Aligned Metal-Fiber Flow Plates for Low-Resistance Fuel Cells

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Solution Overview

Problem

Existing flow plates for fuel cells and electrolyzers face challenges in achieving optimal flexibility, minimizing contact and flow resistances, and enhancing porosity, while maintaining mechanical stability and reducing flow resistance.

Innovation Solution

A method for producing a flow plate with metal fibers, where the fibers are aligned and deposited onto a substrate using an alignment unit, forming a directed structure that creates flow channels, and are connected to the substrate to enhance mechanical stability and porosity, with the fibers' properties determined by the roller's rotation and oscillation, and the fibers' diameter adjusted through groove geometry and wetting properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If metal fibers are used to form flow channels, then porosity and flexibility are improved, but mechanical stability and contact resistance are worsened

Engineering Contradiction:
ImproveporosityVSAvoidmechanical stability
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent combines metal fibers with a polymer binder to create a composite material structure. The metal fibers provide porosity and electrical conductivity, while the polymer binder provides mechanical stability and structural integrity. This composite approach resolves the contradiction between achieving high porosity for gas diffusion and maintaining sufficient mechanical strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a porous structure formed by metal fibers that are sintered together. The sintering process creates a network of interconnected pores that allow gas flow while the sintered metal matrix provides structural support. This porous metal structure simultaneously achieves high porosity for mass transport and sufficient mechanical stability.

Inventive Principle:
Principle #31Porous materials

2Stability of the object's composition

If metal fibers are used for flow channels, then flexibility and porosity are improved, but contact resistance increases

Engineering Contradiction:
ImproveflexibilityVSAvoidcontact resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent controls the physical and chemical parameters of the metal fibers, including their diameter, length, orientation, and surface properties. By optimizing these parameters, the patent achieves a balance between flexibility (through appropriate fiber length and diameter) and low contact resistance (through controlled surface area and conductivity). The sintering temperature and pressure are also controlled to optimize electrical contact.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates regions with different fiber densities and orientations to optimize local properties. Areas requiring high flexibility have looser fiber arrangements, while areas requiring low contact resistance have denser, better-connected metal fiber networks. This spatial variation in structure allows simultaneous optimization of flexibility and electrical conductivity in different regions.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If metal fibers are aligned to reduce flow resistance, then fluid flow is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveflow resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies an aligning force during the fiber deposition or sintering process to pre-orient the metal fibers along the desired flow paths. This preliminary alignment action ensures that the fibers are positioned optimally for gas flow before the final structure is set, reducing the need for complex post-processing steps and simplifying manufacturing while achieving low flow resistance.

Inventive Principle:
Principle #10Preliminary action

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 improves flexibility, reduces contact and flow resistances, and increases porosity, resulting in a flow plate with improved mechanical stability and reduced flow resistance, suitable for use as a bipolar plate or gas diffusion system.

Implementation Method 1

it is proposed that in at least one method step the metal fibers are aligned using at least one alignment unit

Methodology Applied
Scientific EffectAlignment:

Implementation Method 2

the metal fibers are deposited onto at least one substrate... the properties of the metal fibers are determined by the roller's rotation and oscillation

Methodology Applied
Scientific EffectDeposition: Deposition (physical)

Implementation Method 3

the fibers are connected to the substrate to enhance mechanical stability and porosity

Methodology Applied
Scientific EffectConnection:

Data Source

PatentEP3563443B1Method for producing a flow plate for a fuel cell and/or an electrolyzer
Publication Date: 2023.09.06 ROBERT BOSCH GMBH
  • EP3563443B1 patent drawingFigure 1
  • EP3563443B1 patent drawingFigure 2
  • EP3563443B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a flow plate (10a; 10b) for a fuel cell, in particular a PEM fuel cell, and/or an electrolyzer, wherein the flow plate (10a; 10b) is provided with at least one flow element (12a; 12b), which is at least partially made of metal fibers (14a; 14b). According to the invention, in at least one method step, the metal fibers (14a; 14b) are aligned by means of at least one alignment unit (30a; 30b).