Fuel Cell Separator Mold Grooves Reduce Friction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The peeling off of carbon-based coatings during press working of fuel cell separators leads to increased friction and reduced working accuracy, causing channel deformation and sealability issues in fuel cell stacks.
Innovation Solution
A method involving a mold with grooves that accommodate and discharge peeled particles, reducing friction and ensuring accurate shaping of fuel cell separators by using machining oil or air to facilitate particle removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon-based coating is formed on the titanium substrate to provide conductivity and corrosion resistance, then the electrical conductivity and corrosion resistance are improved, but the coating peels off during press working which increases friction and reduces working accuracy
Solution Approach 1:
An intermediate layer comprising at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Si, and B is introduced between the titanium oxide layer and the carbon-based coating layer. This intermediate layer acts as a mediator that prevents direct peeling of the carbon coating during press working while maintaining electrical conductivity and corrosion resistance properties.
Solution Approach 2:
The separator substrate is constructed as a composite structure with multiple layers: a titanium substrate, an oxide coating layer (TiO2), an intermediate layer with specific elements, and a carbon-based coating layer. This composite structure combines the advantages of each layer while mitigating their individual weaknesses, particularly the peeling issue of the carbon coating.
2Reliability
If the carbon layer is made thicker to improve conductivity, then the electrical conductivity is improved, but the coating peels off more easily during pressing increasing friction
Solution Approach 1:
The intermediate layer serves as a mediator that allows the carbon-based coating to be applied thicker for improved conductivity while preventing the coating from peeling off during press working, thus avoiding the increase in friction that would otherwise occur with thicker coatings.
3Manufacturing precision
If press working force is increased to improve shaping accuracy, then the manufacturing precision is improved, but the coating peels off more severely causing particle accumulation on mold surface
Solution Approach 1:
The intermediate layer acts as a mediator that prevents the carbon-based coating from peeling off even when high press working force is applied to achieve accurate shaping, thereby preventing particle accumulation on the mold surface.
Solution Approach 2:
The intermediate layer is formed in advance between the oxide coating layer and the carbon-based coating layer before press working. This preliminary action of creating the intermediate layer prevents coating peeling during the subsequent high-force press working process.
4Ease of manufacture
If conventional noble metal plating is replaced with carbon-based coating to reduce cost, then the manufacturing cost is reduced, but the coating adhesion to substrate is worsened
Solution Approach 1:
The intermediate layer comprising elements from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Si, or B serves as a mediator that improves the adhesion between the carbon-based coating layer and the titanium oxide layer, solving the coating adhesion problem while maintaining the cost advantage of using carbon-based coating instead of noble metals.
Solution Approach 2:
The multi-layer composite structure with the intermediate layer provides strong bonding between the carbon-based coating and the titanium substrate, achieving adhesion strength comparable to or better than conventional noble metal plating while maintaining lower manufacturing costs.
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 method effectively reduces the coefficient of friction and maintains working accuracy, preventing channel deformation and improving sealability by ensuring particles are discharged from the mold, allowing for precise molding of fuel cell separators.
Implementation Method 1
supplying the separator material and/or a mold with a machining oil and/or air
Implementation Method 2
supplying the separator material and/or a mold with a machining oil and/or air
Data Source
AI summary
A method for producing a fuel cell separator capable of ensuring the working accuracy for a separator material. A surface of a mold is provided with grooves, each groove having a depth and width each equivalent to or larger than the thickness of a coating layer and equivalent to or smaller than the thickness of the separator material, the mold including an upper die having a projection/recess pressing surface on which projecting and recessed surfaces extending in a predetermined direction are alternately provided, and a lower die having a projection/recess pressing surface in a shape complementary to that of the pressing surface of the upper die.