Magnetic materials in wireless charging devices

Wireless charging ferrite is a ferromagnetic metal oxide. In terms of electrical properties, the resistivity of wireless charging ferrite is much larger than that of metal and alloy magnetic materials, and it also has higher dielectric properties.


The method of charging batteries built in electronic devices through wireless and contactless wireless charging (Wireless Power Transfer) is rapidly becoming popular. There are various wireless charging methods, but the current mainstream methods are electromagnetic induction and magnetic resonance, which transmit power through magnetic coupling.


Electromagnetic induction and magnetic resonance wireless charging use the magnetic field generated by the receiving and transmitting coils to transmit power in a non-contact manner.


Electromagnetic Induction Wireless Charging

Most of the wireless mobile phone chargers currently on the market are electromagnetic induction. Electromagnetic induction wireless charging has been widely used in electric shavers, electric toothbrushes, mobile phones and other products. Its advantages lie in simple principle and structure and low cost;

However, when the relative position and distance between the transmitting coil and the receiving coil become larger, the power transmission efficiency will drop sharply, so the distance between the coils must be kept relatively close, which is also the disadvantage of this technology.


Magnetic Resonance Wireless Charging

Magnetic resonance wireless charging is a method in which capacitors are inserted between the transmitting side and the receiving side to form an LC resonance circuit, and the resonant frequencies of the transmitting side and the receiving side are matched to perform power transmission. The advantage of this method is that the distance between the coils can be increased, and at the same time, power transmission can be carried out even if the centers of the coils are slightly shifted. This charging method can wirelessly charge multiple mobile devices at the same time.

anti-interence wireless charging ferrite sheet

The main magnetic materials used in wireless chargers are NdFeB permanent magnets, nickel-zinc ferrite thin magnetic sheets, manganese-zinc ferrite thin magnetic sheets, and flexible ferrite magnetic sheets. As the main components of wireless charging technology, various magnetic isolation sheets made of soft ferrite materials play the role of increasing the induced magnetic field and shielding coil interference in wireless charging equipment.


Fixed-position wireless chargers generally use NdFeB permanent magnets as positioning materials, and terminal devices need to be placed in a fixed position to charge and maximize charging efficiency. (Large wireless charging equipment will use permanent ferrite materials instead of NdFeB to reduce costs)。


The permanent magnet material used in wireless charging equipment, on the one hand, serves as a positioning device between the transmitting and receiving, which facilitates the rapid and correct positioning of the terminal equipment; on the other hand, it enhances the magnetic flux between the transmitting and receiving coils and improves the transmission efficiency.


The magnetic performance of wireless charging ferrite also shows that it has high magnetic permeability at high frequency. Therefore, wireless charging ferrite has become a widely used non-metallic magnetic material in the field of high frequency and weak current. Due to the low magnetic energy stored in the unit volume of wireless charging ferrite, the saturation magnetization is also low (usually only 1/3 to 1/5 of pure iron),

Therefore, its application in low-frequency strong current and high-power fields requiring higher magnetic energy density is limited.


With the wide application of wireless charging, the demand for the use of magnetic materials is increasingly strong. Along with this, the processing difficulties of magnetic materials are also exposed among manufacturers. Regarding the processing difficulties of magnetic materials, we can fully understand the main aspects of the processing difficulties from the material characteristics of magnetic materials.

anti-interence wireless charging ferrite sheet

  1. Ferrite raw material

The material characteristics of ferrite raw material are: the green sheet has no toughness, poor adhesion, easy to break, slag, dust, and easy to break under the action of force. The processing requirements are cutting, film stripping, stacking, and dust removal. At present, most of the commonly used methods are manual operations, and it is difficult to form automated operations.


  1. Ferrite magnetic sheet

Material characteristics of ferrite magnetic sheet: This material is highly fragile material, and this material is mainly shipped as sheet material. The slivers of the material will not be broken in the direction of the force. After crushing, perform secondary punching. There are phenomena such as difficulty in taking the slices, easy stacking of magnetic slices and difficulty in separating them.


  1. Ferrite magnetic isolation sheet

Ferrite magnetic isolation sheet: a magnetic sheet material with high hardness. The incoming material is block-shaped and needs to be cut after coating. The material is relatively hard. The traditional processing method is easy to damage the knife, and the sheet processing, traditional The processing method is less efficient.


  1. Nanocrystalline materials

Nanocrystalline material: an extremely brittle magnetic carrier tape material, fragmentation does not follow the direction of force. Ships without inner support core. The common processing method is: paste this kind of carrier tape with double-sided tape and then crush it. It is required to crush without scratches, and the internal fragmentation of the magnetic sheet is uniform. After fragmentation, it is required to carry out die-cutting deep processing after compounding multiple layers, and burrs are not allowed in die-cutting.


Shenzhen PH Functional Materials is a professional Anti interference wireless ferrite sheet supplier, we have many years of production experience and are one of the experts in this industry. Our products mainly include nfc absorber, emi suppressor sheet, emi shielding sheet, etc. If you have any questions about our products, please feel free to contact us.

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