Bipolar Plate Segmentation for Fuel Cell Stack Uniformity
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Solution Overview
Problem
Conventional polymer electrolyte membrane fuel cells (PEMFCs) face issues with non-uniform current and thermal density due to impurities in fuel and oxidant, leading to reduced performance and potential for localized overheating, which complicates fluid flow and increases the risk of gasket blockage and corrosion.
Innovation Solution
The design incorporates a fuel cell stack with alternating bipolar plates having distinct flow channels and manifolds, allowing for different fuel and oxidant flow directions and recirculation, along with an end plate connection unit to manage fluid flow and maintain air-tightness, thereby ensuring uniform current and thermal density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If bipolar plate thickness is reduced to a few mm, then device complexity and weight are reduced, but gasket blockage of manifolds occurs
Solution Approach 1:
The bipolar plate is divided into a plate body and a separate protrusion structure that extends into the manifold. This segmentation allows the main plate to be thin while the protrusion provides the necessary blocking prevention function, resolving the contradiction between reduced weight and maintained reliability.
Solution Approach 2:
The protrusion acts as an intermediary element between the gasket and the manifold interior. It provides mechanical support to prevent gasket blockage without requiring the entire plate to be thick, thus maintaining both weight reduction and reliability.
2Productivity
If fuel and oxidant flow channels are deep, then flow distribution is improved, but gasket blockage risk increases
Solution Approach 1:
The flow channel structure is segmented into the main channel and a separate protrusion element. The protrusion provides structural support to prevent gasket blockage while the channel maintains adequate depth for proper flow distribution, resolving the contradiction between productivity and reliability.
3Productivity
If bipolar plates have deep manifolds, then fluid distribution is enhanced, but manufacturing complexity increases
Solution Approach 1:
The manifold structure is segmented into the base manifold and separate protrusions. This allows the base manifold to maintain adequate depth for fluid distribution while the protrusions can be added through simpler processes, reducing overall manufacturing complexity.
Solution Approach 2:
The protrusions are integrated with the bipolar plate through various manufacturing approaches, combining the fluid distribution function with the blocking prevention function in a single manufactured component, simplifying the overall manufacturing process.
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 enhances the uniformity of current and heat flux along the flow paths, reducing the risk of overheating and extending the fuel cell's lifespan by optimizing fluid flow and preventing gasket blockage, while improving hydrogen utilization and oxidant concentration.
Implementation Method 1
A fuel cell is an electric generator that converts chemical energy of a fuel into electrical energy, through a chemical reaction
Implementation Method 2
a membrane electrode assembly (MEA) comprising an electrolyte membrane 2 disposed between an anode 1 and a cathode 3
Implementation Method 3
a PEMFC having an increased current density and an improved temperature distribution
Data Source
AI summary
Bipolar plates and a fuel cell stack having the bipolar plates. The fuel cell stack includes membrane electrode assemblies (MEAs), and first and second bipolar plates sequentially stacked between the MEAs. The bipolar plates include: flow channels formed on opposing surfaces thereof; four manifolds connected to the flow channels; and through holes to connect to the manifolds of the bipolar plates adjacent thereto.