Fuel Cell Separator Bonding via Controlled Crystallization
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Solution Overview
Problem
Fuel cells face challenges with adhesive strength between separators and sealing members, particularly in harsh usage environments, where the existing thermoplastic resin bonding method may not provide sufficient durability to prevent peeling.
Innovation Solution
A method involving heating a thermoplastic resin to its melting point and holding it within a temperature range ±10°C of its crystallization temperature to promote crystallization, forming a lamellar structure that enhances bonding strength between the resin and separators, thereby improving adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic resin bonding method is used, then manufacturing process is simple, but adhesive strength between separator and sealing member is insufficient in harsh usage environments
Solution Approach 1:
The patent applies parameter changes by controlling the cooling process parameters - specifically holding the thermoplastic resin at its crystallization temperature for a predetermined period to promote crystallization. This temperature and time control transforms the resin's molecular structure to enhance adhesive strength between the separator and sealing member, resolving the contradiction between simple manufacturing and sufficient bonding strength.
Solution Approach 2:
The patent utilizes phase transitions of the thermoplastic resin by heating it to its melting point to transition from solid to liquid state for bonding, then controlling the cooling process to transition back to solid state with enhanced crystallization. This controlled phase transition process ensures both manufacturability and high adhesive strength in harsh environments.
2Strength
If thermoplastic resin is cooled quickly after heating, then manufacturing efficiency is high, but crystallization is insufficient and adhesive strength is reduced
Solution Approach 1:
The patent applies periodic action by implementing a staged cooling process with distinct phases: first holding at crystallization temperature for a predetermined period to promote crystallization, then cooling to room temperature. This periodic temperature control ensures sufficient crystallization for high adhesive strength while maintaining reasonable manufacturing efficiency through optimized time intervals.
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 approach significantly increases the bonding strength between the thermoplastic resin and separators, requiring more energy to peel them apart and thus enhancing the sealing and structural integrity of the fuel cell.
Implementation Method 1
heating the stack structure at a melting point or higher of the thermoplastic resin
Implementation Method 2
holding the stack structure in a temperature range of ±10° C. of a crystallization temperature of the thermoplastic resin to promote a crystallization of the thermoplastic resin
Data Source
AI summary
An object of the present disclosure is to provide a method for manufacturing a fuel cell that ensures developing a high adhesive strength to a separator. One aspect of an embodiment is a method for manufacturing a fuel cell where a pair of separators are mutually bonded with a sealing member. The sealing member includes a thermoplastic resin containing a crystalline polymer as an adhesive layer. The method for manufacturing the fuel cell includes: preparing a stack structure in which the sealing member is disposed between the pair of separators; heating the stack structure at a melting point or higher of the thermoplastic resin; after the heating, holding the stack structure in a temperature range of ±10° C. of a crystallization temperature of the thermoplastic resin to promote a crystallization of the thermoplastic resin; and after the holding, further cooling the stack structure.