Axial Gap Stator Cooling via Conductive Composite and Fins
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Solution Overview
Problem
Axial gap type rotating machines face heat dissipation challenges due to poor thermal conductivity in coil holding members, leading to increased coil temperatures and potential damage during continuous operation as electric generators.
Innovation Solution
A stator with a coil holding member made from materials with thermal conductivity of at least 5 W/mK and electrical conductivity of no more than 1 x 10^-5 S/m, combined with a radiation fin of high thermal conductivity (not less than 150 W/mK) and a cooling fan to enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy resin or Bakelite is used as coil holding member material, then electrical insulation is improved, but thermal conductivity deteriorates
Solution Approach 1:
The patent uses composite materials for the coil holding member that combine electrical insulation with enhanced thermal conductivity. Specifically, it employs materials such as thermally conductive plastics (e.g., polyimide with thermal conductivity ≥5 W/mK) or composite structures incorporating metal plates or heat dissipation layers, thereby achieving both electrical insulation and effective heat dissipation simultaneously.
2Power
If large electric current is passed to achieve higher output, then power generation capability is improved, but heat generation increases
Solution Approach 1:
The patent introduces intermediary heat dissipation structures between the heat-generating coils and the environment. These include cooling fins attached to the coil holding member, heat sinks, or forced cooling channels that act as thermal intermediaries to transfer heat away from the coils, enabling high current operation without excessive temperature rise.
Solution Approach 2:
The patent replaces passive thermal management with active cooling mechanisms. This includes incorporating fans, water cooling systems, or thermoelectric coolers that actively remove heat from the coil assembly, allowing sustained high-power operation by dynamically controlling the thermal environment rather than relying solely on passive conduction.
3Temperature
If cooling mechanism is added to dissipate heat, then temperature control is improved, but device complexity increases
Solution Approach 1:
The patent merges the cooling function with existing structural components. For example, the coil holding member itself is designed to serve dual purposes: mechanical support for the coils and heat dissipation structure through integrated cooling fins or thermally conductive pathways. This integration eliminates the need for separate cooling systems, reducing overall complexity while maintaining effective temperature control.
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
Effective heat dissipation is achieved, preventing coil damage and maintaining operational efficiency even under high current loads, with coil temperatures kept below 80°C during continuous operation.
Implementation Method 1
the coil holding member comprises a material which has a thermal conductivity of not less than 5 W/mK
Implementation Method 2
a radiation fin of high thermal conductivity (not less than 150 W/mK)
Implementation Method 3
a cooling fan to enhance heat dissipation
Implementation Method 4
a cooling fan to enhance heat dissipation
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A stator has a mechanism for effectively dissipating internally generated heat, and is for use in a high power axial gap type rotating machine. The stator comprises a coil holding member and a coil secured to the coil holding member, in which the coil holding member comprises a material having a thermal conductivity of not less than 5 W/mK that is measured compliant with the ASTM E1530 and having an electrical conductivity of not more than 1 x 105 S/m that is measured compliant with the ASTM E345. This stator preferably comprises a radiation fin, having a thermal conductivity of not less than 150 W/mK, and having a bumpy surface so as to increase the surface area thereof threefold or more, at the circumference of the coil holding member.