Metal Housing Layout for Efficient Wireless Charging Alignment
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Solution Overview
Problem
Metal exteriors in devices interfere with wireless charging by causing eddy currents and reducing efficiency, as they can saturate the coil core and lead to inductive heating, which consumes energy intended for charging.
Innovation Solution
The device incorporates a metal housing with slits to break it into electrically insulated segments, a coil core that extends towards the exterior, and a laminated metal plate for alignment instead of a permanent magnet, along with shielding to minimize power transfer loss and eddy currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal exterior housing is used to provide appearance and durability, then device strength and appearance are improved, but wireless charging efficiency deteriorates due to eddy currents and power transfer loss
Solution Approach 1:
The metal housing is divided into multiple electrically insulated segments separated by slits or gaps. This segmentation breaks the continuous metal path, preventing large eddy currents from forming while maintaining the structural integrity and appearance of the metal exterior housing.
Solution Approach 2:
Electrically insulating materials are introduced between metal segments or as coating layers on the metal housing. These intermediary insulating layers block eddy current paths while allowing the metal housing to maintain its mechanical strength and aesthetic appearance.
2Adaptability or versatility
If metal housing is placed within the transmitting coil footprint, then device design flexibility is improved, but charging efficiency deteriorates due to eddy current formation
Solution Approach 1:
The metal housing is segmented into multiple electrically isolated sections using slits, gaps, or insulating barriers. This prevents continuous eddy current loops while allowing the metal housing to remain within the wireless charging coil footprint for design flexibility.
Solution Approach 2:
Electrically insulating features are strategically placed at specific locations on the metal housing where eddy currents would form. This localized approach maintains metal coverage for appearance and durability while preventing harmful eddy currents only where necessary.
3Force
If permanent magnet is used for alignment, then alignment effectiveness is improved, but eddy currents and heating are worsened due to metal plate interactions
Solution Approach 1:
The patent replaces the permanent magnet alignment feature with a non-metallic alternative (such as a plastic or ceramic alignment element). This eliminates the source of eddy currents and inductive heating in the alignment mechanism while maintaining alignment functionality through geometric or magnetic coupling with the charger.
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
This configuration enhances wireless charging efficiency by reducing eddy currents, minimizing heating, and maintaining device durability while allowing efficient power transfer, even with metal exteriors.
Implementation Method 1
the metal housing can be formed of or broken into multiple electrically insulated segments to reduce eddy current formation
Implementation Method 2
the electrical device can include a coil core for the power receiving coil that extends along the power receiving coil toward the exterior of the electrical device
Implementation Method 3
the metal plate can be a laminated plate, such as one having electrically insulated metal strips, which can reduced eddy currents and power transfer loss in the metal plate
Data Source
AI summary
Devices for wireless charging with metal housings. The device comprises a wireless power receiving coil and an associated coil core, wherein the coil core defines a recess and at least a portion of the wireless power receiving coil is disposed in the recess; and a housing comprising one or more metal portions, wherein the housing is configured to receive at least a portion of the wireless power receiving coil and the associated coil core in an opening defined by the one or more metal portions. Alternatively, the device comprises a wireless power receiving coil and an associated coil core; a housing comprising one or more metal portions; and an alignment feature configured to interact with a magnet of a wireless charger to align the device with the wireless charger, wherein the alignment feature comprises a plurality of metal elements that are electrically insulated from each other.