Electrochemical Stack Sealing with Zoned Clamping Pressure
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Solution Overview
Problem
In fuel cell stacks, insufficient clamping pressure on gas supply/discharge units leads to gaps between components, causing gas leakage, as the clamping pressure applied to the electrochemical reaction regions differs from that required for the gas flow passages.
Innovation Solution
An electrochemical module with a pressing mechanism that independently applies clamping pressure to the annular sealing portions, using screw members and an insulating sealing portion to prevent gas leakage, and includes elastic plate-like members to maintain uniform pressure despite thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform clamping pressure is applied to the entire stack surface, then the electrochemical reaction regions are adequately pressed, but the gas supply/discharge units generate gaps causing gas leakage
Solution Approach 1:
The patent applies different clamping pressures to different regions of the stack. The gas supply/discharge units are pressed with higher pressure than the electrochemical reaction regions. This is achieved by providing pressing mechanisms that independently apply pressure to specific areas, ensuring that gas flow passages are sealed without compromising the electrochemical reaction regions.
2Reliability
If higher clamping pressure is applied to gas flow passages, then gas leakage is prevented, but the electrochemical reaction regions experience excessive pressure
Solution Approach 1:
The patent segments the clamping pressure application into distinct zones. Pressing mechanisms are provided that can independently apply pressure to gas supply/discharge units separate from the electrochemical reaction regions. This segmentation allows optimized pressure distribution where gas flow passages receive higher pressure for sealing while reaction regions receive appropriate pressure for electrochemical performance.
3Reliability
If the stack components are tightly assembled, then gas leakage is suppressed, but thermal expansion causes pressure loss and gap formation
Solution Approach 1:
The patent employs elastic plate-like members that can change their physical parameters (deformation) in response to thermal expansion. These members are pressed by the pressing mechanisms and maintain contact pressure on gas flow passage components despite thermal expansion of the stack. The elastic deformation of these members compensates for dimensional changes, maintaining sealing pressure under varying temperature conditions.
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 effectively suppresses gas leakage by ensuring appropriate clamping pressure is applied to both the electrochemical reaction regions and the gas flow passages, maintaining the integrity of the fuel cell stack and reducing internal resistance.
Implementation Method 1
a pressing mechanism that presses a portion to which the annular sealing portion is attached against the clamp in the stacking direction
Implementation Method 2
includes elastic plate-like members to maintain uniform pressure despite thermal expansion
Data Source
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AI summary
An object is to provide an electrochemical module capable of suppressing gas leakage, an electrochemical device, and an energy system. An electrochemical module M includes: a stack obtained by stacking, in a predetermined stacking direction, a plurality of electrochemical elements having a configuration in which an electrode layer, an electrolyte layer, and a counter electrode layer are formed along a substrate, via an annular sealing portion through which first gas that is one of reducing component gas and oxidative component gas flows; a container 200 that includes an upper cover 201 for pressing a first flat face in the stacking direction of the stack and a lower cover 203 for pressing a second flat face on a side opposite to the first flat face, the stack being sandwiched between the upper cover 201 and the lower cover 203; and a pressing mechanism 400 that presses a portion to which the annular sealing portion is attached against the container 200 in the stacking direction.