Coil Unit Magnetic Body Polygonal Ferrite Segmentation
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Solution Overview
Problem
Wireless power supply systems for electric vehicles face issues with impact resistance and local heating due to the concentration of magnetic flux at sharp corners in ferrite layers divided into irregular shapes, leading to potential cracking and intense heating.
Innovation Solution
A coil unit design featuring a magnetic body composed of individual pieces with polygonal or circular principle surfaces opposing in a thickness direction, arranged in rows and columns, preventing cracking and flux concentration, and optionally disposed in a zigzag pattern or layers to enhance permeability and coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ferrite layer is divided into irregularly shaped ferrite sheets to ensure impact resistance, then the mechanical strength and crack resistance are improved, but the sharp corner portions between adjacent pieces cause magnetic flux concentration leading to local intense heating
Solution Approach 1:
The patent applies spheroidality by changing the shape of ferrite sheets from irregular polygons with sharp corners to shapes with rounded corners or circular cross-sections. This curvature elimination of sharp angles prevents magnetic flux concentration at corners, thereby preventing local intense heating while maintaining the divided structure for impact resistance.
2Reliability
If a single large ferrite layer is used to maintain magnetic flux continuity, then the magnetic permeability is improved, but the mechanical stress concentration leads to cracking under impact
Solution Approach 1:
The patent applies segmentation by dividing a single large ferrite layer into multiple smaller ferrite sheets or blocks. This segmentation improves crack resistance by preventing stress propagation across the entire structure, while the close arrangement of divided pieces maintains sufficient magnetic flux continuity for adequate permeability.
3Strength
If ferrite sheets are divided into small pieces to prevent cracking, then the impact resistance is improved, but the adjacent locations between pieces become paths of low magnetic resistance causing flux congregation
Solution Approach 1:
The patent uses spheroidality by providing rounded corners on ferrite sheets, which eliminates sharp angles that would otherwise create low magnetic resistance paths. This ensures more uniform magnetic flux distribution across adjacent pieces while maintaining the segmented structure for crack resistance.
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
Ensures impact resistance, prevents local heating, and improves the actual magnetic permeability and coupling efficiency between power transmitting and receiving coils, effectively addressing the challenges of mechanical stress and flux concentration.
Implementation Method 1
the magnetic flux passing through the magnetic body has a property of congregating to a direct with a low magnetic resistance
Implementation Method 2
coil unit for wirelessly transmitting or receiving the power
Implementation Method 3
there is a linear relationship between the magnetic flux density and the hysteresis loss or eddy current loss of the magnetic body
Implementation Method 4
there is a linear relationship between the magnetic flux density and the hysteresis loss or eddy current loss of the magnetic body
Implementation Method 5
the congregation of the magnetic flux i.e., the increase of the magnetic flux density has a tendency of involving local heating
Data Source
AI summary
A coil unit in which impact resistance is ensured and that has a magnetic body for heating prevention. The coil unit (the power receiving coil unit) includes a winding wire (the winding wire portion) and a magnetic body, wherein in the magnetic body, a plurality of individual pieces with two principle surfaces opposing in a thickness direction are disposed in rows and columns in a direction substantially orthogonal to the thickness direction, and the two principle surfaces are in a polygonal shape and all interior angles forming a polygon are obtuse angles (except for a right angle).