Variable Thickness Stamped Interconnect for Fuel Cell Stack
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Solution Overview
Problem
Existing fuel cell interconnects face challenges in achieving robust electrical contact, minimizing parasitic electrical losses, and maintaining efficient fluid flow while being cost-effective and dimensionally stable, as they often result in high flow restrictions, poor physical integrity, and increased manufacturing costs.
Innovation Solution
A planar fuel cell stack assembly with an interconnect module featuring a stamped metal sheet with parallel and perpendicular slots, allowing for reduced thickness portions for fluid flow and thicker portions for electrical connection, providing a robust and efficient interconnect structure that minimizes electrical resistance and flow restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interconnect contacts the cell surfaces at many closely-spaced locations to minimize electrical resistance, then electrical contact robustness is improved, but fluid flow restriction increases and pumping losses increase
Solution Approach 1:
The interconnect features localized contact regions with higher thickness (e.g., 0.5-2mm) spaced apart from localized flow channels. The contact regions provide robust electrical contact while the flow channels between them enable efficient fluid flow, resolving the contradiction between electrical contact robustness and pumping losses.
2Volume of moving object
If the interconnect height is minimized to provide compactness, then device compactness is improved, but structural robustness and resistance to dimensional changes (creep) deteriorate
Solution Approach 1:
The interconnect uses variable thickness design where thicker regions (0.5-2mm) are strategically positioned at contact points with fuel cells to provide structural support and resistance to creep, while thinner regions maintain overall compactness. This resolves the contradiction between compactness and structural robustness.
3Ease of manufacture
If sheet metal with formed dimples or ridges is used to provide electrical contact, then manufacturing cost is reduced, but physical integrity and strength in the direction perpendicular to the cell surface deteriorate, resulting in creep
Solution Approach 1:
The invention changes the thickness parameter of the sheet metal interconnect from uniform thin gauge to variable thickness with localized thicker regions (0.5-2mm) at contact points. This maintains ease of manufacture through stamping while dramatically improving strength and resistance to creep in the direction perpendicular to the cell surface.
4Strength
If thick sheet metal plates with machined features are used to provide electrical contact, then structural strength is improved, but manufacturing cost increases considerably and electrical contact spacing is greater than desired
Solution Approach 1:
The invention uses stamping processes to create variable thickness features directly in the sheet metal, eliminating the need for machining thick plates. This maintains structural strength through localized thicker regions while dramatically reducing manufacturing cost and enabling closer electrical contact spacing.
5Reliability
If multiple 2-dimensional pieces are stacked and brazed together to form the interconnect, then electrical contact spacing can be optimized, but manufacturing cost increases considerably
Solution Approach 1:
The invention merges multiple functions (electrical contact, fluid flow, structural support) into a single stamped sheet metal component with variable thickness. This eliminates the need for stacking and brazing multiple pieces, optimizing electrical contact spacing while dramatically reducing manufacturing cost.
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 enhances electrical contact robustness, reduces parasitic losses, and maintains efficient fluid flow while being cost-effective and dimensionally stable, improving the overall performance and longevity of the fuel cell stack.
Implementation Method 1
The parallel and perpendicular metal strip portions include portions of reduced thickness that allow for fluid flow between adjacent slots and portions having a greater thickness than the portions of reduced thickness that provide discrete locations of electrical connection between the separator plate and the first fuel cell anode or the second fuel cell cathode
Implementation Method 2
The stamped slots individually extend lengthwise parallel to the direction of fluid flow during operation of the fuel cell stack assembly and are disposed on the metal sheet in a pattern extending parallel and perpendicular to the direction of fluid flow, so as to define at least one metal strip portion between adjacent slots extending parallel to the direction of fluid flow
Data Source
AI summary
A metal interconnect for a fuel cell stack is formed from an electrically conductive metal sheet having at least four stamped slots through the metal sheet, and often many more than four slots. The stamped slots individually extend lengthwise parallel to the direction of fluid flow during operation of the fuel cell stack assembly and are disposed on the metal sheet in a pattern extending parallel and perpendicular to the direction of fluid flow, so as to define at least one metal strip portion between adjacent slots extending parallel to the direction of fluid flow and at least one metal strip portion between adjacent slots extending perpendicular to the direction of fluid flow. The metal strip portion(s) include portions of reduced thickness that allow for fluid flow between adjacent slots and portions of greater thickness that provide discrete locations of electrical connection between the separator plate fuel cell electrode.