Fuel Cell Bipolar Plate Sealing for Weld Seam Corrosion Protection
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Solution Overview
Problem
Bipolar plates in fuel cells face corrosion issues due to coating damage from welding, which exposes them to corrosive environments and increases the risk of coating failure and corrosion at weld seams and adjacent areas.
Innovation Solution
A sealing device, such as an elastomer or polymer composite seal, is applied to cover the materially bonded connections of the bipolar plate halves, providing leak-tight protection and preventing corrosion, which can be clamped, adhesively bonded, or arranged in fluid channels to ensure effective coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to connect bipolar plate halves, then structural strength and sealing are improved, but coating damage and corrosion risk increase
Solution Approach 1:
The bipolar plate is divided into two halves that are connected by welding, with each half having its own coating layer. The sealing device is segmented to cover the weld seam separately, allowing independent optimization of each component's properties.
Solution Approach 2:
A sealing device made of corrosion-resistant material (elastomer, plastic, or polymer composite) is introduced as an intermediary element to cover the weld seam. This sealing device acts as a barrier between the corrosive environment and the damaged coating area, preventing corrosion while maintaining structural integrity.
2Object-affected harmful factors
If coating is applied before welding, then corrosion protection is improved, but welding heat destroys the coating at connection points
Solution Approach 1:
The coating is applied to the bipolar plate halves before welding (pre-coating), providing initial corrosion protection. The sealing device is then added afterward to protect the weld seam area where the coating would be damaged by heat.
Solution Approach 2:
The sealing device is positioned to cover the weld seam area in advance, creating a protective barrier that cushions the coating from thermal damage during the welding process and prevents corrosion at the vulnerable connection points.
3Object-affected harmful factors
If sealing devices are added to protect weld seams, then corrosion protection is improved, but device complexity increases
Solution Approach 1:
The sealing device serves multiple functions simultaneously: it seals the fluid channels, protects the weld seam from corrosion, and provides mechanical support. This multi-functionality reduces the need for separate components and simplifies the overall structure.
Solution Approach 2:
The sealing device is made from flexible materials such as elastomers, plastics, or polymer composites that can be formed into thin films or shells. These flexible sealing elements can conform to the weld seam geometry and are easier to install and replace compared to rigid sealing structures.
Data Source
AI summary
The invention relates to a bipolar plate (30) for a fuel cell (10). The bipolar plate (30) has a first bipolar plate half (32) and a second bipolar plate half (34), and the bipolar plate (30) has at least one fluid channel (36) for carrying at least one fluid (F). The first bipolar plate half (32) has at least one bonded connection (40) to the second bipolar plate half (34), and the bipolar plate (30) comprises at least one sealing arrangement (50) which sealingly covers the at least one bonded connection (40). The invention also relates to a fuel cell and a method for sealingly covering a bonded connection of the first bipolar plate half (32) to the second bipolar plate half (34) of the bipolar plate (30).