Flow Guide Manufacturing Using Sacrificial Elastomer Patterning
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Solution Overview
Problem
The production of fluidic circuits for proton exchange membrane fuel cells is hindered by complex manufacturing processes, high costs, and difficulties in reducing thickness and weight, which affect the compactness and efficiency of fuel cells, particularly due to the limitations of traditional machining and screen printing methods.
Innovation Solution
A method involving the use of a sacrificial elastomer layer to deposit conductive ink, allowing for the formation of fluidic circuits without the need for calendering and enabling the use of more conductive inks, thereby improving conductivity and reducing the constraints associated with screen printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional machining or forming methods are used to produce fluidic circuits, then the channels can be created in electrically conductive plates, but the manufacturing process becomes complicated and production costs remain high
Solution Approach 1:
The patent replaces traditional mechanical machining or forming processes with a screen printing process. The fluidic circuits are created by printing conductive paste patterns onto substrates through screens, eliminating the need for complex mechanical tooling, molds, and multi-step fabrication processes. This substitution of mechanical manufacturing with a printing-based process directly addresses the contradiction by simplifying manufacturing while reducing production complexity.
2Reliability
If screen printing is used to deposit conductive ink directly, then the process is simpler, but the ink formulation is constrained by the need for high thixotropy which limits conductivity
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary element in the screen printing process. This sacrificial layer is printed first to create the desired pattern geometry, then conductive ink is deposited over it. The sacrificial layer acts as a mediator that allows the use of more conductive inks with lower thixotropy requirements, since the pattern definition is already established by the sacrificial layer rather than relying solely on the ink's rheological properties. This resolves the contradiction by decoupling pattern formation from conductivity requirements.
3Volume of moving object
If the plate thickness is reduced to improve compactness, then the fuel cell becomes more compact, but the weight and structural integrity are compromised
Solution Approach 1:
The patent employs composite construction where thin substrates are combined with printed conductive paste layers and sacrificial layer materials to create the fluidic circuit structures. This composite approach allows the use of very thin substrate materials (reducing weight and volume) while the printed paste and sacrificial layers provide the necessary structural definition and electrical conductivity. The composite structure resolves the contradiction by achieving compactness through material layering rather than relying on thick monolithic plates.
4Productivity
If channel width is reduced to improve performance, then the fluidic circuit efficiency increases, but the forming limits of traditional sheet metal processes prevent further reduction
Solution Approach 1:
The patent replaces mechanical forming processes with screen printing to create fluidic channels. Screen printing technology allows for precise control of deposited material dimensions through screen mesh selection and printing parameters, enabling the fabrication of very narrow channels (down to hundreds of micrometers) that are below the capability of traditional sheet metal forming processes. This substitution resolves the contradiction by using a printing-based dimensional control mechanism rather than mechanical forming limits.
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 approach simplifies the manufacturing process, reduces costs, and enhances the conductivity and surface quality of fluidic circuits, leading to improved performance and efficiency in fuel cell operations.
Implementation Method 1
printing, on a first face of the substrate, a first so-called sacrificial layer based on a first elastomer by screen printing using the first mesh screen
Implementation Method 2
depositing on the first face of the substrate, a first conductive layer based on a first electrically conductive ink to form the ribs of the first flow guide
Implementation Method 3
removing the first sacrificial layer
Data Source
Figure 1~2
Figure 3~5
Figure 6A
AI summary
The invention relates to a method for manufacturing at least one flow guide for an electrochemical reactor, comprising providing a substrate (10), providing a mesh screen (11) having openings (111) configured to form at least one negative of a rib pattern (21) of a first flow guide (1), printing, on one face (101) of the substrate, a sacrificial layer (31) based on an elastomer by screen printing using the mesh screen, deposition, on the first face of the substrate, of a conductive layer (33) based on an electrically conductive ink to form the ribs of the first flow guide, and then removing the sacrificial layer. The invention relates to the use of an elastomer-based sacrificial layer whose shape corresponds to the negative of the flow guide to be manufactured. It is then possible to deposit the conductive layer using a method other than screen printing.