Fuel Cell Separator Coating for Contact Resistance
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Solution Overview
Problem
Conventional fuel cell stacks experience an increase in internal resistance over time, limiting output performance due to contact resistance issues in separators, which are not effectively addressed by existing technologies.
Innovation Solution
A fuel cell stack design featuring titanium nitride layers on both surfaces of separators, with a conductive carbon layer only on the surface facing the power generating body to reduce contact resistance and internal resistance, while maintaining low contact resistance between adjacent separators by using titanium nitride layers alone on the second surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanium nitride layer is formed on the separator surface to restrain oxidation, then the contact resistance increases less over time, but the initial contact resistance remains high
Solution Approach 1:
The separator surface is coated with a composite structure consisting of a titanium nitride layer and a conductive carbon layer. The titanium nitride layer provides oxidation resistance and long-term stability, while the conductive carbon layer provides high electrical conductivity to reduce initial contact resistance. This composite coating resolves the contradiction between contact resistance stability and output performance.
Solution Approach 2:
The invention changes the surface properties of the separator by forming a dual-layer coating with specific characteristics. The titanium nitride layer changes the chemical stability parameter, while the conductive carbon layer changes the electrical conductivity parameter. This parameter transformation allows the separator to simultaneously achieve low initial contact resistance and stable long-term performance.
2Power
If the internal resistance of the fuel cell stack is reduced to improve output performance, then the output increases, but the contact resistance between components may increase
Solution Approach 1:
The dual-layer coating on the separator (titanium nitride + conductive carbon) creates a composite material that simultaneously provides low contact resistance and high oxidation resistance. This allows the fuel cell stack to achieve reduced internal resistance and improved output performance while maintaining stable contact resistance between components.
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 design effectively reduces internal resistance and maintains output performance by limiting the increase in contact resistance over time, thereby enhancing the fuel cell stack's efficiency and stability.
Implementation Method 1
the titanium nitride layer restrains oxidation of the surface of the separator, thereby limiting generation of an oxide layer
Implementation Method 2
a conductive carbon layer is formed on the titanium nitride layer... the separator contacts the power generating body via the titanium nitride layer and the carbon layer
Data Source
Figure 1
AI summary
A fuel cell stack (100) includes a plurality of cells (10) that are stacked in a stacking direction. Each cell (10) includes a power generating body (1) and a pair of separators (2). The separators (2) respectively are arranged on opposite surfaces of the power generating body (1) in the stacking direction. Each separator (2) includes a first surface (2a) and a second surface (2b). A titanium nitride layer (3) is formed on the first surface (2a), and a conductive carbon layer (4) is formed on the titanium nitride layer (3). A titanium nitride layer (3) is formed on the second surface (2b). Each separator (2) is in contact with the power generating body (1) via the titanium nitride layer (3) and the carbon layer (4) on the first surface (2a) and is in contact with one of the separators (2) of an adjacent cell (10) via the titanium nitride layer (3) on the second surface (2b).