Fuel Cell Current Collecting Member with Roughened 180-Degree Bend
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Solution Overview
Problem
Conventional fuel cell current collecting members experience deformation and strength reduction due to high heat and creep, leading to uncertain electrical connections due to fluctuations in temperature and pressure, causing contact issues between electrodes and interconnectors.
Innovation Solution
A current collecting member with a connector contact portion, a cell body contact portion, and a connecting portion bent approximately 180 degrees, featuring surface roughness of Rz ≥ 4 µm, and a spacer between these portions to prevent deformation and integration with interconnectors, ensuring stable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic members are used to provide contact force through elasticity, then initial electrical connection is achieved, but contact force is lost over time due to plastic deformation and creep
Solution Approach 1:
The invention changes the material parameters by using a metal plate with controlled surface roughness (Rz ≥ 4 μm) instead of elastic members. This parameter change allows the contact surface to maintain stable electrical connection without the time-dependent degradation associated with elastic material properties.
Solution Approach 2:
The invention replaces the reusable elastic members that degrade over time with a rigid metal plate structure. While the metal plate itself is durable, the design accepts that the contact mechanism relies on the rigid structure rather than recoverable elastic deformation, eliminating the progressive loss of contact force.
2Adaptability or versatility
If elastic members are made to follow cell body deformation, then contact is maintained during temperature/pressure fluctuations, but uncertain electrical connection occurs due to reverse contact with interconnector
Solution Approach 1:
The invention introduces a spacer as an intermediary element between the metal plate and the cell body. This spacer acts as a mechanical mediator that allows the metal plate to follow cell body deformation through controlled displacement, while preventing the plate from making reverse contact with the interconnector, thus eliminating the risk of sintering and uncertain connection.
3Ease of manufacture
If elastic members are brought into contact with interconnector side, then joining characteristics are improved, but elastic members integrate with interconnector making contact with cell body difficult
Solution Approach 1:
The spacer serves as a protective intermediary that prevents the metal plate from directly contacting and sintering with the interconnector. This allows the system to benefit from good joining characteristics without the harmful effect of material integration that would prevent cell body contact.
Solution Approach 2:
The spacer provides beforehand protection by maintaining a controlled gap between the metal plate and interconnector, preventing the harmful sintering effect from occurring in the first place during high-temperature operation.
4Ease of manufacture
If flat surface is used for joining to interconnector, then joining characteristics are excellent, but contact force deteriorates due to plastic deformation in long-term use
Solution Approach 1:
The invention changes the surface parameter by introducing controlled roughness (Rz ≥ 4 μm) to the metal plate. This roughness parameter provides mechanical interlocking capability that maintains contact force over time, replacing the reliance on flat surface joining that degrades through plastic deformation.
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 maintains stable and favorable electrical connections over long-term use by preventing deformation and integration with interconnectors, enhancing friction force and preventing positional deviation during assembly and operation.
Implementation Method 1
the current collecting member comprises asperities having surface roughness of which ten-point average roughness is Rz ≥ 4 μm on an inside surface that is oriented inward in a state where the current collecting member is bent
Implementation Method 2
the current collecting member comprises a connector contact portion that is in contact with the interconnector, a cell body contact portion that is in contact with the cell body, and a connecting portion that is bent approximately 180 degrees and connects the connector contact portion and the cell body contact portion
Data Source
Figure 1
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Figure 3
AI summary
Provided is a fuel cell capable of continuously exhibiting excellent electrical connectivity even when subjected to long-term use. Also provided is a fuel stack. A fuel cell (3) provided with a pair of interconnectors (12, 13) (hereinafter referred to as IC), a cell main body (20) which is positioned between the ICs and in which an air electrode (14) and a fuel electrode (15) are formed on both surfaces of an electrolyte (2), and collector members (18, 19) which are disposed between at least one of the electrodes (14, 15) and the ICs and which electrically connect the air electrode (14) and/or the fuel electrode (15) with the ICs, wherein: a connector contact part (19a) which comes into contact with IC (13), a cell main body contact part (19b) which comes into contact with the cell main body (20), and a connection part (19c) which connects the contact parts and which is bent approximately 180 degrees are continuously formed on collector member (19); irregularities (19e) having a ten-point mean roughness of Rz ≥ 4 µm are formed on the inner surface of the bend; and a spacer (58) is disposed between the cell main body (20) and IC (13) and between the connector contact part (19a) and the cell main body contact part (19b) facing one another.