Fuel Cell Stress Suppression via Elastic Membrane

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Solution Overview

Problem

In fuel cells with electrodes of different dimensions, stress concentration occurs at the periphery of the smaller electrode, potentially damaging the electrolyte membrane and reducing durability.

Innovation Solution

A stress suppressing structure is implemented, including an elastic member with a lower transverse elasticity modulus than the electrolyte membrane, pressure-welded to the first electrode's side, and varying joint strengths or using magnetic materials to relieve pressure on the electrolyte membrane, allowing it to move and deform without concentrating stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the two electrodes have different dimensions with the smaller electrode's periphery located on the inner side, then the fuel cell structure is optimized for performance, but stress concentration occurs in the electrolyte membrane at the periphery of the smaller electrode

Engineering Contradiction:
Improvefuel cell performanceVSAvoidelectrolyte membrane durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A plate-like member is introduced as an intermediary component between the second electrode and the electrolyte membrane. This member presses the second electrode against the electrolyte membrane, creating a controlled deformation that prevents stress concentration at the periphery of the smaller first electrode, thus protecting the electrolyte membrane while maintaining the performance-optimized electrode configuration

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrolyte membrane is allowed to deform in a controlled manner by pressing the second electrode against it. This changes the physical state and positioning parameters of the electrolyte membrane, creating a configuration where the membrane is pressed toward the first electrode, thereby redistributing stress and preventing concentration at critical peripheral locations

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the electrolyte membrane is pressed to prevent stress concentration, then durability is improved, but the membrane may become deformed or damaged

Engineering Contradiction:
Improveelectrolyte membrane durabilityVSAvoidelectrolyte membrane integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The plate-like member is designed to apply controlled pressure beforehand to press the second electrode against the electrolyte membrane. This pre-compression creates a cushioning effect that distributes stress evenly across the membrane surface, preventing both stress concentration and excessive deformation that could lead to damage

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The electrolyte membrane is utilized as a flexible thin film that can be deformed by the pressing action of the second electrode through the plate-like member. This flexibility allows the membrane to adapt to the pressing force without breaking, while the controlled deformation prevents stress concentration at peripheral locations

Inventive Principle:
Principle #30Flexible shells and thin films

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 enhances the durability of the fuel cell by preventing stress concentration on the electrolyte membrane, ensuring its integrity and longevity.

Implementation Method 1

an elastic member having a smaller transverse elasticity modulus than the electrolyte membrane is pressure welded to a first electrode-side of the electrolyte membrane

Methodology Applied
Scientific EffectPressure welding: Welding

Implementation Method 2

a magnetic material producing a repulsive force against the first peripheral section is placed on an opposite side of the second electrode

Methodology Applied
Scientific EffectMagnetic repulsion: Ion Repulsion/Attraction

Implementation Method 3

a magnetic material producing an attractive force to the first peripheral section is placed on an opposite side of the first electrode

Methodology Applied
Scientific EffectMagnetic attraction: Ion Repulsion/Attraction

Data Source

PatentEP2790255B1Fuel cell
Publication Date: 2017.08.16 TOYOTA JIDOSHA KK
  • EP2790255B1 patent drawingFigure 1~2(B)
  • EP2790255B1 patent drawingFigure 3~5
  • EP2790255B1 patent drawingFigure 6~7

AI summary

A fuel cell includes an electrolyte membrane, a first electrode, a second electrode and a stress suppressing structure. The first electrode is joined to one surface of the electrolyte membrane. The second electrode is joined to an other surface of the electrolyte membrane. The first peripheral section which is at least part of periphery of the first electrode is located on an inner side along a planar direction of the first electrode than respective peripheries of the electrolyte membrane and the second electrode. The stress suppressing structure is configured to suppress concentration of stress on a location along the first peripheral section in the electrolyte membrane.