Relief Design for Fuel Cell Plates to Prevent Ice Blockage
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Solution Overview
Problem
Solid polymer electrolyte fuel cells face issues with ice blockages during freeze start-up, which can restrict fluid flow and cause damage, and existing designs lack effective solutions to address these problems.
Innovation Solution
Incorporating relief features such as a landing, relief plenum channel, relief backfeed slot, and relief backfeed port in the reactant flow field plates to provide an alternative path for reactant flow when blockages occur, specifically designed to handle ice blockages by connecting the outlet plenum channel to a relief plenum channel through the gas diffusion layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional backfeed paths are used in reactant flow field plates, then the fuel cell structure is simplified and manufacturing is easier, but ice blockages during freeze start-up restrict fluid flow and cause damage
Solution Approach 1:
The flow field plate is segmented into multiple functional regions: a first plenum chamber region, a second plenum chamber region, and a gas diffusion layer region. The relief plenum channel creates a separate, alternative flow path that is physically distinct from the conventional backfeed path, allowing reactant to bypass ice blockages in the original path through this segmented alternative route.
Solution Approach 2:
The relief plenum channel acts as an intermediary structure that mediates between the first and second plenum chambers, providing a alternative pathway for reactant flow. When the conventional backfeed path is blocked by ice, this intermediary channel allows reactant to reach the gas diffusion layer through a different route, preventing flow restriction.
2Reliability
If relief features are added to provide alternative reactant flow paths, then ice blockage resistance is improved, but manufacturing complexity and device complexity increase
Solution Approach 1:
The relief plenum channel serves multiple functions: it acts as a structural element of the flow field plate, provides an alternative reactant flow path during ice blockage, and maintains proper reactant distribution to the gas diffusion layer. This multi-functionality reduces the need for separate components, thereby simplifying manufacturing despite the added complexity of the relief feature.
Solution Approach 2:
The invention changes the geometric parameters of the flow field plate by adding the relief plenum channel with specific dimensions and configurations. By optimizing these parameters, the relief feature can be integrated into the existing manufacturing processes with minimal modification, balancing the need for ice blockage resistance with ease of manufacture.
Data Source
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AI summary
Flow field plates in solid polymer electrolyte fuel cells can be subject to ice blockages in certain areas during freeze start-up, e.g. the backfeed ports and slots used in some flow field plate designs which connect an outlet plenum channel for a reactant to its outlet. By incorporating a similar and adjacent relief backfeed port, slot and plenum channel arrangement in which the relief plenum channel is separated from the outlet plenum channel by a landing, a relief outlet for the reactant is provided through the adjacent gas diffusion layer.