Fuel Cell End Member Stress Relief via Segmentation

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Solution Overview

Problem

Fuel cell and electrolysis cell stack devices experience cracking in sealing materials due to thermal expansion, leading to gas leaks and reduced long-term reliability.

Innovation Solution

The electrically conductive end members are separated from the manifolds to reduce stress on the sealing material, using a holding member with elastic properties to absorb stress and prevent peeling, and a fixing member to relax stress between cells and the sealing material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrically conductive end member is fixed to the manifold using sealing material, then electrical connection and structural stability are improved, but thermal expansion stress causes cracking in the sealing material leading to gas leaks

Engineering Contradiction:
Improvesealing integrityVSAvoidsealing material durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The electrically conductive end member is divided into two separate components: a first electrically conductive end member fixed to the first manifold, and a second electrically conductive end member fixed to the second manifold. These segments are connected via a flexible cable rather than a single rigid structure, allowing each segment to independently accommodate thermal expansion without transmitting stress to the sealing material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the physical state and flexibility parameters of the connection between end members by introducing a flexible cable with bending characteristics. This cable can deform and absorb thermal expansion stresses, changing the rigid connection into a flexible one that adapts to temperature variations without causing sealing material cracking.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If rigid fixation is used to ensure stable electrical connection, then connection reliability is improved, but thermal expansion causes stress concentration and peeling at the sealing interface

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidthermal expansion stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent transitions from a static rigid connection to a dynamic flexible connection. The cable connecting the two electrically conductive end members is designed to be flexible and capable of bending, allowing it to dynamically absorb and accommodate thermal expansion stresses that occur during operation, thereby preventing stress concentration and peeling at the sealing interfaces.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If the end member structure is simplified for ease of manufacture, then production cost is reduced, but stress distribution becomes uneven causing cracking in the sealing material

Engineering Contradiction:
Improveassembly simplicityVSAvoidlong-term operational reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a flexible cable as an intermediary element between the two electrically conductive end members. This cable acts as a stress-absorbing mediator that distributes thermal expansion forces evenly, preventing localized stress concentration that would lead to cracking. The intermediary cable simplifies the overall structure while maintaining reliability by eliminating the need for complex stress-distribution mechanisms.

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

This configuration effectively suppresses cracking in the sealing material, enhancing the long-term reliability of the cell stack devices by reducing stress and preventing gas leaks.

Implementation Method 1

a holding member with elastic properties to absorb stress and prevent peeling

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a fixing member to relax stress between cells and the sealing material

Methodology Applied
Scientific EffectStress relaxation: Stress Relaxation

Data Source

PatentEP3076467B1Cell stack device, module, and module housing device
Publication Date: 2019.09.11 KYOCERA CORP
  • EP3076467B1 patent drawingFigure 1~2
  • EP3076467B1 patent drawingFigure 3A~4
  • EP3076467B1 patent drawingFigure 5A~6

AI summary

Object: To provide a cell stack device having improved long-term reliability, a module, and a module housing device. Resolution means: A cell stack device provided with a cell stack (5) comprising a plurality of cells (3) that are arranged, a manifold (4) fixing an end of each of the cells (3) thereto with a sealing material (39), and configured to allow a reaction gas to be supplied to the cells (3), and an electrically conductive end member (29) disposed at an end portion of the cell stack (5) in the arrangement direction of the cells (3) and suppressing deformation of the cells (3). A first end of the electrically conductive end member (29) at a side of the manifold (4) is separated from the manifold (4).