Bipolar Plate Graphite Coating Using Laser-Defined Flow Barriers
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Solution Overview
Problem
Existing methods for manufacturing bipolar plates for electrochemical systems face challenges in accurately coating the webs with graphite, leading to performance losses due to undefined channel geometry and loss of graphite coating.
Innovation Solution
A method involving laser treatment of specific surface regions on the webs to create hydrophobic surface structurings, followed by an aging process to increase the areal density of nanostructures, and finally coating the adjacent surface regions with a graphite suspension to prevent flow into non-coated areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite suspension is applied to the webs to improve electrical properties, then the electrical conductivity is improved, but the coating precision deteriorates causing suspension to flow into channels
Solution Approach 1:
The patent applies different surface properties to different regions of the web. The first surface regions are treated with hydrophobic surface structurings (created by laser treatment and aging) to prevent suspension flow, while the second surface regions remain hydrophilic to allow controlled suspension application. This local differentiation of surface properties enables precise coating control.
Solution Approach 2:
The hydrophobic surface structurings are created on the first surface regions before the graphite suspension is applied. This preliminary action establishes flow barriers in advance, preventing the suspension from flowing into the channels during the coating process.
2Manufacturing precision
If the suspension viscosity is adjusted to improve coating control, then the coating precision is improved, but the process complexity increases due to narrow process window
Solution Approach 1:
The patent changes the surface energy parameters of specific regions rather than adjusting the suspension viscosity. By creating hydrophobic surface structurings through laser treatment and aging, the surface properties are modified to provide flow control, eliminating the need for precise viscosity control and its associated narrow process window.
3Reliability
If graphite coating is applied to enhance electrical properties, then the electrical conductivity is improved, but the channel geometry becomes undefined due to suspension flow
Solution Approach 1:
The patent creates localized hydrophobic regions at the boundaries between the web and channel areas. These localized surface property changes act as flow barriers that prevent suspension from entering the channel regions, thereby maintaining well-defined channel geometry while still allowing graphite coating on the web surfaces.
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 enables precise application of graphite coatings on bipolar plates, preventing coating material from reaching non-coated regions and thus enhancing the accuracy and performance of the electrochemical system.
Implementation Method 1
at least two first surface regions of the webs are subjected to at least one laser treatment, in which the at least two first surface regions are irradiated by means of a pulsed laser with laser pulses that have a pulse duration of less than 1 ns, wherein the at least one laser treatment produces surface structurings
Implementation Method 2
the at least two first surface regions are, after the laser treatment, subjected to an aging process, whereby the surface structurings on the at least two first surface regions age, thereby increasing the areal density of the nanostructures
Implementation Method 3
the carrier liquid applied to the region to be coated stops at the edge of the region to be coated, immediately adjacent to the at least two surface regions having the surface structurings, and does not flow over the at least two surface regions with the surface structurings
Data Source
AI summary
The present disclosure relates to a method of manufacturing a bipolar plate for an electrochemical system. The method comprises the steps of providing at least one metallic plate comprising a plurality of webs and channels formed between the webs, subjecting each of at least two first surface regions of the webs to at least one laser treatment, subjecting each of the at least two first surface regions to an aging process, and coating each of at least one second surface region of the webs located between the at least two first surface regions and immediately adjacent to the at least two first surface regions with at least one graphite coating. In addition, the present disclosure also relates to a bipolar plate for an electrochemical system and an electrochemical system comprising the bipolar plate.