Fuel Cell End Plate Bonding for Flatness and Airtight Sealing
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Solution Overview
Problem
In fuel cell manufacturing, the mismatch in thermal expansion coefficients between metal and resin components leads to issues such as poor flatness, thermal shock-induced cracking, and compromised airtightness and insulation performance due to separation and lifting phenomena at the interface between metal inserts and resin portions.
Innovation Solution
A fuel cell design with a metal portion featuring molecular adhesion surface treatment, including etching and anodizing, to enhance bonding with a resin portion, which is embedded in pores on the metal surface, ensuring strong adhesion and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an injection-molded product is ejected from a mold after the resin portion is applied onto the metal insert, then the manufacturing process is completed, but the high-temperature plastic contracts and separation occurs at the interface between the metal insert and the resin portion, leading to formation of a raised portion and poor flatness
Solution Approach 1:
An undercut structure is formed in advance at the interface between the metal insert and the resin portion before injection molding. This preliminary structural preparation prevents separation and raised portions during the ejection process, maintaining flatness without compromising the injection molding ease.
Solution Approach 2:
The metal insert surface is treated to have a porous structure, which enhances the bonding strength between the metal insert and the resin portion. This porous structure allows the resin to penetrate and mechanically interlock with the metal surface, preventing separation during ejection and maintaining flatness.
2Manufacturing precision
If the injection-molded product is manufactured with strict control of injection molding conditions and formation of structural undercut, then initial flatness requirements are met, but a lifting phenomenon occurs between the metal insert and the resin portion, or the resin portion cracks due to thermal shock
Solution Approach 1:
The metal insert surface is treated to have a porous structure, which significantly enhances the bonding strength between the metal insert and the resin portion. This strong bonding prevents lifting phenomena and cracking under thermal shock conditions, improving reliability while maintaining the flatness achieved through strict molding control.
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 solution achieves enhanced adhesion strength, improved watertightness, and increased durability by preventing thermal shock-induced cracking and maintaining airtightness, while reducing the resin portion's dimensions for better manufacturing efficiency and quality.
Implementation Method 1
A fuel cell design with a metal portion featuring molecular adhesion surface treatment, including etching and anodizing, to enhance bonding with a resin portion
Implementation Method 2
A fuel cell design with a metal portion featuring molecular adhesion surface treatment, including etching and anodizing, to enhance bonding with a resin portion
Implementation Method 3
a resin portion, which is embedded in pores on the metal surface
Data Source
AI summary
A fuel cell of the present disclosure includes a cell stack including a plurality of unit cells stacked in a first direction, an end plate disposed on each of two ends of the cell stack and including a metal portion subjected to molecular adhesion surface treatment and a resin portion disposed on at least a portion of the surface of the metal portion, an enclosure coupled to the end plate to envelop the cell stack, and an outer gasket disposed between the enclosure and the end plate and being in contact with the metal portion of the end plate.