Bipolar Plate Channel Embossing for Wall Thickness Control
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Solution Overview
Problem
Existing sheet metal forming methods struggle to achieve wall thickness variations in end products, particularly for channel structures in bipolar plates of electrochemical cells, which compromises both forming efficiency and fluidic performance.
Innovation Solution
A method for embossing a channel structure in a planar metal sheet involves forming parallel channel portions with non-parallel flanks, where material from outside the flanks is displaced into the flanks, allowing for wall thickness reduction and material accumulation in the flanks, thereby achieving desired wall thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sheet metal forming methods are used to create channel structures, then the forming process can be completed, but the wall thickness remains uniform and cannot achieve the desired wall thickness variations for optimized fluidic performance
Solution Approach 1:
The patent applies local quality by creating non-uniform wall thickness distribution in specific regions of the bipolar plate. The channel structures are formed with varying wall thicknesses - thinner walls in regions requiring high fluidic performance and thicker walls in regions requiring structural strength. This is achieved through localized embossing and forming processes that modify material thickness in specific areas rather than uniformly across the entire plate.
Solution Approach 2:
The patent transitions from two-dimensional planar metal sheets to three-dimensional channel structures with varying wall thicknesses. By introducing depth and volume variations through embossing and forming processes, the invention creates complex 3D geometries that enable both fluidic optimization and structural reinforcement within the same component.
2Shape
If deep drawing and pressing methods are used to produce complexly shaped components, then very complexly shaped components with eccentric portions and regions of low material thickness can be produced, but the process complexity increases significantly
Solution Approach 1:
The patent segments the forming process into distinct stages: initial deep drawing to create the basic plate shape, followed by embossing to create channel patterns, and finally pressing to refine the channel structures. Each stage uses relatively simple tooling that performs one specific function, rather than requiring a single complex tool to perform all operations simultaneously.
Solution Approach 2:
The patent performs preliminary actions by first creating the basic plate geometry through deep drawing, then subsequently adding the channel structures through embossing. This sequential approach allows each process step to build upon the previous one, simplifying the tooling requirements for each individual step while achieving the final complex geometry.
3Manufacturing precision
If material is displaced into the flanks during embossing, then wall thickness reduction and material accumulation are achieved, but significant material flow within the plane of the metal sheet is required
Solution Approach 1:
The patent changes material parameters by controlling the embossing depth, flank angles, and pressing forces to achieve desired wall thickness variations. By adjusting these process parameters, the invention optimizes material flow into the flanks to create the required thickness distribution without excessive material displacement that would compromise productivity.
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 method efficiently addresses the conflict between forming and fluidic aspects by allowing significant material flow within the plane of the metal sheet, resulting in channel structures with optimized wall thickness distribution and fluidic performance, suitable for bipolar plates in fuel cells.
Implementation Method 1
forming the plurality of channel portions, wherein each channel portion is formed with two mutually non-parallel flanks in such a way that material of embossing portions of the metal sheet which are located outside the flanks and remain during the entire forming process in the base plane and/or a plane parallel thereto is displaced into the flanks
Data Source
AI summary
The invention relates to a method for embossing a channel structure (3) comprising a plurality of parallel channel portions (5) in a planar metal sheet (11) to form a half-plate (2, 2′), in particular for a bipolar plate (1) of an electrochemical cell, said method having the following steps:providing the planar metal sheet (11) with a uniform initial wall thickness (d5),inserting the metal sheet (11) into a forming tool (12), wherein a base plane (BE) of the sheet (11) defined by the undeformed planar metal sheet (11) is provided to rest on a tool plane defined by a tool part (13) of the forming tool (12),forming the plurality of channel portions (5), each channel portion (5) being designed with two non-parallel flanks (7, 8) in such a way as to allow material from embossing portions (9, 10) of the metal sheet (11), which are located outside the flanks and remain in the base plane (BE) and/or a plane parallel thereto throughout the entire forming process, to be displaced into the flanks (7, 8), each flank (7, 8) extending from the base plane (BE) to an adjacent parallel plane.