Axial Field Motor Side Channel Compressor for Fuel Cells

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Solution Overview

Problem

Existing side channel compressors for fuel cell systems face challenges in compact design due to conflicting installation space requirements and significant heat energy losses when used as heating elements, leading to inefficient cold starts and potential ice bridge formation.

Innovation Solution

The design incorporates a disk-shaped axial field electric motor with a disk-shaped rotor and stator, featuring a cylindrical shoulder for optimal compressor wheel support, a compact air gap arrangement for efficient heating, and a cup-shaped sealing element to reduce heat losses and prevent moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the stator is arranged outside the rotor in a conventional configuration, then the drive unit has a small radial diameter, but the overall compressor requires considerable axial space

Engineering Contradiction:
Improveradial diameter of drive unitVSAvoidaxial space of compressor
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent combines the stator and rotor into a single integrated axial-field electric motor unit where the stator is arranged inside the rotor, merging two separate components into one compact assembly. This integration eliminates the need for separate mounting spaces and reduces the overall axial dimension of the drive unit while maintaining the same radial footprint.

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If the compressor wheel is supported by multiple bearings and a drive shaft, then the compressor wheel is stable, but the device complexity and assembly costs increase

Engineering Contradiction:
Improvestability of compressor wheelVSAvoidcomplexity of drive mechanism
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the drive shaft from the system by directly coupling the rotor to the compressor wheel through the cylindrical extension. This removal of the intermediate drive shaft simplifies the overall mechanism, reduces the number of components, and lowers assembly complexity while maintaining stable support through the integrated bearing arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If the stator is used as a heating element with large surface area, then heating capacity is high, but heat energy losses increase significantly

Engineering Contradiction:
Improveheating capacity of statorVSAvoidheat energy losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies local quality by concentrating the heating function specifically in the cylindrical extension region where ice bridge formation is most critical, rather than distributing heat uniformly across the entire stator surface. This localized heating approach maintains sufficient heating capacity to prevent ice formation at critical points while minimizing unnecessary heat generation and energy losses in other areas.

Inventive Principle:
Principle #3Local quality

4Device complexity

If the electrical components are exposed to the compressor chamber, then the structure is simple, but moisture ingress and heat losses occur

Engineering Contradiction:
Improvesimplicity of structureVSAvoidmoisture ingress to electrical components
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements nesting by placing the electrical components (stator and rotor) inside the cylindrical extension of the rotor, which itself is nested within the compressor wheel assembly. This nested arrangement allows the electrical components to be protected from moisture ingress through the natural structural hierarchy while maintaining a compact overall design. The sealing is achieved through the layered nesting structure rather than additional external barriers.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This configuration enables rapid and energy-efficient preheating, reduces assembly and maintenance costs, and prevents ice bridge formation, ensuring reliable cold starts and increased system reliability by minimizing heat losses and protecting electrical components.

Implementation Method 1

the drive is designed as an axial field electric motor having a stator and a rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The side-channel compressor can utilize the stator as a heating element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3775566B1Side channel compressor for a fuel cell system for conveying and/or compressing a gaseous medium
Publication Date: 2023.05.17 ROBERT BOSCH GMBH
  • EP3775566B1 patent drawingFigure 1
  • EP3775566B1 patent drawingFigure 2
  • EP3775566B1 patent drawingFigure 3

AI summary

The invention relates to a side channel compressor (1) for a fuel cell system for conveying and/or compressing a gas, particularly hydrogen, comprising a housing (3) and a drive (6), wherein the housing (3) has a housing upper part (7) and a housing lower part (8), a compressor chamber (30) which is circulating in the housing (3) about an axis of rotation (4) and has at least one peripheral side channel (19), a compressor wheel (2) located in the housing (3), which is rotatably arranged about an axis of rotation (4) and is driven by the drive (6), said compressor wheel (2) comprising blades (5) arranged on the periphery thereof in the region of the compressor chamber (30), and comprising respectively a gas inlet opening (14) embodied on the housing (3) and a gas outlet opening (16) which are fluidically interconnected via the compressor chamber (30), in particular the at least one side channel (19). According to the invention, the drive (6) is designed as an axial field electric motor (6) which has a stator (12) and a rotor (10), wherein the stator (12) and the rotor (10) have a disc-shaped design and are formed so as to move about the axis of rotation (4), and wherein the stator (12) is arranged next to the rotor in the direction of the axis of rotation (4).