Magnetic isolation sheet for wireless charging receiving end and preparation method thereof

Abstract

The invention belongs to the technical field of wireless charging, and discloses a magnetic isolation sheet for a wireless charging receiving end and a preparation method thereof. The magnetic isolation sheet for the wireless charging receiving end of the present invention is a composite material formed by alternately compounding nanocrystalline sheets and soft magnetic composite material layers, wherein the soft magnetic composite material layer contains soft magnetic powder and a polymer binder, The soft magnetic powder is a scaly iron-based alloy magnetic powder. Due to the magnetic permeability of the soft magnetic composite layer, the magnetic isolation sheet of the present invention makes the magnetic force lines generated by the wireless charging system during the working process more evenly distributed in the magnetic isolation sheet, which further facilitates the improvement of the transmission efficiency of the wireless charging system. In addition, the soft magnetic composite layer material is vitrified or vulcanized under the action of pressure and temperature during the micro-fractionation process of the present invention, which improves the density and magnetic properties of the soft magnetic composite material, and also strengthens the nanocrystalline sheet and the soft magnetic composite layer. of cohesiveness.

Description

technical field [0001] The invention relates to the technical field of wireless charging, in particular to a magnetic isolation sheet for a wireless charging receiving end and a preparation method thereof. Background technique [0002] With the rapid development of electronic technology, wireless charging technology has gradually entered people's daily life and is used in consumer electronics, industrial medical and other fields. Among them, the Qi standard is currently mainly used in the mobile phone wireless charging system, the application frequency is 100kHz-200kHz, and the power is usually small, no more than tens of watts. [0003] The wireless charging system is mainly composed of a magnetic isolation sheet and a coil, and the magnetic conduction and shielding characteristics of the magnetic isolation sheet have an important influence on the power transmission efficiency of the system. Usually, the materials of magnetic isolation sheet mainly include ferrite magnetic...

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Problems solved by technology

The existence of the adhesive layer can ensure that the nanocrystalline magnetic isolation sheet has certain mechanical properties and flexibility, but there are also some problems, such as: (1) Due to the very narrow design space of the mobile phone, the thickness of the magnetic isolation material at the wireless charging receiving end also needs to be strictly Control, the adhesive layer is a non-magnetic material, and the adhesive layer accounts for about 20% of the volume of the entire magnetic isolation sheet. Therefore, the existence of the non-magnetic adhesive layer greatly occupies the space of the magnetic material, resulting in the magnetic properties of the magnetic isolation sheet. There is a certain degree of reduction; (2) The structure of the magnetic isolation sheet is a multi-layer composite structure of multi-layer nanocrystalline sheets and adhesive layers. The adhesive layer isolates adjacent nanocrystalline sheets, resulting in The magnetic field lines cannot be evenly distributed in the magnetic isolation sheet, which affects the power transmission efficiency during the wireless charging process; (3) The adhesive layer is mostly made of high-grade materials with poor thermal conductivity, which affects the heat dissipation of the entire wireless charging system; (4) ) The adhesive layer used in the magnetic isolation material of the wireless charging receiving end is relatively expensive, which greatly increases the cost of the wireless charging system

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