Fuel Cell Conductive Member Structure for Chromium Diffusion Control
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Solution Overview
Problem
Existing fuel cell stack devices face challenges in maintaining battery performance due to the diffusion of chromium (Cr) and the increase in electric resistance caused by zinc spinel portions, which affect the overall efficiency and durability of the conductive members.
Innovation Solution
The conductive member is designed with a specific configuration where the zinc spinel portion is strategically positioned to minimize its overlap area ratio at interfaces facing the element portion and oxidizing atmosphere, thereby reducing Cr diffusion and electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive member containing chromium is used to electrically connect fuel cells, then electrical conductivity is maintained, but chromium diffusion occurs causing battery performance degradation
Solution Approach 1:
A zinc spinel layer is introduced as an intermediary barrier between the chromium-containing conductive member and the electrolyte. This intermediate layer prevents direct contact and diffusion of chromium ions into the electrolyte, thereby protecting battery performance while maintaining electrical conductivity of the overall assembly
Solution Approach 2:
The conductive member is designed as a composite structure combining chromium-containing material with zinc spinel material. This composite approach leverages the high electrical conductivity of chromium-based materials while the zinc spinel component provides diffusion barrier properties, achieving both electrical performance and chemical stability
2Object-generated harmful factors
If zinc spinel portions are added to the conductive member, then chromium diffusion is reduced, but electric resistance increases
Solution Approach 1:
The zinc spinel material is not uniformly distributed throughout the conductive member but is strategically positioned at specific locations where chromium diffusion occurs. This localized placement provides diffusion barrier functionality only where needed, preserving the overall electrical conductivity of the conductive member
Solution Approach 2:
The concentration and distribution of zinc spinel portions are optimized to achieve the right balance between diffusion protection and electrical conductivity. By controlling the amount and positioning of zinc spinel material, the patent minimizes electric resistance while maintaining effective chromium diffusion prevention
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
This configuration enhances the performance of the conductive member, leading to reduced battery performance degradation and improved efficiency of the cell stack device.
Implementation Method 1
the diffusion of chromium (Cr) and the increase in electric resistance caused by zinc spinel portions
Data Source
AI summary
A cell stack device includes at least one cell and at least one conductive member. The cell includes an element portion. The conductive member includes a base member containing chromium, a first layer containing an oxide containing zinc, and a zinc spinel portion located at the interface between the base member and the first layer. The first layer includes a first region facing the element portion. A first overlap area ratio, at which the zinc spinel portion located at a first interface between the first region and the base member overlaps with the first interface, is less than a second overlap area ratio, at which the zinc spinel portion located at a second interface between a second region where the surface of the first layer is exposed to an oxidizing atmosphere and the base member overlaps with the second interface.