Fuel Cell Separator with Carbon and Titanium Nitride Layers
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Solution Overview
Problem
Existing fuel cell separators face challenges in achieving both low contact resistance and durability, as increasing carbon content reduces membrane strength, while increasing resin content increases contact resistance, making it difficult to maintain low resistance over time.
Innovation Solution
A fuel cell design featuring a metal base material with a carbon layer on one surface and a titanium nitride layer on the adjacent surface, along with an optional titanium layer for improved adhesion and corrosion resistance, which reduces contact resistance and maintains durability by suppressing oxidation and oxide membrane formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the content of carbon material is increased to reduce contact resistance, then the contact resistance decreases, but the resin content is reduced and the membrane strength and durability are reduced
Solution Approach 1:
The separator employs a composite structure consisting of a metal base material (stainless steel) combined with functional surface layers (carbon layer and titanium nitride layer). This composite approach allows the bulk metal structure to provide mechanical strength while the surface layers provide electrical conductivity and corrosion resistance, resolving the contradiction between contact resistance and membrane strength.
Solution Approach 2:
Different regions of the separator are assigned different functions: the metal base material provides structural strength and durability, the carbon layer on the power generating unit side provides electrical conductivity for current collection, and the titanium nitride layer on the adjacent separator side provides corrosion resistance. This local differentiation allows each region to optimize its properties without compromising overall performance.
2Strength
If the content of resin is increased to increase membrane strength, then the membrane strength increases, but the content of carbon material is reduced and the contact resistance is increased
Solution Approach 1:
The separator uses a composite structure where the metal base material provides mechanical strength without requiring high resin content. The functional surface layers (carbon and titanium nitride) are applied to the metal surface to provide the necessary electrical conductivity and corrosion resistance, eliminating the need to increase resin content at the expense of conductivity.
Solution Approach 2:
The separator structure differentiates between the bulk metal material (providing strength) and the surface functional layers (providing conductivity and corrosion resistance). This local quality assignment allows the bulk material to be optimized for strength while the surface layers are optimized for electrical and chemical performance.
3Object-affected harmful factors
If a carbon layer is formed on the power generating unit side to reduce contact resistance, then the contact resistance decreases, but the titanium nitride layer is needed on the adjacent separator side to suppress oxidation and maintain durability
Solution Approach 1:
The separator applies different functional layers to different surfaces: a carbon layer on the power generating unit side for electrical conductivity and current collection, and a titanium nitride layer on the adjacent separator side for corrosion resistance and oxidation prevention. This asymmetric surface treatment optimizes each surface for its specific functional requirements.
Solution Approach 2:
The titanium nitride layer acts as a protective intermediary between the metal base material and the corrosive environment (acidic product water with chloride and fluoride ions). This intermediate layer prevents direct contact between the corrosive environment and the metal, thereby maintaining durability while allowing the carbon layer to handle electrical conductivity requirements.
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 solution provides a fuel cell with excellent contact resistance and durability, reducing internal resistance over time and enhancing corrosion resistance, while maintaining high membrane strength and conductivity.
Implementation Method 1
a carbon layer made of carbon and formed on a first surface of the metal base material on a power generating unit side
Implementation Method 2
By forming the titanium nitride layer on the surface of the separator, the oxidation of the surface of the separator can be suppressed, the formation of an oxide membrane can be suppressed
Data Source
AI summary
The present embodiment is a fuel cell including a stacked body of single cells each of which includes a power generating unit and separators disposed on both surfaces of the power generating unit, in which the separators each include a metal base material, a carbon layer made of carbon and formed on a first surface of the metal base material on a power generating unit side, and a titanium nitride layer made of titanium nitride and formed on a second surface of the metal base material opposite to the first surface.