Fuel Cell Stack Displacement Absorption Member Design
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Solution Overview
Problem
Conventional fuel cell stacks face challenges in miniaturization due to difficulties in maintaining displacement absorption functions while reducing thickness, primarily because of the complex shape of electrodes and separators with protrusions and depressions.
Innovation Solution
A fuel cell stack design that incorporates a cooling liquid flow between stacked unit cells, utilizing a displacement absorption member with a spring part and intrusion prevention mechanism to absorb displacement between unit cells, allowing for efficient gas and liquid flow while maintaining a thinner profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If electrodes and separators have protrusions and depressions to distribute load, then load distribution improves, but unit cell thickness increases making miniaturization difficult
Solution Approach 1:
The separator is divided into a flat separator and a separate displacement absorption member with protrusions and depressions. This segmentation allows the displacement absorption function to be separated from the load distribution function, enabling the main separator to remain thin while the displacement absorption member provides the necessary compliance without significantly increasing overall thickness.
Solution Approach 2:
A displacement absorption member is introduced as an intermediary component between the membrane electrode assembly and the flat separator. This intermediary element absorbs displacement and accommodates dimensional changes while maintaining contact pressure, allowing the use of thinner separators without compromising load distribution.
2Length of moving object
If unit cell thickness is reduced for miniaturization, then space efficiency improves, but displacement absorption function deteriorates
Solution Approach 1:
The displacement absorption member has protrusions that locally contact with the membrane electrode assembly at specific points. This local quality approach allows displacement absorption to occur at discrete locations rather than requiring uniform thickness throughout the entire separator, enabling thinner overall construction while maintaining the displacement absorption function at critical interfaces.
Solution Approach 2:
The displacement absorption member is designed with elastic properties that allow it to dynamically adjust to dimensional changes in the membrane electrode assembly. The protrusions can elastically deform to absorb displacement, providing a dynamic response to thermal expansion and contraction without requiring excessive thickness.
3Temperature
If cooling liquid flow space is increased for better temperature control, then heat dissipation improves, but device complexity increases
Solution Approach 1:
The cooling liquid flow passages are integrated into the flat separator structure, which also serves as a structural support and load distribution component. This multi-functionality allows the separator to simultaneously provide mechanical support, load distribution, and cooling functions, improving heat dissipation without significantly increasing device complexity.
Solution Approach 2:
The cooling liquid flow passages are merged with the separator structure rather than being separate components. The flat separator incorporates channels for cooling liquid flow, combining the cooling function with the structural separator function, thereby improving temperature control while avoiding the complexity of separate cooling systems.
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 design effectively maintains displacement absorption functions while achieving miniaturization of the fuel cell stack, reducing pressure loss and enhancing temperature control, thus optimizing performance and space efficiency.
Implementation Method 1
The displacement absorption member includes a spring part having a free end and a fixed end
Implementation Method 2
a cooling liquid flow space between the unit cells
Data Source
AI summary
A fuel cell stack is formed by stacking unit cells and each unit cell is formed by sandwiching a membrane electrode assembly between a pair of separators having depression parts and protrusion parts. A cooling liquid flow space is formed between the unit cells, and a displacement absorption member which absorbs displacement between the unit cells C is disposed in the flow space. The displacement absorption member includes a spring function part having a free end and a fixed end, and an intrusion prevention means which prevents the free end of the spring function part from intruding into the depression part. A displacement absorption function between the unit cells is well maintained, while size reduction of the fuel cell stack is achieved.