Fuel Cell Cathode Electrode Extension for Solid Electrolyte Protection

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Solution Overview

Problem

The current collection assisting layer in solid oxide fuel cells can cause breakage of the solid electrolyte layer due to thermal expansion, leading to gas leakage and short circuits, which reduces power generation efficiency.

Innovation Solution

Extending the end of the cathode electrode outward beyond the current collection assisting layer in the planar direction to function as a cushion and prevent damage to the solid electrolyte layer, while maintaining a conductive path for charge migration through the current collection assisting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a current collection assisting layer is provided between the cathode electrode and the separator to reduce electric resistance, then power generation efficiency is improved, but the solid electrolyte layer may be damaged by protrusions on the current collection assisting layer

Engineering Contradiction:
Improvepower generation efficiencyVSAvoidsolid electrolyte layer integrity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces a protective layer as an intermediary component between the current collection assisting layer and the solid electrolyte layer. This protective layer acts as a buffer that prevents direct contact between the protrusions (burrs) on the current collection assisting layer and the solid electrolyte layer, thereby eliminating the damaging effect while preserving the electrical conductivity function of the current collection assisting layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the separator presses the current collection assisting layer during thermal expansion, then gas channel formation is maintained, but protrusions on the current collection assisting layer damage the solid electrolyte layer

Engineering Contradiction:
Improvegas channel structureVSAvoidmechanical damage to solid electrolyte
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by providing a protective layer in advance between the current collection assisting layer and the solid electrolyte layer. This protective layer is designed to absorb and distribute the mechanical pressure during thermal expansion, preventing the concentration of stress at protrusion points that would otherwise cause damage to the solid electrolyte layer.

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

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

Prevents breakage of the solid electrolyte layer, ensuring stable operation and maintaining power generation efficiency by absorbing thermal expansion stress and reducing electric resistance.

Implementation Method 1

thermal expansion during operation or the like may sometimes cause the separator to press the current collection assisting layer

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the cathode electrode between the current collection assisting layer and the solid electrolyte layer as a cushion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a current collection assisting layer is provided between the cathode electrode and the separator to form a conductive path so as to reduce the electric resistance

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3442064B1Unit cell of fuel cell
Publication Date: 2020.10.14 NISSAN MOTOR CO LTD
  • EP3442064B1 patent drawingFigure 1
  • EP3442064B1 patent drawingFigure 2
  • EP3442064B1 patent drawingFigure 3

AI summary

The fuel cell single cell of the present invention includes: a fuel cell unit in which an anode electrode, an electrolyte layer and a cathode electrode are sequentially laminated; a separator; and a current collection assisting layer disposed between the cathode electrode of the fuel cell unit and the separator. The separator has protruded portions that are in contact with the current collection assisting layer to form gas channels between the separator and the current collection assisting layer. Further, at least a part of an end of the cathode electrode in a planar direction of the cathode electrode extends outward beyond an end of the current collection assisting layer in a planar direction of the current collection assisting layer.