Composite EMI Shielding for Wireless Charging Thermal Management
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Solution Overview
Problem
Existing wireless charging technologies face inefficiencies due to energy loss as heat, particularly in compact electronics, and electromagnetic interference issues, which require precise coil alignment and are not flexible in terms of distance and size, and lack effective thermal management solutions.
Innovation Solution
A composite EMI shielding assembly incorporating a graphite substrate with high thermal conductivity and a magnetic layer for managing magnetic flux, combined with a conductive mesh for broadband shielding, providing both thermal management and electromagnetic interference mitigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a magnetic shield is added to block high frequency magnetic flux from reaching the battery, then electromagnetic interference is reduced, but device thickness increases and thermal management capability deteriorates
Solution Approach 1:
The patent uses a composite material comprising magnetite particles (providing magnetic shielding) dispersed in a polymer matrix (providing flexibility and thermal management). This composite achieves electromagnetic interference protection while maintaining thin profile and thermal conductivity, resolving the contradiction between shielding effectiveness and device thickness.
Solution Approach 2:
The patent modifies the magnetic shield by changing its physical parameters - using nanoscale magnetite particles instead of bulk magnetic materials, and incorporating them into a polymer matrix. This transforms the shield from a rigid, thick component to a flexible, thin coating that provides adequate EMI protection without compromising thermal management.
2Productivity
If the receiving coil is placed in close contact with the battery for efficient power transfer, then wireless charging efficiency is improved, but electromagnetic interference and heat generation increase
Solution Approach 1:
The patent introduces a polymer-coated magnetite composite layer as an intermediary between the receiving coil and battery. This intermediate layer provides magnetic shielding to protect the battery from high-frequency magnetic flux while allowing thermal energy to conduct away from the coil, enabling close coupling without excessive EMI or heat accumulation.
Solution Approach 2:
The patent converts the harmful high-frequency magnetic flux that would otherwise damage the battery into a managed phenomenon by using the magnetite composite to redirect and dissipate magnetic energy. Simultaneously, the polymer matrix converts concentrated heat into manageable thermal energy that can be conducted away, transforming potential harm into controlled energy management.
3Area of moving object
If coil size is reduced to fit compact electronics, then device compactness is improved, but coupling efficiency and power transfer capability deteriorate
Solution Approach 1:
The patent changes the magnetic properties of the environment around the coil by introducing magnetite particles with high magnetic permeability. This modifies the magnetic flux distribution, concentrating and directing magnetic field lines more effectively through the receiving coil, thereby improving coupling efficiency even with smaller coil areas.
Solution Approach 2:
The use of magnetite-polymer composite material creates a magnetic environment that enhances flux concentration and directs magnetic energy more efficiently toward the receiving coil. This composite material acts as a magnetic flux guide, compensating for the reduced coil size and maintaining power transfer efficiency in compact form factors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances wireless charging efficiency by reducing heat generation and electromagnetic interference, allowing for flexible coil alignment and faster charging speeds comparable to wired charging, while maintaining effective thermal management and electromagnetic shielding.
Implementation Method 1
a graphite substrate with high thermal conductivity
Implementation Method 2
a magnetic layer for managing magnetic flux
Implementation Method 3
a conductive mesh for broadband shielding
Implementation Method 4
the transmitter coil (Tx) induces a magnetic field which extends to the receiver coil (Rx) and the alternating magnetic field generates current within the receiver coil (Rx)
Implementation Method 5
high frequency magnetic flux generates eddy-current over the case, causing not only a decline in power transmission efficiency due to iron loss, but also a risk of abnormal heating
Data Source
AI summary
Assemblies having multi-functionalities of any combination of heat spreading, absorption of stray radiation, signal focusing, and shielding are provided. The assemblies may include a heat spreading layer of at least one sheet of a compressed particles of exfoliated graphite, graphitized polymers and combinations thereof. The assemblies may also include at least one magnetic layer, which may provide the benefits of magnetic flux management and/or stray radiation absorption. The assemblies may include an optional plastic coating on one or both of the exterior surfaces. The assemblies may be used to enable fast wireless charging of electronic devices by efficiently focusing magnetic flux for better power transmission efficiency.