Porous Titanium Bipolar Plate With TiN Coating for Lightweight PEM Fuel Cells
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Solution Overview
Problem
Conventional bipolar plates in proton-exchange membrane fuel cells are heavy and costly due to their stainless steel composition, and their manufacturing process is complex, failing to meet the requirements for corrosion resistance, contact resistance, and flexural strength, especially for transportation applications.
Innovation Solution
A bipolar plate made of titanium or titanium alloys with a porous structure and a titanium nitride coating, manufactured using powder metallurgy techniques and gas nitriding, which reduces weight, enhances mechanical resistance, and meets the necessary performance criteria by improving corrosion and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stainless steel is used for bipolar plates, then mechanical strength and durability are improved, but weight increases and cost increases
Solution Approach 1:
The patent applies composite materials by combining titanium substrate with titanium nitride coating layers. The titanium base provides mechanical strength and lightweight properties, while the titanium nitride coating layers enhance corrosion resistance and electrical conductivity. This composite structure resolves the contradiction by achieving both high strength and low weight simultaneously.
Solution Approach 2:
The patent changes the material parameters from conventional stainless steel to titanium-based materials with specific porosity (30-70%) and coating thickness (1-10 μm). These parameter changes enable the bipolar plate to achieve optimal balance between mechanical strength, weight, and electrochemical performance.
2Stability of the object's composition
If stainless steel is used for bipolar plates, then structural integrity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the bipolar plate structure with integrated channels and flow fields before applying the protective coating. The titanium nitride layers are deposited on the pre-formed structure, simplifying the overall manufacturing process compared to post-assembly coating methods.
Solution Approach 2:
The patent merges multiple functions into a single integrated structure: the titanium base plate provides structural integrity, while the titanium nitride coating layers simultaneously provide corrosion protection and electrical conductivity. This merging reduces the number of separate components and assembly steps.
3Reliability
If conventional coatings are applied on stainless steel, then corrosion resistance is improved, but the initial advantage of metal over graphite is eliminated and cost increases
Solution Approach 1:
The patent changes the coating material from conventional coatings (PTFE, graphene, noble metals) to titanium nitride, which can be applied directly on titanium substrate. This parameter change maintains the metal's inherent advantages while achieving superior corrosion resistance through a compatible coating system.
Solution Approach 2:
The patent creates a composite material system where titanium and titanium nitride are chemically compatible. The titanium nitride coating forms a coherent interface with the titanium substrate, maintaining structural integrity while providing enhanced corrosion resistance without the need for intermediate layers or complex multi-layer systems.
4Productivity
If fine channels are designed for fluid distribution, then flow efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent introduces porous titanium materials with controlled porosity (30-70%) to replace or supplement fine channels. The porous structure provides efficient fluid distribution through capillary action and pressure gradients, achieving high flow efficiency without the manufacturing complexity of precision-machined fine channels.
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 titanium-based bipolar plate achieves a 40% weight reduction, improved flow efficiency, and meets the required corrosion and contact resistance standards, while simplifying the manufacturing process and reducing costs.
Implementation Method 1
The porous material and the bipolar plate are then subjected to a gas nitriding treatment in order to form a titanium nitride coating
Implementation Method 2
said plate comprises a porous material arranged in said cavities, wherein the pores of said porous material are interconnected
Data Source
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AI summary
The present invention relates to a bipolar plate of a proton-exchange membrane fuel cell made up of titanium, titanium alloys or any combination thereof comprising a porous titanium material, titanium alloys or any combination thereof and which is completely covered by a titanium nitride coating. In addition, the present invention relates to two methods of manufacturing said bipolar plate by means of metallurgical techniques, the use of space holders, sintering and gas nitriding. Therefore, the present invention is of interest to the industry dedicated to the manufacture of fuel cells.