Fuel Cell Flow Field Plates With Extruded Grooves for Low-Cost Production
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Solution Overview
Problem
The high cost of producing fuel cell reactant and coolant flow field plates, particularly in electric vehicle applications, is attributed to time-consuming and expensive manufacturing processes such as end milling for precise groove formation.
Innovation Solution
The method involves extruding or milling flat porous carbonaceous sheets with straight grooves, cutting them at an oblique angle to create flow field plates with edges aligned differently from the grooves, and using impregnation or stamping to define coolant channels, thereby eliminating the need for expensive end milling and allowing for cost-effective production of fuel cell flow field plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If end milling or similar processes are used to form shaped grooves with sufficient dimensional tolerance, then manufacturing precision is improved, but productivity deteriorates and manufacturing cost increases
Solution Approach 1:
The groove shapes are pre-formed into the flow field plate during the extrusion or molding process itself, rather than being added later through time-consuming end milling operations. This preliminary formation of grooves with adequate dimensional tolerance significantly improves productivity while maintaining acceptable manufacturing precision for fuel cell applications.
2Manufacturing precision
If end milling is used to provide coolant grooves on opposite sides of flow field plates, then manufacturing precision is improved, but manufacturing cost and time increase
Solution Approach 1:
The formation of coolant grooves on opposite sides of the flow field plate is merged with the formation of reactant grooves in a single extrusion or molding operation. This simultaneous formation of multiple groove types eliminates the need for separate end milling steps for coolant channels, reducing both manufacturing cost and complexity while maintaining adequate precision through the precision of the extrusion/molding process itself.
3Manufacturing precision
If traditional manufacturing processes are used for flow field plates, then manufacturing precision is improved, but productivity deteriorates and cost increases
Solution Approach 1:
The traditional mechanical end milling process is replaced with an extrusion or molding process that forms grooves directly during plate production. This substitution eliminates the need for secondary machining operations, dramatically improving productivity and reducing manufacturing costs while maintaining sufficient groove dimensional accuracy for fuel cell performance through proper die or mold design.
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 reduces manufacturing costs by utilizing high-speed, low-cost processes for groove formation and cutting, enabling efficient production of fuel cell flow field plates with improved performance and reduced production expenses.
Implementation Method 1
an elongated sheet of porous hydrophilic carbonaceous substrate material
Implementation Method 2
the extrusion die is configured to create straight grooves separated by ridges in the elongated sheets
Data Source
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AI summary
Fuel cell reactant flow field plates (22, 32) are formed by extruding long sections (17, 25) of carbonaceous material, either with straight grooves (18, 28) formed by the extrusion die, or by end milling or arbor milling, and then cut to a proper size, including cuts in which the edges of the plates are at an angle with respect to the grooves. Cooler plates are formed of water- permeable material (39) in which hydrophobic material (40) is impregnated so as to define coolant channels (42-44) with inlets and outlets (47, 49). A two- layer cooler plate is formed by stamping voids in one layer (51) that define coolant flow channels (52) with inlets (54) and outlets (56) while a second layer (59) is stamped with voids (61, 62) that define coolant inlet and exit headers; juxtaposition of the layers, with or without bonding, form the cooler plate. A cooler plate (65) is made by corrugating thin metal sheet, providing coolant channels (68) for cathodes and coolant channels (73) for anodes when interposed therebetween.