Fuel Cell Collector Structure for Gas Diffusion and Low Contact Resistance
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Solution Overview
Problem
Existing cell units face challenges in achieving both good gas diffusibility and electron conductivity due to increased contact resistance between the separator and auxiliary collector layer, which can be exacerbated by attempts to optimize either gas flow or electron conductivity, leading to insufficient performance in fuel cell stacks.
Innovation Solution
A cell unit design featuring a metal support cell assembly, an auxiliary collector layer with curved portions overlapping gas flow passages defined by a separator with convex/concave shapes, and a connecting portion that regulates relative displacement between the auxiliary collector layer and separator, ensuring balanced surface pressure and improved electron conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary collector layer is embedded in the electrode to reduce contact resistance, then electron conductivity is improved, but gas diffusibility deteriorates
Solution Approach 1:
The auxiliary collector layer is divided into multiple independent protruding portions that contact the separator at discrete points, rather than forming a continuous embedded layer. This segmentation allows gas to diffuse through the spaces between protrusions while maintaining electrical contact points with the separator.
Solution Approach 2:
The auxiliary collector layer transitions from a two-dimensional embedded plane within the electrode to a three-dimensional structure with protrusions extending toward the separator. This dimensional change enables simultaneous achievement of electrical contact (at protrusion tips) and gas diffusion (through the volume between protrusions).
2Reliability
If the contact surface between separator and auxiliary collector layer is increased to reduce contact resistance, then electron conductivity is improved, but gas flow passage area decreases
Solution Approach 1:
The auxiliary collector layer exhibits spatially varying properties: protruding portions with high electron conductivity contact the separator to reduce contact resistance, while the regions between protrusions maintain gas permeability for diffusion. This local differentiation resolves the contradiction between contact area and flow area.
Solution Approach 2:
The auxiliary collector layer utilizes a porous or mesh-like structure that allows gas to pass through while maintaining electrical conductivity. The porous architecture provides both contact points for electron transfer and pathways for gas diffusion simultaneously.
3Reliability
If the auxiliary collector layer is positioned closer to the separator to reduce contact resistance, then electron conductivity is improved, but gas diffusion path is blocked
Solution Approach 1:
The protruding portions of the auxiliary collector layer have curved or rounded tips that contact the separator, rather than flat surfaces. This curvature allows point contact for electrical conduction while leaving the surrounding regions open for gas diffusion paths.
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 contact resistance while maintaining good gas diffusibility, enhancing the overall power generation performance by ensuring symmetrical surface pressure distribution and stable electrical contact.
Implementation Method 1
an auxiliary collector layer 130 that assists electrical contact between the power generation cell 111 and the separator 120
Implementation Method 2
a separator 120 provided with flow passage portions 121 that define gas flow passages F for a gas
Implementation Method 3
load is concentrated at the portion where the power generation cell 111 and the portion of the curved portion 131 of the auxiliary collector layer 130 protruding toward the power generation cell 111 abut each other
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
[PROBLEM] To provide a cell unit that can attain both good gas diffusibility and good electron conductivity. [SOLUTION] A cell unit 100 is made by sequentially stacking a power generation cell 111 including a cathode layer 111C, an electrolyte layer 111E, and an anode layer 111A, an auxiliary collector layer 130 that assists electrical contact, and a separator 120 provided with a flow passage portion 121 that defines a gas flow passage F. The auxiliary collector layer has a curved portion 131 that is disposed so as to overlap the gas flow passage F in the stacking direction, and that is curved so as to project toward the power generation cell side.