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How does nanocrystalline help technology innovation boosts in wireless charging?

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How does nanocrystalline help technology innovation boosts in wireless charging?

Issue Time:2018-12-03
Recently, mobile phone manufacturers such as Huawei have increased the wireless fast charging power to 15W, which has encouraged the entire industry. However, in an interview with the reporter "Magnetic Components and Power", Chen Weihong, chief technology officer of Foshan Zhongyan Amorphous Magnetic Materials, said that to achieve high-power fast charging, wireless charging practitioners currently face many challenges, including: the conversion between electromagnetic Efficiency, tighter magnetic coupling, magnetic interference, thermal effects, position correction, load regulation. These will lead to various problems such as difficult to align the charging position of wireless charging, charging conversion efficiency, and long charging time.

As one of the key components of wireless charging technology, magnetic materials play a role in increasing the induced magnetic field and shielding coil interference in wireless charging equipment. Therefore, wireless charging equipment has high requirements for the performance of magnetic materials, product size, and reliability.

Although products across the ages are eye-catching, novelty and fun are not the key to winning the market. Ultimately, consumers still care about the experience.

Although wireless fast charging can be the key to improving the user experience, it also has the problem of slow charging, so it is urgent to increase the charging power accordingly. However, the traditional ferrite material has a serious heat generation problem during wireless charging, and can no longer meet the demand for high-power charging.

In contrast, nanocrystalline materials contain many possibilities and have great potential for future wireless charging. Therefore, in the application of wireless charging and the design of RX modules, the superiority of nanocrystalline materials is shown to the fullest.

Nanocrystalline materials have a variety of excellent comprehensive magnetic properties such as high saturation magnetic induction (1.2T), magnetic permeability >800, low high-frequency loss under high magnetic induction, and are the materials with the best comprehensive performance on the market. Nowadays, Nanocrystalline stands out in many key parameter tests of magnetic materials with its superior performance, and gradually replaces ferrite as a new choice for many wireless charging manufacturers.

It is understood that the saturation magnetic inductance of Sino-Amorphous Nano-M-Sheet is much higher than that of ferrite, and its anti-saturation ability is much higher than that of ferrite. The magnetic induction intensity of Nano-M-Sheet material does not change much with temperature, it is not easy to be magnetically saturated, and the temperature stability is better than ferrite.

In addition, Nano-M-Sheet material has high saturation magnetic flux and low loss characteristics and excellent thermal conductivity. Under the same wireless charging working conditions, the temperature rise of Nano-M-Sheet material is 7~8℃ lower than that of ferrite. . In contrast, the ferrite material is easy to reach saturation. During wireless charging, as the temperature increases, the magnetic inductance decreases, the shielding performance decreases, the eddy current increases, the heat generation is more serious, and a vicious circle is formed. The performance of Nano-M-Sheet material is very stable below 80 ℃. With the increase of temperature, the magnetic induction decreases, but the change range is very small, only 2.5%.

Foshan Zhongyan Amorphous Technology Co., Ltd. is located in Nanhai District, Foshan City, Guangdong Province. It is a high-tech joint-stock enterprise integrating design, R&D, production and sales of new amorphous and nanocrystalline soft magnetic materials and their components. Materials, strip iron cores, powder magnetic cores, automotive electronics, new energy devices, current sensors, power grid transformers and other products.

At present, the company's industrial production process of amorphous nanocrystalline strips includes smelting, spraying, feeding + inspection, winding and other layer-by-layer processes. The current quenching line speed reaches ~30m/s, and the strip thickness is 18~ 37um, the strip width is 1.5~213mm.

In order to meet new market challenges and comply with the market trend of high efficiency, low loss, and thin specifications, the next R&D plan of Amorphous manufacturers will be carried out at three levels: breakthrough in nanocrystalline products, technological improvement, and development of new products.

In the research and development of nanocrystalline materials, reduce the soft magnetic material Hc and increase Bs for alloy composition optimization. For the current ultra-thin nanocrystalline strip of 18μm, reduce the eddy current loss, increase the frequency bandwidth, and reduce the product thickness to 12~15μm. By increasing the magnetic permeability and increasing the consistency of the product, the target of the constant tension annealing of the nanocrystalline strip material reaches 12000~15000.

It is understood that the nanocrystalline ribbon undergoes crystallization and constant tension heat treatment, which will induce magnetic anisotropy, making the length of the ribbon become a difficult axis of magnetization, thereby controlling the magnetic permeability in a wide range and forming nanocrystals with different magnetic permeability. Soft magnetic material. These low permeability type nanocrystalline soft magnetic materials are characterized by small hysteresis, which can suppress the decrease of permeability at the higher frequency and magnetic field overlap, so they can be applied to the DC superposition in the high frequency region.

In terms of strip on-line insulation coating technology, Sinotrans Amorphous will reduce the loss, increase the frequency bandwidth, and reduce the thickness of the product to complete the technical improvement.

In the future, Amorphous developers will also develop a sub-micron soft magnetic powder that can reduce eddy current loss, increase frequency bandwidth, and reduce product thickness based on the casting sheet technology.