Fuel Cell Separator Titanium Coating Corrosion Resistance
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Solution Overview
Problem
Current fuel cell separators face challenges in achieving a balance between high conductive properties and corrosion resistance, particularly in high-temperature and acidic environments, leading to increased costs due to the use of pure titanium or titanium alloys.
Innovation Solution
A fuel cell separator is developed using a low-price metal substrate, such as stainless steel, with a titanium layer formed on its surface, where the orientation ratio of specific titanium plane intensities from X-ray diffraction analysis is optimized to enhance corrosion resistance, and a conductive layer is applied using a sputtering method with controlled UBM coil current and bias voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure titanium or titanium alloy is used for the separator substrate, then corrosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies composite material structure by combining stainless steel substrate with titanium coating layer. The stainless steel base provides mechanical strength and cost-effectiveness, while the titanium layer deposited on the surface provides corrosion resistance. This composite approach resolves the contradiction by achieving the corrosion protection of titanium alloys without the high material cost of pure titanium or titanium alloy substrates.
Solution Approach 2:
The patent applies local quality principle by providing titanium coating only on the surface regions requiring corrosion resistance rather than using titanium throughout the entire substrate. The titanium layer is selectively deposited on the stainless steel substrate at specific locations where corrosion protection is needed, reducing overall titanium usage and cost while maintaining necessary corrosion resistance performance.
2Reliability
If a titanium layer and conductive layer are formed on a metal substrate, then corrosion resistance and conductive property are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated manufacturing process. The titanium layer formation and conductive layer deposition are combined in a sequential coating process on the stainless steel substrate, where both layers are applied in one manufacturing run. This integration reduces the number of separate processing steps and simplifies manufacturing compared to treating them as separate operations.
Solution Approach 2:
The patent controls manufacturing parameters such as coating thickness, deposition conditions, and material composition to optimize both corrosion resistance and electrical conductivity. By adjusting these parameters within specific ranges, the process achieves dual functionality without requiring complex multi-step procedures, thereby managing manufacturing complexity while meeting performance requirements.
3Ease of manufacture
If low-price metal substrate is used instead of pure titanium, then manufacturing cost is reduced, but corrosion resistance deteriorates
Solution Approach 1:
The patent uses composite material structure combining stainless steel substrate with titanium coating layer. The stainless steel base provides mechanical strength and cost-effectiveness, while the titanium layer deposited on the surface provides corrosion resistance. This composite approach resolves the contradiction by achieving the corrosion protection of titanium alloys without the high material cost of pure titanium or titanium alloy substrates.
Solution Approach 2:
The titanium coating layer acts as an intermediary between the stainless steel substrate and the corrosive environment. This intermediate layer protects the low-cost stainless steel substrate from direct exposure to corrosive conditions, thereby enabling the use of economical metal substrates while maintaining high corrosion resistance through the protective titanium barrier.
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 approach results in a cost-effective fuel cell separator with improved corrosion resistance and conductive properties, as demonstrated by reduced metal dissolution in acidic conditions, while maintaining the required physical durability and conductive performance.
Implementation Method 1
a conductive layer (surface layer) for ensuring the conductive property is formed on a surface of the middle layer
Implementation Method 2
by dividing respective peak intensities of a (100) plane, a (002) plane, and a (101) plane, which are derived from titanium, obtained by an X-ray diffraction analysis (XRD) of a separator surface
Data Source
AI summary
Provided are a low-price fuel cell separator with high corrosion resistance and a method for manufacturing the separator. The present disclosure relates to a fuel cell separator including a metal substrate and a titanium layer containing titanium formed on the metal substrate, and a method for manufacturing the separator. A ratio of a (100) plane to a sum of values obtained by dividing peak intensities of the (100) plane, a (002) plane, and a (101) plane derived from titanium in an X-ray diffraction analysis of a separator surface by respective relative intensities is a constant value or more.