final link of industrialization, bringing the energy efficiency advantages of amorphous materials to civilian vehicles.
Meanwhile, the domestic industry is accelerating the consensus on industrialization. On March 19, the Strategic Alliance for Technological Innovation of the Whole Industrial Chain of Electric Vehicle Electric Drive Systems held a technical exchange meeting on the industrialization of amorphous motors. Representatives from the alliance’s council, technical expert committee, member units, and many external enterprises attended the meeting. Many industry experts and enterprise representatives shared in-depth insights on the technological evolution and industrialization path of amorphous motors, building a communication platform for the coordinated development of the industry.
1. The Eve of Industrialization: Triple Tests of Cost, Materials and Market
Based on the current industry situation, the industrialization of amorphous motors still faces three core challenges: cost, materials and market.
In terms of cost and market, the initial cost of an amorphous motor is about 2–3 times that of a traditional silicon steel motor. This stems partly from the high manufacturing cost of amorphous ribbon itself, and partly from the low yield rate of processing technology in the current small-batch production stage, further pushing up the unit product cost.
The high cost requires consumers to pay for the value improvement brought by new technologies, making the cost pressure relatively controllable when amorphous motors are applied in high-end models above 400,000 yuan. However, in low-frequency and low-speed application scenarios, the iron loss of traditional silicon steel is close to that of amorphous materials, with a cost only one-third of amorphous materials, so the energy efficiency advantage of amorphous motors cannot be reflected. Only in high-frequency and high-speed working conditions above 20,000 rpm can amorphous alloys show an 80% loss advantage over silicon steel. This characteristic makes it difficult for amorphous motors with high costs to gain a foothold in the low-end market, while the limited scale of the high-end market in turn restricts the speed of large-scale industrialization. In addition, the market’s understanding of amorphous motors is insufficient, and the low acceptance of new technologies by a large number of downstream customers further increases the difficulty of market promotion.
At the material system level, the inherent trade-off between saturation magnetic flux density (Bs) and coercivity (Hc) in the existing iron-based amorphous nanocrystalline alloy system has become a core bottleneck restricting its performance improvement and application expansion. Generally, higher saturation magnetic flux density is often accompanied by higher coercivity, and vice versa, making it difficult for such materials to simultaneously meet the dual core requirements of high magnetic flux and low loss in industrial scenarios.
Reviewing the technological evolution of amorphous alloys, taking the first-generation Fe-Si-B-Nb-Cu alloy developed by Yoshizawa et al. as an example, although this system has outstanding high-frequency magnetic properties, its saturation magnetic flux density is relatively low, only about 1.24T, which is difficult to meet industrial applications requiring high magnetic flux. In contrast, the Fe-(Zr, Hf, Nb, Ti, W)-B-Cu alloy developed by Suzuki et al. successfully increased the saturation magnetic flux density to 1.5T~1.7T, but the introduction of easily oxidizable elements in the system not only significantly increased the difficulty of material preparation, but also made it difficult to maintain structural and performance stability in air.
Willard et al. increased the saturation magnetic flux density of the alloy to about 1.61T by adding Co element, but this improvement not only pushed up the preparation cost of the alloy, but also led to a significant increase in coercivity to 10A/m, sacrificing the soft magnetic properties of the material. In addition, the Fe-Si-B-P-Cu system developed by Makino et al., while maintaining a high saturation magnetic flux density, also faces practical challenges such as low amorphous forming ability and harsh heat treatment processes, limiting its large-scale application.
The saturation magnetic flux density of current mass-produced amorphous ribbon is only 1.57–1.64T, much lower than 2.0–2.2T of electrical steel. This gap leads to the magnetic circuit of amorphous motors easily entering the saturation zone in advance under low-speed and high-torque working conditions, resulting in uneven magnetic flux density distribution. Ultimately, torque output drops by about 15%, the efficiency range shifts to the high-speed section, and low-speed efficiency decreases by 10%–12% instead, failing to adapt to the conventional working conditions of traditional passenger vehicles.
In addition, the traditional dipping process can only achieve single vacuum at room temperature, with a glue filling rate of less than 80%, interlaminar shear strength ≤12MPa, and a shedding rate ≥5% under high temperature and high humidity environments, becoming a potential failure point for the long-term operation of amorphous motors. Therefore, synchronously achieving Bs ≥1.75T, further reducing high-frequency iron loss by more than 10%, and withstanding ≥40 times of 180° bending without increasing cost or reducing amorphous forming ability has become a core technical bottleneck urgently to be broken in the field of amorphous motor iron cores, and also a key direction to promote the large-scale industrialization of amorphous motors.
2. Stamping Is the Future, but Cutting Is Still Needed at This Stage
General Electric (GE) of the United States started research on amorphous alloy motor iron core processing technology as early as 1978, and successfully developed a 250W asynchronous motor using amorphous alloy ribbon in 1982, opening the exploration of amorphous alloy applications in the motor field. With the gradual development of amorphous alloy iron core processing technology, more and more researchers have begun to apply amorphous ribbon to the research and development of various motors.
Honeywell disclosed an amorphous metal stator scheme for high-efficiency radial flux motors, which stacks amorphous ribbons of different lengths into arc or C-shaped units, and assembles them into a stator iron core with radial internal teeth after dipping and curing. However, there are a large number of air gaps between the discrete amorphous metal sheets in this scheme, which significantly increases the magnetic circuit reluctance, thereby increasing the driving current required for motor operation and restricting efficiency improvement.
Hitachi proposed another processing method for amorphous stator iron cores: first laminating amorphous ribbons into blocks, then cutting them into polyhedral amorphous units with single-sided or double-sided bow-shaped surfaces, and finally reassembling these units into a complete stator iron core. The iron core components prepared by this scheme have obvious efficiency advantages compared with silicon steel iron cores of the same specification, but there are still air gaps at the joints of adjacent polyhedral amorphous units, which deteriorates the overall magnetic properties of the iron core to a certain extent.
Metglas of the United States proposed a photolithography etching method to prepare amorphous iron core stators by chemically etching laminated sheets. This process can achieve extremely high processing accuracy, but it has high process complexity, low production efficiency and high manufacturing cost, which is only suitable for the processing of small-size amorphous alloy iron cores with complex shapes and cannot meet the mass production requirements of large-size amorphous iron cores.
China’s Advanced Technology & Materials Co., Ltd. proposed a preparation method for radial amorphous alloy stator iron cores: first stacking amorphous alloy sheets of equal length into a laminate of predetermined thickness, annealing to eliminate internal stress, then dipping and curing, and finally cutting into a stator iron core as a whole. This process effectively reduces splicing air gaps, and the prepared amorphous iron core has significantly improved performance compared with traditional silicon steel iron cores, laying an important technical foundation for the industrialized mass production of amorphous motors.
It is not difficult to find that the early manufacturing of amorphous motors mostly adopted the lamination and cutting process, but this process has low production efficiency and is difficult to meet the needs of large-scale industrialization. To improve the production efficiency of amorphous motors, the industry has gradually optimized the processing technology of amorphous ribbon in recent years, and stamping forming technology has become an important development direction. However, the traditional iron-based amorphous alloy ribbon itself has high strength and high hardness (Vickers hardness up to 900HV, about 5 times that of silicon steel), putting extremely high requirements on the existing stamping process.
During stamping, the verticality deviation of the stamping head will lead to uneven stress on the surface of the amorphous alloy workpiece, resulting in insufficient flatness of the finished product surface, and micro-cracks and chipping defects on the edge of the stamped sheet, producing a large number of unqualified products. This not only greatly reduces the stability of the stamping process, causing raw material waste and increased production costs, but also often requires increasing the number of stamping times to balance the stress on the workpiece surface, further increasing production energy consumption.
To address the stamping processing bottleneck of amorphous ribbon, the industry is currently exploring solutions from two directions: first, optimizing the material of the stamping head and stamping process parameters to improve the stress state during processing and alleviate processing difficulties; second, improving the stamping forming characteristics through composition and process regulation targeting the inherent characteristics of amorphous ribbon being hard and brittle and poor in processability. It is worth noting that while optimizing the stamping performance of the ribbon, the core magnetic properties such as high saturation magnetic flux density and low loss must not be lost to give full play to the energy-saving advantages of amorphous alloys.
The stress introduced by conventional silicon steel processing and assembly only leads to a 15%–30% increase in iron loss, while amorphous materials are extremely sensitive to stress. The same process will cause an increase of more than 80% in iron loss, and even a 10-fold performance gap under poor process control. At the same time, dynamic stresses such as thermal expansion and vibration caused by heat generation during motor operation will further lead to the decline and fluctuation of magnetic properties, eventually resulting in the problem of "excellent single-sheet performance but greatly reduced performance after assembly".
Conclusion
The industrialization of amorphous motors is a gradual process. At the current stage, it is necessary to first realize technology verification and small-batch mass production through the implementation of high-end scenarios. Meanwhile, through process upgrading and industrial chain collaboration, costs should be gradually reduced and the standard system improved. Then, with the decline of costs, it will gradually penetrate into the mid-to-low-end market and finally achieve large-scale implementation in all scenarios.
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Email: alvin.zhu@evergrowrs.com