Bipolar Metal Plate Coating for PEMFC Corrosion Resistance
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Solution Overview
Problem
Metal bipolar plates in proton exchange membrane fuel cells (PEMFCs) undergo corrosion in corrosive environments, leading to degradation, release of metal ions, and reduced cell performance and durability, despite existing coatings that provide physical protection but not comprehensive chemical barrier.
Innovation Solution
A metal bipolar plate with a coating comprising conductive fillers, a polymer binder, and a metal cation-absorbing compound, such as a perfluorinated sulphonic acid (PFSA) ionomer, which acts as both a physical and chemical barrier to prevent corrosion and ion release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal bipolar plate is used in a PEMFC, then the cost and size are reduced compared to graphite plates, but the plate undergoes corrosion in the corrosive environment leading to degradation and release of metal ions
Solution Approach 1:
The patent applies composite materials by combining metal bipolar plate with a multi-layer coating system consisting of a polymer binder matrix, conductive filler particles, and metal cation-absorbing compounds. This composite structure provides both the mechanical strength and electrical conductivity of metal plates while adding corrosion protection and ion absorption capabilities through the coating layers, thereby resolving the contradiction between cost/size benefits and corrosion resistance.
2Reliability
If existing coatings are applied to metal bipolar plates, then physical protection is provided, but the coatings do not provide comprehensive chemical barrier against metal ion release
Solution Approach 1:
The patent introduces metal cation-absorbing compounds as an intermediary layer within the coating system. These compounds act as a chemical mediator that actively binds and absorbs metal ions before they can interact with the electrolyte membrane and catalysts. This intermediary function provides comprehensive chemical protection beyond mere physical barrier, preventing harmful ion release while maintaining the physical protection benefits of the coating.
3Reliability
If the metal plate is protected by a coating, then corrosion is reduced, but the coating must maintain electrical conductivity for electron collection
Solution Approach 1:
The patent applies local quality by incorporating conductive filler particles distributed within the polymer binder matrix of the coating. This creates localized conductive pathways and networks within the insulating polymer matrix, ensuring that electrical conductivity is maintained at critical interfaces while the overall coating structure provides corrosion protection. The conductive fillers are strategically positioned to preserve electron collection functionality without compromising the protective barrier.
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 coating significantly enhances the corrosion resistance and durability of the metal plate, maintaining the performance and integrity of the fuel cell by absorbing metal ions and preventing their interaction with the electrolyte membrane and catalysts.
Implementation Method 1
a coating comprising a compound capable of absorbing metal cations, advantageously in the form of an ionomer, for example of the perfluorinated sulphonic acid (PFSA) polymer type
Data Source
Figure 1
AI summary
Metallic plate for proton exchange membrane fuel cell (PEMFC) having, on at least one of its faces, a coating comprising: - fillers of conductive material; - a polymer serving as a binder; - a compound absorbing metallic cations.