Segmented Centering Tube for Fuel Cell Stack Alignment

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Solution Overview

Problem

The existing stacks of membrane/electrode assemblies in fuel cells and electrolyzers face challenges in reducing size and weight, particularly for on-board applications, where the use of cylindrical centering bars as tie rods results in high weight and dimensioning issues, and certain geometries are incompatible with these bars.

Innovation Solution

The method involves using tubes with a stiffening beam during stack formation to ensure precise alignment and positioning of membrane/electrode assemblies and bipolar plates, allowing for thinner walls and reduced weight after beam removal, while maintaining mechanical strength and fluid flow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cylindrical centering bars are used as tie rods to maintain alignment, then alignment precision is improved, but weight and bulk increase

Engineering Contradiction:

Improvealignment precisionVSAvoidstack weight

Core Design Contradiction:

Manufacturing precisionVSWeight of stationary object

Solution Approach 1:

The centering bar is segmented into two functional parts: a thin-walled tubular structure providing alignment guidance and an internal stiffening beam providing mechanical strength. This segmentation allows each part to optimize its function while reducing overall material usage and weight.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The centering bar uses a composite structure combining a thin-walled tube with an internal stiffening beam. This composite approach provides both the alignment precision of a rigid structure and the weight reduction of a thin-walled design, resolving the contradiction between precision and weight.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If cylindrical centering bars are used as tie rods to maintain alignment, then alignment precision is improved, but stack bulk increases

Engineering Contradiction:

Improvealignment precisionVSAvoidstack bulk

Core Design Contradiction:

Manufacturing precisionVSVolume of stationary object

Solution Approach 1:

The centering bar is segmented into a thin-walled tubular structure and an internal stiffening beam, allowing the alignment function to be performed by the thin tube while the beam provides structural support, thereby reducing overall bulk.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thin-walled tubular structure serves as the primary alignment component, using a thin-film approach to minimize bulk while maintaining sufficient stiffness for alignment purposes when supported by the internal beam.

Inventive Principle:

Principle #30Flexible shells and thin films

3Weight of stationary object

If thin-walled tubes are used to reduce weight, then weight is reduced, but mechanical strength decreases

Engineering Contradiction:

Improvecentering bar weightVSAvoidmechanical strength

Core Design Contradiction:

Weight of stationary objectVSStrength

Solution Approach 1:

The stiffening beam is nested inside the thin-walled tube, creating a nested structure where the inner beam provides mechanical strength to support the thin outer wall, allowing weight reduction without sacrificing strength.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The combination of thin-walled tube and internal stiffening beam creates a composite structure where the two elements work together to provide both weight reduction and mechanical strength, resolving the contradiction between these two properties.

Inventive Principle:

Principle #40Composite materials

4Volume of moving object

If certain stack geometries are used to reduce size, then compactness is improved, but compatibility with centering bars deteriorates

Engineering Contradiction:

Improvestack sizeVSAvoidgeometry compatibility

Core Design Contradiction:

Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The tubular centering bar structure with internal stiffening beam provides a universal solution that can accommodate various stack geometries and configurations, allowing the same basic structure to adapt to different compactness requirements without losing compatibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3103154B1Process for facilitated stacking of membrane-electrode assemblies

Publication Date: 2017.10.25 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

The invention relates to a method for manufacturing an electrochemical reactor, comprising the steps of: holding in position a first tube (31) and a shaft (32) extending in the same direction, the first tube comprising a bore in which a beam is housed; forming a stack which alternates bipolar plates (5) and membrane/electrode assemblies, each bipolar plate and each membrane/electrode assembly comprising first and second openings (51, 52) through which the first tube and the shaft respectively extend; compressing the stack between two mechanical components and removing the beam from the bore of the first tube; and connecting the bore of the first tube to a fluid flow circuit of the electrochemical reactor.