Bipolar Plate Coolant Duct Offset for Uniform Fuel Cell Cooling
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Solution Overview
Problem
Conventional bipolar plates in fuel cell stacks do not provide optimal uniform distribution of cooling medium, leading to local overheating or 'hotspots' due to uneven coolant flow.
Innovation Solution
The bipolar plate design features a lateral offset between webs outside the active region, with angled webs creating pass-through openings that fluidically connect adjacent coolant ducts, ensuring uniform coolant distribution before reaching the active region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional bipolar plates are used with aligned webs in the active region, then the structure is simple and manufacturing is easy, but the coolant flow distribution is non-uniform causing local overheating
Solution Approach 1:
The bipolar plate introduces asymmetry by creating a lateral offset between the webs of the first and second individual plates outside the active region. This asymmetric arrangement forms pass-through openings that fluidically connect coolant ducts, transforming the symmetric aligned structure into an asymmetric flow distribution system that achieves uniform coolant distribution and prevents local overheating.
2Temperature
If webs are aligned in the active region, then reactant flow distribution is maintained, but coolant distribution becomes non-uniform leading to hotspots
Solution Approach 1:
The bipolar plate design segments the coolant flow path by creating multiple pass-through openings between adjacent coolant ducts. These openings divide the coolant flow into multiple streams that distribute uniformly across the plate, preventing concentration of flow in specific areas and eliminating hotspots while maintaining proper reactant flow distribution through the aligned webs in the active region.
3Reliability
If uniform coolant distribution is achieved through lateral offset and pass-through openings, then local overheating is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The bipolar plate design incorporates the lateral offset and pass-through openings as pre-planned structural features during the manufacturing stage. By preliminarily establishing the offset arrangement and connecting openings between coolant ducts, the system ensures uniform coolant distribution from the start of operation, preventing thermal management failures before they occur and maintaining reliable operation throughout the fuel cell stack's service life.
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
Prevents local overheating by achieving homogeneous coolant flow across the bipolar plate and fuel cell stack, enhancing thermal management and preventing 'hotspots'.
Implementation Method 1
a lateral offset between the webs of the individual plates outside the active region in such a way that adjacent coolant ducts (6) of the coolant flow field running adjacent thereto are fluidically connected to one another by way of pass-through openings (12) for distributing a coolant flow
Implementation Method 2
a cooling medium is also passed through the bipolar plates due to the heat generated during the reaction of the fuel cells
Implementation Method 3
due to the heat generated during the reaction of the fuel cells, such that three different media are passed through the bipolar plates in the very smallest of space
Data Source
AI summary
A bipolar plate formed from two interconnected individual plates is provided, which individual plates are each formed with a reactant flow field on plate surfaces facing away from each other, which reactant flow field comprises a plurality of flow ducts for a reaction medium which are delimited by walls of webs, wherein the webs and the flow ducts of one of the individual plates extend in an active region opposite to the webs and the flow ducts of the other of the individual plates, so as to form coolant ducts of a coolant flow field extending between the individual plates. Outside of and/or in an edge area of the active region, there is a lateral offset between the webs of the individual plates, in such a way that coolant ducts of the coolant flow field running adjacent thereto are fluidically connected to one another by means of pass-through openings for distributing a coolant flow. The invention also relates to a fuel cell stack with a plurality of such bipolar plates.