Microprotrusion Steel Sheet for Conductive Fuel Cell Separators
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Solution Overview
Problem
Conventional stainless steel separators for fuel cells suffer from high resistance due to passivated layers, leading to increased manufacturing costs and time, and alternative coatings like gold or carbon nitride result in low productivity.
Innovation Solution
A steel sheet with a joint structure featuring microprotrusions having inter-pitch intervals of 1 to 500 nm and an area fraction of 20% or more, including prismatic, rod-shaped, and needle-shaped microprotrusions, enhances hydrophilicity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional stainless steel is used as separator material, then manufacturing cost and weight are reduced, but resistance increases due to passivated layer
Solution Approach 1:
The patent applies parameter changes by controlling the crystal grain size (1-35 μm) and height difference (0.1-1000 nm) of the steel sheet surface, and by forming a joint structure with microprotrusions at specific area fractions (20% or more). These parameter adjustments modify the surface properties to reduce resistance loss while maintaining corrosion resistance through the inherent stainless steel composition.
2Loss of energy
If conductive coating materials such as gold or carbon are applied, then conductivity is improved, but manufacturing cost and time increase
Solution Approach 1:
The patent extracts the need for additional conductive coating processes by directly achieving the required conductivity through the steel sheet's inherent properties. By controlling the crystal grain structure and forming a joint structure with microprotrusions, the steel sheet itself provides sufficient conductivity without requiring external coating materials, thereby eliminating the additional manufacturing steps and improving productivity.
3Ease of manufacture
If conventional stainless steel with smooth surface is used, then manufacturing is simple, but hydrophilicity is poor
Solution Approach 1:
The patent applies parameter changes by controlling the crystal grain size (1-35 μm) and height difference (0.1-1000 nm) of the steel sheet surface, and by forming a joint structure with microprotrusions at specific area fractions (20% or more). These parameter adjustments modify the surface properties to reduce resistance loss while maintaining corrosion resistance through the inherent stainless steel composition.
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 steel sheet achieves excellent hydrophilicity and conductivity, suitable for fuel cell separators, with contact resistance as low as 3.5 mΩ·cm² and contact angle as low as 50°, improving performance and reducing manufacturing complexity.
Implementation Method 1
a steel sheet having excellent hydrophilicity and conductivity includes a joint structure on the steel sheet, wherein the joint structure includes microprotrusions having inter-pitch intervals of 1 to 500 nm in an area fraction of 20% or more
Implementation Method 2
a steel sheet having excellent hydrophilicity and conductivity includes a joint structure on the steel sheet, wherein the joint structure includes microprotrusions having inter-pitch intervals of 1 to 500 nm in an area fraction of 20% or more
Data Source
AI summary
Disclosed is a steel sheet having excellent hydrophilicity and conductivity. The steel sheet having excellent hydrophilicity and conductivity according to an embodiment may include a joint structure on the steel sheet, wherein the joint structure includes microprotrusions having inter-pitch intervals of 1 to 500 nm in an area fraction of 20% or more.