Why is a magnetic shielding plate added to the wireless charging coil?

Why is a magnetic shielding plate added to the wireless charging coil?

As we all know, there are magnetic shielding plates on wireless charging coils. So why are they added? Can they be omitted? Let's follow the explanations of the editor to understand why magnetic shielding plates are necessary for wireless charging.

The magnetic spacer is a magnetic sheet-like accessory material for the coils at both ends of the wireless charger. It is a magnetic material formed through constant high-temperature sintering. Commonly, the coil magnetic spacers are divided into the receiving end (commonly a soft magnetic sheet, very thin in thickness) and the transmitting end receiving end (commonly a hard magnetic sheet, hard and fragile in material, with a thickness of about 0.1 to 0.8 mm).

The wireless charging coil is an electronic component that charges using the principle of electromagnetic wave induction. The inductive coil at the sending end is connected to a wired power source to generate an electromagnetic signal, while the inductive coil at the receiving end senses the electromagnetic signal from the sending end and converts it into current to charge the battery.

The main functions of the magnetic shielding sheet are as follows:

1. Increased the magnetic flux passing through the coil

In areas with a greater magnetic induction intensity in a magnetic field, there are more magnetic field lines. The magnetic shielding sheet has a high magnetic convergence effect. By converging the magnetic field lines in the magnetic field, the magnetic induction intensity becomes greater, and the magnetic flux also increases. This achieves the effect of maximizing the magnetic field energy emitted by the transmitting coil being applied to the receiving coil, thereby improving the electromagnetic conversion efficiency.

II. Isolating the contact between metal objects and electromagnetic signals

In a magnetic field, electromagnetic signals are easily absorbed and attenuated by metals, wasting energy and reducing the efficiency of electromagnetic conversion. Applying a magnetic shielding sheet can effectively isolate the contact between metal objects and electromagnetic signals, reducing the attenuation of the electromagnetic signals and ultimately achieving the effect of shielding against magnetism.

III. Increase the heat dissipation area

The greater the magnetic induction intensity in the magnetic field, the more heat the charging coil will generate. If this heat is not effectively dissipated in the circuit, it will accumulate in a certain space and may cause damage to electronic devices. The heat we feel during wireless charging is exactly from this. By integrating the coil, magnetic plate, and circuit board completely, the contact area of the inductor coil can be increased, which can effectively disperse the heat and transfer it away, reducing the heat generation per unit area.

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