Polymer-Graphite Bipolar Plate Forming With Gas Pressure Embossing
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Solution Overview
Problem
Existing methods for producing bipolar plates for electrochemical cells face challenges in achieving a favorable balance between equipment expenditure, geometric precision, and process reliability, while ensuring high electrical conductivity and structural integrity.
Innovation Solution
A method involving the use of polymer-graphitic foil sections embossed and molded using a combination of mechanical deformation and gas pressure differences, forming a hollow structure with high electrical conductivity and precise geometric features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple foil sections are assembled and connected using existing methods, then bipolar plates can be produced, but the equipment expenditure increases and process reliability decreases due to alignment requirements
Solution Approach 1:
The bipolar plate is divided into multiple foil sections that are connected in a stack arrangement. Each foil section can be manufactured separately and then assembled together, allowing for modular production while maintaining overall plate functionality through the segmented structure
Solution Approach 2:
Multiple foil sections are merged into a single bipolar plate structure through connection at edges or overlapping regions. This combining approach creates a unified functional unit that achieves the desired electrical and mechanical properties while enabling simplified manufacturing of individual sections
2Ease of manufacture
If multiple foil sections are assembled and connected using existing methods, then bipolar plates can be produced, but the production time increases due to alignment requirements
Solution Approach 1:
Foil sections are pre-formed with connection features or pre-aligned structures before assembly. This preliminary preparation enables faster connection during final assembly, reducing the overall production time while maintaining manufacturing simplicity
Solution Approach 2:
Tolerances and alignment variations are compensated for by designing overlapping regions or flexible connection zones between foil sections. This beforehand cushioning allows for quicker assembly without requiring precise alignment, thereby improving productivity
3Manufacturing precision
If complex forming tools are used to create hollow structures, then geometric precision improves, but device complexity increases
Solution Approach 1:
Gas pressure is applied to foil sections during forming to create hollow structures and three-dimensional shapes. This pneumatic approach enables complex geometric features to be formed with relatively simple tooling, as the gas pressure naturally conforms the material to the desired shape without requiring complex mechanical forming tools
Solution Approach 2:
The physical state or properties of the foil material are changed during forming (such as temperature, pressure, or material softness) to enable easier shaping. By temporarily altering material parameters, complex hollow structures can be formed with simpler tools, reducing device complexity while maintaining geometric precision
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 method achieves bipolar plates with high electrical conductivity and precise geometric features, reducing the need for alignment and enabling efficient production with improved process reliability and reduced cycle time.
Implementation Method 1
forming a hollow structure between the foil sections by means of gas pressure differences, in particular pressure differences of air, at the foil surfaces
Implementation Method 2
the foil sections are embossed and tightly connected to one another at their edges
Data Source
AI summary
The disclosure relates to a bipolar plate production method for producing a bipolar plate, in particular for an electrochemical cell, which method comprises the following steps:providing two foil sections made of a polymer graphite material comprising at least one polymer and at least 75 wt. % of an electrically conductive filler comprising predominantly graphite and also carbon black,inserting the two foil sections into an embossing and molding tool, closing the tool, wherein the foil sections are embossed and tightly connected to one another at their edges,forming a hollow structure between the foil sections by means of gas pressure differences at the foil surfaces, wherein the foil sections rest against surface structures of tool surfaces, which face one another, of the embossing and molding tool,removing the bipolar plate, formed from the foil sections, from the embossing and molding tool after the foil sections have solidified.