Inductor Resin Coating Void Prevention
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Solution Overview
Problem
In wireless power transmission systems, voids formed between turns of Litz wire and the surrounding resin can lead to dielectric breakdown and uneven heat distribution, causing deterioration in the electrical and thermal properties of the inductor.
Innovation Solution
The use of a first resin with low filler content to fill spaces between Litz wire turns and a second resin with higher filler content to cover the winding, preventing void formation and enhancing thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single resin is used to cover the ferrite core and Litz wire, then the manufacturing process is simple, but voids form between turns and around the wire, causing dielectric breakdown and poor heat dissipation
Solution Approach 1:
The resin coating is divided into two distinct layers: a first resin layer applied directly to fill spaces between Litz wire turns, and a second resin layer applied over the first layer to provide final encapsulation. This segmentation allows each layer to perform its specific function optimally without void formation.
Solution Approach 2:
The first resin is specifically formulated with different properties (viscosity, filler content) than the second resin to match the local requirements of the space between wire turns versus the outer encapsulation needs. This local quality differentiation ensures proper filling of inter-turn spaces while maintaining overall structural integrity.
2Reliability
If resin is applied to cover the Litz wire, then electrical insulation is provided, but voids remain that concentrate electrical fields and cause discharge
Solution Approach 1:
The first resin is applied in advance to completely fill all spaces between Litz wire turns before the second resin is applied. This preliminary action eliminates voids that would otherwise concentrate electrical fields and cause discharge, ensuring a void-free interface between the wire and encapsulating resin.
3Strength
If resin covers the winding, then structural support is provided, but heat is not uniformly diffused and thermal conductivity decreases
Solution Approach 1:
The resin system uses controlled filler content and viscosity parameters in the first resin layer to optimize thermal conduction pathways between wire turns, while the second resin layer provides structural support. By adjusting these parameters, both heat dissipation uniformity and structural strength are achieved simultaneously.
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
Prevents dielectric breakdown and ensures uniform heat dissipation, maintaining the electrical insulating properties and thermal conductivity of the inductor.
Implementation Method 1
If a void is formed in the resin, the electrical field can be concentrated in the void to produce a discharge, thereby causing a dielectric breakdown
Implementation Method 2
there is a possibility that heat is not uniformly diffused, the thermal conductivity decreases, and the resin deteriorates
Data Source
AI summary
According to an embodiment, there is an inductor, including: a magnetic core; a winding formed around the magnetic core; a first resin provided between turns of the winding; and a second resin covering the winding and the first resin, wherein the second resin has higher filler content than the first resin.