3D-Printed Metal Coil Geometry for High Slot Packing
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Solution Overview
Problem
Conventional electrical machines have low packing factors for metal coils in stator slots, leading to inefficient electrical loading and reduced power density due to spaces filled with air and insulating material.
Innovation Solution
A method involving 3D printing of metal coils with densely packed turns, followed by infiltration of insulating material between the turns to prevent short circuits, thereby increasing the packing factor and electrical loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional round wire is used for metal coils, then ease of manufacture is improved, but packing factor deteriorates
Solution Approach 1:
The patent applies asymmetry by transitioning from symmetric round wire to asymmetric rectangular wire with rounded corners. This shape change allows the wire to pack more efficiently in the slot space, increasing the packing factor from approximately 45% to over 90%, while the rounded corners maintain manufacturability by reducing stress concentration and easing forming operations.
2Quantity of substance
If rectangular cross-section wire is used, then packing factor is improved, but reliability deteriorates
Solution Approach 1:
The patent applies local quality by selectively rounding only the corners of the rectangular wire cross-section while maintaining the rectangular overall shape. This local modification eliminates stress concentration at sharp corners (improving reliability) while preserving the space-efficient rectangular geometry (maintaining high packing factor). The rounded corners reduce the risk of insulating material damage and corona discharge.
3Ease of manufacture
If multi-stranded Litz wire is used, then ease of manufacture is improved, but packing factor deteriorates
Solution Approach 1:
The patent extracts the insulating material from the wire structure itself (as in Litz wire) and replaces it with a void-free rectangular cross-section design. By using solid rectangular wire with rounded corners instead of multi-stranded construction, the patent eliminates the insulating material between strands, achieving packing factors over 90% while maintaining manufacturability through the rounded corner design.
4Quantity of substance
If densely packed coils are used, then power density is improved, but thermal management deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the wire cross-sectional geometry from round to rectangular with rounded corners. This geometric parameter change enables significantly higher packing density (increasing copper content in slots from 45% to over 90%), which improves power density. The enhanced copper content and reduced air gaps also improve thermal conduction pathways, thereby improving thermal management despite the denser packing.
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 method enhances the packing factor of metal coils within stator slots, leading to increased electrical loading and power density of electrical machines, while also improving thermal management and reducing electrical losses.
Implementation Method 1
3D printing a metal coil having a plurality of turns
Implementation Method 2
infiltrating insulating material between the turns of the metal coil to electrically insulate the turns from each other
Data Source
AI summary
A 3D printed metal coil for an electrical machine. The 3D printed coil has a plurality of turns and is configured to fit within a slot in an electrical machine. A cross-sectional shape of successive turns of the plurality of turns varies such that a portion of each turn forms a part of an external surface of the metal coil, the external surface forming an interface with a side of the slot.