Fuel Cell Stack End Plate Fastening with Cylindrical Knock Seals
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Solution Overview
Problem
The existing manufacturing methods for fuel cell stacks face challenges in securely fastening end plates and connecting bars, which can lead to leakage of reaction gases and water ingress, affecting the sealing performance and durability of the fuel cell stack.
Innovation Solution
A manufacturing method that involves inserting a cylindrical knock between the end plate and connecting member holes, with seal members around the knock, and fastening using a fastening member, ensuring proper alignment and sealing between the end plates and connecting bars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cylindrical knock is inserted into the end plate installing hole and connecting bar installing hole to fasten the end plates and connecting bars, then the fastening function is achieved, but the sealing performance deteriorates due to potential leakage of reaction gases and water ingress
Solution Approach 1:
The seal member is inserted into a groove formed on the outer circumference of the cylindrical knock, creating a nested structure where the seal member is housed within the knock assembly. This nested configuration allows the seal member to effectively block the installing holes while the fastening member passes through the knock, achieving both fastening and sealing functions simultaneously.
Solution Approach 2:
The seal member acts as an intermediary element between the cylindrical knock and the installing holes. It mediates the sealing function by being positioned in the groove of the knock, preventing reaction gases and water from leaking through the installing holes while allowing the fastening member to pass through the knock for fastening purposes.
2Ease of manufacture
If conventional fastening methods are used without seal members, then the manufacturing process is simple, but the durability deteriorates due to leakage and water ingress
Solution Approach 1:
The seal member is preliminarily installed into the groove of the cylindrical knock during the knock insertion process, before the fastening member is inserted. This preliminary sealing action ensures that the installing holes are already sealed when the fastening operation commences, preventing leakage and water ingress throughout the assembly process and extending the durability of the fuel cell stack.
3Device complexity
If the cylindrical knock is located to straddle both installing holes, then the fastening structure is simplified, but the sealing precision deteriorates due to potential misalignment
Solution Approach 1:
The groove for the seal member is formed at a specific location on the outer circumference of the cylindrical knock, creating a localized sealing zone. This local quality approach ensures that the seal member is positioned precisely where needed to seal the installing holes, maintaining sealing precision even though the knock itself straddles both holes for structural simplicity.
Data Source
AI summary
A manufacturing method includes providing a cell stack including fuel cells and has a first end and a second end. A first end plate is provided at the first end of the cell stack. The first end plate has a first end plate through hole. A second end plate is provided at the second end of the cell stack. A connecting member is provided to connect the first end plate and the second end plate. A first knock is inserted into the first end plate through hole and into a first connecting member installing hole. A first seal is located between the first knock and the first end plate in the first end plate through hole. The first end plate is moved in the stacking direction to contact the connecting member. A fastening member is inserted into the first knock.