Multi-Layer Coated Collector for Fuel Cell Cr Diffusion
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Solution Overview
Problem
Existing fuel cell devices face issues with chromium (Cr) diffusion from Cr-containing alloy collector members, leading to decreased performance and heat resistance, and high electrical resistance, which are not adequately addressed by previous composite oxide layer configurations.
Innovation Solution
A composite body with a chromium oxide layer, a Zn-Al-Cr spinel type crystal layer, a Zn-Mn spinel type crystal layer, and a zinc oxide layer are sequentially stacked on a Cr-containing substrate to reduce Cr diffusion and improve conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a Cr-containing alloy is used as a collector member, then workability and heat resistance are improved, but Cr diffusion occurs at high temperatures causing decreased fuel cell performance and reduced heat resistance
Solution Approach 1:
A multi-layer coating structure is introduced as an intermediary barrier between the Cr-containing alloy substrate and the external environment. The coating includes a first layer with Cr oxide and Zn-Al-Cr spinel, a second layer with Zn-Mn spinel, and a third layer with ZnO, which collectively prevent Cr diffusion while allowing the substrate to maintain its heat resistance properties
Solution Approach 2:
The solution employs a composite material structure consisting of multiple layers with different compositions and functions. The first layer contains Cr oxide and Zn-Al-Cr spinel for Cr diffusion prevention, the second layer contains Zn-Mn spinel for additional protection and conductivity, and the third layer contains ZnO for surface protection, creating a composite system that addresses both heat resistance and Cr diffusion issues
2Object-generated harmful factors
If a second composite oxide layer with Zn-Cr-Mn spinel structure is formed between substrate and first composite oxide layer, then Cr diffusion is reduced, but electrical resistance increases
Solution Approach 1:
Different regions of the coating structure are assigned different compositions and properties to fulfill specific local functions. The first layer near the substrate contains Cr oxide and Zn-Al-Cr spinel for Cr diffusion prevention, while the second layer contains Zn-Mn spinel with lower Cr content for maintaining electrical conductivity, and the third layer contains ZnO for surface protection, creating a gradient structure that balances diffusion prevention and conductivity
Solution Approach 2:
The composition parameters of each layer are optimized to achieve the desired balance. The first layer has higher Cr content for diffusion prevention, the second layer has reduced Cr content with Zn-Mn spinel for conductivity, and the third layer has ZnO for surface protection. This parameter optimization across layers resolves the contradiction between Cr diffusion prevention and electrical resistance
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 solution effectively reduces Cr diffusion and enhances the electrical conductivity of the collector member, resulting in improved power generation performance for fuel cell stacks and devices.
Implementation Method 1
a chromium oxide layer, a Zn-Al-Cr spinel type crystal layer, a Zn-Mn spinel type crystal layer, and a zinc oxide layer are sequentially stacked on a Cr-containing substrate to reduce Cr diffusion
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
[Object] To provide a composite body in which the Cr diffusion can be sufficiently reduced and conductivity is good, a collector member, a fuel battery cell device, and a fuel battery device. [Solution] The composite body includes a substrate 200 containing Cr, and a coating layer 205 covering at least a part of the substrate 200, in which the coating layer 205 includes a first layer 201 containing Cr among constituent elements excluding oxygen, and including a chromium oxide crystal, a second layer 202 disposed on the first layer 201, containing Zn, Al, and Cr among the constituent elements excluding oxygen, and including a spinel type crystal, a third layer 203 disposed on the second layer 202, containing Zn and Mn among the constituent elements excluding oxygen, and including a spinel type crystal, and a fourth layer 204 disposed on the third layer 203, containing Zn among the constituent elements excluding oxygen, and including a zinc oxide crystal.