Inactive End Cell Assembly for Fuel Cell Contact and Flooding Control
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Solution Overview
Problem
High-temperature fuel cell stacks face issues with electrolyte loss and increased electrical resistance due to creepage and migration at the positive end, and flooding at the negative end, leading to performance deterioration and mechanical mismatch causing contact loss.
Innovation Solution
The end cell assembly incorporates inactive anode parts with nickel foam layers, compliant cathode current collectors, and ribbed/flat cathode structures to maintain electrical contact and mitigate electrolyte migration, using nickel coatings, foils, and copper layers for improved thermal distribution and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-temperature fuel cell stacks operate at high temperatures, then energy conversion efficiency is improved, but electrolyte loss and electrical resistance increase due to creepage and migration
Solution Approach 1:
The patent introduces an intermediate layer between the electrolyte and the current collector to prevent direct contact and reduce electrolyte migration. This intermediary structure acts as a barrier that maintains electrical conductivity while preventing harmful electrolyte loss, thus resolving the contradiction between high-temperature operation and electrolyte stability.
Solution Approach 2:
The patent employs composite material structures combining different materials with complementary properties. The composite design integrates materials with high thermal stability, low electrolyte affinity, and high electrical conductivity to simultaneously achieve high-temperature efficiency and electrolyte retention.
2Power
If high-temperature fuel cell stacks operate at high temperatures, then power output is improved, but contact loss occurs due to mechanical mismatch
Solution Approach 1:
The patent modifies physical parameters such as thermal expansion coefficients and mechanical compliance of the components. By adjusting these parameters, the design accommodates thermal cycling and mechanical stresses at high temperatures, maintaining stable electrical contact and preventing contact loss while preserving high power output.
Solution Approach 2:
The patent introduces dynamic compliance mechanisms that allow components to adapt to thermal expansion and mechanical stresses. The compliant structure can dynamically adjust to maintain contact under varying temperature and load conditions, ensuring reliable electrical connection while enabling high power operation.
3Reliability
If nickel foam layers and compliant current collectors are used, then electrical contact is maintained and resistance is reduced, but device complexity increases
Solution Approach 1:
The patent utilizes porous nickel foam material that provides high surface area and excellent electrical conductivity in a compact form. The porous structure naturally accommodates thermal expansion and maintains contact compliance without requiring additional complex mechanical components, thus improving electrical contact stability while limiting complexity increase.
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 configuration reduces irreversible resistance, maintains contact, and prevents flooding, enhancing the long-term stability and performance of the fuel cell stack by managing electrolyte distribution and thermal variations.
Implementation Method 1
Each inactive anode part comprises a nickel foam anode disposed directly above an anode current collector
Implementation Method 2
each inactive anode part further comprises a nickel coating disposed on the anode current collector
Implementation Method 3
the nickel foam layer is configured to deform around the anode current collector as the anode current collector and the bipolar plate are compressed toward each other
Implementation Method 4
a separator sheet disposed above the nickel foam anode
Data Source
AI summary
An end cell assembly for a fuel cell stack includes an end plate and at least two inactive anode parts disposed adjacent to the end plate. Each inactive anode part comprises a nickel foam anode disposed directly above an anode current collector and a separator sheet disposed 5 above the nickel foam anode.