Fuel Cell Stack Seal Compression via Hydraulic Pressure
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Solution Overview
Problem
Existing fuel cell stack production methods fail to effectively seal the interface between metal separators and membrane electrode assemblies, leading to potential leakage of reactant gases and coolant.
Innovation Solution
A method involving the use of a pressure medium supplied at a higher pressure than normal operation to the coolant flow field, causing the seal member between the bead seal and membrane electrode assembly to be pressed tightly, ensuring a secure seal between the metal separators and the membrane electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal member is provided on the top part of the bead seal to prevent leakage, then sealing function is improved, but the seal may still insufficiently contact the membrane electrode assembly under normal operation pressure
Solution Approach 1:
The patent applies preliminary action by supplying pressure medium to the coolant flow field before or during the stacking process, pre-compressing the seal member against the membrane electrode assembly to ensure adequate contact tightness before the fuel cell stack begins normal operation. This preliminary compression ensures the seal is properly seated and will prevent leakage throughout the operational life of the stack.
Solution Approach 2:
The patent utilizes pneumatics and hydraulics by introducing a pressure medium (liquid or gas) into the coolant flow field to generate compressive force on the seal member. This hydraulic/pneumatic pressure ensures the seal member maintains sufficient contact pressure with the membrane electrode assembly, resolving the issue of inadequate sealing under normal operational conditions.
2Ease of manufacture
If normal stacking pressure is applied during assembly, then assembly process is simple, but the seal member does not tightly contact the membrane electrode assembly
Solution Approach 1:
The patent employs hydraulics by supplying pressure medium to the coolant flow field during or after stacking, using fluid pressure to compress the seal member against the membrane electrode assembly. This approach maintains simple mechanical stacking while adding a hydraulic compression stage that ensures adequate seal contact without complicating the overall manufacturing process.
Solution Approach 2:
The patent applies preliminary action by implementing the pressure medium supply as a dedicated step in the manufacturing process that occurs before the fuel cell stack enters service. This preliminary compression ensures the seal is properly established during manufacturing, separating the sealing assurance function from the operational function and maintaining manufacturing simplicity.
3Reliability
If the seal member is made softer to improve sealing contact, then sealing function is improved, but the structural integrity of the separator assembly may be compromised
Solution Approach 1:
The patent applies parameter changes by controlling the pressure, temperature, and duration of the pressure medium supply to optimize seal compression without requiring changes to the material properties of the seal member or separator. By adjusting operational parameters rather than material properties, the solution maintains structural integrity while achieving adequate sealing contact.
Solution Approach 2:
The patent uses hydraulics to apply controlled compressive force to the seal member, allowing sufficient pressure for sealing contact without requiring the seal member to be overly soft. The hydraulic pressure system provides precise control over the compression force, maintaining both sealing effectiveness and structural integrity of the overall separator assembly.
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 method effectively seals the interface between the metal separators and the membrane electrode assembly, preventing leakage of gases and coolant, thereby enhancing the integrity of the fuel cell stack.
Implementation Method 1
a pressure medium supplying step of supplying pressure medium to a coolant flow field formed between the first metal separator and the second metal separator
Data Source
AI summary
A fuel cell stack includes a first metal separator and a second metal separator sandwiching a membrane electrode assembly. Bead seals are provided on the first and second metal separators. The bead seals protrude toward the membrane electrode assembly. A seal member is provided on a top part of each of the bead seals. In the process of producing the fuel cell stack, pressure medium is supplied to a coolant flow field formed between the first metal separator and the second metal separator. The supply pressure of the pressure medium is set to not less than the supply pressure of a coolant supplied to the coolant flow field during normal operation of the fuel cell stack.