Fuel Cell Separator Coating for Stable Low Contact Resistance
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Solution Overview
Problem
Existing fuel cell separators face challenges in maintaining conductivity over an extended period due to increased contact resistance under harsh fuel cell operating conditions, particularly in commercial vehicles requiring longer service life.
Innovation Solution
A fuel cell separator design featuring a metal substrate with a titanium layer and a carbon layer, where the boundary region between the titanium and carbon layers has a TiC content of 70% or less, along with specific Raman spectrum and orientation ratios, to enhance conductivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanium layer and carbon layer are formed on a metal substrate to ensure conductivity, then initial conductivity is improved, but contact resistance increases over time under fuel cell operating conditions
Solution Approach 1:
The invention changes the chemical composition parameter of the boundary region between the titanium layer and carbon layer by controlling the TiC content to be 70% or less. This parameter change prevents the formation of excessive titanium carbide, which would otherwise increase contact resistance over time, thereby maintaining reliable conductivity throughout the service life.
Solution Approach 2:
The invention uses a composite structure consisting of a metal substrate, titanium layer, and carbon layer with a specifically controlled boundary region. This composite material design combines the corrosion resistance of titanium with the conductivity of carbon while controlling the interface composition to prevent degradation, achieving both improved reliability and extended service life.
2Strength
If the TiC content in the boundary region is increased to improve interface bonding, then adhesion between layers is improved, but conductivity deteriorates due to increased contact resistance
Solution Approach 1:
The invention optimizes the TiC content parameter in the boundary region to be 70% or less, finding the optimal balance point where sufficient adhesion is maintained while preventing excessive contact resistance. This parameter optimization ensures both strong layer bonding and reliable electrical conductivity.
Data Source
AI summary
The fuel cell separator includes a metal base material, a titanium layer provided on the metal base material, and a carbon layer provided on the titanium layer, in which a ratio of TiC components of a boundary area between the titanium layer and the carbon layer is 70% or less.