Fuel Cell Sealing via Moisture-Expanding Polymer
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Solution Overview
Problem
Existing fuel cell sealing technologies require high clamp loads to ensure sealing performance, leading to increased cost and size due to the need for rigid structural members.
Innovation Solution
A fuel cell design incorporating a sealing part with convex and recess features formed from a polymer material that expands with moisture absorption, reducing the clamp load required for sealing by enhancing adhesive properties and allowing sealing in directions intersecting the lamination direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing member is provided between two separators with fit-together convex and recess structures, then sealing performance is improved, but clamp load requirement increases leading to higher cost and larger size
Solution Approach 1:
The sealing structure utilizes changes in the physical state of water (from liquid to ice) and the corresponding volume expansion to generate sealing force. This replaces the need for high mechanical clamp loads with a phase-change-driven sealing mechanism, thereby reducing the required clamp load and associated structural requirements.
Solution Approach 2:
The sealing structure is designed to automatically generate sealing force through the phase change of water within the convex and recess structures. The system self-regulates the sealing pressure based on the amount of water introduced and its phase transition, eliminating the need for external high-load clamping mechanisms.
2Reliability
If high clamp load is applied to ensure sealing performance, then sealing reliability is improved, but structural members require higher rigidity increasing cost and size
Solution Approach 1:
The invention replaces the traditional mechanical clamping system with a phase-change-based sealing mechanism. Instead of relying on high mechanical clamp loads transmitted through rigid structural members, the sealing force is generated internally by the volume expansion of water during freezing, significantly reducing the rigidity requirements for structural members.
Solution Approach 2:
The sealing mechanism exploits the phase transition of water from liquid to solid state. The volume expansion during freezing generates sufficient sealing force to maintain reliable sealing without requiring high mechanical clamp loads or overly rigid structural members, thus resolving the contradiction between sealing reliability and structural strength requirements.
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 design reduces the clamp load needed for sealing, lowers the rigidity and cost of fuel cell components, and improves sealing reliability and durability by utilizing the expansion properties of the polymer material for enhanced adhesion and sealing efficiency.
Implementation Method 1
at least one of the convex part and the recess is formed with a polymer material that expands with moisture absorption
Implementation Method 2
the polymer material expands with generated water or the like generated along with operation of the fuel cell
Data Source
AI summary
A fuel cell includes a separator and a power generating body. The separator and power generating body are laminated each other. The power generating body is equipped at least with an electrolyte membrane. The fuel cell comprises: a sealing part that seals reaction gas supplied for electrochemical reactions at the fuel cell between the power generating body and the separator at an outer circumference part of the fuel cell, wherein a convex part and a recess are fit together in the sealing part. The convex part is formed projecting in the lamination direction on one of the power generating body and the separator, and the recess is formed recessed in the lamination direction on the other of the power generating body and the separator. At least one of the convex part and the recess is formed with a polymer material that expands with moisture absorption.