Modular Axial Flux Stator Assembly for Flexible Liquid Cooling

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Solution Overview

Problem

The stator design of axial flux machines faces challenges in achieving high performance due to complex assembly processes, robustness issues, and limited flexibility in cooling fluid flow patterns, which affect cooling efficiency and durability.

Innovation Solution

A manufacturing method using a mould with movable spacers to compress stator elements and inject molten material, creating a skeleton with integrated cooling channels, allowing for reduced complexity, increased robustness, and adaptable cooling flow patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If liquid cooling is implemented with hollow stator housing and guiding walls, then cooling efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstator structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling channels directly into the stator housing structure, eliminating the need for separate guiding walls. The housing itself forms the cooling fluid pathways, integrating the cooling function into the structural component rather than adding separate cooling elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stator housing serves multiple functions simultaneously: it provides structural support for the stator elements and inherently defines the cooling fluid flow paths. This multi-functionality reduces the need for additional dedicated cooling components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If split cores and multiple assembly steps are used, then cooling channels can be formed, but manufacturing complexity increases

Engineering Contradiction:
Improvecooling capabilityVSAvoidassembly process complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent uses a two-part mold system that segments the molding process into two stages: first forming the housing with integrated cooling channels, then adding the stator elements. This segmentation of the manufacturing process simplifies each individual step while achieving the complex integrated result.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling channels are pre-formed as integral parts of the stator housing before the stator elements are assembled. This preliminary formation of cooling structures eliminates the need for complex post-assembly cooling channel creation.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If sealing measures are added to prevent cooling liquid leakage, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing function is merged into the stator elements themselves rather than being a separate component. The stator elements are designed to seal against the housing, integrating the sealing function into the primary structural elements.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If coils are securely anchored, then durability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecoil anchoring robustnessVSAvoidanchoring structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The anchoring function is merged into the housing structure through direct molding. The housing is formed with integrated anchoring features that secure the stator elements and coils during the molding process itself, eliminating the need for separate anchoring components.

Inventive Principle:
Principle #5Merging (Combining)

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 results in a stator with improved copper fill factor, enhanced cooling efficiency, reduced assembly costs, and increased durability by minimizing gaps and ensuring direct contact between cooling fluid and coils, while allowing for flexible design adjustments.

Implementation Method 1

applying an injection moulding process, such that the stator elements are overmoulded, thereby obtaining the structure

Methodology Applied
Scientific EffectInjection moulding:

Implementation Method 2

applying an injection moulding process, such that the stator elements are overmoulded

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

a cooling liquid is circulated inside a hollow stator housing, thereby directly submerging the coils in the cooling liquid

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the cooling fluid is forced against the respective coils, thereby allowing for an efficient heat evacuation

Methodology Applied
Scientific EffectHeat evacuation: Heat Exchanger

Implementation Method 5

radially compressing the stator elements, thereby reducing gaps between the coils and the elongated portion of respective spacers

Methodology Applied
Scientific EffectRadial compression: Compression

Data Source

PatentEP4492636A1Modular stator for an axial flux machine
Publication Date: 2025.01.15 MAGNAX BV
  • EP4492636A1 patent drawingFigure 1
  • EP4492636A1 patent drawingFigure 2
  • EP4492636A1 patent drawingFigure 3

AI summary

Method for manufacturing a stator of an axial flux machine, comprising: - providing a ring-shaped intermediate structure (1000), comprising: o stator elements (300) fixed in a skeleton; o radial channels (1301), present between any pair of adjacent stator elements (300); - providing a flow distributor (1500, 1900), the flow distributor (1500, 1900) and the intermediate structure (1000) being provided as separate parts; - mounting the flow distributor (1500, 1900) on the inner (1006) or outer surface (1007) of the intermediate structure (1000), wherein: o the flow distributor (1500, 1900) comprises a circumferential wall (1501, 1901), the circumferential wall comprising one or more recesses (1502, 1503, 1902), thereby defining at least one circumferential channel in fluid communication with one or more of the radial channels (1301), and o the flow distributor (1500, 1900) is adapted to define a flow pattern when circulating a cooling fluid between the stator elements (300).