Fuel-Cell Unit Cell Bonding Structure for Thermal Stress Stability

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Solution Overview

Problem

Fuel-cell unit cells with existing structures face mechanical durability issues due to stress and thermal expansion differences between components, leading to potential fractures and misalignment during manufacturing and usage.

Innovation Solution

A fuel-cell unit cell design featuring a bonding layer that fixes the support frame, membrane-electrode assembly, and gas diffusion layers together, ensuring stability and alignment, even under stress and temperature changes, thereby enhancing mechanical durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a support frame and membrane-electrode assembly are bonded together by a bonding layer, then the structural integrity is improved, but stress concentration and fracture risk increase due to thermal expansion differences and manufacturing stresses

Engineering Contradiction:
Improvestructural integrityVSAvoidfracture resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The bonding layer is divided into multiple discrete bonding regions rather than a continuous layer. These segmented bonding regions are positioned at specific locations where stress concentration is minimized, allowing the structure to maintain integrity while reducing fracture risk in high-stress areas

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bonding layer has non-uniform distribution with different bonding strengths at different locations. The bonding density and strength are optimized locally based on the stress distribution pattern, providing strong bonding where needed while maintaining flexibility and stress relief in critical areas

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the support frame and gas diffusion layer are made of different materials with different coefficients of thermal expansion, then the structural stability is improved, but relative position changes and stress application occur during temperature changes

Engineering Contradiction:
Improvestructural stabilityVSAvoidthermal stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The bonding layer's physical and chemical parameters are specifically selected to match or bridge the thermal expansion properties of the support frame and gas diffusion layer. This parameter optimization reduces thermal stress by creating a gradient transition that accommodates differential expansion while maintaining structural stability

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the membrane-electrode assembly is exposed due to a gap between support frame and gas diffusion layer, then assembly accessibility is improved, but deformation and fracture risk increase due to gas pressure differences

Engineering Contradiction:
Improveassembly accessibilityVSAvoidresistance to gas pressure
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The bonding layer acts as an intermediary element that fills and seals the gap between the support frame and gas diffusion layer. This intermediary structure provides mechanical support to the membrane-electrode assembly, preventing deformation from gas pressure differences while maintaining controlled accessibility for assembly operations

Inventive Principle:
Principle #24Intermediary (Mediator)

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 bonding layer configuration significantly reduces the likelihood of fractures and misalignment, enhancing the mechanical durability and reliability of the fuel-cell unit cell during manufacturing, stacking, and operation.

Implementation Method 1

a bonding layer; between a first separator and an outer peripheral edge portion of a first gas diffusion layer, the bonding layer bonds the first separator and the outer peripheral edge portion together; between the first separator and an outer peripheral edge portion of a membrane-electrode assembly, the bonding layer is bonded to the outer peripheral edge portion of the membrane-electrode assembly; and between the first separator and a support frame and/or between a second separator and the support frame, the bonding layer bonds these parts together

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3799175B1Fuel-cell unit cell
Publication Date: 2023.08.30 TOYOTA JIDOSHA KK
  • EP3799175B1 patent drawingFigure 1
  • EP3799175B1 patent drawingFigure 2A
  • EP3799175B1 patent drawingFigure 2B

AI summary

Disclosed herein is a fuel-cell unit cell, at a first part of which: the fuel-cell unit cell has a bonding layer (60); between a first separator (30) and an outer peripheral edge portion (22a) of a first gas diffusion layer (22), the bonding layer (60) bonds the first separator (30) and the outer peripheral edge portion (22a) together; between the first separator (30) and an outer peripheral edge portion (21a) of a membrane-electrode assembly (21), the bonding layer (60) is bonded to the outer peripheral edge portion (21a) of the membrane-electrode assembly (21); and between the first separator (30) and a support frame (50) and/or between a second separator (40) and the support frame (50), the bonding layer (60) bonds the support frame (50) and the separator (30, 40) together.